Introduction - Research Explorer · Web viewMaher, R.; Khan, A.; Rahimtoola, S.; Bratthal, D.:...

Comparison of two tooth-saving preparation techniques

Salim Rahimtoola

COMPARISON OF TWO TOOTH-SAVINGPREPARATION TECHNIQUES

ACADEMISCH PROEFSCHRIFT

ter verkrijging van de graad van doctoraan de Universiteit van Amterdamop gezag van Rector Magnificusprof. mr. P.F. van der Heijden

ten overstaan van een door het college voor promoties ingesteldecommissie, in het openbaar te verdedigen in de Aula der Universiteit

op 8 september 2005, te 11.00 uur

door

Salim Rahimtoola

Geboren te Karachi, Pakistan

Promotor: Prof. Dr. P.R. Wesselink

Co-promotor: Dr. W.E. van Amerongen

Faculteit der Tandheelkunde

This thesis was prepared under supervision of the Department of Cariologie Endodontology Pedodontology of the Academic Centre for Dentistry Amsterdam

(ACTA), The Netherlands, under the auspices of the Netherlands Institute for Dental Sciences (IOT).

Parts of this thesis have been published, or will be submitted to dental journals, so that some overlap of information is unavoidable. Particularly, the descriptions of the material and methods, used to study each of the characteristics, contain repeated information.

List of published chapters:

Chapter 2 is published in J. Dent. Child. 1997: September - October 334 – 339 (Authors: Rahimtoola, S.; van Amerongen W.E.)

Chapter 3 is published in J. Dent. Child. 2000: March - April 123 – 127 (Authors: Rahimtoola, S.; van Amerongen W.E.; Maher, R.; Groen, H.)

Parts of chapter 4, 5, 6 and 7 are published in J. Dent. Child. 2002: January – April 16 – 26 (Authors: Rahimtoola, S.; van Amerongen W.E.) and Comm Dent Oral Epidemiol 1999: December 431-435 (Authors: van Amerongen W.E.; Rahimtoola, S.).

TABLE OF CONTENTS

CHAPTER 1 INTRODUCTION 9

CHAPTER 2 DESIGN OF THE STUDY 15

CHAPTER 3 PAIN RELATED TO DIFFERENT WAYS OF MINIMAL INTERVENTION IN THE TREATMENT OF SMALL CARIOUS LESIONS. 27

CHAPTER 4 PREPARATION SIZE RELATED TO DIFFERENT WAYS OF MINIMAL INTERVENTION IN THE TREATMENT OF DENTAL CARIES 37

CHAPTER 5 EFFECT OF PREPARATION AND RESTORATION TIMES 47

CHAPTER 6 SURVIVAL OF CLASS 1 GLASS IONOMER AND AMALGAM RESTORATIONS AFTER 2 YEARS 55

CHAPTER 7 EFFECT OF LOCATION, CAVITY SIZE, TREATMENT TIME AND OPERATOR ON TWO YEAR SURVIVAL 71

CHAPTER 8 EFFECT OF FATIGUE DUE TO CAVITY PREPARATION. 81

CHAPTER 9 GENERAL DISCUSSION, CONCLUSIONS AND RECOMMENDATIONS 91

CHAPTER 10 SUMMARY 99

CHAPTER 11 SAMENVATTING 105

Acknowledgements 111

Chapter 1

INTRODUCTION

10

Dental caries still remains a widespread problem from a global perspective.1 Not only do carious lesions go untreated in people living under impoverished conditions in developing countries,2-6 but also in many disadvantaged communities in highly industrialized countries.7-10 Untreated caries often progress to large painful cavities for which the only treatment, if at all provided, is extraction of the diseased tooth. Until now treatment for dental caries required expensive equipment and extensively trained personnel.11 Therefore in many situations, lack of electricity and necessary facilities make it impossible for the oral health personnel to provide appropriate treatments.

In Pakistan, the prevalence of dental caries may be as low as 1.2 DMFT for 12 year olds and 3.1 DMFT for the entire population.12 The goal of WHO for 2000 was a DMFT of 313. However, the analysis of the DMFT figure of 12 year olds shows a high score of 1.05 for untreated dental decay12. For a population of 120 million with 2600 registered dentists,14

this indicates a lack of treatment either due to public unawareness, unaffordability, non-availability or improper distribution of dental services.

Scientific research and the development of adhesive restorative materials have opened newer avenues for the management and conservative treatment of dental caries. The Atraumatic Restorative Treatment (ART) is one of such approaches. It is based on removal of decayed tooth substance with only hand instruments and filling the subsequently clean cavity with adhesive restorative materials like glass ionomer15. The concept of excavating caries with only hand instruments however is not new. For generations dentists have relied on it when equipment was out of order or the patient too frightened to accept the normal equipment in the dental office. However, only temporary materials were used which would last long.16 What is different with ART is the development and the use of improved restorative materials like glass ionomer. The chemical bonding with the tooth and fluoride releasing properties of these restorative materials have provided the scientific basis for controlling dental caries by maximal prevention and minimal invasiveness. Developed in the mid 1980’s,17 this approach has the potential of providing treatment for dental caries at primary health care settings under poor conditions.

The ART technique has been evaluated under realistic field conditions18,19 and the results suggest that it is very promising for the treatment of one-surface carious lesions especially in the permanent dentition.20

Previous studies on ART have evaluated the longevity of restorations and fissure sealants, while many questions related to the atraumatic aspect, operator variances and the efficacy of this approach still remain unanswered. For this purpose the present study was designed to evaluate under field conditions various aspects of ART using different restorative materials such as glass ionomer and amalgam, and to compare this method with a similar approach using rotary equipment instead of hand instruments.

Chapter 2 discusses the overall study design developed to accomplish the objectives. The framework is of an experimental design in which the restorative materials along with the restorative technique are the primary variables. Glass ionomer serve as test restorations

11

whereas amalgam restorations are the controls. A split mouth design was used to obtain similar working conditions. Furthermore, evaluation procedures to determine the initial quality of the restorations are also discussed.

Chapters 3 and 4 discuss the atraumatic aspects of the ART approach. Operative pain and cavity size has been used as indicators of trauma or atrauma. Moreover, the patient and operator factor has also been discussed.

Chapter 5 discusses the time taken to prepare and restore the cavity, factors influencing the treatment time and its effect on the survival of the restoration.

Results of survival of restorations and fissure sealants are presented in chapter 6. Efficacy of the glass ionomer sealant placed along with the restoration by the press finger technique in preventing future caries is also discussed in this chapter.

Variables influencing the survival of restorations are discussed in chapter 7. Comparisons are made between the two restorative techniques. The characteristics studied are location of restoration, cavity size, treatment time and the operator.

In chapter 8, the effect of wrist muscle fatigue due to cavity preparation with hand instruments is discussed. Differences in cavity preparation time have been used as indicator of wrist fatigue.

Finally chapter 9 discusses the results of the clinical study, conclusions are drawn up and recommendations for future research are made.

References

1. World Health Organization. Oral Health programme. WHO: Global Oral Data Bank, 1995.

2. Frencken, J.; Manji, F.; Mosha, H.: Dental caries prevalence amongst urban children in East Africa. Community Dent Oral Epidemiol. 14:94-8, 1986.

3. Chironga, L.; Manji, F.: Dental caries in 12 years old urban and rural children in Zimbabwe. Community Dent Oral Epidemiol. 17:31-3, 1989.

4. Matthesen, M.; Baelum, V.; Aarlev, I.; Fejerskov, O.: Dental health of children and adults in Guinea-Bissau, West Africa in 1986. Community Dent Health. 7:123-33, 1990.

5. Addo-Yobo, C.; Williams, S.A.; Curzon, M.E.J.: Dental caries experience in Ghana among 12 years old urban and school children. Caries Res. 25:311-4, 1991.

12

6. Koloway, B.; Kallis, D.G.: Caries, gingivitis and oral hygiene in urban and rural pre-school children in Indonesia. Community Dent Oral Epidemiol, 20:157-8, 1992.

7. Holt, R.D.; Winter, G.B.; Downer, M.C.; Hay, I.; Bellis, W.: A fourth study of caries in preschool children in Camden. Br Dent J, 181:405-10, 1996.

8. Nugent, Z.J. and Pitts, N.B.: Change and results overview 1985/6-1995/6 from British Association for the Study of Community Dentistry (BASCD) coordinated National Health Service survey of caries prevalence. Community Dent Oral Epidemiol, 14:30-54, 1997.

9. Zerfowski, M; Koch, M.J.; Neikusch, U.; Staehle, H.J.: Caries prevalence and treatment needs of 7-10 year old school children in southwestern Germany. Community Dent Oral Epidemiol, 25:348-51, 1997.

10. Truin, G.J.; König, K.G.; Bronkhorst, E.M.; Frankenmolen, F.; Mulder, J.; van’t Hof, M.A.: Time trends in caries experience of 6 and 12 year old children of different socioeconomic status in the Hague. Caries Res, 32:1-4, 1998.

11. Frencken, J. and Makoni, F.: A treatment technique for tooth decay in deprived communities. World Health, 47:1:15-17, January-February 1994.

12. Maher, R.: Dental disorders in Pakistan - A national pathfinder study. J. Pakistan Med Asso, 41:10:250-252, October 1991.

13. WHO: Prevention methods and programs for oral disease. Report of a WHO expert committee, Technical report series 713, 1:9, 1984.

14. WHO: Report on intercountry meeting on the development of oral health policies. W.H.O. Regional office for the Eastern Mediterranean. Geneva, 38, August 1991.

15. Frencken, J.; Phantumvanit, P.; Pilot, T.: Manual for the Atraumatic Restorative Treatment. (ART) technique for dental caries. February 1994 p6.

16. Pilot, T.: Introduction- ART from a global perspective. Community Dent Oral Epidemiol, 27:6:421-22, December 1999.

17. Smith, A.J.E.; Chimiba, P.D.; Kalf-Scholte, S.; Bouma, J.: Clinical pilot study on new dental filling material and preparation procedures in developing countries. Community Dent Oral Epidemiol, 18:309-12, December 1990.

18. Frencken, J.E.; Songpaisan, Y.; Phantumvanit, P.; Pilot, T: An Atraumatic Restorative Treatment technique: Evaluation after one year. International Dent J, 44:460-464, October 1994.

13

19. Frencken, J.; Makoni, F.; Sithole, WD.; Hackenitz, E: Three year survival of one-surface ART restorations and glass ionomer sealents in a school oral health programme in Zimbabwe. Caries Res, 32:119-126, 1998.

20. Phantumvanit, P.; Songpaisan, Y.; Pilot, T.; Frencken, J: Atraumatic Restorative Treatment (ART): A three-year community field trial in Thailand - Survival of one-surface restorations in the permanent dentition. J Public Health Dent, 56:3:141-145, July 1996.

14

Chapter 2

DESIGN OF THE STUDY

16

Introduction

Dental caries is a multifactorial disease that has afflicted human race since ancient times.1-

5 Its prevalence has been showing changing patterns in different parts of the world. The WHO global oral data bank indicates improvements in most industrialized nations and deterioration for most developing countries where it is becoming a public health problem.2

Dental caries is virtually left untreated in the majority of populations in these economically underdeveloped countries, often leading to many large and painful cavities.6-

10 If any treatment is provided at all, it is in the form of extraction. The main reason for not providing care revolves around the need for expensive dental equipment and extensively trained personnel. There has been a general lack of more appropriate techniques to allow for primary health care under conditions that that provide no electricity or dental equipment (mobile or fixed).

For Pakistan, the prevalence of dental caries could be worse; a national survey in 1988 showed a mean DMFT level of 1.2 for twelve-year-olds, one of the indicator ages, and 3.1 for the entire population.11 This level according to the WHO is very low. The global goal for oral health, for the year 2000, is 3 DMF teeth at twelve years of age. 12 This may not remain true, however, for all times: the WHO global data base in Geneva indicates that changes have frequently occurred in national caries figures: for some countries it has been for worse, due to increase in the consumption of sugar and sweets or after better caries data have been recorded.13 Furthermore an analysis of the Pakistan DMFT figure for twelve-year-olds shows a very high score, D=1.05, suggesting a lack of treatment due either to public unawareness or non-availability of dental services. Pakistan’s demographic data shows that for a population of 120 million there are about 2,600 registered dentists.14

Seventy percent of these oral health personnel serve the population living in urban areas, which is 30 percent of the entire population. For a developing country with a low and an unevenly distributed number of oral health care providers, the dental situation, therefore, can be expected to deteriorate readily into a major healthcare problem.

Scientific research and advanced technological developments have provided new restorative materials, opening the discussion about new concepts in conservative treatment of caries. One of these concepts is the Atraumatic Restorative Technique -ART. This treatment approach was developed in the mid-1980s and introduced clinically in Malawi some years later.15 It is based on removing infected tooth material, using only hand instruments and filling the subsequently cleaned cavity with adhesive material such as glass ionomer.16 This development has led to a shift from the concept of “disease” (filling holes in teeth) towards that of “health” (trying to preserve teeth and gums through small interventions and oral health promotion activities), and it can improve not only the oral health of people living where electricity is not available, but also of those who live where nobody can afford to buy and maintain expensive dental equipment.17 The ART has been evaluated under realistic field conditions, and results suggest that it is very promising for the treatment of one-surface lesions especially in permanent teeth.18-22

Advantages of the approach to patient care should include simplicity, good patient acceptance, fluoride leaching capacity, and good marginal seal of the cariostatic and

17

adhesive filling material.23-30 Disadvantages can be fatigue of preparing cavities with hand instruments, increasing the chances of leaving residual caries; the requirement for accurately handling the material; and inadequate strength of filling materials.27, 31-35 All studies on ART have evaluated the longevity of restorations using glass ionomer cement (GIC) as a restorative and fissure filling material. The atraumatic aspect of ART and the effect of operator variance have not yet been evaluated extensively. Other materials and techniques have not been tested under similar field conditions.

The purpose of this study is to evaluate under field conditions various aspects of ART, using different materials such as amalgam and GIC, and to compare this method with a similar approach using rotating instruments instead of hand instruments. This approach, eliminating the principle of “extension for prevention”36 is referred to as the “minimal cavity preparation technique” (MCP).

Objectives of the Study

To test clinically the quality of glass ionomer restorative material compared with amalgam in one-surface cavities prepared with the ART technique.

To compare the efficacy of ART with MCP.

To compare the treatment time needed in both ART and MCP. To investigate the influence of possible wrist fatigue on the size of the

preparation.

To investigate the operative and postoperative sensitivity in both techniques.

To investigate the operator effect, based upon:

Preparation size differences in both techniques. Preparation and restoration time required in both techniques. Quality of the restorations. Operative and postoperative sensitivity.

Materials and Methods

Overall Design

Two clinical studies were designed to achieve the objectives.

Study 1: Treatment of one-surface carious lesions with the ART technique, using glass ionomer and amalgam as restorative materials.

Study 2: Treatment of one-surface carious lesions with a minimal cavity preparation technique, using glass ionomer and amalgam as restorative materials.

18

Materials

Tytin (Kerr) was used for all amalgam restorations, because of good clinical results during a previous long-term amalgam study.37

Fuji IX glass ionomer (GC) material was used for all glass ionomer restorations based upon improved physical properties and because this material was developed by the manufacturer especially for the ART technique.38-40

Dycal (Dentsply/Caulk) was used as a base in deep cavities and Vaseline Petroleum Jelly was used as an expedient to apply to the glass ionomer fillings.

All restorations from each brand were from one batch to avoid variations in material properties.

Trial Design

In this study glass ionomer restorations serve as a test group and amalgam restorations as a control. It was preferred to use test and control restorations within one dentition, using a split month technique to obtain similar study conditions. A minimum of two and a maximum of four restorations were placed in one dentition. Depending upon the number of restorations, a patient could participate in either study 1 or study 2 or both. Only one-surface cavities in the occlusal, buccal or lingual surfaces of permanent molars and premolars were selected. In order to enter the cavities with hand instruments, the selected cavities should have a diameter of at least 1 mm. Based on a clinical trial in Thailand, the selection was focused on small cavities, with a maximum initial entrance of about 2mm.19

Five operators took part in the study and all were trained and calibrated regarding selection, treatment procedures and practice before the start of the study.

Population of Study

Four hundred patients with low and middle socioeconomic status were selected from seven schools of Karachi. The age ranged from six to sixteen years, mean age, 11.4 years. The mean DMFT in this study was 3.06 (SD: 1.29).

The distribution of patients according to gender was 47.3 percent males and 52.7 percent females.

Each patient was treated by any of the five operators. All treatments were done on-site (at school) and informed consent was obtained from school authorities with agreement to conduct out evaluation sessions in the future. The table 2.1 shows the distribution of restorations per dentist, per restorative material, per study. A total of 914 restorations were placed, 555 with Fuji IX and 359 with Tytin. Of these restorations 460 were made according to the ART procedure and 454 with the MCP technique.

Operator FUJI IX (GIC.) TYTIN (Amalgam)ART MCP ART MCP Total

19

1. 57 54 57 54 2222. 62 62 62 62 2483. 48 48 -- -- 964. 62 62 62 62 2485 50 50 -- -- 100Totals 279 276 181 178 914

Table 2.1: Distribution of restorations per dentist per restorative material per study.

The distribution of restorations according to the tooth surface was 685 (74.9 percent) at the occlusal surface, 195 (21.3 percent) on the buccal and 34 (3.7 percent) on the lingual.

Restorative Procedures

All restorative procedures were described in detail to ensure consensus by all operators. The materials used were handled as recommended by the manufacturers.

In study 1, one-surface restorations were made using hand instruments. Access to the cavity was made by increasing the access with a hatchet or hoe. Soft carious dentin was removed, using spoon excavators, while care was taken to remove all the unsupported enamel.

In study 2, one-surface restorations were made, using an air turbine. Access to the cavity was made by widening the opening with a high-speed cylindrical diamond stone bur; the remaining soft carious dentin was removed by using a stainless steel round bur and checked with a spoon excavator. In both studies, special attention was given to cleaning the dentinoenamel junction and removing all unsupported enamel.

If necessary a Ca(OH)2 base was applied to the deepest areas of the cavity. In case of glass ionomer restorations the conditioning of the cavity was done with a drop of Fuji IX liquid on a mixing pad. A cotton wool pellet moistened with water was dipped in the drop of liquid, after removing excess of water by touching the pellet against a cotton roll. The conditioner was brushed on the entire cavity surface, including the remaining fissures, for 10 seconds. After washing three times with clean cotton wool pellets dipped in water, the cavity was dried with dry pellets. The liquid and powder were dispensed and mixed, strictly following the manufacturer’s instructions. The mixture was then applied into the cavity and the remaining fissures. A small amount of Vaseline was applied on the gloved forefinger and the material was brought under pressure so that the glass ionomer could flow into the cavity and fissures. After a few seconds the finger was removed sideways so as not to dislodge the filling materials. Some Vaseline was applied on a ball burnisher and the material was pressed again by moving through the fissure, starting in the center of the occlusal surface. Excess of material was displaced to the slopes of the cusps and removed with a large excavator after which the bite was checked and adjusted till the patient could close normally. Some more Vaseline was applied with a cotton pellet, and the patient was asked not to eat for one hour. In case of amalgam restorations, single spill Tytin capsules were mixed in an

20

amalgamator following manufacturer instructions. The amalgam was carried into the cavity using an amalgam carrier, and condensed with pluggers, slightly overfilling the cavity. The excess was removed with an Ash 6 Special plastic instrument after the patient was asked to rinse with water. The occlusion was checked and adjusted if necessary with a large spoon excavator, and the patient was asked not to eat for one hour.

Before restoration the cavity size was measured (width of the entrance) using specially designed cavity measuring instruments (figure 2.1) having a width from 1mm to 6mm with stops of 0.5mm.

Figure 2.1: Cavity measuring instrument

<= Tip of the instrument

The treatment time was measured, using a stopwatch. It was divided into: Preparation time, the time necessary to prepare the cavity and remove all the

decayed tissue. It included the period from the actual start of cavity preparation, until the cavity was ready for filling.

Restoration time, starting from placing the base in the already dried cavity (if necessary), conditioning, placement of the filling, and the finishing of the filling.

Evaluation Procedures

Separate formats were developed for the collection of baseline and evaluation data. The baseline data were recorded by the operator, while the later evaluation data were recorded by two other dentists. These baseline and evaluation records are based on the guidelines for clinical studies of ART, in order to make some comparison with other ART studies possible, and on clinical studies on the behavior of posterior resin composite restorations by Kreulen et al.41,42

Baseline Evaluation

This was divided in four parts:

21

General information was collected e.g. number of the study, number of the evaluation, patient trial number, tooth number, restoration number for patient etc.

Information about the patient was collected such as age, gender, DMFT, and the presence of abrasion on tooth.

Clinical information was recorded such as location of the restoration, condition of the remaining fissures, the use of a base, the size of the cavity, treatment time, day number of each restoration and operative sensitivity (pain felt during preparation or placement of the restoration).

A diagram was made to mark the place and outline of the restoration.

The baseline evaluation was done at the time of placement of restoration. Following evaluations were planned for 3 months, one year and two years.

Postoperative Evaluation

In addition to the general information, postoperative evaluation was divided into 2 parts: Clinical information was collected e.g. DMFT, postoperative sensitivity (pain felt

after the restoration was finished). The quality of the restoration was assessed according to the following criteria:

0= Present, correct.1= Margin defect or surface wear less than 0.5 mm.2= Wear of surface > 0.5 mm.3= Defect at margin > 0.5mm or more.4= Combination of 2 and 3.5= Restoration has (almost) completely disappeared.6= Restoration not present because other treatment has been performed for whatever reason.7= Tooth absent 9= Unable to diagnose.

When a restoration was replaced or repaired the reason was registered.

In case of glass ionomer the fissure filling part was assessed according to the ensuing criteria:0=Present, correct.1= Fissure filling partly disappeared.5= Fissure filling has (almost) completely disappeared.6= Not present because other treatment has been performed.7= Tooth absent.9= Unable to diagnose.

For the assessment of caries, related to either the restoration or the fissure filling, the subsequent criteria has been used:0= Sound, no discoloration.1= Discoloration at surface, but it is hard.2= Discoloration (in-depth) but hardness cannot be assessed.

22

3= Caries connected to the restoration.4= Caries related to the pit and fissures on the same surface of the tooth.5= Combination of 3 and 4.8= Caries anywhere else on the tooth surface.9= Unable to diagnose.

A drawing was made showing the outline of the remaining restoration and fissure filling.

The evaluation was done at site (in school), using a ball ended CPITN periodontal probe.40

Caries for the purpose of this study was defined as “a break in the enamel or a cavity in the tooth; the dentine in the cavity had to be softer than the surrounding dentine.”41

Discussion

The framework of the study presents an experimental design in which the restorative material, along with the restorative technique, is the primary variable. The secondary variables are the dentist and the tooth in which the restoration was placed. Even though it is impractical to expect standard oral conditions amongst the study population, patients were selected according to stringent criteria in order to achieve some degree of equivalency. The mean DMFT found in this study was (3.07) higher than that for twelve-year-olds in a previous study (1.2).11 This can be attributed to the fact that the population in this study was selected on the basis of having at least two one-surface carious lesions. Consequently children with fewer cavities could not participate in the study. Alternately it may indicate a further deterioration in the oral health status of the population.

The number of GIC restorations was larger than the number of amalgam restorations, as all the restorations had to be made in a two month time period in order to avoid a lengthening of the period of the subsequent evaluations. Because two dentists joined the study at a later stage, it was decided for them to participate in both the studies, rather than to make restorations with different materials.

The “atraumatic restorative technique” as its name suggests, is intended to be atraumatic not only for the tooth but also psychologically for the patient; it was considered important, therefore, to test the perception of operative sensitivity (pain felt during the procedure), as this is an important determinant of the acceptance of treatment procedure by the patient. Another such determinant is the postoperative sensitivity. This can be related to the trauma a restorative procedure or a restorative material causes to the pulp, or to the failure to obtain a proper marginal integrity.

Because the assessment for the quality of restoration is planned to be done at field setting, it is important to keep the quality assessment procedure simple. As in other ART studies, a CPITN probe has been selected as a tool for assessment in order to compare the possible results.43

23

The CPITN probe has a standard ball end of 0.5 mm in diameter, has different markings for lengths and can be used to access the filling without causing any damage to the margins or disturbing any recalcification process occurring on the tooth surface. Compared to the other methods, the use of the CPITN probe is rather rough means for the assessment of the quality of a restoration. The results of this study will consecutively have a more indicative character related to the quality of the restoration.

The first postoperative evaluation is planned at an average interval of three months from placement of all restorations. This interval is also based upon logistic reasons. Especially the quality of the fissure filling is expected to be influenced by this decision because of the limited retention capacity of glass ionomers to enamel.44

The diagram of the extent of restoration and fissure filling is a rather approximate measurement, but compared with other methods such as impression and plaster model techniques, it is much simpler and easier to perform with the minimum of material and facilities in a field setting.

References

1. Maher, R.; Khan, A.; Rahimtoola, S.; Bratthal, D.: Prevalence of mutans streptococci in Pakistan children. J Pakistan Med Asso, 42:9:213-215, September 1992.

2. Prevention methods & programs for oral disease. Report of a WHO expert committee, tech. report series 713, W.H.O. 1984.

3. Burt, B.A.; Eklund, S.A.: Dentistry, Dental practice and the Community, 4th ed.: W.B.Saunders Company. 1992.

4. Moore, W.J.; Corbett, M.E.: The distribution of dental caries in ancient British population. 1 Anglo Saxon period. Caries Res, 5:151-168, 1971.

5. Moore, W.J.; Corbett, M.E.: The distribution of dental caries in ancient British population II. Iron Age, Romano-British and Medieval periods. Caries Res, 7:139-153, 1973.

6. Frencken, J.; Manji, F.; Mosha, H.: Dental caries prevalence amongst urban children in East Africa. Community Dent Oral Epidemiol, 14:94, 1986.

7. Chironga, L.; Manji, F.: Dental caries in 12 years old urban and rural children in Zimbabwe. Community Dent Oral Epidemiol, 17:31, 1989.

8. Matthesen, M.; Baelum, V.; Aarlev, I.; Fejerskov, O.: Dental health of children and adults in Guinea-Bissau, West Africa in 1986. Community Dent Health, 7:123, 1990.

9. Addo-Yobo, C.; Williams, S.A.; Curzon, M.E.J.: Dental caries experience in Ghana among 12 years old urban and schoolchildren. Caries Res, 25:311, 1991.

24

10. Koloway, B.; Kallis, D.G.: Caries, gingivitis and oral hygiene in urban and rural pre-school children in Indonesia. Community Dent Oral Epidemiol, 20:157, 1992.

11. Maher, R.: Dental disorders in Pakistan - A national pathfinder study. J. Pakistan Med Asso, 41:10:250-252, October 1991.

12. Prevention methods and programs for oral disease. Report of a WHO Expert Committee, Technical report series 713, W.H.O., 1:9. 1984.

13. Appropriate use of fluoride for human health. W.H.O., Geneva.2: 33. 1986.

14. Report on intercountry meeting on the development of oral health policies. W.H.O. Regional office for the Eastern Mediterranean. August, 1991.

15. Smith, A.J.E.; Chimiba, p.D.; Kalf-Scholte, S.; Bouma, J.: Clinical pilot study on new dental filling material and preparation procedures in developing countries. Community Dent Oral Epidemiol, 18:309, 1990.

16. Frencken, J.; Phantumvanit, P.; Pilot, T.: Manual for the Atraumatic Restorative Treatment. (ART) technique for dental caries. February, 1994.

17. Frencken, J.; Makoni, F.: A treatment technique for tooth decay in deprived communities. World health 47th year, W.H.O., 1:16, Jan - Feb. 1994.

18. Pitiphat, W.; Bhudhasri,V.; Phontumvanit, P.; Frencken J.: Atraumatic treatment of dental caries in rural Thailand. J Dent Res, 72:838, 1993.

19. Phantumvanit, P.; Songpaisan, Y.; Frencken, J.; Pilot, T.: Atraumatic restorative treatment technique. Evaluation after one year. J Dent Res, 4:73, April, 1994.

20. Frencken, J.; Songpaisan, Y.; Phantumvanit, P.; Pilot, T.: An atraumatic restorative treatment technique: Evaluation after one year. Int Dent J, 44, 1994.

21. Pitiphat, W.; Phantumvanit, P.; Songpaisan, Y.; Frencken, J.; Pilot, T.: Atraumatic Restorative Treatment technique (ART)- Evaluation after two years. J Dent Res, 75, 1995.

22. Phantumvanit, P.; Songpaisan, Y.; Pilot, T.; Frencken, J.: Atraumatic Restorative Treatment (ART): A three-year community field trial in Thailand - Survival of one surface restorations in permanent dentition. J Public Health Dent, 56: 3: 141-145, July 1996.

25

23. Wilson, A.D.; Prosser, J.K.; Powis, D.M.: Mechanism of adhesion of polyelectrolyte cements to hydroxyapatite. J Dent Res, 62:590-592, 1983.

24. Wilson, A.D.; Prosser, H.J.: A survey of in organic and polyelectrolyte cements. Br Dent J, 157:449-454, 1984.

25. Powis, D.R.; Folleras, T.; Merson, S.A.; Wilson, A.D.: Improved adhesion of a glass ionomer cement to dentine and enamel. J Dent Res, 61:12:1416-1422, December 1982.

26. Wilson, A.D.; Prosser, J.K.: Biocompatibility of glass ionomer cement. J.Dent Asso S Afr, 37:872-879, 1982.

27. Tay, W.M.; Lynch, E.: Glass ionomer cements - clinical usage and experience (1). Dental Update, 11-15, January-February, 1990.

28. Cardenas, H.L.; Madhure, V.; Baldwin, J.O. Burgess; Chan, D.C.N.: Short term fluoride release of restorative material. J Dent Res, (AADR Abstracts) 74:768:107, March 1995.

29. van Amerongen, E.: Caries under glass ionomer restorations. J Public Health Dent, 56:3:150-154, 1996.

30. Billington, R.W.; Williams, J.A.; Pearson, G.J.: Variation in powder / liquid ratio of a restorative glass ionomer cement used in dental practice. Brit Dent J, 169:6:164-167, September 1990.

31. Maldonado, A.; Swartz, M.L.; Phillips, R.W.: An invitro study of certain properties of glass ionomer cement. JADA. 96:785-791, 1978.

32. Swift, E.J.: An update on glass ionomer cements. Quintessence Int, 19:125-130, 1988.

33. Mc Kinney; Antonucci, J.; Rupp, N.: Wear and microhardness of glass ionmer cements. J Dent Res; 66:1134-1139, June 1987.

34. Mc Comb, D.; Sirisko, R.; Brown, J.: Comparison of physical properties of commercial glass ionomer cements. J Can Dent Assoc, 9:699-701, September 1984.

35. Hicks, M.J.; Flaitz, C.M.; Silverstone, L.M.: Secondary caries formation in vitro around glass ionomer restorations. Quintessence Int, 17:521-532, 1986.

36. Black, G.: Operative dentistry Vol. III, Treatment of dental caries. Chicago: Medico-dental publ Co., 6:138, 1936.

26

37. Akerboom, H.B.M.; Advokaat, J.G.A.; Borgmeijer, P.J.: Amalgam restauraties nader bekeken. Amsterdam :Vrije Universiteit thesis. 1985.

38. Dao, T.H.Quan; Tran, T.N.G.A.: Fluoride release from Fuji IX and fast setting GIC’s. J Dent Res, 74;317-440, July 1995.

39. Yoshimura, M.; Komatsu, H.; Seki, E.; Watanabe, S.: Glass ionomer using various filling procedures. J Dent Res. 74:1281-561 abstract, July 1995.

40. Suzuki, Y.; Tosaki, S.; Hirota, K.: Physical properties of glass ionomer for retorative filling. J Dent Res, 74:1282-561 abstract, July 1995.

41. Guidelines for clinical studies of the Atraumatic Restorative Treatment (ART) technique and materials. W.H.O. Collaborating Centre for Oral Health Services Research, University of Groningen, The Netherlands. July 1995.

42. Kreulen, C.M.; Van Amerongen, W.E.; Akerboom, H.B.M.; Borgmeijer, P.J.; Kemp-Scholte, Ch.M.: A clinical study on direct and indirect class II posterior composite resin restorations: Design of the investigation. J Dent Child, 58:281-288, July-August 1991.

43. Ainamo, J.; Barmes, D.; Beagrie, G.; Cutress, T.; Martin, J.; Sardo-Infirri, J.: Development of the World Health Organization (WHO) community periodontal index of treatment needs (CPITN). Int Dent J, 32(3):281-91, 3, September 1982.

44. Weerheijm, K.L.; Kreulen, C.M.; Gruythuysen, R.J.M.: Comparison of two glass ionomer cement materials used as fissure sealing. Eur Acad Ped Dent, 3rd congress, abstract 118, 87, June 1996.

27

Chapter 3

PAIN RELATED TO DIFFERENT WAYS OF MINIMAL INTERVENTION IN THE TREATMENT OF SMALL CARIOUS LESIONS.

28

Introduction

Pain during invasive treatment of dental caries is a common phenomenon, when a tooth has not been anesthetized prior to cavity preparation. Sensory innervations in the dental pulp consist of exclusively nociceptive nerve fibres.1 Due to this structural and functional organization, pulpal nerve activation by any stimulation induces pain. The nerve fibers extending into the pulpodentinal zone function as high-threshold mechanical nociceptors that are sensitive to mechanical tissue deformation or injury in the pulp/dentin border. Many physical stimuli, applied to the intact tooth or, especially to the exposed dentin can activate this receptor structure mechanically.2 Reduced pressure or dehydrating stimuli such as air blast and dry heat applied to exposed dentine has been found to produce outward movements of the fluid in the tubules, as manifested by aspiration of odontoblasts and pain.3 This movement of the tubule fluid is due to capillary action. Even the application of a dry piece of paper to the dentin can exert such an effect.4 Cold when applied to the exposed dentin causes a rapid centrifugal movement of tubule fluid causing sharp pain.2 It has also been shown that the tooth reacts to dental caries by dentin sclerosis and by forming reparative dentin, thereby decreasing the permeability of dentin and thus shielding the pulp from irritation.5-9

Pulp tissue reactions in response to cavity preparation are well known.10-12 They have been attributed to thermal changes in the pulp caused by grinding or cutting, dehydration of the exposed dentine or desiccation and severance of odotoblastic processes.13,14 The gravity of the pulp response is dependent upon the depth of cavity and possible pulp exposures.15,16

Notwithstanding the fact that the development and use of local anesthetics in dentistry has controlled discomfort to a great extent, pain still is one of the major issues associated with the conservative treatment of dental caries.

The Atraumatic Restorative Treatment (ART) is a procedure suggested to be atraumatic or at least less traumatic than conventional restorative procedures for the tooth to be treated. This procedure is based upon the restoration of decayed teeth by removing the soft carious tooth substance using only hand instruments and restoring the cavity with an adhesive material like glass ionomer cement (GIC).17 It was primarily developed for treating people living in underserved areas of the world, where resources and facilities such as electricity are limited.18

Although the ART approach has been received well by both children and adults who belong to population groups hardly ever exposed to regular oral health care, it has not yet been proven that this particular procedure really causes less pain during treatment compared to more conventional techniques with rotating instruments.19

This article describes the findings of a study on pain registered with one-surface restorations applied by just hand instruments (ART), compared with those applied in a more conventional way, using high- and low-speed handpieces to remove dental decay, and filling the resultant cavity with amalgam or GIC. Besides the influence of the preparation technique, the influences of the type of restorative materials, the patient, and the dentist are also evaluated.


29

This study forms part of a longitudinal study20 evaluating one-surface restorations made in permanent teeth by means of hand instruments only (like ART), and rotating instruments (Minimal Cavity Preparation, MCP). Based on a split-mouth design each patient received one or two restorations of glass ionomer cement (Fuji IX, GC) and an equal number of amalgam restorations (Tytin, Kerr). A total of 914 restorations were placed in 408 patients; 359 with two and forty-nine with four restorations. Forty-seven and three tenths percent of the patients were male, while 52.7 percent were females. In case of two restorations one technique has been applied, either the "ART" procedure or the “MCP” technique. In the remaining group two restorations have been made with one technique and two with the other. Most of the patients did not have any previous experience with the dental treatments. Five operators took part in this study and all were trained and calibrated regarding selection, treatment procedures and practice before starting the study. Each patient was treated by any of the five operators and all treatments were done at site (school). The age of the patients ranged from six to sixteen years (mean age 11.4 years). All restorative procedures were described in detail to ensure consensus in treatment by all operators. The materials used were handled as recommended by the manufacturers.

The selection of the restorative technique to be employed was done randomly. To avoid bias the operators did not know in advance which patient was to be treated when, because the patients were sent individually to the clinic by school authorities according to availability. The selection of treatment technique was done before the operator had a chance to see the patient or examine the cavity.

In case of preparations made with only hand instruments, widening the entrance with a hatchet or hoe established access to the cavity. Soft decayed tooth material was then removed using spoon excavators. Unsupported enamel was removed with a hatchet or hoe.

In the MCP technique, preparations were made using an air turbine. Access to the cavity was achieved by widening the entrance with a high-speed cylindrical diamond bur (speed 250,000-270,000 rpm, with water cooling) and remaining soft carious dentine was removed by using a stainless steel round bur (1000-1500 rpm, without cooling). A spoon excavator was only used to check for the presence of any remnants of caries. In both types of preparations special attention was given to cleaning of the dentinoenamel junction and care was taken to remove all the unsupported enamel. If necessary a Calcium hydroxide base was applied to the deepest areas of the cavity in both techniques.

The selection of the restorative material to be placed was accomplished by mixed sampling (random and convenient). The glass ionomer was applied after conditioning of the cavity and condensation of the amalgam was done with hand pluggers.20

Immediately after the completion of the restorative procedure each patient was asked whether any pain was felt during treatment. The answer was recorded as yes or no on the assessment form. Frequency distributions are presented for the results; logistic regression analysis tests were performed. All data analysis was conducted on SPSS 6.1 (Windows).Results

30

Table 3.1 shows the number of teeth with and the number of teeth without pain in relation to the restorative technique used in patients with two and four restorations. Pain was present in 237 (26 percent) out of a total of 914 restored teeth. In patients with four restorations, forty (20 percent) of 196 restored teeth exhibited pain; while in patients with two restorations, 197 (27 percent) of 718 restorations exhibited pain. A break-up of patients with two restorations shows that of 362 teeth restored by the ART technique, seventy (19.3 percent) exhibited operative sensitivity; while 127 (35.7 percent) of 356 teeth restored by the MCP technique exhibited pain.

Restorations per Patient Restorative Technique PainAbsent Present Total

2 restorations per ART 292 70 362Patient MCP 229 127 3564 restorations per ART 82 16 98Patient MCP 74 24 98

Total 677 237 914

Table 3.1: Pain experience in relation to restorative technique in patients with two and four restorations.

Data of patients with four restorations were excluded from further analysis because of the possibility of a bias, furthered by the fact that both techniques were used in each of these patients. Any unpleasant experience with the first technique in these patients may cause distress and increase, therefore, the possibility of pain occurring with the second technique, thereby introducing a bias.

The distribution of reports of pain according to the operator is shown in table 3.2. The proportion of painful procedures was highest (44 percent) in the case of operator 5 in connection with both ART (32 percent) and MCP (56 percent) techniques. Operator 3 showed the smallest proportion of painful operations (5.9 percent).

Operator PainART MCPAbsent Present Absent Present Total

1 53 19 45 21 1382 68 8 48 28 1523 41 1 38 4 844 96 26 76 46 2445 34 16 22 28 100Total 292 70 229 127 718

Table 3.2: The distribution of pain reports according to operator.

Further statistical analysis of the data was done using a logistic regression test (backward: Likelihood ratio estimates method) in which the proportion of painful operations was the

31

dependent variable while operative technique, operator, the restorative material, age and gender were placed as independent variables. The distribution of painful operations according to operator showed that operator 5 was still related with the highest (p<0.01) and operator 3 with the lowest proportion (p<0.01).

Results further showed that the proportion of painful operations was significantly higher in patients in whom restorations were placed with MCP technique (p<0.01), whereas no significant difference in the frequency of pain reports was found according to age distribution and gender. A difference in the pain reports was also found between teeth restored with glass ionomer (Fuji IX) and teeth restored with amalgam: the latter showed a higher incidence (p<0.05).

PAIN REPORTSART MCPabsent present total absent present total

First GIC 103 23 126 81 43 124Treatment AMG 41 14 55 32 22 54

Total 144 37 181 113 65 178Second GIC 82 19 101 72 28 100Treatment AMG 66 14 80 44 34 78

Total 146 33 181 116 62 178

Table 3.3: Distribution of pain reports according to the restorative technique, material and treatment session.

Table 3.3 shows the distribution of reports of pain according to restorative technique, material, and treatment session. Comparatively fewer amalgam fillings were placed in the teeth that were treated first than in those that were treated second, in both techniques.

To get more information about the patient effect, to what extent it could be expected that the patient had a similar reaction during the two consecutive treatments was considered.

FIRST TREATMENT SECOND TREATMENTNo pain Pain Total

No pain 137 7 144Pain 11 26 37Total 148 33 181

Table 3.4: Relation between pain reports of the first and second treatment sessions in connection with the ART technique.

Table 3.4 shows the relationship between the reports of pain the first and second treatment sessions in connection with the ART technique. There was a significant relationship in the reported pain between the two sessions (Chi-square=84.47, p= 0.00).

32

FIRST TREATMENT SECOND TREATMENTNo pain Pain Total

No pain 94 19 113Pain 22 43 65Total 116 62 178

Table 3.5: Relation between the pain reports of the first and the second treatment sessions in connection with the conventional restorative technique (MCP).

A similar relationship in pain reports (table 3.5) was observed between the first and the second treatment sessions using the conventional restorative technique (Chi-square = 44.25, p= 0.00).

Discussion

In this study the operations with the MCP technique evoked pain significantly more often than with the ART technique. This may be attributed to the use of turbine drills in MCP technique. Heat production during tooth preparation due to inadequate cooling, drop in the intra pulpal temperature due to over cooling or improper cooling, and mechanical damage are major sources of trauma and pain.14, 15,21,22 Since dentin contains protoplasmic processes of the odontoblasts, cutting of dentin is in essence cutting of viable cells. Furthermore, when drills are used for cavity preparations many new healthy dentinal tubules are opened, traumatizing the odontoblastic processes within them as hydrodynamic fluid movements in the dentinal tubules can be introduced even from the most superficial dentin, if the tubules are patent. While trauma is minimised as only soft carious dentin is removed by using hand instruments such as excavators, most of the dentinal tubules surrounding it are sclerosed.24,25

Moreover, it has been explained that when cavity preparations are made under dry conditions at 5000-6000 rpm, the nuclei of the odontoblasts are aspirated into the pulpal ends of the cut tubules, due to capillary forces.25,26 This can be avoided if sufficient water spray or water jet is used during the cavity preparation.26 An experiment in which air water spray handpieces were used at about 250,000 rpm, odontoblast nuclei appeared to have been aspirated into the dentinal tubules, even if spray of these units was used at maximal capacity.25

In our study, high-speed rotating instruments were used at a speed of 250,000 rpm with air/water spray just to widen the access to the cavity and to remove any unsupported enamel. The remaining carious dentine from the pulpal floor and the dentinoenamel junction was removed with slow speed rotating instruments (1000-1500 rpm) without water-cooling. Consequently the chances of trauma to the pulp during cavity preparation were minimal. The registration of significantly more pain during the MCP technique than during the ART technique can be explained, therefore, by the use of too much pressure or by the removal of more sound tooth material than necessary.

The selection of the restorative technique was to be made randomly. It was revealed, however, that atleast two operators preferred to use the ART technique in the largest cavities. Nevertheless they did not exhibit the highest number of pain reports. Moreover, another

33

operator (5) who had made a proper random choice of the restorative technique, because his selection was based on small cavities, exhibited the highest number of reports of pain. Furthermore, enquiries also revealed that this operator might have prepared cavities more continuously. Previous studies have shown that during protracted preparation, the temperature of the pulp chamber may be increased to such levels that thermal damage to the pulp tissue may be anticipated; intermittent cavity preparations, therefore, are more acceptable.15 The significant difference in the incidence of painful restorative procedures amongst operators establishes the operator effect.

Pain is in itself a very subjective item: children can translate any unpleasant experience into pain, and in fact it is very difficult to define pain as such. The sound and vibration of a bur may be experienced and explained as pain. The same may be true for the scrapping action of the excavator but to a lesser extent. Also anxiety can play a role in the subjective experience of pain. The results in table 3.4 and 3.5 illustrate partly the subjectivity of this phenomenon: there is a considerable chance that a patient will complain of pain again in those cases where the first treatment had been painful.

The effect of the restorative material can be explained by the fact that fewer amalgam restorations were made during the first treatments compared to the second ones (table 3.3).

Conclusions

The real ART-technique (preparation with hand instruments and restoration with glass ionomer) is less painful to patients compared to conventional restoration techniques (preparation with rotating instruments and restoration with amalgam).Pain reported by the patient in the first session has a predictive value for pain experience in the following sessions.

The individual operator effect is an important factor in experiencing pain during cavity preparation.

References

1. Byers M.R.: Dental sensory receptors. Int Rev Neurobiol, 25:39-94, 1984.

2. Brannstrom M.; Astrom A.: A study on the mechanism of pain elicited from dentine. J. Dent. Res, 43:4:619-25, 1964.

3. Brannstrom M.: Sensitivity of dentine. Oral Surg Oral Med Oral Path, 21:517-29, April 1966.

4. Brannstrom M.; Linden, L.A.; Astrom, A.: The hydrodynamic of the dental tubule and pulp fluid. A discussion of its significant in relation to dentinal sensitivity. Caries Res, 1:310-317, 1967.

34

5. Stanley, H.R.: The detection and prevalence of reactive and physiologic sclerotic dentine, reparative dentine and dead tracts beneath various types of dentinal lesions according to tooth surface and age. J Oral Pathol, 12:257, August 1983.

6. Barber D.; Massler M.: Permeability of active and arrested carious lesions to dyes and radioactive isotopes. J Dent Child, 31:26, 1964.

7. Berggren H.: The reaction of the translucent zone to dyes and radio-isotopes. Acta Odontol Scand, 23:197, 1965.

8. Fish E.W.: An experimental investigation of the enamel, dentine and dental pulp. John Bale Sons and Danielson, Ltd., London, 1933.

9. Miller W.A.; Massler M.: Permeability and staining of active and arrested lesions in dentine. Br Dent J, 112:187, 1962.

10. Brannstrom M.; Johnson, G.; Linden, L.A.: Fluid flow and pain response in the dentine produced by hydrostatic pressure. Odont Revy, 20:1-16, 1969.

11. Langeland, K.: Histological evaluation of pulp reactions to operative procedures. Oral Surg Oral Med Oral Path, 12:1235-49,1357-71, 1959.

12. James, V. E.; Schour, I.; Spence, J. M.: Response of human pulp to gutta percha and cavity preparation. J Amer Dent Asso, 639-50, 1954.

13. Jarby, S.: On temperature measurements in teeth. Odont T, 66:421-71, 1958.

14. Bhaskar, S. N.; Lilly, G.E.: Intrapulpal temperature during cavity preparation. J Dent Res, 44:4:644-47, July- August 1965.

15. Lauer, H. Ch.E.; Kraft; Rothlauf, W.; Zwingers, Th.: Effects of the temperature of cooling water during high-speed and ultrahigh speed tooth preparation. J Prosth Dent, 63:4:407-413, April 1990.

16. Cotton, W.R.: Bacterial contamination as a factor in healing of pulp exposures. Oral Surg Oral Med Oral Path, 38:441, September 1974.

17. Frencken, J.; Phantumvanit, P.; Pilot, T.: Manual for the Atraumatic Restorative Treatment. (ART) technique for dental caries. February 1994.

18. World Health Organization- Revolutionary new procedure for treating dental caries- Press release WHO/28, 7thApril 1994.

19. Frencken, J.; Makoni, F.: A treatment technique for tooth decay in deprived communities, World Health Organization. 47th year 1:16, Jan - Feb. 1994.

35

20. Rahimtoola, S.; Amerongen, E. V.: Comparison of two tooth saving preparation techniques in a treatment approach of one-surface cavities, Design of a study. J. Dent Child, 64:5:334-339, September-October 1997.

21. Klotzer, WT.: Die Traumatische Schadigung der Pulpa bei der Uberkronung. Dtsch Zahnarztl Z, 39:791-4, 1984.

22. Polman-Moy AC.: Temperaturmessungen in Zahnhartsubstanzen beim normal-, hoch- und hochsttourigen Schleifen. Dtsch Zahnarztl Z, 18:130-135, 1963.

23. Frank RM.; Voegel JC.: Ultrastructure of human odontoblast process and its mineralisation during dental caries. Caries Res, 14:367, 1980.

24. Yamada T.; Nakamura K.; Iwaku M. et al: The extent of odontoblast process in normal and carious human dentine. J Dent Res, 62:798, 1983.

25. Langeland. K.: En sammenligning av pulpareaksjoner pa low og high speed preparering og om pulpareaksjoner pa fyllingsmaterialet Cavinyl, Norske Tannl Tid, 66:994, 1956.

26. Langeland, K.: Tissue changes in dental pulp. Odontol Tidskr, 65:243, 1957.

36

Chapter 4

PREPARATION SIZE RELATED TO DIFFERENT WAYS OF MINIMAL INTERVENTION IN THE TREATMENT OF DENTAL CARIES

38

Introduction

Dental caries is an infectious disease that results from interplay of three predominant factors: the host, the microflora, and the diet or substrate.1 It is a result of demineralisation of enamel, dentine and cementum initiated by acids produced by oral bacteria. Cavitation will occur over time unless a demineralized area is remineralized.2

In many countries, the main method for treating dental caries is extraction of the diseased tooth. This often leads to the dental crippling of many individuals. Despite their existence, the conventional treatment and prevention techniques for dental caries are not utilized in many locations because they are either not available, not affordable, or require sophisticated and expensive equipment and extensively trained personnel.3

Scientific researches done in the economically developed countries and analogous investigations into the caries process have led to a better understanding of its dynamics. This has in turn resulted in a shift from the traditional approach of maximal intervention and invasiveness of oral care based on Black’s principles of cavity design and the use of amalgam to the approach of minimal intervention and invasion, maximal caries prevention and the use of adhesive restorative materials.4 One of these concepts is the Atraumatic Restorative Treatment (ART). This treatment approach was developed in mid 1980’s and introduced some years later in a clinical setting in Malawi5. It is based on removing infected tooth material using only hand instruments and filling the subsequently cleaned cavity with adhesive material such as glass ionomer.6

ART is a procedure, which is relatively atraumatic.3,7 It was primarily developed for treating people living in underserved areas of the world where resources and facilities such as electricity and trained manpower are limited.7 It has been well received by both children and adults who belong to population groups hardly ever exposed to regular oral health care.3

Moreover, in chapter 3 it has been shown that the ART technique involves less pain during cavity preparation compared with a more conventional restorative technique.8 The ART approach may also be more tooth saving compared with conventional techniques employing rotary instruments. As the ART technique involves the use of hand instruments alone, it therefore may require more chairside time for larger cavities. Likewise, larger cavities may require more chairside time for placing glass ionomer and amalgam restorations.

A study of the cavity sizes using ART and conventional preparation techniques, including the operator effect, treatment times and the patients’ perception was therefore conducted.


This study forms part of a longitudinal study9 evaluating one surface restorations made in permanent teeth by means of hand instruments (like ART) and rotating instruments (Minimal Cavity Preparation, MCP). Informed consent was obtained from the participants of the study, their parents and school authorities. A total of 914 restorations was placed in 408 patients: 359 patients received two, and 49 four restorations. In the case of two restorations, one preparation technique was applied, either with hand instruments only or

39

with rotary instruments. In the case of four restorations, two restorations were made with one technique and two with the other. The preparation technique to be applied was selected at random. The age of patients ranged from six to sixteen years (mean age 11.4 years). The baseline assessment showed a DMFT of 3.15 for the ART group and 2.98 for the MCP group.

Five operators took part in the study, but two of the five operators did not strictly follow the randomization procedure for the selection of the treatment technique. Therefore, the data of these two operators were excluded from the current analysis. The distribution of restorations according to preparation technique and the restorative material for the remaining restorations is shown in Table4.1

Preparation technique

Operator 2 3 5 Total

Hand GIC 62 48 50 160Instruments Amalgam 62 -- -- 62Rotary GIC 62 48 50 160Instruments Amalgam 62 -- -- 62

Table 4.1: The distribution of restorations per preparation technique, material and operator.

Of the remaining three operators, only one made restorations using both Fuji IX (GC International Corp.) and Tytin (Sybron/Kerr) (each patient had at least one preparation with glass ionomer and one with amalgam), while the other two operators made restorations with glass ionomer only. Therefore, data of all the restorations of the 3 operators were used to compare ART and MCP techniques (222 restorations per technique), while the data of all restorations of operator 2 were used to compare GIC and Amalgam restorations (124 restorations per material).

The operators were trained and calibrated regarding selection, treatment procedures, and practice before the study. The materials used were handled as recommended by their manufacturers. Each patient was treated by one of the operators and all treatments were done on site (in school). The selection of the restorative procedure to be employed was done randomly. In case of preparations made with only hand instruments, widening the entrance with a hatchet or a hoe created access to the cavity. Soft decayed tooth material was then removed using spoon excavators. Unsupported enamel was removed using again a hatchet or a hoe.

In the MCP technique, preparations were made using an air turbine. Access to the cavity was achieved by widening the entrance with a high speed cylindrical diamond bur of 1mm diameter (speed 250,000 to 270,000 rpm, with water cooling) and remaining soft carious dentine was removed by using a stainless steel round bur (speed 1,000 to 1,500 rpm, without cooling). A spoon excavator was only used to check for the presence of any remnants of caries. In both types of preparations special attention was given to cleaning of the enamel-

40

dentin junction and care was taken to remove all the unsupported enamel. The width of the entrance to the cavity was then measured using specially designed cavity measuring instruments having a diameter ranging from 1mm to 6mm with size increases of 0.5mm between instruments (fig 4.1)

Fig 4.1: Cavity measuring instrument

<= Tip of the instrument

If necessary a calcium hydroxide base was applied to the deepest areas of the cavity. Glass ionomer was applied after conditioning of the cavity. Condensation of amalgam was carried out with hand pluggers.11

The treatment time was measured using a stopwatch. It was divided into:1. Preparation time: the time necessary to prepare the cavity and remove all decayed tissue.

(It includes the period of actual start of cavity preparation, until the cavity was ready for filling); and

2. Restoration time: starting from placing the base in the already dried cavity (if necessary), conditioning, placement, and finishing of the filling.

For data analysis purposes, the cavity sizes were categorized in mm3 to account for the width and depth (three-dimensional estimation). The linear measurements had a difference of 0.5mm, so an average value for the cavity size was first estimated. For example: a measured cavity entrance of 1mm means that the actual width of the opening could be 1mm to 1.499mm so an average of 1.25mm was taken. The final cavity size in mm3 was computed using the formula r2h, where is a constant with a value of 3.142, r is the average radius of the opening of the cavity which is = average size of the cavity/2 and h is the height of the cavity which is supposed to be equal to the average width of entrance of the cavity. For this example the cubic measure will be: 3.142 * (1.25/2)2 * 1.25 = 1.5mm3.All data analysis was performed using SPSS 6.1.

Results

The mean cavity size was 5.1 mm3 (SD 8.6) for Handinstruments ‘H’, while in the case of Rotary ‘R’ the mean cavity size was 6.2 mm3 (SD 8.1). A Wilcoxon rank sum test showed a significant difference between these two groups (p< 0.01).

Kruskal-Wallis Anova test was applied to check for inter operator differences in mean cavity sizes resulting in significant dissimilarities (p<0.05) between the preparations of the three operators (table 4.2).

41

Operators RESTORATIVE TECHNIQUEover all mean ART MC

Pp value (Wilcoxon rank sum test)

2 5.5 5.3 5.7 <0.013 6.1 4.2 8.1 <0.055 5.6 5.5 5.7 >0.05

Table 4.2: Mean cavity size difference according to the operators and the restorative technique.

The intra-operator mean cavity size difference according to the restorative technique showed a significant difference in the mean cavity sizes of teeth prepared by ‘H’ and ‘R’ in the patients of operators 2 and 3. The cavities prepared by the ‘R’ technique were larger. There was however no statistically significant difference between the mean cavity size of ‘H’ and ‘R’ in the patients of operator 5.

A strong relationship between the cavity size and pain reports was also observed. The data of only those patients in whom two restorations were placed was utilized for this analysis (table 4.3). This was done to overcome any patient bias. The difference between mean cavity sizes of teeth with and without discomfort was significant (Wilcoxon rank sum test, p<0.01). When discomfort was reported, the mean cavity size was larger. This relationship was also true when each technique was analyzed individually (‘H’ p<0.01, ‘R’ p<0.05).

REPORTED PAINRestorative technique Absent Present p value (Wilcoxon

mean cavity size (mm3)

Mean cavity size (mm3)

rank sum test)

All cases 9.6 19.9 <0.01ART 11 34.2 <0.01MCP 7.8 12.1 <0.05

Table 4.3: Relationship between mean cavity size and pain reports.

Further analysis of this phenomenon according to the operators showed a significant difference in mean cavity sizes amongst the operators (table 4.4) with (Kruskal-Wallis anova p<0.01) and also without (Kruskal-Wallis anova p<0.01) reports of discomfort. When no discomfort was reported, operator 2 made the smallest cavities. In cases where pain was reported, operator 5 made the smallest cavities.

42

Operator Mean cavity size (mm3) p valueReported painabsent

Reported painpresent

Wilcoxon rank sum test

2 4.5 6.4 <0.053 4.8 31 <0.055 5.4 5.8 >0.05

Table 4.4: Distribution of mean cavity size according to the operator and pain reports.

To study the relationship between cavity size and treatment time, the cavity size data was grouped in four categories in ascending order according to their size. The last category was an aggregate of all the largest cavity sizes as a very small number of cases were in each of these large cavity size categories.

The distribution of preparation times of ‘H’ and ‘R’restorations according to the cavity size groups is shown in table 4.5. There were significant differences in the preparation times amongst the four cavity size groups of ART (Anova, p < 0.05) restorations. The group comprising of the largest cavity sizes required more time for cavity preparation. Similar differences were insignificant for the ‘R’ preparations.

Cavity size groups

No. Mean preparation time (minutes)

St. deviation Anova p value

Hand InstrumentsGroup 1 87 4.22 1.22Group 2 101 4.20 1.21 p<0.05Group 3 23 5 1.28Group 4 11 5.16 1.44Rotary instrumentsGroup 1 25 2.04 0.42Group 2 153 2.12 0.43 p>0.05Group 3 29 2.16 1.07Group 4 15 3.0 1.21

Table 4.5: The distribution of preparation times of ART and MCP restorations for the cavity size groups.

The restoration times for the separate cavity size groups (table 4.6) showed significant differences in the amalgam restorations (Anova, p<0.01): The group comprising of the largest sized cavities required more time to restore. However, for the GIC restorations, similar differences in the restoration times for the cavity size groups were not significant.

43

Cavity size groups

No. Mean restoration time (minutes)

St. deviation Anova p value

FUJI IXGroup 1 37 4.53 .50Group 2 70 5.02 .40 p>0.05Group 3 7 5.00 .34Group 4 10 5.30 .42TYTINGroup 1 27 4.37 .41Group 2 82 4.35 .46 p<0.01Group 3 12 5.15 1.36Group 4 3 6.00 0.00

Table 4.6: The distribution of restoration times of GIC and Amalgam restorations according to the cavity size groups.

Discussion

In this study, a specially designed cavity-measuring instrument was used to measure the size of the cavity. This instrument being rather simple could easily be applied to the entrance of the cavity9 and was used by all the operators without any difficulty. However, one drawback of this instrument was that only the largest width of the opening of the cavity could be measured. It was therefore necessary to manipulate the measurements in such a way that the width and the depth of the cavity were also accounted for. Moreover, the depth of a cavity is at least equal to the thickness of the enamel i.e. 1.5-2mm. However, the actual depth or height of the cavity could be much more, and the depth may also vary at different places at the base of the cavity. Similarly the shape of the entrance of the cavity can be different, it can be round, oval or of various other shapes whereas the shape of the tip of the measuring instrument was round. Also the diameter of the measuring instruments had differences of 0.5mm, therefore an average value of the width of the opening of the cavity was estimated. This estimate for an individual cavity opening size was also used as its height and the data could only be categorised in mm3. Because it can be expected that the measurement errors will be considerable, the collected data can only be used to get an approximate impression of the real cavity size. The error will be however, similar for all operators and for the ART as well as the MCP technique. Therefore, the data can only be used for comparison of the different variables.

The removal of hard dentin and enamel is practically impossible when only hand instruments are used for cavity preparation. The results of this study show a larger mean

44

cavity size for the MCP technique if the cavities are randomly divided between the ART and MCP group. It can be debated that the use of hand instruments alone does not ensure the removal of all carious tooth material10, but this is not necessarily a fault as the removal of only infected dentine and not the affected dentine has been advocated10. Recent studies have suggested that perhaps caries need not always be removed completely from the deeper parts of the cavity.10,11 Where under favourable conditions the cariogenic micro-organisms have shown reduction in number and viability12-15 concurrent with arrested carious lesions.16,17,18

Looking at the mean cavity sizes of the three operators it can be seen that they had a larger mean cavity size for the MCP group. However, this difference was statistically significant for operator’s 2 and 3. The use of high-speed turbine rotating instruments is associated with over cutting of healthy tooth tissue leading to larger sized cavities. In this study the MCP technique has been associated with more pain reactions than the ART technique8. When turbine drills are used, heat production during tooth preparation due to inadequate cooling, drop in the intra pulpal temperature due to over cooling or improper cooling, and mechanical damage are major sources of trauma19-22 and pain. Since dentin contains protoplasmic processes of the odontoblasts, cutting of dentin is in essence cutting of viable cells. When drills are used for cavity preparations many new healthy dentinal tubules are opened causing trauma to the odontoblastic processes within them.

The results of this study have also suggested a strong relationship between cavity size and pain reports. The mean cavity size was larger in cases where pain reactions were reported. This result seems to be rather obvious, because larger preparation means closer to the pulp, a larger cavity surface with more dentinal tubules or a greater chance of over cutting healthy tooth tissue. All can lead to more reactions during treatment.

An operator effect has also been disclosed by the results of this study. At least one operator made larger cavities with the MCP technique. Furthermore, the preparation time of ART restorations was affected by the cavity size. Whereas soft decayed tooth material can be removed very easily involving relatively less amount of time, the more marginally affected dentin which is discolored and relatively hard requires much more effort and time to be removed if only hand instruments are employed for this purpose. Similarly, the removal of unsupported enamel by hand instruments requires relatively more time then when mechanically driven instruments are employed. This may have resulted in the long preparation time requirement of the largest cavity size group of ART restorations.

However, cavity size group did not affect the restoration time of GIC restoration, while the restoration time of amalgam restorations was affected by cavity size. Amalgam is plugged manually and the larger the cavity size, the more amalgam has to be plugged in to fill the cavity requiring more time. In the case of GIC restorations, large amounts of material can be mixed and placed altogether into the cavity at the same time, irrespective of the size of the cavity.

45

Conclusions

The ART technique is associated with minimal loss of healthy tooth structure resulting in cavity preparations of smaller size. It is also less traumatic to the patient as it has been associated with less pain reactions.

The individual operator effect has come out as an important factor in determining the extent of tooth substance loss due to cavity preparation.

References

1. Newbrun, E. (ed): Cariology. 2nd ed. Baltimore: Williams and Wilkins, 1983.

2. Horowitz, A.M.: Introduction to the symposium on minimal intervention techniques for caries. J Public Health Dent, 56:3(special issue):133-34, 1996.

3. Frencken, J. and Makoni, F.: A treatment technique for tooth decay in deprived communities, World Health Organisation. 47th year, 1:16, January-February 1994.

4. Elderton, R.J. (ed): The dentition and dental care. Oxford: Heinemann, 1990.

5. Smith, A.J.E.; Chimiba, P.D.; Kalf-Scholte, S.; Bouma, J.: Clinical pilot study on new dental filling material and preparation procedures in developing countries. Community Dent Oral Epidemiol, 18(6):309-12, December 1990.


7. World Health Organization: Revolutionary new procedure for treating dental caries- Press release WHO/28, 7thApril 1994.

8. Rahimtoola, S.; van Amerongen, E.; Maher, R.; Groen, H.: Pain related to different ways of minimal intervention in the treatment of small carious lesions. J Dent Child, 67:2:123-127, March-April 2000.

9. Rahimtoola, S. and van Amerongen, E.: Comparison of two tooth saving preparation techniques in a treatment approach of one surface-cavities. Design of a study. J Dent Child, 64:5:334-39, September-October 1997.

10. Fusayama, T.: New concepts in operative dentistry; differentiating two layers of carious dentine and using an adhesive resin. Berlin: Quintessence, 1980.

11. Weerheijm, K.L.; de Soet, J.J.; van Amerongen, W.E.; de Graaff, J.: The effect of glass ionomer cement on carious dentine: an in vivo study. Caries Res, 27:5:417-23, 1993.

46

12. Jerominus, D.J.; Till, M.J.; Sveen, O.B.: Reduced viability of microorganisms under dental sealants. J Dent Child, 42(4):275-80, July-August 1975.

13. Handelman, S.L.; Washburn, F.; Wopperer, P.: Two-year report of sealant effect on bacteria in dental caries. J Am Dent Assoc, 93(5):967-70, November 1976.

14. Mertz-Fairhurst, E.J.; Schuster, G.S.; Williams, J.E.; Fairhurst, C.W.: Clinical progress of sealed and unsealed caries. Part II. Standardized radiographs and clinical observations. J Prosthet Dent, 42(6):633-7, December 1979.

15. Jensen, O.E. and Handelman, S.L.: Effect of an autopolymersing sealant on viability of microflora in occlusal dental caries. Scan J Dent Res, 88(5): 382-8, October 1980.

16. King, J.B.; Crawford, J.J.; Lindhal, R.L.: Indirect pulp capping: A bacteriologic study of deep carious dentin in human teeth. Oral Surg, 20:633-71, 1965.

17. Going, R.E.; Loesche, W.J.; Grainer, D.A.; Syed, S.A.: The viability of microorganisms in carious lesions five years after covering with a fissure sealant. J Am Dent Assoc, 97:455-62, September 1978.

18. Mejare, I. and Mjor, I.A.: Glass ionomer and resin based fissure sealants: a clinical study. Scan J Dent Res, 98:345-50, August 1990.

19. Lauer, H.Ch.E.; Kraft; Rothlauf, W.; Zwingers, Th.: Effects of the temperature of cooling water during high-speed and ultrahigh speed tooth preparation. J Prosth Dent, 63:4:407-13, April 1990.

20. Klotzer, W.T.: Die Traumatische Schadigung der Pulpa bei der Uberkronung. Dtsch Zahnarztl Z, 39:791-4, 1984.

21. Polman-Moy, A.C.: Temperaturmessungen in Zahnhartsubstanzen beim normal-, hoch- und hochsttourigen Schleifen. Dtsch Zahnarztl Z, 18:130-5, 1963.

22. Bhaskar, S.N. and Lilly, G.E.: Intrapulpal temperature during cavity preparation. J Dent Res, 44:4:644-47, 1965.

47

Chapter 5

EFFECT OF PREPARATION AND RESTORATION TIMES

48

Introduction

G.V. Black first introduced minimal preparation techniques in the early 1900’s.1,2 He divided carious pits and fissures into four groups based on the size of the carious lesion and the degree of dentine involvement,3 along with the technique for preparation of minimal cavities using hand instruments. However, as only non-adhesive restorative materials were available at that time, he proposed that the cavities be prepared by rotating instruments (hand pieces) for mechanically retained restorative materials like amalgam.3

The development of new adhesive restorative materials has radically changed restorative dentistry. The need for maximal intervention, extension for prevention and mechanical retention of a restoration has now been transformed to the concepts of minimal intervention and invasion. One of such concepts of minimal intervention and invasion is the Atraumatic Restorative Treatment technique (ART).

ART is based on removal of decayed tooth material with just hand instruments and filling the subsequently prepared cavity with glass ionomer restorative material.4 Developed in mid 1980’s, this technique was primarily meant for treating people living in underprivileged areas of the world where resources such as electricity and trained manpower are limited.5

Many studies have evaluated the ART technique and the results have supported its application.6 It has been well received by both children and adults who belong to population groups hardly ever exposed to regular oral health care7. The three year survival rates for the glass-ionomer (GIC) restorations placed with the ART technique was equal8 to the three year survival of one surface amalgam restorations made by utilizing a conventional preparation and restorative technique.9,10 In Pakistan, a study was conducted to compare the ART technique with another more conventional treatment technique.11 Results of this study suggested that ART with GIC (Fuji IX) was comparable with the more conventional restorative technique (chapter 6). Moreover the ART technique was less painful to the patient12 and less traumatic to the tooth structure13 (chapter 3 and 4) than the more conventional restorative technique.

As the ART technique involves the use of hand instruments only therefore it may therefore require more chairside time for cavity preparation. Likewise, the placement of glass ionomer restorations may also require more time then placing amalgam restorations.

This paper presents the differences in the preparation and restoration times and the effect of material, cavity size and operator on the treatment times. The influences of the restoration time on the survival of restorations have also been discussed.


This study forms part of a longitudinal study11 evaluating one surface restorations made in permanent teeth by means of just hand instruments (ART) and rotating instruments used with minimal cavity preparation (MCP). A total of 914 restorations were placed in 408 patients: 359 received two and 49 four restorations. In case of two restorations one preparation technique was applied: either with just hand instruments or with rotating

49

instruments. In case of four restorations, two restorations were made with one technique and two with the other. The preparation technique to be applied was selected at random.

The age of the patients ranged from six to sixteen years (mean age 11.4 years). The baseline epidemiological survey showed a DMFT of 3.15 for the ART group and 2.98 for the MCP group.

Five operators took part in this study and all were trained and calibrated regarding selection, treatment procedures, and practice before starting the study. However, two (operators 1&4) of the five operators did not strictly follow the randomization procedure for the selection of treatment technique. Therefore the data of these two operators were excluded from the current analysis. Of the remaining three operators, only one (operator 2) made restorations using both Fuji IX and Tytin while the other 2 (operators 3 & 5) made restorations with Fuji IX only. Operator 2 restored in each patient at least one preparation with glass ionomer and one with amalgam.

The data of all the restorations of the 3 operators were used to compare ART and MCP techniques (222 restorations per technique), while the data of all restorations of operator 2 were used to compare GIC and Amalgam restorations (124 restorations per material). Each patient was treated by any of the operators and all treatments were done at site (school). All restorative procedures were described in detail to ensure consensus in treatment by all operators. Moreover, the materials used were handled as recommended by the manufacturers.

In case of preparations made with hand instruments only, access to the cavity was achieved by widening the entrance with a hatchet or a hoe. Soft decayed tooth material was then removed using spoon excavators. Hatchet or a hoe was again used to remove any remaining unsupported enamel. In the minimal cavity preparation technique (MCP), preparations were made using an air turbine. Access to the cavity was achieved by widening the entrance with a high speed cylindrical diamond bur of 1mm diameter (speed 250,000 to 270,000 rpm, with water cooling) and remaining soft carious dentin was removed by using a stainless steel round bur (speed 1,000 to 1,500 rpm, without cooling). A spoon excavator was only used to check for the presence of any remnants of caries. In both types of preparations special attention was given to the cleaning of the dentino enamel junction and care was taken to remove all the unsupported enamel. The width of the entrance to the cavity was then measured using specially designed cavity measuring instruments having a diameter ranging from 1mm to 6mm with a size difference of 0.5mm between instruments.

If necessary a calcium hydroxide base was applied to the deepest areas of the cavity in both studies. Glass ionomer was applied after conditioning of the cavity. Condensation of amalgam was carried out with hand pluggers11.

The treatment time was measured using a stopwatch. It was divided into:1. Preparation time: the time necessary to prepare the cavity and remove all decayed

tissue. It includes the period of actual start of cavity preparation, until the cavity was ready for filling.

50

2. Restoration time, starts from placing the base in the already dried cavity (if necessary), conditioning, placement of filling and finishing of the filling.

All evaluations were done on site (in schools), making use of a ball-ended CPITN periodontal probe14, separate evaluations were done at baseline and at 3 month, 6 month, 1 year, 11/2 and 2 year after placement of restorations. Pairs of evaluators examined each patient together, and the final score was based on consensus. One operator evaluated all of the restorations, along with one of the other operators, who did not evaluate their own restorations.

All data analysis was done using SPSS 6.1 for Windows.

Results

Preparation time

The mean preparation time of the ART restorations (both GIC and amalgam restorations) was 4.28 minutes (std. dev. 1.24), while the mean preparation time of the MCP restorations (both GIC and amalgam restorations) was 2.15 minutes (std. dev. 0.51). The ART preparations required significantly more time (table 5.1) than the MCP preparations (T test, p< 0.01).

No. of restorations

Mean preparation time (min)

St. dev T test(p value)

ART 222 4:28 1:24 < 0.01MCP 222 2:15 0:51

Table 5.1: Mean preparation times for ART and MCP restorations.

The location of restoration did not effect the preparation time, as there was no significant difference in the preparation times of the cavities prepared on the occlusal, buccal and lingual surfaces in both the ART and MCP restorations.

Restoration time

The mean restoration time of GIC and Amalgam restorations (both ART and MCP preparations) were 5.01 (std dev 0.43) and 4.41 (std dev 0.53) minutes respectively. The difference was statistically significant (T-test, p< 0.01). The GIC restorations required more time to be placed than amalgam restorations (table 5.2).

No. of restorations

Mean restoration time (min)

St. dev T test(p value)

GIC 222 5:01 0:43 < 0.01Amalgam 222 4:41 0:53

Table 5.2: Mean restoration times for GIC and amalgam restorations.

51

The location of restoration did not effect the restoration time, as there were no significant differences in the restoration times of the occlusal, buccal and lingual restorations made with both GIC and amalgam.

Operator

Operator-wise differences in the mean preparation time are shown in table 5.3. There were significant differences in preparation time of ART restorations amongst the operators (Anova, p<0.01) and at least one operator required less time to prepare ART restorations. Similar differences in the mean preparation time amongst the operators were insignificant for MCP restorations.

No. Mean preparation time

Std. Deviation

Anova (p value)

ARTOperator 2 124 4.54 1.10Operator 3 48 4.16 1.27 p<0.01Operator 5 50 3.36 1.29MCPOperator 2 124 2.22 0.47Operator 3 48 2.07 0.58 p>0.05Operator 5 50 2.06 0.53

Table 5.3: Operator-wise distribution of mean preparation time (in minutes).

Distribution of mean restoration time for the restorations placed by the 3 different operators is shown in table 5.4. Data of only GIC restorations were used for this purpose, as two operators did not place any amalgam restorations. Statistically significant difference was observed; one operator required less time, while another required more time to place glass ionomer restorations.

No. Mean restoration time

Std. deviation

Anova (p value)

FUJI IXOperator 2 124 5.01 0.43Operator 3 96 4.06 0.44 p<0.01Operator 5 100 3.19 0.38

Table 5.4: Operator-wise distribution of mean restoration time (in minutes).

Survival of restorations

Differences in the preparation times of acceptable and failed ART restorations (both GIC and amalgam restorations) were insignificant. Similarly, differences in the preparation

52

times of acceptable and failed MCP restorations (both GIC and amalgam restorations) were also insignificant.

Differences in the restoration times of acceptable and failed GIC restorations (both ART and MCP preparations) were insignificant. Similar, differences in the restoration times of acceptable and failed amalgam restorations (both ART and MCP preparations) were also insignificant. However, the present data for the ART restorations made with GIC showed that the failed restorations had a significantly lower restoration time than the successful restorations (chapter 7).

Discussion

The average time required to place ART-GIC restorations was 9.16 minutes. This is less than the treatment time reported for ART in previous studies15. The treatment time for the ART restorations in the 1994 and 1995 ART studies in Zimbabwe was 19.8 and 15.8 minute’s respectively8. This shows a steady reduction in the treatment time. In the present study, the treatment time was divided into preparation time and restoration time. Because both the preparation and restoration times were recorded separately, the time required for seating the patient, communicating to him about the procedure, initial identification of the cavity and its isolation before cavity preparation and re-isolation before the restorative phase were not included. This may have lead to a reduction in the time required to place ART restorations in the present study compared to the previous ART studies.

The present study showed that the ART restorations required more preparation time then the MCP restorations. ART technique involves cavity preparation with hand instruments only and therefore requires more physical labor and time for cavity preparation when compared with the MCP technique, which involves airotors and mechanical cutting instruments for tooth preparation.

Furthermore, the preparation time of ART restorations was affected by the cavity size (chapter 4). Whereas soft decayed tooth material can be removed very easily involving relatively less amount of time, the more marginally affected dentine which is discolored and relatively hard requires much more effort and time to be removed if only hand instruments are employed for this purpose. Similarly, the removal of unsupported enamel by hand instruments requires relatively more time than when mechanically driven instruments are employed. This may have resulted in the high preparation time requirement of the largest cavity size group of ART restorations.

The present study also suggested more restoration time for GIC restorations then amalgam restorations. Glass ionomers are technique sensitive materials; manufacturer instructions have to be strictly followed to get the optimum restoration. Even with a lot of experience, getting the optimum mix and following the restoration protocol, it still requires considerable time. However the restoration time of GIC restorations was not affected by the cavity size while the restoration time of amalgam restorations was affected by cavity size (chapter 4). Amalgam is plugged manually and the larger the cavity size, the more amalgam has to be plugged in to fill the cavity requiring more time. In the case of GIC

53

restorations, large amounts of material can be mixed and placed altogether into the cavity at the same time, irrespective of the size of the cavity.

The fact that significant differences existed in the restoration times of successful and failed ART-GIC restorations suggests that the differences in the restoration time may influence the survival of GIC restorations.

The present study also suggested a strong operator effect for both the ART preparations and the GIC restorations. Both GIC restorations and to a lesser extent, ART preparations are technique sensitive. Moreover in the dental profession as in other professions, the skills of dentists vary. The fact that the survival of ART-GIC restorations was affected by the differences in restoration time suggests that the variation amongst the operators in the treatment time may also influence the survival of GIC restorations.

Conclusions

ART restorations require more preparation time than the MCP restorations. Glass ionomer restorations require more restoration time than the amalgam

restorations. The operator affected both the preparation time of ART restorations and the

restoration times of GIC restorations. The survival of GIC restorations may be influenced by variances in the restoration

times.

References

1. Black, C.E. and Black, B.M.: From pioneer to scientist. Life story of Green Vardiman Black, “Father of Modern Dentistry” and his son Arthur Davenport Black. Saint Paul, MN: Bruce Publishing, p224 1940.

2. Black, A.D. (ed.): G.V. Black’s work on operative dentistry. Vol.II Technical procedures in making restorations in the teeth. Chicago, IL: Medico-Dental Publishing, p138 1936.

3. Black, A.D. (ed.): G.V. Black’s work on operative dentistry. Vol.III Treatment of dental caries. Chicago, IL: Medico-Dental Publishing, p55-6, 60, 117-48 1936.

4. Frencken, J., Phantumvanit, P., Pilot, T. Manual for the Atraumatic Restorative Treatment (ART) technique for dental caries, February 1994.

5. World Health Organization- Revolutionary new procedure for treating dental caries- Press release WHO/28, 7thApril 1994.

6. Frencken, J.E., Songpaisan, Y., Phantumvanit, P., Pilot, T. An atraumatic restorative treatment technique: Evaluation after one year. Int Dent J, 44:460-464, October 1994.

54

7. Frencken, J.; Makoni, F. A treatment technique for tooth decay in deprived communities, World Health Organization. 47th year 1:16, January-February 1994.

8. Frencken, J., Makoni, F., Sithole, W.D., Hackenitz, E. Three year survival of one-surface ART restorations and glass ionomer sealants in a school oral health programme in Zimbabwe. Caries Res, 32:119-126, 1998.

9. Phantumvanit, P., Songpaisan, Y., Pilot, T., Frencken, J. Atraumatic Restorative Treatment (ART): A three year field trial in Thailand - Survival of one-surface restorations in permanent dentition. J Public Health D, 56:3:141-145, July 1996.

10. Frencken, J.E. and Holmgren, C.J. How effective is ART in the management of dental caries? Community Dent Oral Epidemiol, 27:6:423-30, December 1999.

11.Rahimtoola, S. and van Amerongen, E.: Comparison of two tooth saving preparation techniques in a treatment approach of one-surface cavities. Design of a study. J Child Dent, 64:5:334-339, September-October 1997.

12. Rahimtoola, S., van Amerongen, E., Maher, R.; Groen, H. Pain related to different ways of minimal intervention in the treatment of small caries lesions. J Dent Child, 67:2:123-127, March-April 2000.

13. van Amerongen, W.E.; Rahimtoola, S.: Is ART really atraumatic? Community Dent Oral Epidemiol, 27:6:431-5, December 1999.

14. Ainamo, J.; Barmes, D.; Beagrie, G.; Cutress, T.; Martin, J.; Sardo-Infirri, J.: Development of the World Health Organization (WHO) community periodontal index of treatment needs (CPITN). Int Dent J, 32:3:281-91, September1982.

15. Frencken, J.; Makoni, F.; Sithole, W.D.: Atraumatic restorative treatment and glass-ionomer sealants in a school oral health programme in Zimbabwe: Evaluation after 1 year. Caries Res, 30:428-433, 1996.

55

Chapter 6

SURVIVAL OF CLASS 1 GLASS IONOMER AND AMALGAM RESTORATIONS AFTER 2 YEARS

56

Introduction

The development of adhesive restorative materials such as glass ionomer cements has made possible the realization of minimal intervention and invasion concepts for the treatment of dental caries. One of these concepts is the Atraumatic Restorative Treatment (ART) technique or approach, which is based on removal of decayed tooth material with hand instruments and filling the subsequently prepared cavity with a glass ionomer (GIC) restorative material.1 This technique has been evaluated under field conditions with encouraging results.2 Although the two studies are not strictly comparable, the three-year survival for single-surface GIC restorations placed with the ART technique3 was equal to the three-year survival of one-surface amalgam restorations placed with a conventional preparation and restorative technique.4 The ART approach, because of its simplicity and minimal invasiveness,5 may be the much needed adjunct to oral health promotion programs in the overall primary health care setting. However, the success of the ART restorative technique and the material needs to be further evaluated.

For this purpose, a study was conducted in Pakistan evaluating various aspects of ART when compared with minimal cavity preparation (MCP) using rotary instruments, under the same field conditions.6 The current paper describes the two-year restoration survivals for the ART and MCP techniques, using both methods with GIC and amalgam as restorative materials. Moreover, two-year survival of glass ionomer fissure sealants is also described and a comparison of the caries incidence between these teeth and the teeth restored with amalgam will be presented.


This study forms part of a prospective study6 evaluating one-surface restorations in permanent teeth, with cavities prepared by hand instruments only (ART) or by rotary instruments (MCP). A total of 914 restorations was placed in 408 patients: 359 patients received two, and 49 four, restorations. In the case of two restorations, one preparation technique was applied, either with hand instruments only or with rotary instruments. In the case of four restorations, two restorations were made with one technique and two with the other. The preparation technique to be applied was selected at random. The age of patients ranged from six to sixteen years (mean age 11.4 years). The baseline assessment showed a DMFT of 3.15 for the ART group and 2.98 for the MCP group.

Five operators took part in the study, but two of the five operators did not strictly follow the randomization procedure for the selection of the treatment technique. Therefore, the data of these two operators were excluded from the current analysis. The distribution of restorations according to preparation technique and the restorative material for the remaining restorations is shown in table 6.1. Of the remaining three operators, only one

57

made restorations using both Fuji IX (GC International Corp.) and Tytin (Sybron/Kerr) (each patient had at least one preparation with GIC and one with amalgam), while the other two made restorations with Fuji IX only.

Preparation technique

Operator 2 3 5 Total

Hand GIC 62 48 50 160Instruments Amalgam 62 -- -- 62Rotary GIC 62 48 50 160Instruments Amalgam 62 -- -- 62

Table 6.1: The distribution of restorations per preparation technique, material and operator.

The operators were trained and calibrated regarding selection, treatment procedures, and practice before the study. The materials used were handled as recommended by their manufacturers. Each patient was treated by one of the operators and all treatments were done on site (in school).

In the case of the ART technique, preparations were made with hand instruments only, while for the MCP technique, preparations were made using an air turbine. For both types of preparations, special attention was given to the removal of caries at the dentino-enamel junction, and care was also taken to remove all unsupported enamel. If necessary a Calcium Hydroxide base was applied to the deepest areas of the cavities. The GIC was applied after cavity conditioning; this was done with a drop of Fuji IX liquid on a mixing pad. After a cotton pellet, moistened in water, was dipped in the liquid drop, it was brushed on the entire cavity surface including the remaining fissures for 10 seconds. The surface was then washed three times with a clean cotton wool pellet dipped in water and dried with dry pellets.

The liquid and powder was then dispensed and mixed following strictly the manufacturer instructions. Thereafter, the mixture was applied into the cavity and the remaining fissures. A small amount of Vaseline was applied on the gloved forefinger and the material was brought under pressure so that the glass ionomer could flow into the cavity and fissures. After a few seconds the finger was removed sideways. Some Vaseline was applied on a ball burnisher and pressed the material again by moving through the fissure, starting in the center of the occlusal surface. Excess of material was displaced to the slopes of the cusps and removed with a large excavator, the bite was checked and adjusted till the patient could close normally. Some more Vaseline was applied with a cotton pellet and the patient was asked not to eat for one hour.

Condensation of the amalgam was carried out with hand pluggers6.

All evaluations were done on site (in schools), making use of a ball-ended CPITN periodontal probe7. Separate evaluations were done at baseline and at 3 mth, 6 mth, 1 yr, 11/2 and 2 yr after placement of restorations. Pairs of evaluators examined each patient together, and the

58

final score was based on consensus. One operator evaluated all of the restorations, along with one of the other operators, who did not evaluate their own restorations.

The quality of the restoration was assessed according to the following criteria: 0= Present, correct.1= Margin defect or surface wear less than 0.5 mm.2= Wear of surface > 0.5 mm.3= Defect at margin > 0.5mm.4= Combination of 2 and 3.5= Restoration has (almost) completely disappeared.6= Restoration not present because other treatment has been performed for whatever reason.7= Tooth absent. 9= Unable to diagnose.

Codes 0-1 were considered successful restorations and codes 2-5 were considered failed restorations.

Dental caries related to the restoration was evaluated using the following criteria:0= Sound, no discoloration.1= Discoloration at surface, but it is hard.2= Discoloration (in-depth) but hardness cannot be assessed.3= Caries connected to the restoration.4=Caries related to the pits and fissures on the same surface of the tooth.5= Combination of 3 and 4.8= Caries anywhere else on the tooth surface.9= Unable to diagnose.

Caries for the purpose of this study was defined as “a break in the enamel or a cavity in the tooth; the dentine in the cavity has to be softer than the surrounding dentine”. Hence, codes 0-2 were not considered caries, while codes 3 and 5 were considered caries to be related to the restoration. In this study, the restorations were considered failed if they had quality codes 2-5 and /or caries codes 3 and 5.

The fissure sealant was assessed according to the ensuing criteria:0=Present, correct.1= Fissure filling partly disappeared.5= Fissure filling has (almost) completely disappeared.6= Not present because other treatment has been performed.7= Tooth absent.9= Unable to diagnose.

Codes 0 and 1 were considered as acceptable fissure sealant and code 5 was considered as failed fissure sealant. Codes 6, 7 and 9 were considered as censored.

A drawing was made showing the outline of the (remaining) fissure sealant and the restoration. For data analysis the outline drawing was divided and coded into 7 different

59

sections as shown in figure 6.1(maxillary posterior teeth) and 6.2 (mandibular posterior teeth).

Figure 6.1: Drawing outlining the fissures for maxillary posterior teeth.

Figure 6.2: Drawing outlining the fissures for the mandibular posterior teeth.

All data were analyzed using SPSS 6.1 for windows (SPSS Inc., Chicago, USA).


The data from all GIC restorations placed by the three operators were used to estimate and compare the survivals of ART and MCP techniques (160 restorations per technique), while the data from all restorations of one operator only were used to estimate and compare the survivals of GIC and amalgam restorations (124 restorations per material). Cumulative survivals were estimated using the Kaplan-Meier method, and logrank tests were used to compare the survival curves.

60

Fissure sealants

The fissure sealants placed in the teeth restored with ART and the MCP techniques were all grouped together, as there was no difference in the procedure for placing GIC restorations and sealants. The caries incidence in the teeth with fissure sealants has been compared with the teeth restored with amalgam. Relative risk was calculated using Epi-info 6.04b.

For simplicity, in the present paper the restorations made with only hand instruments including the actual ART restorations will be designated as ‘H’. Restorations made with rotary instruments will be designated as ‘R’. Similarly, ‘A’ will denote amalgam and ‘G’ will denote glass ionomer restorations. So ‘HA’ will mean amalgam restorations made with hand instruments and ‘RG’, glass ionomer restorations made with rotary instruments (MCP).

Results


Out of 444 restorations, 24 (5.4%) were lost to follow-up over the 2-year period. These cases were considered as being censored for data analysis.

Caries was associated with one failed ‘R’ restoration, but with no failed ‘H’ restorations. Caries was associated with one out of the nine failed amalgam restorations and with none of the 15 failed GIC restorations.

Caries (codes 3 and 5) was not associated with acceptable restorations and no pit and fissure caries (caries code 4) were associated with acceptable ‘HA’ and ‘HG’ restorations. However, out of 213 acceptable ‘RA’ and ‘RG’ restorations two showed pit and fissure caries; one restoration was a ‘G’ (1/154) and one was an ‘A’ (1/59).

The cumulative survival rates after 2 years for HG and RG restorations were 93.8% and 92.9% (figure 6.3).

Figure 6.3: Cumulative survival of glass ionomer restorations made with hand and rotary instruments after 2 years.

61

The cumulative survival rates after 2 years for HA and RA restorations were 89.6% and 95% respectively (figure 6.4). Further analysis was done using Kaplan Meier tests that adjusted the data for loss to follow up and incomplete survivals.

Figure 6.4: Cumulative survival of amalgam restorations made with hand and rotary instruments after 2 years.

When using GIC as the restorative material (figure 6.5), no statistically significant difference (Kaplan Meier) was observed between the survival rate of ‘H’ (94.2%) and ‘R’ (96.1%) restorations after 2 years.

Figure 6.5: Comparison of survival curves for H (ART) and R (MCP) restorations when using Fuji IX (GIC) as the restorative material.

62

2-year survival curves (figure 6.6) for the performance of Tytin amalgam in both the ‘H’ (89.6%) and ‘R’ (95%) groups showed a better performance for amalgam in the ‘R’ group, but the difference was not statistically significant.

Figure 6.6: Comparison of survival curves for H (ART) and R (MCP) restorations when using Tytin (amalgam) as the restorative material.

Overall, teeth restored with ‘G’ (Fuji IX), (98.3%, 2 yr survival) performed better (Kaplan Meier p<0.05) than those restored with ‘A’ (Tytin), (92.3%, 2 yr survival). Moreover for ‘HA+G’ preparations (figure 6.7), Fuji IX (98.2%) performed better (p=0.05) than Tytin (89.6%).

Figure 6.7: Comparison of survival curves for G (Fuji IX) and A (Tytin) for H (ART) restorations.

63

Survival of the fissure sealants

Table 6.2 shows the retention of fissure sealants after two years. Out of a total of 320 teeth in which the fissure sealants were initially placed, 5.3% had the sealant completely intact, 57.8% had the sealant partially present, while the fissure sealant was completely lost from 36.9% of the teeth.

Quality code* Fissure sealant0 17 (5.4%)1 185 (57.8%)5 118 (36.8%)total 320

Table 6.2: The retention of fissure sealants after two years.

*Legend:0 = present, perfect.1 = partially present.5 = completely lost.

Taking into account the “lost to follow-ups” and “partial survivals”, the survival percentage (partial and complete) of the fissure sealant after 2 years was 61.9% (Kaplan Meier estimator, figure 6.8).

Figure 6.8: Two-year survival of the fissure filling.

Caries

64

Caries was observed in 0.3% of the originally sealed pits and fissures while 1.6% of the teeth restored with amalgam (unsealed teeth) developed pit and fissure caries in the two-year period. The relative risk for developing caries in sealed versus unsealed surfaces was 0.20 (95% confidence interval: 0.02, 2.13). Of the sealed teeth, 9 already had initial fissure caries at baseline. After 2 years the fissure sealants were perfectly present in 1 tooth, partially present in 6 and completely lost from 2 of these teeth. None of the 9 teeth developed caries after 2 years.

Effect of the location of the actual restoration (figure 6.9)

The survival analysis of the fissure sealant showed a significantly better survival when the fissure sealant was associated with occlusal restorations than with non-occlusal restorations (p<0.01). Figure 6.9: Two-year survival of the fissure sealant in the occlusal and non-occlusal

restorations.

Remaining fissure sealant

The distribution of the remaining fissure sealant at each evaluation in maxillary and mandibular teeth is shown in figure 6.10.

Maxillary teeth: The palatal part of the fissure sealant showed the lowest retention at baseline. After two years the fissure sealant showed the best retention in the mesial pit and the worst retention in the palatal fissure, followed by the occluso-palatal fissure and the distal fossa (see fig 6.1).

65

Mandibular teeth: At baseline, the fissure sealant showed the lowest retention in the buccal vestibular area while the best-retained part was the mesial fossa area. After 2 years the lowest retention was in the occluso-buccal area while the fissure sealant showed the best retention between the central pit and the distal fossa (see fig 6.2).

Maxillary teeth showed significantly more complete loss of sealants (46.7%) than mandibular teeth (33%) (p <0.05). Also, significantly more partial survival of sealants was observed in the mandibular teeth (62.6%) than in the maxillary teeth (45.6%) (p<0.01).

20% of the sealants were completely lost in the first year while, 16.8% were lost in the second year. The difference was statistically insignificant.

Figure 6.10: The distribution of the remaining (%) fissure sealants and the restorations at each evaluation.Shaded codes 1 to 8 are parts of the fissure as shown in fig. 6.1 and 6.2.

66

Operator Effect (figure 6.11): There were significant differences in survival of fissure sealants amongst the operators (p <0.01). The fissure sealantsof operator 3 showed the best survival.

Figure 6.11: Operator wise two-year survival of the fissure sealant.

Discussion

The 2-year lost to follow-up rate for the restorations was low at 5.4 %. Apart from migration to other areas, dropouts from school were the main reason for this attrition. Maximum efforts were made to increase attendances, however, some attrition is inevitable in a field trial such as this one.

As with all types of restorations, survival rates decrease over time. Both ‘HG’ and ‘RG’ restorations gave similar results over a 2-year period. However, the ‘H’ preparations restored with GIC gave a better cumulative 2-year survival rate than those restored with amalgam. The survival rates for the ‘Hand instrument’ technique with GIC are similar to those reported in previous studies from field settings in Thailand4 and in Zimbabwe.3

Figure 6.12 shows that the 2-year survival rate was lowest in the Thailand and highest in the Pakistan study. Experience gained in the application of the ART technique may have contributed to this upward trend, but the use of different GIC’s and operators’ skill may also be other reasons.

67

Figure 6.12: Survival curves for one-surface ART restorations in permanent teeth restored with glass ionomer.

In this study, GIC gave marginally better survival rates than amalgam, even with the ‘rotary’ technique. Fuji IX, the GIC used in this study was specifically designed for the ART technique and has better mechanical properties than the first-generation GIC’s. Also, as described in the design of this study6, only small one-surface carious lesions were selected in permanent posterior teeth. This minimized the contact of restored surfaces with the opposing teeth during functional occlusion, thus reducing the possibility of excessive wear or fracture, especially for the GIC restorations.

Not surprisingly, the survival of amalgam was poorer than GIC in the ‘H’ group as with, hand instruments only, the resulting cavity shape usually provide little macro mechanical retention for materials lacking adhesive properties. Technical errors by the operators were probably responsible for the complete loss of restorations. Moreover, unacceptable marginal defects could have been caused by improper cavo-surface angles leaving thin sections of restorative material at the margins of the cavities.

Unlike previous studies of the ART technique, caries was not observed with these restorations. Improvements in the technique from experience gained over the years may have contributed to this result, and a strict emphasis was placed on one of the pillars of the ART approach8, and of restorative care in general, which is to insure that the outline of the cavity preparation and the dentino-enamel junction were free of caries. However, caries was observed with one failed ‘RA’ restoration, where the amalgam had been completely lost. In such situations, it is difficult to determine whether the caries was residual, or developed after the restoration had been lost. Marginally more caries was associated with amalgam than with GIC restorations. One advantage of the GIC was that the pits and fissures adjacent to the restoration could be sealed using the press finger technique, which may give additional protection to the teeth.

68

Amalgam has long been the preferred restorative material for posterior teeth. The 2-year survival rate of 95% for the single surface ‘rotary’ amalgam restorations in this study compares well with the various survival percentages that have been reported for amalgam: 98.3% restoration success and 97% treatment success of non-extended occlusal amalgam restorations at 2-year interval9, 94-86% 4-year survival in four different alloys10, 86.6% 3-year survival rate11 and 63% 5-year survival rate among 13-14 year olds.12 Moreover, the survival rate of GIC in this study relates favorably with those reported for amalgam.

Longer duration studies on the performance of ART and GIC restorations are recommended especially since the 3rd year evaluation of the present study indicated a success of 95.3% for ‘HG’ and 91.4% for ‘RG’ restorations. However, 174 restorations of only two operators were available for the evaluation.

Survival of fissure sealants

The criteria used to assess the quality of a fissure sealant have been designed considering the reported weakness of glass ionomer as a fissure sealant. Both ‘HG’ and ‘RG’ approaches include the sealing of the margins of restorations and the pits and fissures adjacent to it. The evaluation criteria were designed to measure the frequency and gradation of loss, taking into account the exact position of the restoration. To assess these two elements and because the same material was used for both the restoration and the fissure sealant, a drawing was made of the restoration and fissure sealant at baseline and at all the following evaluations.

The retention percentage of fissure sealant in the present study is low and is similar to those reported for the ART study done in Zimbabwe.3 Glass ionomer materials have a poorer retention than resin composite materials.13 However, the primary reason for placing a sealant is not the length of sealant retention itself but to stop the development and progress of caries.

A previous study14 comparing glass ionomer restorative material as a fissure sealant with resin has shown that even when glass ionomer sealant was retained for a relatively short period of time, its caries preventive effects were greater than those of resin sealant.

Frencken et al.3 reported that when glass ionomer restorative material was used as fissure sealant, unsealed surfaces with early caries had an almost 4 times higher chance of developing caries. In the present study, unsealed pit and fissures were not at a greater risk of developing caries compared to the sealed surfaces. However, it still is advisable to place a glass ionomer sealant along with a glass ionomer restoration by the ‘press-finger technique’ since the extra prevention comes at no added expense.

An analysis of the remaining extent of the fissure sealant in the present study has shown that the most frequent loss was from the non-occlusal areas and areas that usually do not exhibit very deep fissures or grooves. These areas may not provide good mechanical retention for the fissure sealant. Moreover, maxillary teeth have a smaller extension of

69

fissures; they therefore showed more complete loss of sealants. While mandibular teeth usually have a larger network of fissures and grooves, they exhibited more partial retention of sealants.

A general observation amongst the study population revealed a high prevalence of betel nut chewing habit. Betel nut chewing is very common in this part of the world. Betel nut being inexpensive is processed with different flavouring agents and sweeteners that make it very attractive to chew on. It is therefore readily available and its use very common. The chewing of this hard nut may cause increased stresses on the fissure sealant leading to its breakdown. The low complete retention percentage of the fissure may also have resulted because of this habit.

Similar to the ART study of Zimbabwe3 the present study also showed the presence of an operator effect for sealant retention. It is difficult to say that the glass ionomer sealants are technique sensitive. There are good, average and poor performers in all professions. Likewise, the performance of different dentists may vary according to their individual ability. However, the fact that one dentist had a two-year complete and partial sealant retention percentage of 81.5 suggests that this procedure can be performed satisfactorily.

Conclusions

From the results of the present 2-year study, the ART technique was a suitable method for the treatment of one-surface carious lesions in the permanent dentition.There were relatively few failed restorations for the two materials evaluated.

ART preparations restored with GIC showed better survivals then the ART preparations restored with amalgam. Amalgam survivals improved in the MCP group, but the type of preparation did not influence the GIC survivals.

Fuji IX seems to exhibit better physical properties than the first generation GIC’s, however further research is required to improve its physical properties.

The role of glass ionomer restorative material as sealants in combination with the glass ionomer restoration in the prevention and control of dental caries requires studies of longer duration.

The effect of betel nut chewing on the fissure sealant and the restoration requires further research.

References

1. Frencken, J.E.; Phantumvanit, P.; Pilot, T: Manual for the atraumatic restorative treatment technique of dental caries, ed. 2. Groningen, WHO Collaborating Centre for Oral Health Services Research, University of Groningen. February 1994.

70

2. Frencken, J.E.; Songpaisan, Y.; Phantumvanit, P.; Pilot, T: An atraumatic restorative treatment technique: Evaluation after one year. Int Dent J, 44:460-464, October 1994.

3. Frencken, J.E.; Makoni, F.; Sithole, WD.; Hackenitz, E: Three year survival of one surface ART restorations and glass ionomer sealants in a school oral health programme in Zimbabwe. Caries Res, 32:119-126, 1998.

4. Phantumvanit, P.; Songpaisan, Y.; Pilot, T.; Frencken, J.E.: Atraumatic restorative treatment (ART): A three year field trial in Thailand - Survival of one surface restorations in permanent dentition. J Pubic Health Dent, 56:3:141-145, July, 1996.

5. Frencken, J. and Makoni, F.: A treatment technique for tooth decay in deprived communities, World Health Organization. 47th year, 1:16, January-February 1994.

6. Rahimtoola, S.; Amerongen, W.E.: Comparison of two tooth saving preparation techniques in a treatment approach of one surface cavities, Design of a study. J. Dent Child, 64:5:334-339, September-October 1997.

7. Ainamo, J.; Barmes, D.; Beagrie, G.; Cutress, T.; Martin, J.; Sardo-Infirri, J. : Development of the World Health Organization (WHO) Community Periodontal Index of Treatment Needs (CPITN). Int Dent J, 32:281-91, September 1982.

8. Frencken, J.; Pilot, T.; Songpaisan, Y.; Phantumvanit, P.: Atraumatic Restorative Treatment (ART): Rationale, technique and development. J Public Health Dent, 56:3(special issue): 135-140, 1996.

9. Kusner, W.; Markitziu, A.; Hirschfeld, Z.; Fisher, D.; Sciaky, I.: Four-year follow-up of occlusal amalgam restorations in extended vs. non-extended cavity preparation. Isr J Dent Sci, 2:90-93, November 1988.

10. Smales, RJ.; Webster, DA.; Leppard, PI.: Survival predictions of four types of dental restorative materials. J Dent, 19:5:278-282, October 1991.

11. Crabb, HSM.: The survival of dental restorations in a teaching hospital. Br Dent J, 2:150:11:315-318, June 1981.

12. Walls, AWG.; Wallwork, MA.; Holland, IS.; Murray, JJ.: The longevity of occlusal amalgam restorations in first permanent molars of child patients. Br Dent J, 23:158:4:133-136, February 1985.

13. Simonsen, R.J.: Glass ionomer as fissure sealant: A critical review. J Public Health Dent, 56:3(special issue): 146-149, 1996.

14. Arrow, P. and Riordan, P.J.: Retention and caries preventive effects of a GIC and a resin based fissure sealant. Community Dent Oral Epidemiol, 23:5:282-285, October 1995.

71

Chapter 7

EFFECT OF LOCATION, CAVITY SIZE, TREATMENT TIME AND OPERATOR ON TWO YEAR SURVIVAL

72

Introduction

The development of adhesive restorative materials such as glass ionomer cements has revolutionized the concepts of restorative care in the management of dental caries. With the modernization of treatment procedures on the principles of minimal intervention,1

treatment modalities requiring no electrically driven equipments can now be incorporated in an overall primary health care approach towards oral health.

The Atraumatic Restorative Treatment technique or ART is one of such approaches. This approach is based on the removal of decayed tooth substance using only hand instruments. The cleaned cavity is then filled with an adhesive filling material, presently glass ionomer.2

ART has been evaluated under real field conditions and the results have been satisfactory.3

In Pakistan, a study was conducted to compare the ART technique with another more conventional treatment technique (Minimal Cavity Preparation ‘MCP’).4 Results of this study suggest that the ART technique is a suitable short-term method for the treatment of one-surface carious lesions in the permanent dentition. Moreover, ART preparations restored with glass ionomer (GIC) survived better than the ART preparations restored with amalgam. The survival of amalgam improved in the MCP group, but the type of preparation did not affect the survival of GIC restorations (chapter 6). These results may yet be influenced by variables such as, location of restoration, cavity size and the operator. This paper discusses the effects of these variables on the results of the Pakistan study.


This study forms part of a longitudinal study4 evaluating one-surface restorations made in permanent teeth by means of just hand instruments (ART) and rotating instruments (Minimal Cavity Preparation ‘MCP’). A total of 914 restorations were placed in 408 patients; 359 patients received two restorations and 49 received four restorations. In case of two restorations one preparation technique was applied, either the ART procedure or the MCP technique. In the remaining group two restorations were made with the ART technique and two with the other. The selection of the restorative technique to be applied was made ad random. Fuji IX glass ionomer was used to restore 555 preparations while Tytin amalgam was used to restore 359 preparations.

Five operators took part in the study, but two of the five operators did not strictly follow the randomization procedure for the selection of the treatment technique. Therefore, the data of these two operators were excluded from the survival analysis (chapter 6). Of the remaining three operators, only one made restorations using both Fuji IX (GC International Corp.) and Tytin (Sybron/Kerr) (each patient had at least one preparation with GIC and one with amalgam), while the other two made restorations with Fuji IX only. Therefore the restorations made with Fuji IX only were used for the current analysis. The operators were trained and calibrated regarding selection, treatment procedures, and practice before the study. All restorative procedures were described in detail to ensure consensus in treatment by all operators. Moreover, the materials used were handled as recommended by the manufacturers.

73

Each patient was treated by one of the operators and all treatments were done on site (in school). The age of the patients ranged from six to sixteen years (mean age 11.4 years). The baseline epidemiological survey showed a DMFT of 3.15 for the ART group and 2.98 for the MCP group.

In case of preparations made with only hand instruments, access to the cavity was achieved by widening the entrance with a hatchet or a hoe. Soft decayed tooth material was then removed using spoon excavators. Hatchet or a hoe was again used to remove any remaining unsupported enamel. In the MCP technique, preparations were made using an air turbine. Access to the cavity was achieved by widening the entrance with a high speed cylindrical diamond bur of 1mm diameter (speed 250,000 to 270,000 rpm, with water cooling) and remaining soft carious dentin was removed by using a stainless steel round bur (speed 1,000 to 1,500 rpm, without cooling). A spoon excavator was only used to check for the presence of any remnants of caries. In both types of preparations special attention was given to the cleaning of the dentino-enamel junction and care was taken to remove all the unsupported enamel. The width of the entrance to the cavity was then measured using specially designed cavity measuring instruments having a diameter ranging from 1mm to 6mm with a size difference of 0.5mm between instruments.

In very deep preparations a Ca(OH)2 base was applied to the deepest areas of the cavity in both studies. Glass ionomer was applied after conditioning of the cavity. Condensation of amalgam was carried out with hand pluggers4.

The treatment time was measured using a stopwatch. It was divided into:1. Preparation time: necessary to prepare the cavity and remove all decayed tissue. It

includes the period of actual start of cavity preparation, until the cavity was ready for filling.

2. Restoration time: starting from placing the base in the already dried cavity (if necessary), conditioning, and placement and finishing of the filling.

All evaluations were done on site (in school) using a ball ended CPITN periodontal probe5. Separate postoperative evaluations were done at the intervals of 3 months, 6 months, 1year, 11/2 year, 2 years. Pairs of evaluators examined each student together. The assessment was based on consensus.

The quality of the restoration was assessed according to the following criteria: 0= Present, correct.1= Margin defect or surface wear less than 0.5 mm.2= Wear of surface > 0.5 mm.3= Defect at margin > 0.5mm.4= Combination of 2&3.5= Restoration has (almost) completely disappeared.6= Restoration not present because other treatment has been performed for whatever reason.

74

7= Tooth absent 9= Unable to diagnose.

Codes 0-1 were considered successful restorations, codes 2-5 was considered failed restorations and codes 6,7 and 9 were considered as censored.

Dental caries related to the restoration was evaluated using the following criteria:0= Sound, no discoloration.1= Discoloration at surface, but it is hard.2= Discoloration (in-depth) but hardness cannot be assessed.3= Caries connected to the restoration.4=Caries related to the pit and fissures on the same surface of the tooth.5= Combination of 3&4.8= Caries anywhere else on the tooth surface.9= Unable to diagnose.

Caries for the purpose of this study was defined as “a break in the enamel or a cavity in the tooth; the dentine in the cavity had to be softer than the surrounding dentine”. Hence, codes 0-2 were not considered as caries, while codes 3 and 5 were considered as caries to be related to the restoration. In this study, the restorations were considered failed if they had quality codes 2-5 and /or caries codes 3 and 5.

The cavity sizes were categorized in mm3 to account for the width and depth (three-dimensional estimation). (chapter 4) Table 7.1 shows the distribution of cavity size after tooth preparation according to ART, MCP and the three operator groups.

Cavity sizeNo. Mean (mm3) Std.dev.

ART 160 5.5 9.9

MCP 160 6.7 9.3Operator2 124 6.6 12.53 96 6.1 9.25 100 5.5 4.9

Table 7.1: Distribution of mean cavity size.

For data analysis purposes, the cavity size data was grouped in four categories in ascending order according to their size. The last category was an aggregate of all the largest cavity sizes as a very small number of cases were there in each of these large cavity size categories.

All data analysis was done using SPSS 6.1 for Windows. Cumulative survival was estimated using Kaplan-Meier method, and logrank tests were used to compare the survival curves. Student t-tests and Anova was used to check for differences in the means.

75

For simplicity, in the present paper the restorations made with only hand instruments including the actual ART restorations will be designated as ‘H’. Restorations made with rotary instruments will be designated as ‘R’. Similarly ‘G’ will denote glass ionomer restorations.

Results

‘HG’ restorations (2yr survival, table 7.2)

The results indicated no statistically significant difference in the survival of occlusal and non-occlusal restorations. The differences in survival according to cavity size groups were statistically significant (p<0.05), the largest cavity size group showed the poorest survival compared to the rest of restorations. The mean cavity sizes of successful and failed restorations were 5.3mm3 (std. dev. 10) and 8mm3 (std. dev. 8.4) respectively. The difference in the mean cavity sizes was statistically insignificant.

There were significant differences in the survival of ‘HG’ restorations amongst the three operators (p<0.05). The restorations of operator 5 showed the lowest survival rate.

The mean cavity preparation time of successful and failed restorations were 4.13 (std. dev. 1.24) and 4.40 (std. dev. 2.10) minutes respectively. The difference in the preparation time was statistically insignificant. However, significant difference was observed between the mean restoration times of successful (4.22, std. dev. 0.59) and failed (3.40, std. dev. 1.13) ‘HG’ restorations (p<0.05). The session of treatment (morning/afternoon) did not effect the survival of restoration.

Cavity size group Operator Location1 2 3 4 2 3 5 occlusal Non-

occlusalHand Instruments

96.7 94.2 94.1 77.8 98.3 95.8 88 92.8 100

Rotary Instruments

100 96.9 100 78.6 98.3 90.9 98 94.8 100

Table 7.2: The effect of cavity size, operator and location on the survival (%) of HG and RG restorations after 2 years.

‘RG’ restorations (2yr survival, table 7.2)

The location of restoration did not effect its survival. There were however significant differences in the survival of restorations according to the cavity size categories (p<0.01) and the largest cavity size category gave the poorest survival rate. The mean cavity size of successful and failed ‘RG’ restorations was 6mm3 (std. dev. 7.2) and 24.9mm3 (std. dev. 27.7) respectively. The difference was statistically not significant.

76

The inter-operator difference in the survival of ‘RG’ restorations was statistically significant (p< 0.05). The restorations of operator 3 showed the poorest survival rate.

Mean cavity preparation times of the successful and failed restorations were 2.08 (std. dev. 0.49) and 3.2 (std. dev. 1.3) minutes respectively. The difference was statistically insignificant. Similarly, the difference in the mean restoration time of successful (4.07 min, std. dev 0.59) and failed (3.5 min, std. dev. 0.45) restorations was also insignificant.

The session of treatment (morning/afternoon) did not effect the survival of ‘RG’ restorations.

Operator effect

There were differences amongst the operators in the survival of occlusal restorations (p<0.05). However these differences were more distinct in MCP (figure 7.1), (p<0.05) than in ART restorations (figure 7.2), (p<0.07). No differences amongst operators were observed in the survival of non-occlusal restorations.

Figure 7.1: Survival curves for occlusal MCP restorations according to the operators.

77

Figure 7.2: Survival curves for occlusal ART restorations according to the operators.

Moreover, there were differences amongst operators in the survival of first two relatively smaller category cavity size restorations (p<0.05). Operator 5 showed the lowest survival rate in the first category while in the second category operator 2 showed the highest survival rate. Further analysis indicated that this difference amongst the operators was significant for ART restorations (figure 7.3) in the first category (p< 0.01) and for MCP restorations (figure 7.4) in the second category (p<0.05).

Figure 7.3: Survival curves for ART restorations in the smallest cavity size category according to the operators.

78

Figure 7.4: Survival curves for MCP restorations in the second (4.21) cavity size category according to the operators.

Patient effect

The gender and age of the patient did not effect the survival of restorations.

Discussion

In contrast to the results of previous studies on ART6 restorations, we found that the location of restorations did not significantly effect the survival. The glass ionomer material used in this study was specifically designed for ART restorations, which has better physical properties than the first generation GIC’s as used by Phantumvanit et al6. Moreover, both ART and MCP techniques when utilized for small one-surface carious lesions usually result in considerably small cavities. This minimizes the contact between the restored surface and the opposing tooth during functional occlusion consequently reducing the possibility of wear or fracture of the restoration.

This study also indicates that the survival of ‘RG’ restorations was affected by a greater cavity size. Larger restorations may wear or fracture more easily due to increased stresses during functional occlusion. Both ART and MCP techniques result in minimal loss of healthy tooth tissue. In large cavities this may result in shapes that are less retentive, while the contact with the opposing tooth during occlusion and articulation is increased.

Similar to the ART study in Zimbabwe3 and in contrast to the ART study in Thailand,6 an operator effect was noted for the ‘HG’ restorations in the present study. All the operators underwent a thorough training course on the ART approach prior to this study. Nonetheless the operator effect could not be eliminated. Moreover, the time taken to place

79

the glass ionomer restoration appears to effect the survival of restorations especially ‘HG’ restorations. Glass ionomer restorations are technique sensitive. Its quality improves with the insertion of properly mixed (not too wet and not too dry) material. Where mixing can only be done by hand, even after a lot of prior practice there may still be differences amongst operators. The cavity and adhesion can also affect the quality of GIC restorations. The dehydration of the cavity affects adhesion7. This can occur where turbines and air syringe are used but is unlikely to happen in the ‘HG’ group where only cotton pellets are used.

Similarly, GIC’s require some time period after insertion to complete initial setting before the restoration can be disturbed. If this time period is too short, then the retention and the final quality of the restoration can be adversely affected.

The differences in the restoration times between successful and failed restorations for both the ‘HG’ and ‘RG’ groups should be similar as GIC was used to restore them. However, this was not true in the present study. Only a significant difference was observed between the successful and failed restorations of the ‘HG’ group. This seems to indicate a critical time requirement for GIC restorations, which makes the difference between success and failure significant. The fact that the restoration time of failed ‘HG’ restorations was the least of all GIC restorations (‘HG’+’RG’) seems to indicate that this critical time is important for the success of GIC restorations. The manufacturers of GIC’s do not give any minimum time requirement for the placement of successful GIC restorations, nor do they specify any waiting time period after the placement of the restoration before the restoration can be finished and the patient can finally close his mouth. However, this time period seems to affect the success of restorations and therefore requires further research.

It can be concluded that the location of restorations does not effect the survival of ART restorations in the treatment of one-surface carious lesions. Cavity size does effect the survival of restorations: the larger the preparation, the larger the chance for failure of the restoration. The operator factor affects both ART and MCP restorations. Fuji IX seems to exhibit better physical properties then the first generation GIC’s, however further research is required to improve its physical properties. The ART technique is a feasible approach towards the treatment of dental caries especially of one-surface lesions.

References 1. Elderton, R. (ed): The Dentition and Dental Care. Oxford, Heinemann, 1990.

2. Frencken, J.; Phantumvanit, P.; Pilot, T.: Manual for the Atraumatic Restorative Treatment. (ART) technique for dental caries, February 1994.

3. Frencken, J.; Makoni, F.; Sithole, W.D.; Hackenitz, E.: Three year survival of one-surface ART restorations and glass ionomer sealants in a school oral health programme in Zimbabwe. Caries Res, 32:119-126, 1998.

80

4. Rahimtoola, S.; van Amerongen, E.: Comparison of two tooth saving preparation techniques in a treatment approach of one-surface cavities, Design of a study. J Dent Child, 64:5:334-339, September-October 1997.

5. Ainamo, J.; Barmes, D.; Beagrie, G.; Cutress, T.; Martin, J.; Sardo-Infirri, J.: Development of the World Health Organization (WHO) community periodontal index of treatment needs (CPITN). Int Dent J, 32:281-91, September 1982.

6. Phantumvanit, P.; Songpaisan, Y.; Pilot, T.; Frencken, J.: Atraumatic Restorative Treatment (ART): A three year field trial in Thailand - Survival of one-surface restorations in permanent dentition. J Public Health Dent, 56:3(special issue):141-145, July 1996.

7. Mount, G.J.: An atlas of glass ionomer cements. London, Dunitz, 1990.

81

Chapter 8

EFFECT OF FATIGUE DUE TO CAVITY PREPARATION.

82

Introduction

The development of adhesive restorative materials such as glass ionomer has realized concepts of minimal intervention and invasion in the treatment of dental caries. The Atraumatic Restorative Treatment (ART) technique is one of such concepts. This technique is based on removal of decayed tooth material with just hand instruments and filling the subsequently prepared cavity with glass ionomer restorative material1. Developed in mid 1980’s, ART was primarily meant for treating people living in underprivileged areas of the world where resources such as electricity and trained manpower are limited.2 ART has been evaluated by several scientific studies and results have supported the application of this technique.3 It has been well received by both children and adults who belong to population groups hardly ever exposed to regular oral health care.4 The three-year survival rate for the GIC restorations placed with the ART technique was equal5 to the three-year survival of one-surface amalgam restorations made by utilizing a conventional preparation and restorative technique.6 In Pakistan, a study was conducted to compare the ART technique with another more conventional treatment technique.7 Results of this study suggested that ART with GIC (Fuji IX) was comparable with the more conventional restorative technique (chapter 6). Moreover the ART technique was less painful to the patient8 and less traumatic to the tooth structure (chapter 4) than the more conventional restorative technique. However the ART restorations are influenced by the operator5 (chapter 7). This operator effect may result from wrist fatigue caused by prolonged tooth preparation exclusively with hand instruments. The present chapter discusses the effect of fatigue due to cavity preparation in the study conducted in Pakistan.


This study forms part of a longitudinal study7 evaluating one-surface restorations made in permanent teeth by means of just hand instruments (ART) and rotating instruments used with minimal cavity preparation (MCP). A total of 914 restorations were placed in 408 patients: 359 received two and 49 four restorations. In case of two restorations one preparation technique was applied: either with just hand instruments or with rotating instruments. In case of four restorations, two restorations were made with one technique and two with the other. The preparation technique to be applied was selected at random.

Five operators took part in this study and all were trained and calibrated regarding selection, treatment procedures, and practice before starting the study. However, two (operators 1&4) of the five operators did not strictly follow the randomization procedure for the selection of treatment technique. Therefore the data of these two operators were excluded from the current analysis. Of the remaining three operators, only one (operator 2) made restorations using both Fuji IX and Tytin while the other 2 (operators 3 & 5) made restorations with Fuji IX only. Hence the data of only GIC restorations was used for the present analysis. Each patient was treated by any of the operators and all treatments were done on site (in school). The age of the patients ranged from six to sixteen years (mean age 11.4 years). The baseline epidemiological survey showed a DMFT of 3.15 for the ART group and 2.98 for the MCP group.

83

All restorative procedures were described in detail to ensure consensus in treatment by all operators. Moreover, the materials used were handled as recommended by the manufacturers.

In case of preparations made with only hand instruments, access to the cavity was achieved by widening the entrance with a hatchet or a hoe. Soft decayed tooth material was then removed using spoon excavators. Hatchet or a hoe was again used to remove any remaining unsupported enamel.

In the minimal cavity preparation technique (MCP), preparations were made using an air turbine. Access to the cavity was achieved by widening the entrance with a high speed cylindrical diamond bur of 1mm diameter (speed 250000 to 270000 rpm, with water cooling) and remaining soft carious dentine was removed by using a stainless steel round bur (speed 1000 to 1500 rpm, without cooling). A spoon excavator was only used to check for the presence of any remnants of caries. In both types of preparations special attention was given to the cleaning of the dentino enamel junction and care was taken to remove all the unsupported enamel. The width of the entrance to the cavity was then measured using specially designed cavity measuring instruments having a diameter ranging from 1mm to 6mm with a size difference of 0.5mm between instruments.

If necessary a calcium hydroxide base was applied to the deepest areas of the cavity in both studies. Glass ionomer was applied after conditioning of the cavity. Condensation of amalgam was carried out with hand pluggers.7

Two sessions of treatment were conducted each day during the restorative phase, the first session was in the morning till the lunch break (am) and the second session was after lunch (pm). The restorations were numbered according to the sequence of placement in each session. For data analysis the restorations placed in the morning and the afternoon sessions were further subdivided into 4 groups according to their sequence of placement as follows:Group1: Restorations numbered 1 to 5 in each session.Group2: Restorations numbered 6 to 10 in each session.Group3: Restorations numbered 11 and higher in each session.

The treatment time was measured using a stopwatch. It was divided into:1. Preparation time: the time necessary to prepare the cavity and remove all decayed

tissue. It includes the period of actual start of cavity preparation, until the cavity was ready for filling.

2. Restoration time: starting from placing the base in the already dried cavity (if necessary), conditioning, placement of filling and finishing of the filling.

All evaluations were done on site (in school) using a ball ended CPITN periodontal probe9. Separate postoperative evaluations were done at the intervals of 3 month, 1yr, 11/2 yr. and 2 years. Pairs of evaluators examining each student together conducted evaluations. The final assessment was based on consensus.

The cavity sizes were categorized in mm3 to account for the width and depth (three-dimensional estimation, chapter 4). For data analysis purposes, the cavity size data was

84

grouped in four main categories according to their size; the last group included all the largest categories as a very small number of cases were there in each of these large categories. All data analysis was done using SPSS 6.1 for windows. T-test and Anova were used to check for differences in means.

Results

The mean preparation time of the restorations placed in the morning and afternoon sessions are shown in table 8.1. ART preparations made in the afternoon session required significantly more time than the morning preparations (p<0.05). While for the MCP restorations, the preparation time differences between morning and afternoon preparations were insignificant (p>0.05).

Mean preparation timeNo. am No. pm t-test p value

ART 108 4.01 52 4.45 p< 0.05MCP 80 2.10 80 2.11 p> 0.05

Table 8.1: The mean preparation time of ART and MCP restorations placed in the morning and afternoon sessions.

Overall, the ART restorations required significantly more time for cavity preparation than the MCP restorations (p< 0.01).

Since preparation time differences may exist amongst the morning as well as the afternoon restorations, and as the preparation times may also be affected by the size of the cavity, the data was further analyzed accordingly.

ART restorations

Time differences between morning and afternoon preparations for all the four cavity size groups were statistically insignificant. Table 8.2 shows the preparation times of the three groups of ART restorations made in the morning and afternoon sessions according to their sequence of placement. Significant preparation time differences existed between the morning sessions (p<0.05), while preparation time differences in the afternoon sessions were insignificant.

85

ARTMorning No. Mean preparation time

(minutes)Anova (p value)

Group1 44 4.20Group2 39 4.06 p< 0.05Group3 25 3.19AfternoonGroup1 15 4.32Group2 15 4.28 p> 0.05Group3 22 5.05

Table 8.2: The mean preparation time of the six groups of ART restorations according to the sequence of placement in the morning and afternoon sessions.

Amongst the preparations made in the morning session, the first group required more time then the last group (p<0.01). Amongst the preparations made in the afternoon session, the first group required less time than the last group (p<0.05). Overall the morning first group required significantly less time for cavity preparation than the last afternoon group (p<0.01).

MCP restorations

Preparation time differences were insignificant between the restorations placed in the morning and afternoon sessions for all the four cavity size groups.

Preparation times of restorations placed in the morning and afternoon sessions according to the sequence of their placement is shown in table 8.3. Differences between morning restorations were not significant. Likewise, preparation time differences between afternoon restorations were also not significant.

MCPMorning No. Mean preparation

time (minutes)Anova (p value)

Group1 38 2.04Group2 27 2.11Group3 15 2.24 p> 0.05AfternoonGroup1 14 2.21Group2 23 2.07 p> 0.05Group3 43 2.09

Table 8.3: The mean preparation time of the six groups of MCP restorations according to the sequence of placement in the morning and afternoon sessions.

86

Amongst the restorations placed in the morning session, the first group required significantly less time than the last group (p<0.05). While differences between the afternoon restorations first and the last group were insignificant. Similarly, preparation time differences between morning first and afternoon last group were also insignificant.

Operator

The preparation times of the morning and afternoon restorations were further analyzed separately for each operator (table 8.4). Operator 5 did not make any ART preparations in the afternoon session. However, his last morning group of ART restorations required significantly less preparation time than the morning first group (p < 0.05). Preparation times of morning and afternoon MCP restorations of operator 5 were similar. Likewise, the preparation time differences between morning and afternoon restorations (both ART and MCP) of operator 2 were insignificant.

Mean preparation timeNo. am No. pm t-test p value

Operator 2ART 27 4.53 35 4.41 > 0.05MCP 28 2.27 34 2.08 > 0.05Operator 3ART 31 3.56 17 4.52 < 0.05MCP 30 2.08 18 2.06 > 0.05Operator 5ART 50 3.36 - - -MCP 22 1.51 28 2.17 > 0.05

Table 8.4: Operator wise distribution of mean preparation times of ART and MCP restorations placed in the morning and afternoon sessions.

The afternoon ART restorations of operator 3 had a significantly larger mean preparation time than the morning ART restorations (p< 0.05). However, preparation time differences between his morning first and morning last group, afternoon first and afternoon last group of ART restorations were insignificant. Similarly, preparation time differences between the morning first and afternoon last group of ART restorations made by operator 3 were also not significant. The difference in the preparation times of the morning and afternoon MCP restorations of operator 3 was statistically insignificant.


Cumulative survival of restorations was estimated using the Kaplan Meier technique and logrank tests were used to compare the survival curves of morning and afternoon restorations.

87

The differences in the survival of morning and afternoon ART (figure 8.1) restorations were statistically insignificant. Similarly, the differences in the survival of morning and afternoon MCP (figure 8.2) restorations were also statistically insignificant. Similarly, differences in the survival of morning and afternoon restorations (both ART and MCP) for each of the three individual operators were also insignificant.

Figure 8.1: Survival of ART restorations placed in the morning and afternoon sessions.

Figure 8.2: Survival of MCP restorations placed in the morning and afternoon sessions.

88

Discussion

Muscle fatigue is a very complex concept especially since it can be accompanied by load on respiration, circulation and neuro-muscular function. Fatigue in static work produces a sensation of discomfort and sometimes-even pain.10 It is a common experience that heavy muscular work results in variable, often long lasting increase in tremor displayed by the muscle groups involved. Surgeons performing minute and delicate surgery often find that their skills are impaired as a consequence of the tremor generated by gardening or playing squash on the preceding day. Moreover, long lasting increases in finger tremor can be produced by intense brief effort to contract muscles.11 Similarly, cavity preparation solely with hand instruments over a protracted time period may also cause muscle tremor and even lead to symptoms of muscular fatigue in the muscle group involved.

In the present study, ART technique required significantly more preparation time than the MCP technique. Moreover, the afternoon ART restorations required significantly more preparation time than the morning ART restorations. In both static and dynamic muscular work, maximal force can be maintained for a few seconds only thereafter the muscles stiffen and eventually refuse to obey the subjects will. However, muscle fatigue is a reversible phenomenon provided proper periods of rest or mild exercise are inserted. In a practical environment this will lead to an increase in the time required for cavity preparation. The present study also showed significant preparation time differences between morning first and morning last, afternoon first and afternoon last and morning first and afternoon last groups of ART restorations. The preparation time gradually decreased in the morning session to reach its lowest in the morning last group, thereafter it increased in the afternoon session to reach its highest in the afternoon last group. A plausible explanation for this phenomenon is difficult. It may be that, despite muscle fatigue is gradually increasing in the morning session, effort is made by operators to finish their work briskly before breaking off for lunch. Possibly this exertion cannot be done during the afternoon.

Since fatigue is reversible, if the untrained muscles are engaged in vigorous exercise, they initially become painful and hard. However, once the symptoms fade away in 4 to 6 days, repair of damaged tissue results in a stronger muscle that is less susceptible to further injuries even if further exercise is much more severe.

The results also suggest the presence of an operator effect. One operator required more time to prepare ART restorations in the afternoon then in the morning session. Furness et al.12 found that long lasting increases in finger tremor was of central nervous origin. Moreover, the disposition to subdue the feeling of fatigue is very different among individuals. Co-operative and well-motivated operators can maintain a muscular contraction to the point of fatigue whereas others terminate the activation before reaching that point.10

Muscle fatigue did not seem to affect the survival of ART restorations of the present study. No significant differences were found in the survival of ART restorations placed in the morning and afternoon sessions.

89

Conclusion

If preparation time is used to measure fatigue due to cavity preparation then it does seem to affect consecutive cavity preparations by the ART technique. Moreover, it also shows dissimilar effects in different operators. Muscular fatigue is a very subjective and complex subject. Therefore the effects of muscle fatigue due to cavity preparation should be further investigated.

References


2. World Health Organization: Revolutionary new procedure for treating dental caries- Press

release WHO/28, 7thApril 1994.

3. Frencken, J.E.; Songpaisan, Y.; Phantumvanit, P.; Pilot, T.: An Atraumatic Restorative Treatment technique: Evaluation after one year. Int Dent J, 44:460-464, October 1994.

4. Frencken, J. and Makoni, F.: A treatment technique for tooth decay in deprived communities, World Health Organization. 47th year 1:16, January-February 1994.

5. Frencken, J.; Makoni, F.; Sithole, W.D.; Hackenitz, E.: Three year survival of one surface ART restorations and glass ionomer sealants in a school oral health programme in Zimbabwe. Caries Res, 32:119-126, 1998.

6. Phantumvanit, P.; Songpaisan, Y.; Pilot, T.; Frencken, J.: Atraumatic Restorative Treatment (ART): A three year field trial in Thailand. Survival of one-surface restorations in permanent dentition. J Public Health Dent, 56:3:141-145, July 1996.

7. Rahimtoola, S. and van Amerongen, E.: Comparison of two tooth saving preparation techniques in a treatment approach of one-surface cavities. Design of a study. J Dent Child, 64:5:334-339, September-October 1997.

8. Rahimtoola, S.; van Amerongen, E.; Maher, R.; Groen, H.: Pain related to different ways of minimal intervention in the treatment of small caries lesions. J Dent Child, 67:2:123-127, March-April 2000.

9. Ainamo, J.; Barmes, D.; Beagrie, G.; Cutress, T.; Martin, J.; Sardo-Infirri, J.: Development of the World Health Organization (WHO) Community Periodontal Index of Treatment Needs (CPITN). Int Dent J, 32:281-91, September 1982.

10. Astrand, P. and Kaare, R.: Textbook of work physiology: Physiological basis of exercise. USA: McGraw-Hill Inc Book Company, 1977, p115.

90

11. Furness, P. and Jessop, J.: Prolonged changes in physiological tremor, following a brief maximal voluntary contraction of human muscle. J Physiol, 258:2:72-73, June 1976.

12. Furness, P.; Jessop, J.; Lippold, O.C.J.: Long lasting increases in muscle tremor of human hand muscles following brief, strong effort. J Physiol, 265:3:821-831, March 1977.

91

Chapter 9

GENERAL DISCUSSION, CONCLUSIONS AND RECOMMENDATIONS

92

The ART approach for the management of dental caries has become possible through better understanding of the caries process that permits minimal invasion and the development of reliable and effective adhesive restorative materials.1-2

Developed primarily for the underserved populations, it employs simple equipment and a minimum of facilities3. Defining the long-term efficacy for the ART approach is not easy, because the technique is simple, costs less than traditional treatment approaches that require expensive equipment, and benefits4-5 the population that would otherwise remain untreated. Moreover, comparing ART restorations with traditional amalgam and composite restorations is also difficult, especially since it has been under investigation for a relatively short period of time6 as compared to traditional amalgam restorations that have been studied for decades and are still under investigation.7

For traditional restorations, long-term performance is the expression of excellence8. Still, to compare ART restorations placed in a field setting with traditional amalgam and composite restorations made in expensive and hi-tech dental clinic setups would be inappropriate. Comparing dental treatment types gains value if glass ionomer and amalgam restorations are made with similar techniques under identical situations. It is beyond doubt that the quality of any restoration at the start of its lifetime should meet certain minimally accepted standards. For the glass ionomer restoration wear and marginal integrity, and for amalgam restorations marginal integrity is generally regarded as prognostic factors for long-term performance.9

Various techniques have been advocated to evaluate restorations, all of which have their own limitations. For evaluating a large number of restorations in a field setting the evaluation methodology has to be relatively simple and comparable. In other ART studies the CPITN probe10 has been used to evaluate restorations. This method is rather rough and has only an indicative value for the quality of a restoration. However, it has the advantage of rendering the results comparable to other ART studies11-16. Holmgren et al.12 applied both the ART criteria and USPHS criteria to the same ART restorations in permanent teeth and reported no significant differences in the survival outcomes between the two sets of criteria. Lo et al.14 suggested that the ART criteria are more stringent than the USPHS criteria. Thus, although the USPHS criteria have not been used in the present study, it is reasonable to assume that the results are to a large extent comparable to those from non-ART studies.Furthermore, a split mouth plot design was used to detect any differences between glass ionomer and amalgam restorations without confounding patient characteristics.17, 18 Tytin (Kerr) as the amalgam of choice was used because of good clinical results in previous studies19. The amalgam restorations serve as a reference and provide an indication of the quality of glass ionomer restorations, the operator’s level of working and as an indirect comparison between the two restorative techniques. For making a direct comparison between the two treatment approaches, application of both the treatments in one dentition is to be preferred. This is possible in only a few patients as small numbers of patients can meet this selection criterion leading to a great decline in the total number of restorations to

93

be placed. Also, the comparison of operative pain due to cavity preparation between the two approaches would be difficult in such a situation as the patient type can affect the final outcome.

The results of this study provide a view on the efficacy of ART compared with the MCP technique. Apart from the quality and longitivity of restorations, other important issues examined included the atraumatic aspect of the treatment approaches in question and the operator influences. Both of these issues have effect on the acceptance and quality of both treatment approaches.

In the preceding chapters a profile of major factors influencing these issues and the results of treatments with glass ionomer and amalgam with both ART and MCP techniques have been presented.

Ideally, a combination of factors should be considered to determine whether the interactions between independent variables influence the outcome. Compared to non-invasive approaches in the management of dental caries such as diet counseling, oral hygiene promotion, fluoride application etc., the ART approach is invasive, as it is impossible to remove soft carious tooth tissue before restoration without some form of drilling or scraping. Therefore some patients will always consider that they experienced some discomfort that can be regarded as a form of trauma to the patient.20 Yet, ART must be contemplated in the context of other restorative procedures for caries. On the basis of the results of the present study, more discomfort was associated with cavity preparation when this was done with rotary instruments rather than with only hand instruments. Similar effects were observed when cavities were filled with amalgam instead of glass ionomer. Moreover, the use of hand instruments alone resulted in smaller cavity preparations than those produced using rotary instruments. Hence, ART may be considered as relatively atraumatic to the tooth and the patient when compared with other restorative procedures employing rotary instruments for cavity preparation. Nevertheless, operator variability and patients’ anxiety may govern the immensity of trauma or atrauma associated with a treatment procedure.

Besides being atraumatic, the acceptance of treatment approach amongst oral health practitioners may be influenced by the time requirement for placing restorations and fatigue related to the performance of the procedure. From the results of the present study, ART required more cavity preparation time compared with cavity preparation by rotary instruments; glass ionomer restorations required more placement time than amalgam restorations and ART preparations were associated with some muscle fatigue. Wrist muscle fatigue in this study was symbolized by variability of preparation time for consecutive cavity preparations. This indirect method of measuring muscle fatigue is of indicatory value only. Practicability restricts the use of more complicated measures for gauging wrist muscle fatigue in a large clinical field trial such as this one.

Despite of relatively short duration, the longitivity of ART restorations in the present study was similar to the more recent studies on this approach.11-13, 16 Besides being better than the survival of amalgam restorations of this study, the survival of glass ionomer

94

restorations was alike for both the treatment techniques, possibly because of improved physical properties of Fuji IX (GC Corporation Singapore) compared to the previously available glass ionomers.15

A recent 6-year study21 comparing occlusal ART restorations with occlusal conventional amalgam restorations showed no differences in survival. However in that same study secondary caries was observed with 2% with glass ionomer and 10% with amalgam restorations. The main reason for the replacement of amalgam restorations in general practice is secondary caries. 22-24 This failure characteristic was very low in other ART studies13 and was almost non-existent in the present study. Still, the survival of glass ionomer restorations can be influenced by short restoration time as elucidated by the ART glass ionomer restorations. The manufacturers of Fuji IX do not give any required waiting time before the restoration can be adjusted after its placement in the cavity.

Operative pain or discomfort, preparation time and fatigue do not influence the short-term survival of restorations. While larger cavity sizes may affect the survival of glass ionomer restorations.

The results were greatly influenced by operator variations. Prior to this study, the operators underwent rigorous training and calibration in performing ART and MCP restorations and the treatment protocols. Nevertheless, the operator effect could not be eliminated. When many operators participate in a study, differences in performance are often reported.25 This was also true for the ART studies done in Zimbabwe11, 16 and Syria.13

However, in a recent study in China12 no operator effect was noted. It has been elucidated before26

but it is necessary to follow a training course on ART before practicing the approach.

The efficacy of both treatment approaches and of glass ionomer restorations in controlling dental caries could not be demonstrated by the results. Even though the ART and MCP study groups had a DMFT higher than the general population, still secondary caries was almost non-existent in the study populations. Since existing caries lesions are evidences of past risks and the patients cannot arbitrarily assumed to be at a higher risk for future caries lesions, the efficacy of the ART approach or glass ionomer alone for caries prevention cannot be proved yet.

Conclusions

1. The study showed that the operator affects the results of restorative treatment to a large extent.

2. The ART approach is relatively atraumatic when compared with restorative treatment by rotary instruments.

3. Operative pain or discomfort appears also to be patient related.

95

4. Given the preparation techniques used, ART requires more time than preparation by rotary instruments.

5. Given the restorative materials used, glass ionomer restorations require more placement time than amalgam restorations.

6. If variability in preparation time is used as an indicator for fatigue then fatigue is associated with consecutive cavity preparations by the ART technique.

7. The survival of ART glass ionomer restorations is comparable with the survival of MCP glass ionomer restorations.

8. Glass ionomer restorations showed better survival than amalgam restorations when used in small one-surface cavities.

9. Shorter restoration time may influence the survival of glass ionomer restorations in a negative way.

10. The results of the present study form a basis for long term clinical research.

Further research

Despite results of the present study many questions still remain unanswered; some of which are as follows: is carious tooth tissue removed to the same extent with hand instruments as with

rotary instruments, is there a relationship between the pressure the operator uses during cavity

preparation and the parameters of discomfort and cavity size, is there a relationship between behavioral management capabilities of the operator

and reported discomfort, is there a relationship between cultural background of patients and reported

discomfort, would the levels of discomfort reported be dramatically different if an independent

investigator made inquiries, will the levels of fatigue observed change if other methods of gauging muscle fatigue

are used as a measure, are glass ionomer restorations alone and the ART approach effective in controlling

dental caries in high-risk individuals, would the results of quality and survival be different if an independent evaluator

performs the evaluations, is the long-term survival of ART glass ionomer restorations as comparable with glass

ionomer restorations made with rotary instruments and with conventional amalgam restorations as it is in this short-term clinical trial.

Further clinical research is required to answer the questions arising from the present study.

96

Recommendations

Based on the experience obtained with the present study, the following recommendations can be made: Applying experimental and control restorations to the same mouth is a good method

of comparing different restorative materials especially when previous reference values are not available. Moreover, a split mouth design reduces the population size.

A thorough ART training is necessary before using this method on a regular basis. Manufacturers should pay more attention to the handling characteristics of hand

mixed versions of glass ionomers in order to contribute to a decrease of operator effect.

It is not advisable to use the results of this and similar studies for the treatments according to the ART technique other than for class 1 lesions.

The quality assessment criteria used in the present study should be preferred over the more complicated USPHS criteria. It enhances the possibility of worldwide comparison of clinical studies on the behavior of restorative materials.

If the study aims to determine the long-term performance of treatment approaches or restorations, it is advisable to consider and compare the costs of treatment.

References

1. Elderton, R. (ed): The Dentition and Dental Care. Oxford, Heinemann, 1990.

2. Frencken, J.E.; Pilot, T.; Songpaisan, Y.; Phantumvanit, P.: Atraumatic Restorative Treatment (ART): rationale, technique, and development. J Public Health Dent, 56(3): 135-140, July 1996.

3. Pilot, T.: Introduction- ART from a global perspective. Community Dent Oral Epidemiol, 27:421-2, December 1999.

4. Mickenautsch, S.; Munshi, I.; Grossman, E.S.: Comparative cost of ART and conventional treatment within a dental school clinic. S Afr Dent J, 57:52-58, February 2002.

5. Mjör, I.A.; Burke, F.J.T.; Wilson, N.H.F.: The relative cost of different restorations in the UK. Br Dent J, 182:286-289, 1997.

6. Smales, R.J.; Yip, H.K.: The atraumatic restorative treatment (ART) approach for the management of dental caries. Quintessence Int, 33:427-432, June 2002.

7. Monse-Schneider, B.; Heinrich-Weltzien, R.; Schug, D.; Sheiham, A.; Borutta, A.: Assessment of manual restorative treatment (MRT) with amalgam in high-caries Filipino children: results after 2 years. Community Dent Oral Epidemiol, 31(2):129-35, April 2003.

97

8. Mjör, I.A.; Dahl, J.E.; Moorhead, J.E.: Age of restorations at replacement in permanent teeth in general dental practice. Acta Odontol Scand, 58:97-101, 2000.

9. Hickel, R.; Manhart, J.: Longevity of restorations in posterior teeth and reasons for failure. J Adhes Dent, 3(1): 45-64, spring 2001.

10. Ainamo, J.; Barmes, D.; Beagrie, G.; Cutress, T.; Martin, J.; Sardo-Infirri, J.: Development of the World Health Organization (WHO) community periodontal index of treatment needs (CPITN). Int Dent J, 32:281-91, September 1982.

11. Frencken, J.; Makoni, F.; Sithole, W.D.: ART restorations and glass ionomer sealants in Zimbabwe: survival after 3 years. Community Dent Oral Epidemiol, 26:372-81, 1998.

12. Holmgren, C.J.; Lo, E.C.M.; Hu, D.Y.; Wan, H.C.: ART restorations and sealants placed in Chinese school children- results after 3 years. Community Dent Oral Epidemiol, 28:314-20, 2000.

13. Taifour, D.; Frencken, J.E.; Beiruti, N.; van't Hof, M.A.; Truin, G.J.; van Palenstein Helderman, W.H.: Comparison between restorations in the permanent dentition produced by hand and rotary instrumentation- survival after 3 years. Community Dent Oral Epidemiol, 31(2): 122-8, April 2003.

14. Lo, E.C.; Luo, Y.; Fan, M.W.; Wei, S.H.: Clinical investigation of two glass ionomer restoratives used with the atraumatic restorative treatment approach in China: two-years results. Caries Res, 35:458-63, Nov-Dec 2001.

15. Phantumvanit, P.; Songpaisan, Y.; Pilot, T.; Frencken, J.E.: Atraumatic Restorative Treatment (ART). Survival of one-surface restorations in permanent dentition. J Public Health Dent, 56(3): 141-5, July 1996.

16. Frencken, J.; Makoni, F.; Sithole, W.D.; Hackenitz, E.: Three year survival of one-surface ART restorations and glass ionomer sealants in a school oral health programme in Zimbabwe. Caries Res, 32:119-126, 1998.

17. Hujoel, P.P.; Derouen, T.A.: Validity issues in split-mouth trials. J Clinical Periodontology, 19:625-7, 1991.

18. Tobi, H.; Kreulen, C.M.; Gruythuysen, R.J.M.; van Amerongen, W.E.: The analysis of restoration survival data in split mouth designs. J Dent. 26:293-8, 1998.

19. Akerboom, H.B.M.; Advokaat, J.G.A.; Borgmeijer, P.J.: Amalgam restauraties nader bekeken. Amsterdam :Vrije Universiteit thesis. 1985.

20. van Amerongen, W.E.; Rahimtoola, S.: Is ART really atraumatic? Community Dent Oral Epidemol, 27:431-5, December 1999.

98

21. Mandari, G.J.; Frencken, J.E.; van’t Hof, M.A.: Six-year success rates of occlusal amalgam and glass ionomer restorations placed using three minimal intervention approaches. Caries Res, 37(4): 246-53, Jul-Aug 2003.

22. Qvist, J.; Qvist, V.; Mjör, I.A.: Placement and longevity of amalgam restorations in Denmark. Acta Odontol Scand, 48:297-303, 1990.

23. Mjör, I.A; Qvist, V.: Marginal failures of amalgam and composite restorations. J Dent, 25:25-30, 1997.

24. Mjör, I.A; Moorhead, J.E.; Dahl, J.E.: Reasons for replacement of restorations in general dental practice. Int Dent J, 50:361-66, 2000.

25. Jokstad, A.; Bayne, S.; Blunck, U.; Tyas, M.; Wilson, N.: Quality of dental restorations. FDI commission project 2-95. Int Dent J, 51:117-58, 2001.

26. Frencken, J.E.; Holmgren, C.J.: Atraumatic Restorative Teatment for dental caries. STI, Nijmegen 1999.

99

Chapter 10 SUMMARY

100

Dental caries is left virtually untreated in many economically underprivileged countries, and also in many disadvantaged communities in highly industrialized countries. Lacking are the treatment techniques that can be accomplished without access to electricity and dental equipment. Thus, caries is increasingly becoming a serious public health problem in many populations.

For Pakistan the prevalence of dental caries may be as low as 1.2 DMFT for 12 yr olds. However, an analysis of this DMFT figure shows a very high score for D = 1.05, suggesting a lack of treatment due either to public unawareness or nonavailability of dental services.

Scientific research and the development of adhesive restorative materials have opened newer avenues for the management and conservative treatment of dental caries. The Atraumatic Restorative Treatment (ART) is one of such approaches. The ART technique has been evaluated under realistic field conditions and the results suggest that it is very promising for the treatment of one-surface carious lesions especially in the permanent dentition. Previous studies on ART have evaluated the longevity of restorations and fissure sealants, while many questions related to the atraumatic aspect, operator variances and the efficacy of this approach still remain unanswered. For this purpose the present study was designed to evaluate under field conditions various aspects of ART. The aims of this study were:

To test clinically the quality of glass ionomer restorative material compared with amalgam in one surface cavities prepared with the ART technique.

To compare the efficacy of ART technique with a similar approach using rotary equipment minimal cavity preparation (MCP).

To compare the treatment time needed in both ART and MCP technique.

To investigate the influence of possible wrist fatigue on the size of the preparation.

To investigate the operative and postoperative sensitivity in both techniques.

To investigate the operator effect:A: preparation size differences in both techniques.B: preparation and restoration time required in both techniques.C: quality of the restorations.D: operative and postoperative sensitivity.

To achieve this, two clinical studies were designed (chapter 2).

Study 1: Treatment of one-surface carious lesions with the ART technique using glass ionomer and amalgam as restorative material.

101

Study 2: Treatment of one-surface carious lesions with a minimal cavity preparation technique using glass ionomer and amalgam as restorative material.

In these studies, glass ionomer restorations serve as test group and amalgam restorations as control. It was preferred to use both test and control in one dentition using a split mouth design to obtain similar conditions. Tytin (Kerr) was used as the amalgam of choice while Fuji IX (GC) was used for all glass ionomer restorations. Only small one-surface cavities in permanent molars and premolars were selected. Five operators took part in this study and all were trained and calibrated before the start of the study. Each patient was treated by one of the five operators. All restorative procedures were described in detail to ensure consensus by all operators. Cavity size was measured using specially designed cavity measuring instruments. Treatment time was measured with a stopwatch and was separated into preparation and restoration time. Separate evaluations were planned at baseline, 6months, 1yr, 11/

2 yr and 2 yr intervals.

Pain registered with one-surface cavity preparation and restoration is presented in chapter 3. Pain during invasive treatment of dental caries is a common phenomenon observed if no local analgesia has been used before cavity preparation. Atraumatic restorative technique is a suggested procedure, which is at least less traumatic for the patient to be treated. Although the ART approach has been received well by both children and adults who belong to population groups hardly ever exposed to regular oral health care, it has not yet been proven that this particular procedure really causes less pain during treatment compared to more conventional techniques with rotating instruments. In the present study, pain was reported in connection with tooth restoration in 19.3% of the cases when the ART technique was used which is significantly less than with a conventional restorative technique (35.7%). Moreover, a significant operator related variation was found in the portion of treatments reported to be painful (from 5.9 to 44%). Finally the results show a clear relationship in the pain reports between the first and the following treatments in both ART and the conventional technique groups.

In chapter 4, the traumatic effect of two different ways of cavity preparation has been investigated by measuring the size of the preparation. Moreover, the relationship between cavity size and treatment times, the operator and the patient factor has also been evaluated. The results show that there was a significant difference (p<0.01) in the mean cavity size of teeth restored by ART when compared with those restored in a more conventional way. An operator effect was also noted and at least one operator made larger cavities with the ART technique (p<0.01). There was also a clear relation between cavity size and pain during cavity preparation: the larger the size of the cavity, the greater the chance of pain during cavity preparation (p<0.01). The relationship between cavity size and treatment time showed that for ART restorations, the largest cavity size group required the most time to prepare (p<0.05). Also, the restoration time of amalgam was the most in the largest cavity size group (p<0.01).

Chapter 5 discusses the findings of the study on treatment times of the restorations made with ART and another more conventional restorative technique. Since the ART technique involves the use of hand instruments alone therefore it may require more chairside time

102

for cavity preparation. Likewise, the placement of glass ionomer restorations may also require more time then placing amalgam restorations. Furthermore, this chapter presents the differences in the preparation and restoration times and the effect of material, cavity size and operator on the treatment times. Results suggest that ART preparations require more time than MCP and glass ionomer restorations require more restoration time then the amalgam restorations. The operator factor affects both the preparation time of ART restorations and the restoration times of GIC restorations. Moreover, the survival of GIC restorations may be influenced by variances in the restoration times.

Chapter 6 describes the results of the survival of restorations and fissure sealants made with hand instruments and with more conventional technique utilizing rotary instruments after two years. Both glass ionomer and amalgam were used to restore the teeth. Evaluations were done at the intervals of 3mth, 6mth, 1yr, 11/2yr and 2yr. The 2-year lost to follow up rate was 5.4%. No caries was associated with ART restorations. However, caries was associated with 1 failed MCP restoration restored with amalgam. The 2yr survival percentages for ART preparations restored with GIC and amalgam were 98.2% and 89.6% respectively, while similar survival percentages for MCP preparations restored with GIC and amalgam were 98.3% and 95% respectively. ART preparations restored with GIC showed better survivals then the ART preparations restored with amalgam. Amalgam survivals improved in the MCP group, but the type of preparation did not influence the GIC survivals.

The survival percentage of the fissure sealants (partial and complete) was 61.9%. Caries was observed in the pits and fissures in 0.3% of the teeth that had been sealed while 1.6% of the teeth restored with amalgam (unsealed teeth) developed pit and fissure caries in the two-year period. Fissure sealant associated with the occlusal restorations showed better survival than with the non-occlusal.

It is concluded that the use of glass ionomer restorative material as sealants in combination with the glass ionomer restoration is beneficial for the prevention and control of dental caries.

The effect of variables such as location, cavity size, treatment time and operator on the survival of restorations is discussed in chapter 7. The location of restoration did not effect the survival of ART restorations in the treatment of one-surface carious lesions. The cavity size did affect the survival of both ART (GIC) and MCP (GIC) restorations; also the operator factor influenced the survival of both the ART and the MCP restorations. The success of ART glass ionomer restorations was influenced by the restoration time, however this effect requires further investigation.

In view of the fact that the operator influences the ART restorations of the present study, this operator effect may result from wrist fatigue caused by prolonged tooth preparation exclusively with hand instruments. Chapter 8 discusses the effect of fatigue due to cavity preparation in the study conducted in Pakistan. Muscular fatigue is a very subjective and complex subject. If preparation time is used to measure fatigue due to cavity preparation

103

then it does seem to affect consecutive cavity preparation by the ART technique. Moreover, it also shows dissimilar effects in different operators.

In chapter 9, the general discussion, the significance and limitations of our study are described and recent developments are discussed, conclusions drawn and suggestions made. Within the limitations of this PhD study, the final conclusions are:

The survival of ART glass ionomer restorations is comparable with the survival of glass ionomer restorations made with another more conventional treatment technique using rotary instruments.

Glass ionomer restorations showed better survival than amalgam restorations when used in small one-surface cavities.

The operator affects the results of restorative treatment to a large extent.

The ART approach is relatively atraumatic when compared with restorative treatment by rotary instruments.

Operative discomfort appears also to be patient related.

ART requires more time than preparation by rotary instruments.

Glass ionomer restorations require more placement time than amalgam restorations.

If the variability of preparation time is used as an indicator for fatigue then, fatigue is associated with consecutive preparation by ART technique.

Shorter restoration time may negatively influence the survival of glass ionomer restorations.

The present study forms a basis for long term clinical research.

104

Chapter 11

SAMENVATTING

106

Cariës blijft nog steeds in veel ontwikkelingslanden onbehandeld, evenals trouwens bij veel sociaal economisch lagere bevolkingsgroepen in geïndustrialiseerde landen. Behandeltechnieken ontbreken door de afwezigheid van elektrische voorzieningen en tandheelkundige apparatuur. Cariës is derhalve in toenemende mate een serieus volksgezondheidsprobleem voor grote populaties. In Pakistan is de cariësprevalentie, uitgedrukt in DMFT bij 12-jarige kinderen 1,2. Uit analyse van dit DMFT-getal kan echter worden opgemaakt dat de factor D relatief hoog is, namelijk 1,05. Hieruit kan worden geconcludeerd dat er een grote behandelachterstand is ten gevolge van onwetendheid van de patiënt of een gebrek aan tandheelkundige dienstverlening. Wetenschappelijk onderzoek en de ontwikkeling van adhesieve restauratiematerialen hebben nieuwe wegen geopend voor het behoud van carieuze gebitselementen.

De “Atraumatic Restorative Treatment” (ART) is één van die managementstrategieën. De ART-techniek is geëvalueerd onder realistische klinische omstandigheden en uit de resultaten kan worden opgemaakt dat de techniek voor éénvlaks restauraties vooral in blijvende elementen veelbelovend is. Studies tot nu toe richtten zich in het bijzonder op de levensduur van restauraties en sealants, terwijl vragen over het atraumatische aspect, de invloed van de operateur en de effectiviteit nog niet beantwoord zijn. Om die redenen is het onderhavige onderzoek opgezet om onder veldcondities diverse aspecten met betrekking tot ART te evalueren.

Het doel van deze studie was: de kwaliteit van glasionomeercement te toetsen op basis van een vergelijking met

amalgaam, toegepast in éénvlakspreparaties, vervaardigd volgens de ART-methode.

de effectiviteit van de ART-methode te vergelijken met een gelijksoortige benadering met behulp van roterend instrumentarium (MCP).

het vergelijken van de behandeltijd bij beide methoden.

het onderzoeken van mogelijke vermoeidheidsverschijnselen in de pols op de grootte van de preparatie.

het onderzoeken van de gevoeligheid tijdens en na de behandeling bij beide methoden.

het onderzoeken van de invloed van de behandelaar op:A. verschillen in preparatiegrootte bij beide technieken,B. preparatie- en restauratietijd bij beide technieken,C. de kwaliteit van de restauratie,D. gevoeligheid tijdens en na de behandeling.

Om dit doel te bereiken zijn er twee onderzoeken uitgevoerd (hoofdstuk 2)

107

Onderzoek 1: behandeling van éénvlakscaviteiten volgens de ART-methode waarbij glasionomeercement en amalgaam als restauratiemateriaal zijn gebruikt.

Onderzoek 2: idem als onderzoek 1, maar dan volgens een minimale caviteitspreparatietechniek, met behulp van roterend instrumentarium.

In beide studies diende het glasionomeercement als het testmateriaal (Fuji IX GC) en het amalgaam als controle (Tytin, Kerr). Er werd de voorkeur aan gegeven om beide materialen toe te passen in een “split-mouth design”, teneinde verzekerd te zijn van vergelijkbare omstandigheden. Alleen kleine éénvlakscaviteiten in blijvende molaren en premolaren werden geselecteerd. Vijf behandelaars namen deel aan het onderzoek en werden getraind en gekalibreerd vóór aanvang van de behandelingen. Iedere patiënt werd door één van de vijf behandeld. Ter voorkoming van verschillen in wijze van behandelen waren de procedures in detail beschreven. De preparaties werden gemeten met een speciaal voor dit doel ontworpen instrument. Behandeltijden werden vastgesteld met behulp van een stopwatch. Er werd onderscheid gemaakt tussen preparatie- en restauratietijd. Evaluaties waren gepland direct na behandeling, 6 maanden, na1, 1½ en na 2 jaar.

Pijn bij prepareren en restaureren van éénvlakscaviteiten is beschreven in hoofdstuk 3. Pijn bij invasieve behandelingen van cariës is een veel voorkomend fenomeen als geen lokale analgesie is toegepast. Van de atraumatic restorative treatment wordt gesuggereerd dat deze methode in elk geval minder traumatisch is voor de patiënt. Hoewel ART goed is ontvangen door zowel kinderen als volwassenen die eerder nog nauwelijks betrokken zijn geweest bij tandheelkundig gezondheidszorg, is het nog niet aangetoond dat deze specifieke behandelmethode ook werkelijk minder pijn tijdens de behandeling veroorzaakt in vergelijking tot meer conventionele technieken waarbij roterend instrumentarium wordt gebruikt. In dit onderzoek werd pijn in directe relatie tot de restauratieve behandeling geregistreerd in 19,3% van de gevallen als de ART techniek werd toegepast. Dit was significant minder dan bij een conventionele restauratieve behandelmethode (35,7%). Bovendien bleek de behandelaar een significante invloed op de geregistreerde behandelingen met pijn: tussen de behandelaars varieerde het percentage tussen de 5,9 en 44%. Tenslotte is er een duidelijke relatie in de gerapporteerde pijn tussen de eerste en volgende behandelingen, zowel bij de ART als bij de conventionele behandelmethode.

In hoofdstuk 4 is het traumatische effect van de twee methoden van caviteitsreparatie onderzocht door het meten van de grootte van de preparaties. Bovendien is de relatie tussen de preparatiegrootte enerzijds en de behandeltijden, de behandelaar en de patiëntenfaktor anderzijds geëvalueerd. De resultaten laten zien dat er een significant verschil is (p<0.01) tussen de grootte van preparaties vervaardigd volgens de ART-methode en volgens de meer conventionele manier. Een operateurseffect is eveneens waargenomen: tenminste één behandelaar maakte grotere preparaties met de ART-methode (p<0.01). Ook was er een duidelijke relatie tussen preparatiegrootte en pijn tijdens de behandeling: hoe groter de preparatie, des te groter de kans op een pijn registratie (p<0.01). Evenzeer was er een relatie tussen de preparatiegrootte en –tijd: hoe groter, des te meer tijd het prepareren kostte (p<0.05).

108

Ook de restauratietijd met amalgaam was het langst bij de grootste caviteiten (p<0.01).

Hoofdstuk 5 handelt over de bevindingen met betrekking tot de behandeltijden die geregistreerd zijn tijdens de vervaardiging van ART- en meer conventionele restauraties. Omdat de ART-methode impliceert dat alleen handinstrumenten worden gebruikt, kan dit tot consequentie hebben dat het prepareren meer tijd vergt. Bovendien zou het aanbrengen van een glasionomeercement restauratie meer tijd kunnen kosten dan van een amalgaamrestauratie. Verder handelt dit hoofdstuk over de verschillen in de preparatie- en restauratietijd en het effect van het materiaal, de preparatiegrootte en de behandelaar op genoemde tijden. Uit de resultaten kan worden opgemaakt dat ART-preparaties meer tijd vergen dan MCP en restaureren met glasionomeercement meer tijd dan met amalgaam. Het operateurs effect is terug te vinden in de preparatietijd bij de ART-methode en de restauratietijd bij gebruik van glasionomeercement restauraties afhankelijk te zijn van variaties in restauratietijd.

In hoofdstuk 6 worden de resultaten na twee jaar beschreven met betrekking tot het succes van restauraties en sealants vervaardigd met louter handinstrumenten of op meer conventionele wijze met gebruikmaking van roterend instrumentarium. Zowel glasionomeercement als amalgaam werd gebruikt als restauratiemateriaal. Evaluaties waren uitgevoerd na 3 en 6 maanden, en na 1, 1 ½ en 2 jaar. Het percentage restauraties dat na twee jaar niet geëvalueerd kon worden, bedroeg 5,4.

Naast ART-restauraties werd geen cariës aangetroffen. Naast één MCP-restauratie met amalgaam werd cariës gevonden. Het succespercentage van ART-preparaties, gerestaureerd met glasionomeercement en amalgaam was respectievelijk 98,2 en 89,6%, terwijl dit percentage bij MCP-preparaties uiteen liepen van 98,3 tot 95. ART- glasionomeercementrestauraties scoorden beter dan ART-amalgaamrestauraties. Amalgaam voldeed beter in de MCP-groep, terwijl de wijze van prepareren geen invloed had op het succespercentage van glasionomeercement. Het succespercentage van glasionomeercementsealants (partieel en geheel aanwezig) was 61,9%. Van de molaren die waren gesealed bleek 0,3% pit-of fissuurcaries te bevatten, terwijl dit bij de met amalgaam gerestaureerde elementen lag op 1,6% na twee jaar. Sealants die in directe verbinding stonden met occlusale restauraties voldeden beter dan die op andere vlakken. Er kan geconcludeerd worden dat een glasionomeercement restauratiemateriaal dat als sealant wordt gebruikt in combinatie met een glasionomeercementrestauratie een positieve invloed heeft op de preventie en de controle van cariës.

Het effect van variabelen als de locatie en grootte van de preparatie, de behandeltijd en de operateur op het succespercentage van restauraties is beschreven in hoofdstuk 7. De locatie van de restauratie had geen invloed op het succes van éénvlaks-ART-restauraties in tegenstelling tot de grootte van de preparaties die wel invloed had op zowel glasionomeercementrestauraties in de ART- als in de MCP-groep. Ook de behandelaar heeft effect op het succes van ART- en MCP restauraties. Hoewel de restauratietijd invloed leek te hebben op het succes van ART-glasionomeercementrestauraties, is hiernaar meer onderzoek noodzakelijk.

109

Gezien het feit dat de behandelaar invloed heeft op het succes van ART-restauraties, zou de oorzaak daarvan kunnen liggen in vermoeidheid in de pols bij langdurig gebruik van handinstrumenten bij prepareren. In hoofdstuk 8 wordt dieper ingegaan op het effect van vermoeidheid door prepareren tijdens deze studie in Pakistan. Spiervermoeidheid is een zeer complexe en bovendien subjectieve materie. Als preparatietijd het criterium is om vermoeidheid bij handmatig prepareren vast te stellen dan lijkt het inderdaad invloed te hebben op opeenvolgende preparaties. Bovendien is het effect niet bij iedere behandelaar hetzelfde. In hoofdstuk 9, de algemene discussie, worden het belang en de beperkingen van het onderhavige onderzoek belicht en afgezet tegen de recente literatuur. Op grond daarvan worden conclusies getrokken en suggesties gedaan. Binnen de beperkingen van dit promotieonderzoek zijn de uiteindelijke conclusies:

Het succes van ART-glasionomeercementrestauratie is vergelijkbaar met dat van glasionomeercementrestauratie vervaardigd volgens een meer conventionele techniek met behulp van roterend instrumentarium.

In kleine éénvlaks preparaties voldoet glasionomeercement beter dan amalgaam.

De behandelaar heeft grote invloed op het resultaat van restauratieve behandeling.

De ART-methode is relatief atraumatisch in vergelijking tot behandeling met roterend instrumentarium.

“Discomfort”tijdens de behandeling is patiëntafhankelijk.

Behandelingen volgens de ART-methode kost meer tijd dan die met roterend instrumentarium.

Het vervaardigen van een glasionomeercementrestauratie vergt meer tijd dan van een amalgaamrestauratie.

Als de variatie in preparatietijd gebruikt wordt als indicatie voor spiervermoeidheid, dan is deze geassocieerd met opeenvolgende preparaties met handinstrumentarium.

Kortere restauratietijden kunnen een negatieve invloed hebben op het succespercentage van glasionomeercementrestauraties.

De onderhavige studie kan als uitgangspunt dienen voor lange termijn klinisch onderzoek.

110

Acknowledgements

I am greatly indebted to Prof. Dr. Taco Pilot, the initiator of this project, without whose vision and support this may not have been achieved. A special thanks is given to my promotor Prof. Dr. Paul R. Wesselink for his assistance and guidance in the completion of this thesis. Also to Dr. Evert van Amerongen, my supervisor, for the project and the thesis for his dedication, guidance and assistance during the project and in the completion of this thesis. He has given freely and generously of his knowledge and experience.

I am also grateful to Dr. Rehana Maher my facilitator through the project for her unflagging support and assistance. A special thanks goes to the operators and my colleagues, Dr. Rauf Shah, Dr. Haleem , Dr. Kharel and Dr. Sania for their help, enthusiasm and dedication in implementing the operative phase of the study, to GC Corporation Singapore for providing Fuji IX, and to Kerr for providing Tytin.

A word of thanks also goes out to the principals and administrations of the five schools that took part in the study for their cooperation, to the Aga Khan School Health Services for providing the mobile dental equipment. Also to the Dental Clinics Aga Khan University for their collaboration and support through the project and to the Baqai Dental College also for the support and cooperation throughout the project, to Mr Iqbal Azam and Mr Rasul Bux for their help in data entry and analysis.

Last but not the least a very special thank goes to Mrs Nasima Rahimtoola without whose support and dedication and help this work may not have been completed.

Finally, I would like to thank anyone whom I have not mentioned and who played a role in assisting in this research.

112

Introduction - Research Explorer · Web viewMaher, R.; Khan, A.; Rahimtoola, S.; Bratthal, D.:...

Documents

Transcript of Introduction - Research Explorer · Web viewMaher, R.; Khan, A.; Rahimtoola, S.; Bratthal, D.:...