Ass

impl

Mahmut Sumer,

aAssociate Professor, Department ofbAssistant Professor, Department ofcSpecialist Dentist, Oral and DentaldAssistant Professor, Department ofeAssociate Professor, Department of

Sumer et al

essment of heat generation during

ant insertion

DDS, PhD,a Ilker Keskiner, DDS, PhD,b

Ugur Mercan, DDS, PhD,c Ferhat Misir, DDS, PhD,d andSoner Cankaya, PhDe

University of Ondokuz Mayis, Faculty of Dentistry, Samsun, Turkey;University of Bulent Ecevit, Faculty of Dentistry, Zonguldak, Turkey;University of Ordu, Faculty of Medicine, Ordu, Turkey

Statement of problem. Many studies have investigated the heat generated during implant preparation, but data are neededto better predict heat generation during implant insertion.

Purpose. The purpose of this study was to measure the heat generated during insertion of an implant at speeds of 30, 50, and100 rpm, and with manual insertion.

Material and methods. Sixty-four uniform fresh bovine femoral cortical bone specimens were used. After the cortical bonewas drilled, 3 different implant insertion speeds and the manual insertion of the implant were evaluated for 2 differentimplant diameters. The temperature was measured with 2 Teflon-insulated, type K thermocouples. Data were analyzed by 2-way ANOVA, and the Tukey honestly significant difference test (a¼.05).

Results. The highest thermal change for 4.1-mm-diameter implants was found at a speed of 100 rpm (9.81�C �2.29�C), andthe lowest thermal change was 3.69�C �0.85�C at a speed of 30 rpm. A statistically significant difference was found between100 rpm and the other 3 insertion procedures. The highest thermal change for a 4.8-mm-diameter implant was found at aspeed of 100 rpm (8.79�C �1.53�C), and the lowest thermal change was 4.48�C �0.85�C at a speed of 30 rpm. Nostatistical difference was observed with manual, 30 rpm, and 50 rpm; however, a statistically significant difference was foundbetween 100 rpm and the other 3 insertion procedures.

Conclusions.Manual implant insertion and at speeds of 30 rpm and 50 rpm generated lower heat compared with insertion at100 rpm. (J Prosthet Dent 2014;-:---)

Clinical Implications

The heat generated during implant insertion and the most appropriaterotational speeds should be considered by dentists when placingimplants.

In implant surgery, bone tissuepreparation is generally performed withcutting tools at high speeds.1 Trau-matic surgery will lead to connectivetissue formation around the implant,which causes an unsuccessful implanttreatment.2 One of the most important

Oral andPeriodontHealth CeOral andBiostatist

factors for atraumatic surgery is tominimize the bone temperature in-crease during osteotomy preparation.3

Heat is always generated duringimplant drilling because of the contactbetween the drill and the bone wall.Bone tissue is sensitive to heating at

Maxillofacial Surgery, University of Ondokuz Mology, University of Ondokuz Mayis, Faculty ofnter, Adana, Turkey.Maxillofacial Surgery, University of Bulent Ecevics, University of Ordu, Faculty of Medicine.

47�C.2 Even a moderate rise in tem-perature of bone tissue during drillingmay be hazardous to bone healing.4

The implant placement procedureincludes implant insertion after bony tis-sue preparation. Implants can be insertedmanually or at different speeds when

ayis, Faculty of Dentistry.Dentistry.

it, Faculty of Dentistry.

Thermocouple Thermocouple

1 mm

1 mm1 mm

1 mmBone surface

1 Schematic drawing of implant and thermocouples.

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2 Initial and maximum temperatures (�C) for4.1-mm-diameter implant.

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using a handpiece. Several in vivo andin vitro studies have been done concern-ing the heat generated during implantpreparation, and several factors, such asdrilling size, pressure, shape and type ofthe drill, drilling time, irrigation systems,and drilling speed, have been found toaffect heat generation.5-10 In addition,the influence of bone quality, implant de-sign, thread shape, implant diameter, andimplant length have been studied.11-13

However, information about heat gener-ation during dental implant insertion islimited. Markovic et al14 investigatedthe effect of surgical technique, implantmacrodesign, and insertion torque onbone temperature changes during im-plant placement. The purpose of thepresent study was to measure the heatgenerated during insertion of an implantat speeds of 30, 50, and 100 rpm, andwith manual insertion. The null hypoth-esis was that no difference would befound in the heat generated duringimplant insertion among 3 insertionspeeds and hand insertion, and alsobetween 2 implant diameters.

MATERIAL AND METHODS

Sixty-four specimens of corticalbones from bovine femurs obtainedfrom a local butcher shop were used inthe present study. Specimens with thesame cortical layer thickness (3 mm)and compatible with Type II bone ac-cording to the Lekholm and Zarb clas-sification15 were selected to provideuniform experimental conditions. One-way ANOVA was done to determinethe number of specimens required ineach test group, and specimen size wasdefined as at least 3 for each group(a¼.05; power of the test, 95%). Allosteotomies were performed by thesame operator according to the manu-facturer’s recommendations. Implantsites were prepared to the definitivediameter of 3.5 mm (for the implantwith a 4.1-mm diameter) and 4.2 mm(for the implant with a 4.8-mm diam-eter) with a series of drills withincreasing diameter. After the corticalbone had been drilled, threads werecut with the tapping device. Four new

The Journal of Prosthetic Dentis

self-tapping implants (Straumann)10 mm in length were used. Implanta-tion procedures were undertaken withthe use of a conventional dental hand-piece (W&H). An insertion torque of50 Ncm was used.

Three different implant insertionspeeds (30, 50, 100 rpm) and manualinsertion of the implant were evaluatedfor 2 different implant diameters (4.1and 4.8 mm). The temperature wasmeasured with 2 Teflon-insulated, typeK thermocouples (model 5SRTC-TT-KI-36; Omega Engineering), which wereinserted into 1-mm holes prepared1 mm away from the bone surface and1 mm away from the implant surface(Fig. 1). The temperature differencebetween the 2 thermocouples wasconsidered to be a maximum of 1�C.No irrigation was used during implantinsertion. Thermocouples were read bya Four Channel, Handheld Data LoggerThermometer (model HH147; OmegaEngineering), which allowed for con-stant, real-time temperature readings.The initial temperature and themaximum temperature were recorded.

try

The temperature measured with 2thermocouples and the mean valueswere recorded. Temperature valueswere stored in a personal computer,and data were analyzed with the 2-wayANOVA procedure of statistical soft-ware (SPSS 13.0; SPSS Inc). Differencesin the means were detected by using theTukey honestly significant differencetest (a¼.05).

RESULTS

The initial and the maximal tem-peratures for both implants are shownin Figures 2 and 3. The highest thermalchange for the 4.1-mm-diameterimplant was found at a speed of 100rpm; the lowest thermal change was3.69�C �0.85�C at a speed of 30 rpm.A statistically significant difference wasfound between 100 rpm and the other3 insertion procedures (P<.001). Inaddition, a statistically significant dif-ference was found between 30 rpm andthe manual procedure (P<.001). Thehighest thermal change for the 4.8-mm-diameter implant was found at a speed

Sumer et al

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0.00Manual 30rpm 50rpm 100rpm

4.8 mm diameter

Initial temperatureMaximum temperature

3 Initial and maximum temperatures (�C) for4.8-mm-diameter implant.

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of 100 rpm; the lowest thermal changewas 4.48�C �0.85�C at a speed of30 rpm. No statistical difference wasobserved among manual, 30 rpm,and 50 rpm (P>.05); however a sta-tistically significant difference wasnoted between 100 rpm and the other3 insertion procedures (P<.001). Nostatistical difference was observed at allspeeds and with the manual procedurebetween 4.1- and 4.8-mm-diameterimplants (P>.05). The mean values ofchange from the initial temperature forimplants at speeds of 30, 50, and 100rpm, and with manual insertion areshown in Table I.

DISCUSSION

The results of the present studydemonstrated that implant placementat a speed of 100 rpm generated higherheat compared with insertion at speedsof 30 and 50 rpm, and with manualinsertion. Therefore, the null hypothesiswas rejected. However, no differencewas noted in terms of heat generationduring implant insertion between 2 im-plants with different diameters. Dental

Table I. Mean values of change from in

ImplantDiameter, mm

Implant

Manual 30 rpm

4.1 5.94 �1.39 3.69 �0.85

4.8 5.14 �1.42 4.48 �0.85

Total 5.54 �1.42b 4.08 �0.92

SD, standard deviation.F¼1.243, df¼1, P¼.270 for diameter; F¼38.6, df¼P¼0294 for interaction (diameter � traits).a,b,cMeans within row with different superscript let

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implants are used in various locationsin treatment and are placed with var-ious techniques that include differentdrill speed, pressure, drill geometry,irrigation system, drill type, drillingtime, and drilling depth. These variableshave been studied for their role inheat generation during implant drilling;however, heat generation at differentspeeds during implant insertion has notpreviously been studied.

Matsuoka et al16 measured thefriction heat during the self-tapping ofan orthodontic miniscrew and used1.2-mm-thick bone as a model formaxillary bone and 2.0 mm formandibular bone. In the study byMarkovic et al,14 specimens with acortical layer thickness of 2 mm wereselected because of their similaritieswith the human maxillary jaw bone. Inthe present study, a 3-mm cortical bonethickness was used as a model ofmandibular bone. The bone quality issignificant when an implant placementsite is selected. Implants inserted intothe mandible have higher survivalrates11 because of a higher ratio ofcompact bone. Insertion torque is a

itial temperature

Insertion, mean (SD)

50 rpm 100 rpm Total

5.67 �1.34 9.81 �2.29 6.28 �2.70

5.10 �1.40 8.79 �1.53 5.88 �2.14c 5.39 �1.36b 9.30 �1.95a 6.08 �2.42

3, P<.001 for traits; F¼1.269, df¼3,

ters are significantly different (P<.05).

significant predictor of bone heatingduring implant placement. Althoughhigher insertion torque values arerelated to higher temperatures, aninsertion torque of 30 to 40 Ncm hasbeen considered safe in terms of theirthermal effect on bone tissue.14 Forsmooth implant placement, higherinsertion torque values might be used,according to the manufacturer’s rec-ommendations. In this study, a 50-Ncminsertion torque was used.

Because of the compact and spongycomponents of bone, more heat isgenerated in the superficial part of acavity. A significant temperature in-crease was reported in cortical boneat a depth of 1 mm with increasinginsertion torque values compared withthe deeper parts of the osteotomies.14

In spongy bone, bone temperature de-creases with increasing osteotomydepth. Therefore, in the present study,the temperature was measured 1 mmaway from the bone surface, wheremore heat generation was expectedduring implant insertion. To improveaccuracy, the measurements should beperformed on the surface as close aspossible to the drilling implant site.16

Atraumatic preparation has beenconsidered an important influence onimplant success, and the avoidance ofexcess heat generation during the sur-gical procedure is essential.5 In additionto the the implant site preparation, theplacement of an implant can also causebone overheating.14 Implant placementprocedure parameters, such as implantsurface topography, thread design, thepatient’s bone quality, diameter ofosteotomy, implant length, implantdiameter, and surgical technique, mayhave a thermal effect on the adjacentbone. The surface topography isdependent on surface orientation androughness. Experimental investigationshave demonstrated that the boneresponse is influenced by the implantsurface topography.13 Thread shapeand thread details could significantlyaffect the periimplant stress patterns.12

Threads could affect heat generationduring implant insertion because theosteotomy diameter is generally smaller

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than the diameter of the implant andthe coefficient of friction between thethreads and the bone might beexceeded.

The implant diameter could beconsidered as a more effective designparameter than the implant length forcontrolling overloading risk.12 Thechosen depth of the implant site prep-aration in the present study was10 mm, and 2 different implant di-ameters were used. The diameter of theimplant (4.1 or 4.8 mm) was not foundto be related to the heat increase duringimplant insertion. However, multipleinsertions of the same implant shouldbe considered because reusing implantscan influence heat production duringinsertion because of changes in theimplant surface characteristics.

Drill geometry affects heat produc-tion, and temperatures increase whendrills are used multiple times.8 Noneself-tapping implants produced aslightly higher thermal increase thanself-tapping implants during placementat the investigated osteotomy depths of1, 5, and 10 mm. In addition, implantsplaced in sites prepared by bone drillingrevealed higher temperature increasesduring insertion than those placed afterthe lateral bone condensing techniqueat all osteotomy depths.14 Markovicet al14 reported the possible benefits ofplacing self-tapping implants with lowinsertion torque into sites preparedwith the lateral condensing technique.In the present study, self-tapping im-plants were used for 2 different im-plants diameters.

Matsuoka et al16 investigated theheat generated when a self-drillingorthodontic miniscrew was used atspeeds of 50, 100, 150, and 250 rpmaccording to the cortical bone thicknessand found that, as revolution speed

The Journal of Prosthetic Dentis

increased, the temperature in the boneincreased significantly. A temperatureincrease of 10�C to 47�C would attainthe upper threshold for bone survival.16

In the present study, a significantlygreater temperature increase wasobserved at 100 rpm compared with 30and 50 rpm during the insertion of animplant. Further clinical studies shouldbe undertaken to determine the heatgenerated during implant insertion.

CONCLUSION

Within the limitations of this in vitrostudy, implant insertion by hand and atspeeds of 30 and 50 rpm generatedlower heat than insertion at 100 rpm.

REFERENCES

1. Eriksson RA, Adell R. Temperaturesduring drilling for the placement ofimplants using the osseointegrationtechnique. J Oral Maxillofac Surg 1986;44:4-7.

2. Eriksson AR, Albrektsson T. Temperaturethreshold levels for heat induced bone tissueinjury: a vital-microscopic study in the rabbit.J Prosthet Dent 1983;50:101-7.

3. Yacker MJ, Klein M. The effect of irrigationon osteotomy depth and bur diameter.Int J Oral Maxillofac Implants 1996;11:634-8.

4. Eriksson AR, Albrektsson T. The effectof heat on bone regeneration: an experi-mental study in the rabbit using the bonegrowth chamber. J Oral Maxillofac Surg1984;42:705-11.

5. Tehemar SH. Factors affecting heat genera-tion during implant site preparation: a reviewof biologic observations and future consid-erations. Int J Oral Maxillofac Implants1999;14:127-36.

6. Abouzgia MB, James DF. Measurementsof shaft speed while drilling throughbone. J Oral Maxillofac Surg 1995;53:1308-15.

7. Sharawy M, Misch CE, Weller N, Tehemar S.Heat generation during implant drilling: thesignificance of motor speed. J Oral MaxillofacSurg 2002;60:1160-9.

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8. Chacon GE, Bower DL, Larsen PR,McGlumphy EA, Beck FM. Heat productionby 3 implant drill systems after repeateddrilling and sterilization. J Oral MaxillofacSurg 2006;64:265-9.

9. Sumer M, Misir AF, Telcioglu NT, Guler AU,Yenisey M. Comparison of heat generationduring implant drilling using stainless steeland ceramic drills. J Oral Maxillofac Surg2011;69:1350-4.

10. Benington IC, Biagionni PA, Briggs J,Sheridan S, Lamey PJ. Thermal changesobserved at implant sites during internal andexternal irrigation. Clin Oral Implants Res2002;13:293-7.

11. Adell R, Lekholm U, Rockler B, Branemark PI.A 15-year study of osseointegrated implantsin the treatment of the edentulous jaw. Int JOral Surg 1981;10:387-416.

12. Vairo G, Sannino G. Comparative evaluation ofosseointegrated dental implants based onplatform-switching concept: influence ofdiameter, length, thread shape, and in-bonepositioningdepthon stress-basedperformance.Comput Math Methods Med 2013:250929.

13. Abuhussein H, Pagni G, Rebaudi A,Wang HL. The effect of thread pattern uponimplant osseointegration. Clin Oral ImplantsRes 2010;21:129-36.

14. Markovic A, Misic T, Milicic B, Calvo-Guirado JL, Aleksic Z, Dinic A. Heatgeneration during implant placement inlow-density bone: effect of surgical tech-nique, insertion torque and implant macrodesign. Clin Oral Implants Res 2013;24:798-805.

15. Lekholm U, Zarb GA. Patient selection andpreparation. In: Branemark PI, Zarb GA,Albrektsson T, editors. Tissue integrated pros-theses: Osseointegration in clinical dentistry.Chicago: Quintessence; 1985.p. 199-210.

16. Matsuoka M, Motoyoshi M, Sakaguchi M,Shinohara A, Shigeede T, Saito Y, et al.Friction heat during self-drilling of an ortho-dontic miniscrew. Int J Oral Maxillofac Surg2011;40:191-4.

Corresponding author:Dr Mahmut SumerOndokuz Mayis UniversitesiDis Hekimligi FakultesiAgiz Dis ve Cene Cerrahisi Anabilim DaliSamsunTURKEYE-mail: msumer1970@yahoo.com

Copyright ª 2014 by the Editorial Council forThe Journal of Prosthetic Dentistry.

Sumer et al