Removal of root substance withthe Vectort-system comparedwith conventional debridementin vitroBraun A, Krause F, Frentzen M, Jepsen S: Removal of root substance with theVectort-system compared with conventional debridement in vitro. J Clin Periodontol2005; 32: 153–157. doi: 10.1111/j.1600-051X.2005.00651.x. r BlackwellMunksgaard, 2005.

AbstractObjective: The aim of the present study was to assess the removal of root substancewith the Vectort-system depending on different irrigation fluids and to compare theresults with conventional methods for root debridement.

Material and Methods: Forty extracted human teeth were treated using four differentmethods: Vectort-system with polishing fluid and metal curette (VP), Vectort-system with abrasive fluid and metal curette (VA), conventional ultrasonic system (U)with insert tip ‘‘P’’ and hand instrument. Treatment of the calculus-free root surfaceswas carried out for a total of 12min. using an artificial periodontal pocket. At intervalsof 120 s, the removal of dental hard tissues was assessed using a three-dimensional(3D) laser scanning device and the Match 3D software with an accuracy of0.00001mm3.

Results: No difference in the removal of root substance with the hand instrument(0.0055mm3/s) and the Vectort-system using the abrasive fluid (0.0044mm3/s) couldbe observed (p5 0.51). Using these two systems, a larger amount of root substance(po0.05) was removed compared with the other methods (U: 0.0023mm3/s, VP:0.0022mm3/s), which did not differ from each other (p5 0.76).

Conclusions: The present study indicates that the Vectort-system in combinationwith polishing fluid or conventional ultrasonics might be used for root debridementwithout extensive root substance removal.

Key words: artificial periodontal pocket; handinstrumentation; periodontal treatment;removal of root substance; ultrasonicinstrumentation

Accepted for publication 25 May 2004

It is widely accepted that initiation andprogression of periodontitis are depen-dent upon the presence of microorgan-isms capable of causing inflammation.Therefore, during initial periodontaltreatment, supra- and subgingival pla-que as well as firmly adhering calculusshould be removed. As calculus takesmonths or years to build up again, theprincipal objective of supportive perio-dontal therapy is to remove subgingivalplaque. Thus, the periodic mechanicalremoval of subgingival bacterial plaqueis essential for controlling inflamma-tion, because bacteria can re-populatepockets within a few weeks following

active therapy (Sbordone et al. 1990). Inthe past, periodontal debridement wasprimarily performed with hand instru-ments. More recently, power-driveninstruments have been modified toprovide better access to deep probingsites, offering the possibility of moreefficient subgingival instrumentation(Holbrook & Low 1994). Clinically,the available data do not indicate adifference between ultrasonic and man-ual debridement in the treatment ofchronic periodontitis (Drisko et al.2000, Tunkel et al. 2002). Using theseinstruments, it is not always possible toprevent loss of root substance. Because

of cumulative effect, even minor sub-stance removal per scaling session mayresult in severe root damage over time(Zappa et al. 1991).

A novel ultrasonic device (Vectort)generates ultrasonic vibrations that areconverted by a resonating ring, so that ahorizontal oscillation is deflected verti-cally. As a result, the instrument tipmoves parallel to the root surface and isrecommended to be used in conjunctionwith irrigation fluids containing hydro-xyl apatite or silicon carbide (Hahn2000). The tooth surface is supposed tobe cleaned because of hydrodynamicforces such as cavitation or acoustic

Andreas Braun, Felix Krause,Matthias Frentzen and Søren Jepsen

Department of Periodontology, Operative

and Preventive Dentistry, University of Bonn,

Germany

153

J Clin Periodontol 2005; 32: 153–157 doi: 10.1111/j.1600-051X.2005.00651.x Copyright r Blackwell Munksgaard 2005

microstreaming (Walmsley et al. 1990,Khambay & Walmsley 1999) ratherthan by the chipping action of theinstrument tip (Hahn 2000). The man-ufacturers claim the system to be lessaggressive than hand instruments con-cerning removal of root cementum andperiodontal soft tissues (Hahn 2000).This principle is comparable with ultra-sonic cleaning baths or lithotriptorsystems. Avoiding vibrations appliedhorizontally to the root surface, thetreatment with the Vectort-system hasbeen shown to be less painful thantreatment with conventional systems(Braun et al. 2003). It could be demon-strated that clinical parameters such aspocket depths and bleeding on probingimproved in a similar way, followingthe use of the Vectort-system or handinstruments (Klinger et al. 2000). Theultrasonic device is recommended to beused in conjunction with differentirrigation fluids; therefore, effects onthe root surface might be different.

Hence, the aim of the present in vitrostudy was to assess subgingival removalof root substance by the Vectort-system depending on different irrigationfluids and to compare the results withconventional periodontal techniques forroot instrumentation.

Material and Methods

A total of 40 periodontally involvedfreshly extracted human teeth werecollected from different patients andstored in a physiological saline solution.The time span between tooth extractionand the following treatment of the teethdid not exceed 1 week. For each tooth,the entire root surface was gentlycleaned using hand instruments (Hu-Friedy, Leimen, Germany) until itappeared devoid of calculus and perio-dontal ligament, using a loupe at � 3.5magnification. Baseline scanning imagesof the root surfaces were captured andsubsequently, 10 teeth each were treatedusing four different methods: Vectort-system (Duerr Dental, Bietigheim-Bis-singen, Germany) turned to the usual‘‘70%’’ setting with hydroxyl-apatite-containing polishing fluid and metalcurette insert at 25 kHz (VP), Vectort-system with silicon-carbide-containingabrasive fluid and metal curette insert at25 kHz (VA), conventional ultrasonicsystem (U) turned to the ‘‘high’’ settingwith insert tip ‘‘P’’ at 31 kHz (EMS,Nyon, Switzerland) and hand instrument(Hu-Friedy). The teeth were cleaned

before treatment and the prior attach-ment levels were not recognizable to theoperator. Laser scanning of the rootsurface allowed detection of root sub-stance removal along the whole surface,so that there was no need to define anexact area to be treated. Ultrasonicinstruments were used with the tipparallel to the root surface and withcontinuous adaptation to the root sur-face. When using the curette, the cuttingedge was first identified and placedagainst the tooth surface to be scaledwith the terminal shank parallel to thatsurface. In this position, the idealworking angulation for the cutting edgeaccording to the manufacturer’s instruc-tion could be achieved. The instrumen-tation of all teeth was performed by oneinvestigator well trained in periodontaltreatment, who was endeavoured to useall instruments with a clinically appro-priate force of application. Additionally,prior to the instrumentation of the 40teeth in the experimental groups, lateralforce measurements were performed.Using an artificial periodontal pocketmodel as shown below and a vice-likesupport placed on a laboratory balance(BL 510-OCE, Sartorius, Goettingen,Germany), the investigator treated aroot surface devoid of calculus withthe four different methods included inthe study for a total of 200 s each. Atintervals of 10 s, the applied forcewas recorded by a second investigator.This preliminary survey showed thatthe operator applied a lateral force of4.76 � 0.24N with the hand instrument,

0.83 � 0.11N (U), 0.68 � 0.10N (VP)and 0.69 � 0.09N (VA) while treatingthe root surfaces.

Treatment of the root surfaces wascarried out for a total of 12min. usingan artificial periodontal pocket model;teeth were fixed on glass slides andcovered with a non-transparent rubberdam (Coltene/Whaledent, Langenau,Germany), so that the root surface wasnot visible to the operator. At intervalsof 120 s, the removal of dental hardtissues was assessed by a secondoperator, using a three-dimensional(3D) laser scanning device (Willytec,Munich, Germany), built to measurecomplex, 3D tooth surfaces (Fig. 1).Each sample was prepared for laserscanning with a dye surface coating(Met-L-Chek, Santa Monica, CA, USA)and scanned from apical to coronal by alaser beam, projected via an opticsystem onto the root surface. Thereflection of the beam was observed atan angle of 201 by a high-resolutionCCD camera (Sony, Koln, Germany)with an accuracy of 28 mm (width),25mm (length) and 2.5mm (height).The trimmed tooth surface opposite tothe surface treated with an experimentalprocedure was fixed by means of asilicone impression material (Voco,Cuxhaven, Germany) to facilitate areproducible position of the tooth inthe scanning device. To evaluate rootsubstance loss, scanning images of theroot surfaces were superimposed andsubtracted using the Match 3D super-imposition software (Willytec) (Fig. 2).

Fig. 1. Laserscan 3D (Willytec), with tooth prepared for laser scanning.

154 Braun et al.

For statistical analysis, normal dis-tribution of the values was analysedwith the Shapiro–Wilk test. Since not allvalues were normally distributed, ana-lysis of variances of the ranks withsubsequent comparison of mean ranksand calculation of homogeneous groups(Scheffe) were used to analyse theamount of root substance removaldepending on the different treatmentmethods. Differences were consideredas statistically significant at po0.05.

Results

Measuring the volumes of teeth re-positioned in the scanning device with-out root instrumentation revealed anaccuracy of 0.00001mm3 (Table 1).Comparing values for root substanceremoval at intervals of 2min. withineach single experimental group, nostatistical difference could be observedbetween the intervals (p40.05). Remo-val of root substance with the Vectort-system depended on the used fluid(VA: 0.0044mm3/s, VP: 0.0022mm3/s,po0.05, Fig. 3, Table 1). The amountof removed root substance with the handinstrument (H: 0.0055mm3/s) did notdiffer significantly from the value mea-sured for the Vectort-system using theabrasive fluid (p5 0.51). Values for theconventional ultrasonic system (U:0.0023mm3/s) and the Vectort-systemusing the polishing fluid were statisti-cally not different (p5 0.76). Usingthese two systems, a minor amount ofroot substance was removed comparedwith hand instrumentation and theVectort-system with abrasive fluid(po0.05, Table 2).

Discussion

In the past, extensive cementumremoval by scaling and planing of theroot surface was required to removeroot-associated endotoxins for success-ful mechanical periodontal therapy(Aleo et al. 1975). However, endotoxinis only superficially associated withcementum and calculus. As it is easilyremoved by washing, brushing, lightscaling or polishing the tooth surface(Smart et al. 1990, Chiew et al. 1991,Drisko et al. 2000), periodontal healingcan be achieved without extensivecementum removal. Avoiding vibra-tions applied horizontally on the rootsurface, the oscillation pattern of theVectort-system avoids a hammering

action of the insert tip against the toothsurface. Therefore, the system wasclaimed to be less aggressive than handinstruments concerning removal of rootcementum and periodontal soft tissues(Hahn 2000). Indeed, this oscillationpattern might explain the little amountof root substance removed in the present

study when using the system with thepolishing fluid. Thus, higher values forroot substance removal with the abra-sive fluid seem to be caused solely bythe choice of the irrigation fluid. Usingthe standard ultrasonic system, treat-ment could be shown to be as gentle asthe Vectort-system with the polishing

Fig. 2. Tooth after treatment (a), prepared with dye surface coating (b) and scanned withLaserscan 3D (c).

Table 1. Removal of root substance (mm3/s)

H U VP VA Control

Mean value 0.0055 0.0023 0.0022 0.0044 0.00000599Standard deviation 0.0018 0.0012 0.0007 0.0021 0.00000399Number of teeth 10 10 10 10 10

Highest removal of root substance with H and VA, least removal using U and VP.

U, conventional ultrasonic instrument; H, hand instrument; VP, Vectort-system with metal curette

insert and polishing fluid; VA, Vectort-system with metal curette insert and abrasive fluid and

control group without treatment.

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.00 100 200

Hand instrumentVector abrasive fluidConventional ultrasonic instrumentVector polishing fluid

300 400Time [s]

Rem

oval

of r

oot s

ubst

ance

[mm

3 ]

500 600 700 800

Fig. 3. Amount of root substance removal over time. Every group calculated from 10 teeth.Highest root substance loss was obtained using the hand instrument, and the slowest loss wasobtained using the Vectort-system with polishing fluid.

Root substance removal with the Vectort-system 155

fluid. Higher aggressiveness of handinstruments to the root substance com-pared with the Vectort-system incombination with the polishing fluidmay have been because of the lack of atrue cutting edge of the Vectort instru-ments. An in vitro study compared thevolume of bovine root substance lossusing sonic, ultrasonic and hand instru-ments (Schmidlin et al. 2001). Inaccordance with the present study, theresults showed that hand instrumentsremoved most root substance. Evaluat-ing different working parameters onroot substance removal using the EMSPiezon Master 400 piezoelectric ultra-sonic scaler (Electro Medical SystemsSA, Nyon, Switzerland), the volume ofsubstance removal was measured(Flemmig et al. 1998a). The overallinfluence of time on defect volume forpooled lateral forces, tip angulationsand power settings revealed an efficacyof approximately 0.33mm3 per 80 s.This value (0.0041mm3/s) is compar-able with the values in the present study(0.0022mm3/s up to 0.0055mm3/s).Evaluating the Sonicflex Lux 2000sonic scaler (KaVo America Corp.Biberach, Germany) an efficacy of0.4mm3 per 80 s could be observed(Flemmig et al. 1997). This value(0.005mm3/s) is also comparable withthe values of the present study. The

result for the CaviMed magnetostrictiveultrasonic scaler (Dentsply, Konstanz,Germany) (approximately 0.0055mm3/s, Flemmig et al. 1998b) corresponds tothe value measured for the hand instru-ment in the present study. In an attemptto quantitate root substance loss byscaling with hand instruments, a profil-ometer was used (Zappa et al. 1991). Incontrast to the present study, only thedepth of substance loss could be mea-sured with the profilometer. Dependingon the force applied to the instrument,40 strokes with a curette removed anamount of 148.7 up to 343.3 mm rootsubstance. This demonstrates the greatimportance of adjusting lateral forceswhen substance loss is evaluated. Addi-tionally, with an increasing number ofstrokes the amount of substanceremoved per stroke can become less(Zappa et al. 1991). This may bebecause of the dulling of the curettes.A standardization of applied lateralforces was realized with the perfor-mance of all treatments by one investi-gator. As different investigators maytend to remove either small or largeamounts of root substance, the limita-tion to one operator allows for an inter-instrumentation comparison within theexperimental set-up. Not only lateralforces but also power settings andtip angulations can influence root sub-

stance removal (Flemmig et al. 1997,1998a, b). In the present study, instru-ments were used with the tip or terminalshank adapted parallel to the root sur-face, according to the common use ofultrasonic and hand instruments. Theroot surface was covered with a non-transparent rubber dam. Therefore, itwas difficult to retain this condition.However, this set-up resembles theclinical situation of a root surfaceinstrumentation without surgical access.Investigating working parameters of asonic and piezoelectric ultrasonic scaleron root substance removal, it was shownthat this angulation might preventsevere root damage (Flemmig et al.1997, 1998a, b). All ultrasonic instru-ments were used with the same powersettings and with continuous adaptationto the root surface. This should haveresulted in a lateral pressure of approxi-mately 0.75N (Clark et al. 1968). Thisassessment is in accordance with theresults of the preliminary survey of thisstudy. Lateral forces of 0.83 � 0.11Nwith the conventional ultrasonic instru-ment, 0.68 � 0.09N with the Vectort-system and the polishing fluid and0.69 � 0.10N with the Vectort-systemand the abrasive fluid were applied bythe operator. Lateral forces were notmeasured during treatment of theexperimental groups, as the investigatorwas well trained in periodontal treat-ment and the standard deviation of theapplied forces in the preliminary surveywas low. Assessing calculus removalwith a sonic scaler, the mean debride-ment force was 0.87 � 0.27N for anovel paddle-like scaler tip and0.79 � 0.22N for a conventional scalertip (Petersilka et al. 2003). In general,application forces influence defect depth(Ritz et al. 1991, Kocher & Plagmann1997b). However, at lateral forces high-er than 0.5 or 1.0N the resulting defectdepth decreased (Kocher & Plagmann1997a). This observation was as a resultof dampening of the instrument,although in some studies only a slightor no decrease of defect depth at higherlateral forces could be measured (Flem-mig et al. 1997, Kocher et al. 2001).Lateral forces observed when usinghand instruments in the present studyare in the range of values measured forworking strokes by means of a piezo-electric receiver built into the uppershank of a curette (Zappa et al. 1991).

A gentle root-surface instrumentationhas a high priority during the perio-dontal maintenance phase. In conclu-

Table 2. Statistical analysis of root substance loss using the different debridement modalities

Shapiro–Wilk-test (normal distribution)

H U VP VA

w-value 0.90 0.96 0.96 0.84Normal distribution Yes Yes Yes No

ANOVA of ranks

sum of squares degrees of freedom mean square F-value p-value

3016.20 3 1005.40 15.65 o0.052313.30 36 64.26

Multiple comparisons of mean ranks (Scheffe-test)

treatment number homogeneous groups (po0.05)

A B

VP 10 10.2U 10 14.1VA 10 26.1H 10 31.6p-value within group 0.758 0.510

Not all values were normally distributed and therefore analysed using a non-parametric test

(a5 0.05).

U, conventional ultrasonic instrument; H, hand instrument; VP, Vectort-system with metal curette

insert and polishing fluid; VA, Vectort-system with metal curette insert and abrasive fluid; ANOVA,

analysis of variance.

156 Braun et al.

sion, the present study indicates that theVectort instruments in combinationwith the polishing fluid might be usedfor debridement without extensive rootsubstance removal. The amount of rootsubstance removal was shown to besimilar to a conventional ultrasonicinstrument. Because it is not knownwhich forces must be applied to removefirmly adhering calculus, the volume ofremoved root substance cannot beequated with the calculus volume. Thus,further studies have to evaluate calculusremoval by the treatment methods usedin this study.

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Address:

Andreas Braun

Department of Periodontology, Operative and

Preventive Dentistry

University of Bonn

Welschnonnenstr. 17

53111 Bonn

Germany

E-mail: andreas.braun@uni-bonn.de

Root substance removal with the Vectort-system 157