An in vitro investigation on the loss of root substance in scaling with various instruments

There are differing opinions as to the extent to which root cementum has to be removed during root surface instrumentation over and above that of the debridement of plaque and calculus. Similarly, the amount of tooth material removed by individual instruments is also unclear, but a trend towards less damaging methods of root surface debridement has evolved in recent years. The purpose of this in vitro study was to determine the amounts of root substance removed by 4 different methods of instrumentation, hand curette, ultrasonic scaler, airscaler and fine grit diamond bur. Measurement of tooth substance loss was carried out with a specially constructed measuring device at 360 sites on 90 mandibular incisors following 12 working strokes with a clinically appropriate force of application. Only a thin layer of root substance (11.6 microns) was removed by the ultrasonic scaler, compared to the much greater losses sustained with the airscaler (93.5 microns), the curette (108.9 microns) and the diamond bur (118.7 microns).     

Evaluation of different methods to clean titanium abutments. A scanning electron microscopic study.

The cleaning effectiveness of different treatment methods for titanium abutments was evaluated using scanning electron microscopy (SEM). In the mandible of 4 beagle dogs, 25 titanium abutments were installed (modum Brånemark). After 16 weeks of plaque accumulation, mineralized deposits had formed on 23 abutments. Each of these abutments was subjected to one of the following treatment methods: scaling with (1) metal, (2) plastic, or (3) ultrasonic instruments;(4) air-polishing, (5) weekly rubber cup polishing or (6) daily brushing with a conventional toothbrush. Fourteen abutments were removed immediately after treatment. On 9 abutments, the scaling procedures and air-polishing were repeated after another 16 weeks of plaque accumulation. The abutments were prepared for SEM, and each of them was viewed and photographed at 3 different magnifications. The photomicrographs were evaluated by 3 examiners who, guided by reference pictures, gave each abutment a “cleanliness” score, ranking from 0 to 5. Regular rubber cup polishing and regular brushing resulted in the highest surface cleanliness, while the air-polishing procedure showed the lowest cleanliness score. None of the 3 scaling methods created a cleanliness score better than 3. The 3 scaling methods were considered equal in their cleaning effectiveness. No differences could be observed between surfaces treated 1 x or 2 x Taken the present findings and those of other studies concerning the effects of scaling on the surface roughness and biocompatibility into consideration, it was concluded that plastic scalers may be the instruments of choice for debridement of titanium implant surfaces.     

Ultrasonics in periodontics

Abstract The vibrating tips of ultrasonic instruments have been shown to remove deposits mechanically. Calculus removal is equally effective with ultrasonic or hand instruments, whereas stain removal has been shown to be better with the former. It has been observed that ultrasonic instruments remove heavy supragingival calculus faster than hand instruments. According to the evidence available most patients and operators prefer ultrasonic scaling to hand scaling. The effect of in vivo ultrasonic scaling on root surface has not been established. Various factors possibly influencing the occurrence of tooth surface roughness subsequent to ultrasonic scaling have been pointed out. No harmful effects have been found in the adjacent periodontal structures following ultrasonic instrumentation. However, it has been suggested that the cavitation spray accompanying ultrasonic instrumentation may carry pathogenic organisms. The advantages and the disadvantages of ultrasonic instruments have been evaluated.     

Instrumentation of furcation with modified sonic sealer inserts: study on manikins, Part I

Abstract. The purpose of this study was to determine the suitability of different scaling instruments for the debridement of furcations. 12 upper and 12 lower replicated molars with through-and-through furcutions were instrumented 3 × with 5 different types of instruments: (i) hand instruments; (ii) hand instruments in conjunction with diamond burrs: (iii) a conventional ultrasonic sealer insert: (iv) a conventional sonic sealer insert; (v) a set of 2 modified diamond coated sonic sealer inserts with different angulated shafts. The plastic replicas were fixed in a manikin head without replicated soft tissues. Following debridement, weight loss and % of instrumented furcation area were assessed. In the ease of lower molars, it made little difference whether they were treated with hand instruments, hand instruments combined with diamond burrs, or diamond-coated sonic sealer inserts. On upper molars, however, significantly more area was instrumented with the diamond-coated inserts than with the other instruments. Substance removal was greater with diamond-coated inserts than with the other devices. In conclusion, an effective debridement of the furcation seems possible only with an odontoplasty, in which a furcation is fitted to the instrument by means of intensive instrumentation, thus leading to substance loss. To improve results with these instruments, further research is necessary.     

Broken instrument removal--two cases

This paper reports two clinical aids for the removal of broken instruments in root canals using a combination of hand instrumentation and ultrasonic devices. This technique is based on two phases: hand instrumentation with stainless-steel K-file instruments for bypassing the fragments, and K-files mounted on an ultrasonic handpiece for loosening and retrieval of the broken instruments. This method offers the following advantages: conservation of the remaining dentin wall of the root canal and elimination of the necessity for surgical treatment.     

Efficiency of the Vector -system compared with conventional subgingival debridement in vitro and in vivo

OBJECTIVE: To assess the efficacy of the novel ultrasonic Vector -system system for subgingival debridement and to compare the results with conventional periodontal instrumentation in vitro and in vivo. MATERIAL AND METHODS: Forty extracted human teeth were treated in vitro: Vector -system with polishing (VP) and abrasive fluid (VA), conventional ultrasonic system (U) and hand instrument (H). At intervals of 40 s, calculus removal was assessed using a 3D laser scanning device. Eight single-rooted teeth were treated in vivo with the Vector -system or hand instruments. Subgingival plaque samples were obtained for microbiological evaluation. After extraction, residual calculus was assessed by means of digitized planimetry. RESULTS: In vitro efficiency of hand instruments was statistically higher compared with the conventional ultrasonic system (p < 0.05) and the Vector -system with no difference between U and VA (p > 0.05) and VA and VP (p > 0.05). Residual calculus following in vivo instrumentation was not different in the Vector and the hand instrument group (p > 0.05) but treatment time with the Vector -system was statistically higher (p < 0.05). A similar reduction of periopathogenic bacteria could be observed in both groups. CONCLUSION: Using the Vector -system, root surfaces can be debrided as thoroughly as with conventional instruments. However, treatment is more time consuming than conventional debridement.     

两种刮治方法对老年牙周炎患者的临床疗效及患者疼痛感受的比较

目的:比较两种刮治方法对老年牙周炎患者的临床疗效及患者疼痛感受的差异,以期为临床提供参考.方法:选择老年牙周炎患者30名,随机分为两组,A组接受常规牙周刮治,用Gracey刮治器分四区段手工刮治,B组接受一次性超声全口龈下刮治,用EMS超声龈下工作尖一次性完成全口刮治.治疗结束后即刻用视觉模拟评分法(visual analogue scale,VAS)对患者行疼痛评估,并记录治疗时间.两组分别于刮治开始前和治疗后6周记录全口牙周情况:菌斑指数(plaque index,PLI)、探诊深度(probing depth,PD)、附着丧失(attachment loss,AL)、牙龈出血指数(bleeding index,BI).结果:用两种刮治方法对老年牙周炎患者进行治疗后,患者各项临床指标均较术前明显改善(P<0.05);两者PD、AL和BI的改变差异无统计学意义(P>0.05),与A组相比,B组的PLI改善更明显(P<0.05).手工刮治和超声刮治在牙周基础治疗中患者主观感受疼痛VAS值分别为(37.7±10.5)mm和(27.9±8.4)mm,后者约为前者疼痛值的74%,两者差异有统计学意义(P<0.05).超声刮治所用时间明显少于手工刮治.结论:在老年牙周炎患者的牙周基础治疗过程中,两种刮治方法疗效均确切,超声刮治能明显减轻老年患者在牙周治疗过程中的疼痛感,减少就诊时间.     

The efficacy of sonic and ultrasonic appliances on root canal debridement

The purpose of this study was to compare the debridement efficacy of hand, sonic (MM-3000), and ultrasonic (Cavi-Endo) appliances, utilizing the same K-type files and a constant flow irrigation system, in the mesial root canals of extracted human mandibular 1st and 2nd molars. Only those roots with a canal curvature of between 10 and 30 degrees, by Schneider's method, were used in this study. The instrumentation time per mesial root canal for each treatment group was also evaluated. Following canal preparation and histological processing, the middle and apical cross-sections were examined to determine the percentage of canal and isthmus cleanliness, and the percentage of planed canal walls in the main canal area. Statistical analysis indicated no significant difference in canal and isthmus cleanliness at the middle and apical levels. All techniques achieved a high level of canal cleanliness. However, step-back hand instrumentation had the greatest percentage of planed canal walls in the main canal area at every portion of the root. Sonic instrumentation, in this study, was significantly faster than hand instrumentation in preparing the root canal system.     

Clinical effects after subgingival polishing with a non-aggressive ultrasonic device in initial therapy

OBJECTIVES: The Vector ultrasonic system provides root debridement supported by different abrasive irrigation fluids. The aim of this study was to investigate the clinical outcome of initial therapy with subgingival low-abrasive debridement. MATERIAL AND METHODS: Twenty patients, who had at least two teeth with pocket depths >5 mm in each quadrant, took part in this prospective randomized clinical study. Patients were treated in a split-mouth design as one test quadrant (1) subgingivally with Vector fluid polish (VU-H) and as three control quadrants, (2) with only supragingival polishing (PO-H), (3) with hand instruments (HI-H) performed by a hygienist and (4) with hand instruments (HI-D) performed by a dentist. At baseline, 3 and 6 months after treatment, pocket depths and attachment levels (ALs) were measured and bleeding on probing (BOP) was recorded. RESULTS: At 6-month evaluation, all groups showed an improvement in clinical parameters. No statistically significant differences in any of the investigated parameters could be observed between the Vector group and the hand scaling groups, or when comparing the results of the two different operators. CONCLUSION: This study demonstrates that Vector treatment with polishing fluid was able to reduce pocket depths and the prevalence of BOP and improve clinical AL in a similar way as scaling with curettes.     

Full-mouth ultrasonic debridement versus quadrant scaling and root planing as an initial approach in the treatment of chronic periodontitis

AIM: To evaluate the clinical efficacy of (i) a single session of "full-mouth ultrasonic debridement" (Fm-UD) as an initial periodontal treatment approach and (ii) re-instrumentation of periodontal pockets not properly responding to initial subgingival instrumentation. Methods: Forty-one patients, having on the average 35 periodontal sites with probing pocket depth (PPD) > or =5 mm, were randomly assigned to two different treatment protocols following stratification for smoking: a single session of full-mouth subgingival instrumentation using a piezoceramic ultrasonic device (EMS PiezonMaster 400, A+PerioSlim tips) with water coolant (Fm-UD) or quadrant scaling/root planing (Q-SRP) with hand instruments . At 3 months, all sites with remaining PPD> or =5 mm were subjected to repeated debridement with either the ultrasonic device or hand instruments. Plaque, PPD, relative attachment level (RAL) and bleeding following pocket probing (BoP) were assessed at baseline, 3 and 6 months. Primary efficacy variables were percentage of "closed pockets" (PPD< or =4 mm), and changes in BoP, PPD and RAL. RESULTS: The percentage of "closed pockets" was 58% at 3 months for the Fm-UD approach and 66% for the Q-SRP approach (p>0.05). Both treatment groups showed a mean reduction in PPD of 1.8 mm, while the mean RAL gain amounted to 1.3 mm for Fm-UD and 1.2 mm for Q-SRP (p>0.05). The re-treatment at 3 months resulted in a further mean PPD reduction of 0.4 mm and RAL gain of 0.3 mm at 6 months, independent of the use of ultrasonic or hand instruments. The efficiency of the initial treatment phase (time used for instrumentation/number of pockets closed) was significantly higher for the Fm-UD than the Q-SRP approach: 3.3 versus 8.8 min. per closed pocket (p<0.01). The efficiency of the re-treatment session at 3 months was 11.5 min. for ultrasonic and 12.6 min. for hand instrumentation (p>0.05). CONCLUSION: The results demonstrated that a single session of Fm-UD is a justified initial treatment approach that offers tangible benefits for the chronic periodontitis patient.     

Effects of bur abrasive particle size and abutment composition on preparation of ceramic implant abutments

STATEMENT OF PROBLEM: Amid increasing use of preparable ceramic implant abutments, there is a lack of quantitative data to show which abrasive particle size of diamond bur yields the fastest reduction and provides the smoothest surface. PURPOSE: The research aim was to determine the effects of diamond bur abrasive particle size and abutment material composition on preparation efficiency, prepared surface roughness, and surface deterioration of diamond burs. MATERIAL AND METHODS: Fifteen alumina (Cera Base) and 15 zirconia (ZiReal) implant abutments were each machined using a high-speed hand piece with a diamond bur having 1 of 3 abrasive particle sizes (150, 100, or 30 microm) (n=5). Control abutments (n=5) were analyzed without machining. Abutments were weighed before starting and between machining cycles. Three profilometry measurements (root mean square surface roughness) were made for each abutment. Scanning electron micrographs were made of each bur. Lost abrasive particles were then counted on each micrograph through a randomly placed template. Two-way analysis of variance (alpha=0.05) was used to test for significant effects. RESULTS: Bur abrasive particle size and ceramic type had a significant interactive effect on the amount of material removed (P<.001). Super coarse (150 microm) burs yielded the roughest surfaces for each abutment material (P<.001), and prepared alumina surfaces were rougher than zirconia surfaces (P<.001). Super coarse burs showed the highest proportion of lost particles (P<.001). Abutment composition did not significantly affect bur wear. CONCLUSION: Super coarse burs yielded the most efficient material removal for alumina abutments. All abrasive particle sizes removed a similar amount of material from zirconia abutments. Fine-grained alumina abutments experienced greater material removal and rougher prepared surfaces compared with zirconia abutments. Material was removed by an intergranular fracture mechanism for alumina abutments, in contrast to transgranular fracture for zirconia abutments.     

Proof of efficacy of different modified sonic sealer inserts used for debridement in furcations – a dummy head trial

Abstract The purpose of this study was to determine the suitability of different scaling instruments for surgical removal of hard and soft bacterial deposits and for the removal of soft accretions only for maintenance treatment within furcations. 12 upper and 12 lower plastic replicated molars, with through-and-through furcations, were instrumented 3× with 4 different types of instruments: (1) hand instruments: (2) a conventional sonic sealer insert: (3) a set of 3 modified sonic sealer inserts with budded tips and different angulated shafts; (4) a set of 3 sonic sealer inserts with a plastic- coating and different angulated shafts. The plastic replicas were fixed in a dummy head without any replicated soft tissues. In the furcation area, an easily removable surface coating material was applied to the teeth to represent the “plaque” and a second, more stubborn lacquer layer representing “calculus/cementum”. Following instrumentation, the following parameters were recorded to assess efficacy: time required for instrumentation, loss of weight, depth of substance removal at the furcation entrance, % of furcation area instrumented, whereby removal of these 2 layers was judged separately. Only minor differences were observed between hand instruments, conventional and budded sonic sealer inserts as to loss of weight, depth of substance loss and area instrumented. The plastic-coated sonic sealer inserts were just as effective in surface layer removal representing “plaque” as the 3 other instruments, but resulted in less loss of weight and less depth of substance removal. In conclusion, the more aggressive hand instruments, the conventional and budded sonic sealer insert, are preferably used for the surgical phase to increased ease of entry into the furcation dome. An effective debridement of the furcation roof seems only possible with an odontoplastic, for which a furcation is fitted to the instrument by means of an intensive instrumentation, thus leading to weight loss and pronounced substance removal. The plastic-coated sonic sealer inserts seems to be a reasonable choice for maintenance treatment within furcation, since this treatment phase is usually restricted to removal of soft bacterial deposits.     

A comparative in vitro study of a magnetostrictive and a piezoelectric ultrasonic scaling instrument

BACKGROUND: The effects of magnetostrictive ultrasonic instruments and piezoelectric ultrasonic instruments on tooth surfaces seem to differ with regards to root debridement. AIM: The purpose of this study was to compare a magnetostrictive ultrasonic scaling instrument with a piezoelectric ultrasonic scaling instrument and a hand curette regarding time taken, calculus removal, tooth surface roughness (Ra), and SEM examination before and after instrumentation. METHODS: 30 extracted human teeth with subgingival calculus were assigned to one of three treatment groups (n=10). The working force was standardised for both ultrasonic instruments at 200 g and for the curette at 500 g. RESULTS: The results revealed that the time needed for instrumentation was 126.1+/-38.2 s for the curette, significantly more than for the piezoelectric ultrasonic instrument (74.1+/-27.6 s; p<0.05) and 104.9+/-25.4 s for the magnetostrictive ultrasonic instrument. Remaining calculus was similar for all three groups. The end Ra values were significantly worse for the piezoelectric instrument (2.02+/-0.41; p<0.05) compared to 1.42+/-0.48 for the curette and 1.36+/-0.41 for the magnetostrictive instrument. The SEM examination revealed the smoothest surfaces but, subjectively, the most tooth substance loss after the curette, followed by the magnetostrictive instrument, with the least substance loss, and then the piezoelectric instrument, with medium substance loss. CONCLUSION: The piezoelectric ultrasonic scaler was more efficient than the magnetostrictive ultrasonic scaler in removing calculus but left the instrumented tooth surface rougher.     

Laser treatment as an adjunct to debridement of periodontal pockets

The aim of the study was to investigate 1) whether laser treatment would enhance periodontal healing after debridement, 2) if laser treatment would facilitate instrumentation, and 3) if laser treatment would provide sufficient analgesia. The used apparatus produced radiation equivalent to a Nd:YAG-laser and was equipped with a water spray. 27 individuals with periodontitis took part in the study. Single-rooted teeth in one quadrant were assigned test teeth by lot with contralateral teeth serving as controls. Test areas were first laser irradiated to produce analgesia. The root surfaces were treated with the laser set at higher power and scaled with curettes followed by lasing again. Control areas were treated by scaling alone. Reduction of PPD and bleeding index after healing were similar in test and control areas. Laser treatment reduced the need of conventional anaesthetics, resulted in diminished bleeding and enhanced visual control at debridement. Thin calculus deposits were very easy to remove with hand instruments after lasing. The hemostatic effect of the laser may be an asset when performing periodontal scaling in individuals with a compromised coagulation mechanism.     

不同邻面抛光方法对牙釉质表面粗糙度及表面形貌的影响

目的：评价4种邻面抛光方法对邻面釉质表面粗糙度及显微形貌的影响,为邻面抛光方法的选择提供依据。方法：选择21颗离体牙前磨牙,沿颊舌面中线纵剖后获得邻面釉质试件42枚,再用自凝塑料包埋,暴露邻面釉质,用浮石粉抛光,并超声清洗。将42个试样均分为6组,分别作如下处理：A组空白对照,不做处理;B组：阴性对照,采用标准金刚砂车针切磨触点及其周围釉质,切磨后不抛光;其余4组为实验组,经标准金刚砂车针切磨后分别采用以下方法抛光：C组：极细粒度金刚砂车针抛光;D组：裂钻抛光;E组：矽粒子抛光;F组：彩虹抛光条抛光。之后用粗糙度仪测定釉面粗糙度,并进行扫描电镜观察。结果：标准金刚砂车针切磨后粗糙度大幅度增加（P〈0.05）,釉质表面发生明显条形凹陷性缺损;经4种方法抛光后,釉质表面粗糙度均有显著下降（P〈0.05）,显微形貌均较阴性组光滑,其中矽粒子抛光组可达到较空白对照组更为光滑的表面。结论：实验涉及的4种不同邻面抛光方法均有助于降低釉质切磨区域的表面粗糙度,但抛光效果存在差异;采用矽粒子抛光可完全抵消牙体预备时旋转器械对邻牙邻面的切磨作用,获得最为光滑的釉质表面。     

An evaluation of finishing instruments for an anterior and a posterior composite

The same finishing instruments and techniques revealed no significant differences in the surface roughness of the anterior and posterior composites. The smoothest surface was achieved with Mylar strips; the smoothest instrumented surface was achieved with a series of abrasive disks, but a fine diamond bur with 25 micron particles produced the roughest surface. However, an x-fine diamond with 15 micron particles produced a surface smoothness superior to that produced with a white stone and similar to the smoothness produced with a carbide bur and rubber point. Diamond finishing with slow speed produced a somewhat smoother finish than with high speed. SEM analysis revealed qualitative differences in surface texture even though the average roughness was not shown to differ.     

Periodontal healing after treatment with either the Titan-S sonic scaler or hand instruments

Several types of air turbine scalers have recently been introduced as an alternative to ultrasonic equipment in periodontal therapy. The aim of this investigation was to compare clinical, periodontal healing after scaling with the Titan S air turbine scaler and hand instruments. Twelve patients referred to the School of Dental Hygiene, J?nk?ping, Sweden, for treatment of moderately advanced periodontitis participated in the study. After examination, diagnosis, treatment planning, and information, the teeth of the left and right quadrants were randomly assigned to Titan S or hand instruments scaling ("split mouth design"). The treatment was given by 6 dental hygiene students. Final re-examination was performed 3 months after instrumentation. After treatment, a marked improvement of periodontal conditions, expressed as number of tooth surfaces with plaque, number of sites with probing pocket depth greater than or equal to 4 mm and percentage of sites showing bleeding on probing to the bottom of the pocket, was obtained. No difference in results was observed when comparing Titan S and hand instrumentation. The time required for instrumentation was, however, shorter for Titan S than for hand instruments. Based on the results of this study, it may be concluded that, in patients with moderately advanced periodontitis, periodontal healing after scaling with the Titan S and hand instruments is comparable.     

Roughness of enamel surfaces after different bonding and debonding procedures

Background and Aim

Maintaining an intact enamel surface is an essential aspect of orthodontic therapy; however, various therapeutic measures can affect this surface. The aim of our study was to evaluate roughness of the enamel surface after different conditioning and polishing procedures.

Materials and Methods

42 bovine incisors were submitted to conventional abrasion (using 37% phosphoric acid), to air abrasion, and a combination of the two. Brackets were put in place and then debonded, and the remaining adhesive removed with a carbide bur or via air abrasion. The enamel surface??s roughness was assessed using a confocal laser scanning microscope (CLSM).

Results

Mean roughness (R_a) was 33.1. There were no statistically significant differences among the six groups, or in R_q values. Under CLSM, the roughness after polishing via air abrasion appeared even. Although it was macroscopically smoother after polishing with a carbide bur, the surface showed a wave-like pattern.

Conclusion

The method of enamel conditioning revealed no significant effect on the enamel surface after debonding. Neither polishing via air abrasion nor carbide bur resulted in differences in superficial roughness. However, the carbide bur left a wave-like pattern on the enamel surface.     

Root debridement of single-rooted teeth with a diamond-coated sonic scaler insert during flap surgery. A pilot study

In our laboratory, we modified inserts of a sonic scaler to increase effectivity of root surface instrumentation during flap surgery. The present clinical study investigates whether use of this diamond-coated, thickened insert facilitates more rapid root debridement compared to hand instruments and whether clinical wound healing is influenced by the type of instrument used. In 13 patients with moderate to advanced periodontal destructions, flap surgery was carried out on single rooted teeth with probing depth of > or =6 mm. The mean amount of time saved by root debridement with the diamond-coated insert was 60% over curets. Regardless of the used instrumentation method probing depths and attachment level changes were altered and remained unchanged for 2 years after surgery. In conclusion the newly-developed, diamond-coated sonic scaler insert facilitates more rapid root debridement during flap surgery than hand instruments without disadvantageously affecting clinical healing.     

Impact of Er,Cr:YSGG laser therapy on the cleanliness of the root canal walls of primary teeth

Root canal therapy might be required for primary teeth displaying signs of pulpal inflammation or necrosis. Cleaning and shaping followed by obturation of the canal space with a resorbable paste have been widely performed with remarkable clinical success. However, lengthy endodontic procedures might be contraindicated when treating certain pediatric patients. The aim of this study was to compare the cleanliness of the root canal walls of primary teeth and the time required for the completion of the cleaning and shaping procedures performed by the Er,Cr:YSGG laser, manual or rotary instrumentation techniques. Thirty-five extracted, single-rooted, primary teeth were divided into 4 groups: I, canals were instrumented with Profile .04 rotary instruments to a master apical file size #35; II, the laser was used (parameters: 1.50 W, 20 pps, 30% water and 50% air) with a Z3 laser tip (0.32-mm diameter); III, canals were instrumented with stainless steel K-files; and IV, no instrumentation was performed (control). The teeth were split in 2 halves and prepared for scanning electron microscopy analysis. Images from the coronal, middle, and apical thirds of the roots were analyzed independently by 2 calibrated, blinded evaluators. Statistical analysis revealed significant differences among the groups (Kruskal-Wallis, P = .0001). The techniques were not capable of providing completely clean canals. Treatment with Er,Cr:YSGG laser provided similar cleanliness when compared with rotary instrumentation technique and was superior to manual instrumentation. The laser technique required less time for completion of the cleaning and shaping procedures when compared with both rotary or hand instrumentation.