Conventional Rotary Instruments Research Articles

Evaluation of Root Canal Debridement of Human Molars Using the GentleWave System

IntroductionStudies using conventional endodontic protocols show insufficient cleaning of root canal systems, often resulting in persistent infection and treatment failure. The GentleWave System (GWS; Sonendo, Inc, Laguna Hills, CA) has been shown to result in a higher tissue dissolution rate in a study using bovine muscle. The purpose of this study was to compare the debridement efficacy of the GWS with a traditional method for cleaning root canals. MethodsForty-five freshly extracted molars were randomly separated into 3 treatment groups (n = 15/group): group 1, no treatment; group 2, conventional rotary instrumentation and needle irrigation; and group 3, minimal instrumentation and the GWS treatment. Roots were prepared per standard histologic tissue processing after hematoxylin-eosin staining; sections were microscopically examined, and the percentage of soft tissue and debris remaining within the canals was morphometrically calculated. Images of the apical and middle regions of the roots were blindly analyzed. ResultsSignificant differences (Welch's t test) were found between groups 2 and 3 in both apical (P = .0015) and middle (P = .0179) regions of the mesial roots of mandibular molars and mesiobuccal roots of maxillary molars. Groups 2 and 3 resulted in cleaning 67.8% and 97.2% of the mesiobuccal and mesiolingual root canals of mandibular molars and the mesiobuccal canals of maxillary molars, respectively, whereas the results were similar among groups 2 and 3 in the apical and middle regions of distal roots. Groups 2 and 3 revealed significantly less debris than group 1 (P < .005). ConclusionsThe GWS showed a significantly greater cleaning capacity and reduction in residual debris within the mesiobuccal and mesiolingual canals of mandibular molars and the mesiobuccal canals of maxillary molars than those cleaned conventionally.

Root canal shaping by single-file systems and rotary instruments: a laboratory study.

The aim of this study was to compare the shaping ability of two single-file systems and conventional rotary instruments in severely curved root canals of extracted human molars. Mesiobuccal canals of 120 mandibular molars with angles of curvature ranging between 25(°) and 35(°) and radii of curvature from 5 to 9 mm, were divided into three groups (n=40). In each group the canals were instrumented with either WaveOne (W), Reciproc (R) or ProTaper (P). The time required for canal shaping and the frequency of broken instruments were recorded. The standardized pre and post-instrumentation radiographs were taken to determine changes in working length (WL) and straightening of canal curvature. The presence of blockage or perforation was also evaluated. Data were analyzed using the one-way analysis of variance (ANOVA) and post-hoc Tukey's test. The level of significance was set at 0.05. Both single-instrument systems reduced the canal preparation time by approximately 50% (P<0.05). No incidence of broken instruments from single-file systems was reported; however, two F2 instruments in the P group were broken (P<0.05). Reduction in WL and straightening of canal curvature was observed in all three systems with the highest scores belonging to P system (P<0.05). No case of blockage or perforation was found during shaping in any group. Single-file systems shaped curved canals with substantial saving in time and a significant decrease in incidence of instrument separation, change in WL, and straightening of canal curvature.

SUBJECTIVE ACCEPTANCE OF PEDIATRIC PATIENTS DURING CAVITY PREPARATION WITH Er:YAG LASER AND CONVENTIONAL ROTARY INSTRUMENTS

SUMMARY Aim: The aim of the present study is to evaluate and compare the subjective acceptance in children during hard dental tissue therapy using Er:YAG laser 2940nm and conventional rotary instruments. Methods and materials: The study included ninety 6-12-years-old children with matched carious lesions (D3 threshold, WHO system), divided into two equal treatment groups. In the intervention group the cavities were prepared with Erbium:YAG laser 2940nm and in the control group with conventional rotary instruments, without anaesthesia. After cavity preparation patient’s subjective acceptance was assessed by a questionnaire concerning primary stress triggers. Results: The annoyance factor (vibration) was found as a stress trigger in the majority of control children (86.7%), while in the intervention group it was found in 2.2% of cases. The most anxiety provoking items in the intervention group were smell (67.7%) and taste (42.2%). The sound was found to be a stress trigger in more than half of control children (62.2%) and less than one-fifth of the children in the intervention group (15.6%). The study results showed significant difference in these items between two groups (p< 0.001). Conclusions: The Erbium:YAG lasers reduce three of four stress triggers in ‘4S‘ principle - vibration, sight and sound. They are a good treatment option for fearful children since they have acceptable efficiency in treatment of pediatric anxiety disorders compared to the mechanical preparation.

Current update of chemomechanical caries removal methods.

Chemomechanical caries removal is an excellent method for minimally invasive caries excavation, and the removal agents are either sodium hypochlorite (NaOCl)- or enzyme-based. The NaOCl-based agents include GK-101, GK-101E (Caridex) and Carisolv, and the enzyme-based agents include Papacarie and the experimental material, Biosolv. This review outlines the changes in chemomechanical caries removal methods and focuses on recently published laboratory and clinical studies. The historical development, mechanism of action, excavation time and biological effects on pulp and dental hard tissues are described. Based on existing evidence, the currently available chemomechanical caries removal methods are viable alternatives to conventional rotary instrument methods. Chemomechanical methods could be extremely useful in very anxious, disabled and paediatric patients. It does seem some of these agents would still benefit from quicker excavation times in order to achieve more universal acceptance. However, as a means of conserving the caries-affected dentine, chemomechanical caries removal is possibly much more successful than conventional rotary instrumentation.

Is Erbium:Yttrium-Aluminum-Garnet Laser Versus Conventional Rotary Osteotomy Better in the Postoperative Period for Lower Third Molar Surgery? Randomized Split-Mouth Clinical Study

Lasers have been extensively used in dentistry for several applications. We investigated and compared the use of an erbium:yttrium-aluminum-garnet laser and conventional rotary instruments for bone removal in third molar surgery. We implemented a randomized, split-mouth clinical trial. Patients with bilateral and symmetrical third molar impaction referred to the Department of Oral and Maxillo-Facial Sciences, "Sapienza" University of Rome, were enrolled in the study. Each patient was treated once with the erbium:yttrium-aluminum-garnet laser and once with conventional rotary instruments for bone removal during third molar surgery. Pain, swelling, and trismus were taken into account to match the 2 techniques.In addition, the times required to complete osteotomy and for the full operation were recorded. Descriptive and bivariate statistics were computed, and the P value was set at .05. The sample was composed of 15 patients (8 men and 7 women) ranging in age from 18 to 30 years. Pain perceived in the laser-treated group was significantly less than that in the conventional group(P = .0013). This also was true for trismus (P = .0002) and swelling. The operating time for osteotomy was longer in the laser group. The results of this study suggest that the laser could be an interesting alternative to conventional rotary instruments. Future studies with a larger number of patients are required to confirm the conclusions achieved from this work.

Evaluation of the microleakage of different class V cavities prepared by using Er:YAG laser, ultrasonic device, and conventional rotary instruments with two dentin bonding systems (an in vitro study)

This study aimed to evaluate the extent of microleakage in class V cavities prepared with bur, Er:YAG laser, and ultrasonic, hybridized with two different bonding agents ("Single bonding" solvent-free bonding agent and "Swiss TEC SL bond" alcohol-based solvent). Thirty freshly extracted human premolars were divided into three groups (n = 10), on each tooth, two cavities were prepared on the buccal and the lingual surfaces, and each group was subdivided into two subgroups (n = 5). Group 1: 20 cavities were prepared by using Er:YAG laser (500 mJ, 10 Hz, 63.69 J/cm(2)) (subgroup1a: Single bonding was used with 10 cavities; subgroup 1b: Swiss TEC SL bond was used with 10 cavities). Group 2: 20 cavities were prepared by using ultrasonic (subgroup 2a: Single bonding was used with 10 cavities; subgroup 2b: Swiss TEC SL bond was used with 10 cavities). Group 3: 20 cavities were prepared by using burs (subgroup 3a: Single bonding was used with 10 cavities; subgroup 3b: Swiss TEC SL bond was used with 10 cavities). Cavities were restored with a micro-hybrid composite resin. After thermocycling, the specimens were immersed in 2 % methylene blue solution for 4 h and then sectioned in the bucco-lingual direction. Dye penetration was scored based upon the extent of the dye using a stereomicroscope. The two-way ANOVA test and paired t-test revealed no statistically significant differences among the methods of preparation (conventional, laser, and ultrasonic). However, statistical differences were found between the adhesives tested: the "Single bonding", which represented the solvent-free bonding agent, had lower microleakage values than "Swiss TEC SL bond", which represented the alcohol-based bonding agent. Based on the results of this study, it can be concluded that the Erbium:Yttrium-Aluminum Garnet (Er:YAG) laser and ultrasonic are as effective as the conventional method for preparing cavities and the extent of microleakage depends on the type of the bonding agents.

Behavioral changes in preschoolers treated with/without rotary instruments.

Background:Behavioral dentistry is an interdisciplinary science which needs to be learned, practiced, and reinforced in order to provide quality dental care in children.Aim:To assess the anxiety experienced during dental treatment in preschool children with/without rotary instruments using behavioral scale.Study and Design:Sixty pediatric patients of preschool age with bilateral occlusal carious lesions extending into dentin were selected for the study. Carious lesions were removed using conventional rotary instruments on one side and Papacarie – chemomechanical caries removal of approach on contra lateral side. Both cavities were restored with glass ionomer cement (Fuji IX). Anxiety scores were determined using ‘Modified Child Dental Anxiety Scale’ (Wong et al, 1998) during the various clinical stages of the treatment course.Results:Children experienced relaxed behavior when subjected to Papacarie method of caries removal compared to conventional method using rotary instruments.Conclusion:This study helped us to provide behavioral measures and introduce children to dentistry in a nonthreatening setting.

Stress Generation during Self-Adjusting File Movement: Minimally Invasive Instrumentation

IntroductionAlthough nickel-titanium (NiTi) rotary instruments may produce a well- tapered root canal with a low tendency of aberrations, these are generally perceived to have a high fracture risk during use and may produce significant forces on root dentin during instrumentation, which may induce a dentinal defect or crack in the apical part of the root. This study compared mathematically the stress generated by the Self-Adjusting File (ReDent-Nova, Ra'anana, Israel) with conventional rotary instruments during the movement of 3 NiTi endodontic file designs in a curved root canal. MethodsStresses were calculated using finite element analysis. Three file designs with tip size ISO #20 were used in this study. Finite element models of ProFile #20/.06 (Dentsply Maillefer, Ballaigues, Switzerland) (a constant tapered shaft), ProTaper Universal F1 (Dentsply Maillefer) (a progressively changing taper shaft), and SAF 1.5 mm (a mesh shaft) were activated within a curved root canal model. The stress generations resulting from the simulated shaping movement were evaluated in the apical root dentin area. ResultsThe SAF induced the lowest von Mises stress concentration and the lowest tensile principal stress component in root dentin. The calculated stress values from ProTaper Universal F1 and ProFile #20/.06 were approximately 8 to 10 times bigger than that of the SAF. ConclusionsStress levels during shaping and the susceptibility to apical root cracks after shaping vary with instrument design. The design of the SAF may produce minimal stress concentrations in the apical root dentin during shaping of the curved canal, which may increase the chance of preservation of root dentin integrity with a reduced risk of dentinal defects and apical root cracking.

Comparison of a Novel Trephine Drill with Conventional Rotary Instruments for Maxillary Sinus Floor Elevation

The purpose of this study was to compare a newly designed trephine drill (SLA KIT, Neobiotech) with conventional rotary instruments for maxillary sinus floor elevation based on operative time, postoperative pain, and perforation rates. Twenty-five patients were treated with a bilateral sinus floor elevation procedure with rotary trephine and conventional instruments. One side was treated with conventional rotary instruments, while the contralateral side was treated with rotary trephine instruments, with a 2-week gap between surgeries. Operative time was measured with a chronometer in seconds as the time from soft tissue incision to primary closure of the incision with the last suture. Pain was scored on a 10-point visual analog scale at 24 hours after surgery. The presence of tears and perforations was determined by direct visualization and the Valsalva maneuver. Twenty-five patients were included in the study. Operative time was shorter when the trephine drill was used (11.1 ± 2.4 minutes) than with conventional rotary instruments (15.1 ± 2.9 minutes). Sinus membrane perforation was observed in eight patients when conventional rotary instruments were used, while the trephine drill resulted in two sinus perforations. Mean pain scores were 2.01 ± 0.11 after using the trephine drill and 2.25 ± 0.76 when conventional rotary instruments were used. No significant difference was found in postoperative pain scores. The trephine drill technique may result in decreased perforation rates and operative time.

Effect of piezoelectric instruments on healing propensity of alveolar sockets following mandibular third molar extraction

Background/purposeThe purpose of this study was to investigate whether the use of piezoelectric instruments affected the healing propensity of alveolar sockets after mandibular third molar extraction, compared with conventional rotary instruments. Materials and methodsThirty patients with impacted bilateral symmetrical mandibular third molars participated in this investigation. We conducted a randomized, crossover study using conventional rotary instruments for extraction on one side and piezoelectric instruments on the other. We evaluated the healing of periodontium at the distal side of the mandibular second molar by probing depth and attachment level. All data including pocket depth and bone healing at the distal side of the mandibular second molar were evaluated with paired t tests for comparison. ResultsAlthough the average pocket depth after extraction with piezoelectric instruments was slightly less than with conventional instruments, there was no statistically significant difference between the two groups. At one month after extraction, the attachment level at the distal side of the mandibular second molar was better where extraction was done with piezoelectric instruments than conventional instruments (P < 0.05), though no significant difference between the two extraction methods was observed at two months postoperation. ConclusionPeizoelectric instruments have potential to promote initial bone healing after molar extraction.

Ultrasonic Margin Preparation for Fixed Prosthodontics: A Pilot Study

Atraumatic, oscillating ultrasonic instruments have recently been developed for prosthodontic margin finishing. This in vitro observational pilot study aimed to compare the condition of crown preparation margins finished using new ultrasonic instruments with margins finished with conventional rotary instruments. Two extracted human canine teeth were prepared for crowns. A split-tooth model was used to refine the margins: half of the margin was finished with conventional rotary instruments, the other with ultrasonic instruments. The profiles of the margins were observed using scanning electron microscopy, and a quantitative comparison of surface roughness was obtained using surface roughness analysis software. The margins finished with the ultrasonic instruments exhibited a better-defined axial wall/margin angle and a smoother marginal surface. Rotary instruments produced a sharper and more continuous external line angle. Two-dimensional surface roughness analysis showed that the margins produced with the ultrasonic instruments were approximately half as rough as the margins prepared with the conventional rotary instruments. The ultrasonic instruments produce margins in better condition than the current standard and appear to have some practical advantages. Preparations for fixed prosthodontics finished with these ultrasonic instruments created better-defined margins, which could result in more successful prostheses.

Piezoelectric vs. conventional implant site preparation: ex vivo implant primary stability

This study aims to determine differences in primary stability between implants placed in cortical bone following Piezoelectric or conventional site preparation, as assessed by resonance frequency analysis (RFA) and reverse torque testing (RTT). Four fresh bovine ribs were acquired and surgical guides fabricated with five sites per rib (n=20), for proper site preparation. Implant sites were prepared via conventional drilling technique as per manufacturer's instruction (Implantium) or via Piezoelectric (Mectron) implant site preparation using the Implant Prep kit. Twenty 10mm long, 3.6mm diameter Implantium implants were placed with 35Ncm torque; 10 implants per preparation method. RFA was assessed via the Osstell Mentor. Five values were taken per implant. All implants where subjected to a reverse torque in increasing increments of 5 until 50Ncm force was reached. The five RFA values per site were averaged and plotted by placement technique. A paired t-test statistical analysis was run. The average RFA values showed no statistical significance between the 10 test (RFA=69.04±5.11) and 10 control (RFA=70.94±6.41) sites (P>0.05). All implants in both groups withstood RTT up to 50Ncm force without movement and thus showed no statistical differences. Results of this ex vivo study imply that the Piezoelectric implant site preparation affords similar primary implant stability in comparison to conventional rotary instrumentation in cortical bone.

A Randomized Clinical Evaluation of Ultrasound Bone Surgery Versus Traditional Rotary Instruments in Lower Third Molar Extraction

The purpose of this study was to investigate and compare, in a randomized and controlled clinical trial, the use of ultrasound bone surgery devices and the use of rotary instruments in lower third molar extractions. We selected 26 patients (12 women and 14 men) for this study; the mean age was 31.2 years (range, 24-45 years). A randomized clinical trial was planned. Patients in the control group received treatment with the conventional rotary instruments; patients in the test group received treatment with the ultrasound bone surgery tools. Twenty-six third molars were allocated to the test and control groups according to a computer-generated randomization list. All the surgical procedures were performed by the same surgeon. Pain, trismus, cheek swelling, and number of analgesics taken were evaluated at baseline (before surgery) and at the first-, third-, fifth-, and seventh-day visits. Pain levels (evaluated on a visual analog scale) were higher in the control group when compared with the ultrasonic group; however, no statistically significant differences were found. On the contrary, the number of analgesics taken in the test group was significantly lower when compared with the control group. The occurrence of trismus was significantly higher in the control group when compared with the test group. The clinical values of cheek swelling were higher in the rotary group when compared with the ultrasound group at the fifth-day visit. This study showed that the use of ultrasound bone surgery for third molar extraction significantly reduced the occurrence of postsurgical trismus, the occurrence of swelling, and the number of analgesics taken after surgery.

Application of ultrasound in bone surgery: Two case reports

The present study describes some of the applications of ultrasound in bone surgery, based on the presentation of two clinical cases. The Piezosurgery® ultrasound device was used (Tecnología Mectron Medical, Carasco, Italy). In one case the instrument was used to harvest a chin bone graft for placement in a bone defect at level 1.2, while in the other case a bony window osteotomy was made in the external wall of the maxillary sinus, in the context of a sinus membrane lift procedure. The Piezosurgery® device produces specific ultrasound frequency modulation (25-29 kHz), and has been designed to secure increased precision in application to bone surgery. This instrument produces selective sectioning of the mineralized bone structures, and causes less intra- and postoperative bleeding. One of the advantages of the Piezosurgery® device is that it can be used for maxillary sinus lift procedures in dental implant placement. In this context it considerably lessens the risk of sinus mucosa laceration by preparing the bony window in the external wall of the upper maxilla, and can be used to complete the lifting maneuver. The use of ultrasound in application to hard tissues can be regarded as a slow technique compared with the conventional rotary instruments, since it requires special surgical skill and involves a certain learning curve.

Laser use vs. handpiece for tooth preparation: A preliminary in vitro study

The key fields of research of dental lasers have focused on the use of different wavelengths on hard and soft tissues; however it is not clear whether they can be used for tooth preparation for full coverage restorations or not. The objective of this study was to investigate the possibility of tooth preparation for full coverage restorations using a scanner assembly added-on Er:YAG laser system and compare the tooth preparation durations performed with dental drills and the laser. The 20 freshly extracted human molar teeth were allocated to two groups (A and B) of 10. Group A was prepared with dental drills, whereas group B was prepared with a scanner assembly added-on Er:YAG laser system. The preparation duration means of the groups were calculated and analyzed by one-way analysis of variance. The difference between group A (20, 2±1, 9 min) and B (45, 2±|3, 1 min) (P&amp;lt;0.01) was significant. Laser preparation took more time than the conventional rotary instrumentation. The recommended amount of tooth reduction for full coverage restorations could be accomplished by the laser tooth preparation. Tooth preparation using Er:YAG laser with laser application for wide area system took more time than the rotary instruments.

Clinical evaluation of a chemomechanical method for caries removal in children and adolescents

Objective. The purpose of this study was to make a clinical comparison of the chemomechanical method for caries removal and the conventional rotary instruments technique when used in children and adolescents. Material and Methods. The study comprised 120 patients aged 3–17 years randomized into two groups: caries were removed chemomechanically in 60 patients and 60 patients received conventional treatment with rotary instruments. The outcome variables were: clinically complete caries removal, pain during caries removal, need for local anesthesia, treatment time, preferences of patients, and clinical success of the restorations during the 12-month evaluation period. Results. Complete caries removal was achieved in 92% of chemomechanically treated teeth and in all teeth treated with rotary instruments (p>0.05). The chemomechanical method significantly reduced the need for local anesthesia (p<0.001). Eighty-five percent of patients treated with Carisolv and 47% treated with rotary instruments were satisfied with the treatment (p<0.05). The mean time for chemomechanical caries removal was 11.2±3.3 min and 5.2±2.8 min for caries removal with rotary instruments (p<0.001). At the end of the 12-month evaluation period, there was no observed influence of the caries removal method on the survival of the restorations. Conclusions. The chemomechanical caries removal technique is an adequate alternative to the conventional rotary instruments method and is advantageous in pediatric dentistry.

Dental caries: Therapeutic possibilities

Contemporary tendencies in dentistry are based on the concept of maximal protection of healthy tooth tissues. Caries removal has been done traditionally with mechanical rotary instruments that are fast and precise. However, conventional cavity preparation has potential adverse effects to the pulp due to heat, pressure and vibrations. Moreover, drilling often causes pain and requires local anaesthesia, and these procedures are frequently perceived as unpleasant. Etiology, development and prevention of dental caries are better understood today and new restorative materials that bond micromechanically and/or chemically to dental tissues have been introduced. Thus, development of a new, less destructive caries removal technique is allowed. In the last decades, many alternative methods have been introduced in an attempt to replace rotary instruments. These are claimed to be efficient and selective for diseased tissues and to offer comfortable treatment to the patients. New methods include air abrasion, air polishing, ultrasonic, polymer burs, enzymes, systems for chemo-mechanical caries removal, and lasers. The aim of this paper was to discuss various caries removal techniques and possibilities of their use in clinical practice. Based on the literature review it can be concluded that none of the new caries removal methods can completely replace conventional rotary instruments.

Radiation-induced root surface caries restored with glassionomer cement placed in conventional and ART cavity preparations: Results at two years

There are no published studies comparing the clinical performances of more-viscous glass-ionomer cement (GIC) restorations when placed using conventional and atraumatic restorative treatment (ART) cavity preparation methods to restore root surface caries. One dentist used encapsulated Fuji IX GP and Ketac-Molar to restore 72 conventional and 74 ART cavity preparations for 15 patients who had received cervicofacial radiation therapy. Two assessors evaluated the restorations at six, 12, and 24 months for retention, marginal defects and surface wear, and recurrent caries. After two years, the cumulative restoration successes were 65.2 per cent for the conventional and 66.2 per cent for the ART cavity preparations, without statistical or clinical significance (P > 0.50). Restoration dislodgement accounted for 82.8 per cent and marginal defects for 17.2 per cent of all failures. There were no instances of unsatisfactory restoration wear or recurrent caries observed. Teeth with three or more restored cervical surfaces accounted for 79.3 per cent of all failures (P < 0.0001). For root surface caries restored with GIC, the use of hand instruments only with the ART method was an equally effective alternative to conventional rotary instrumentation for cavity preparation. Larger restorations had higher failures, usually from dislodgement.

Survival of glass ionomer restorations placed in primary molars using atraumatic restorative treatment (ART) and conventional cavity preparations: 2-year results

To compare the survival of glass ionomer cement (GIC) restorations placed in a dental clinic setting using both the atraumatic restorative treatment (ART) approach with hand instruments, and conventional cavity preparation with rotary instruments. Two encapsulated high-strength conventional GICs (Fuji IX GP, Ketac-Molar Aplicap) were placed in 82 Class I and 53 Class II preparations and one encapsulated non-gamma 2 amalgam alloy (GK-amalgam) was placed in 32 Class I preparations, in the primary molars of 60 Chinese children with a mean age of 7.40 +/- 1.24 (SD) years. Thus, 9 treatment groups were formed. After two years, there were no significant survival differences found among 7 of the 9 treatment groups (p = 0.99). However, two groups comprising Fuji IX GP and Ketac-Molar Aplicap placed in Class II cavities prepared using the ART approach showed significantly lower restoration survivals (p < 0.001). Only 3 of the 72 initially sealed fissures adjacent to the restorations appeared to retain any GIC material. In a clinic setting, both the ART hand instrument and conventional rotary instrument methods were equally suitable for high Class I restoration survival, but not for Class II restoration survival where the conventional cavity preparation method was preferable.

In vitro comparison of the efficacy of Carisolv and conventional rotary instrument in caries removal.

The purpose of this in vitro study was to compare the efficacy of a new chemomechanical caries removal agent, Carisolv (MediTeam AB, Sävedalen, Sweden), with conventional slow-speed rotary instrument (bur). Fourteen extracted human molar teeth with deep dentine caries and no enamel coverage were selected for the study. Their laser fluorescence values were over 30 (DIAGNOdent; KaVo, Biberach, Germany). After the teeth were sectioned through the centre of the carious lesion, one half was removed with conventional drilling (bur); the other half was removed with Carisolv gel. Removal of carious dentine was continued until the lesion was deemed caries-free by visual and tactile criteria. The preparation time for each caries removal technique was also noted. The two halves of each tooth were fixed in 10% buffered-formaldehyde for 1 week. They were then decalcified, dehydrated and embedded in paraffin blocks for histological studies. After taking serial sections of 5 microm thickness, sections were mounted on glass slides, deparaffinized, dehydrated and stained with toluidine blue for observation under a light microscope. Each section was examined for the presence of bacteria. Complete removal of caries was achieved in 13 (93%) of 14 conventionally prepared teeth, and 5 (36%) of 14 chemomechanically prepared teeth (P < 0.05). Mean (+/-SD) time for caries removal was 272 s (+/-53.3) with Carisolv, and 116 s (+/-49.4) with drilling. The results of this study suggest that conventional rotary instrument (bur) was more effective than Carisolv in removal of carious tissue and also takes shorter time.