ProTaper Universal System Research Articles

Incidence of apical crack formation and propagation during removal of root canal filling materials with different engine driven nickel-titanium instruments.

ObjectivesTo determine the incidence of crack formation and propagation in apical root dentin after retreatment procedures performed using ProTaper Universal Retreatment (PTR), Mtwo-R, ProTaper Next (PTN), and Twisted File Adaptive (TFA) systems.Materials and MethodsThe study consisted of 120 extracted mandibular premolars. One millimeter from the apex of each tooth was ground perpendicular to the long axis of the tooth, and the apical surface was polished. Twenty teeth served as the negative control group. One hundred teeth were prepared, obturated, and then divided into 5 retreatment groups. The retreatment procedures were performed using the following files: PTR, Mtwo-R, PTN, TFA, and hand files. After filling material removal, apical enlargement was done using apical size 0.50 mm ProTaper Universal (PTU), Mtwo, PTN, TFA, and hand files. Digital images of the apical root surfaces were recorded before preparation, after preparation, after obturation, after filling removal, and after apical enlargement using a stereomicroscope. The images were then inspected for the presence of new apical cracks and crack propagation. Data were analyzed with χ2 tests using SPSS 21.0 software.ResultsNew cracks and crack propagation occurred in all the experimental groups during the retreatment process. Nickel-titanium rotary file systems caused significantly more apical crack formation and propagation than the hand files. The PTU system caused significantly more apical cracks than the other groups after the apical enlargement stage.ConclusionsThis study showed that retreatment procedures and apical enlargement after the use of retreatment files can cause crack formation and propagation in apical dentin.

The root canal shaping ability of WaveOne and Reciproc versus ProTaper Universal and Mtwo rotary NiTi systems

Aim: The aim of this study is to compare the root canal shaping ability of two reciprocating instruments: WaveOne and Reciproc versus two rotary instruments – ProTaper Universal (PTU) and Mtwo. Materials and Methods: A total of 160 simulated root canals in resin blocks were constructed with two curvatures located at two positions creating four different combinations: 20°/8 mm, 20°/12 mm, 40°/8 mm, and 40°/12 mm. Canals were prepared using continuous rotation (PTU and Mtwo) or reciprocating (WaveOne and Reciproc) instruments according to the manufacturer's recommendations. Each system was used to prepare 10 canals of each shape. Each file or a set of files was used to prepare one canal. Using Image Analysis Software, pre- and post-instrumentation matching images were superimposed and analyzed for canal width and transportation. Instrument fractures, time of preparation, and change in working length were also recorded. The effect of instrument and canal type on shaping ability were analyzed using two-way ANOVA test followed by post hoc Pearson Chi-square test and sum of squares test at level of significance 5%. Results: The largest mean canal width and transportation values were associated with the Mtwo system (P Conclusions: Continuous rotation and reciprocating files were safe and maintained the original canal anatomy. However, continuous rotation instruments have a higher tendency for canals transportation and aberrations, especially with larger curvatures. Reciprocating files were faster than continuous rotation files in shaping simulated root canals in resin blocks.

Apical extrusion of debris in four different endodontic instrumentation systems: A meta-analysis.

Background:All endodontic instrumentation systems tested so far, promote apical extrusion of debris, which is one of the main causes of postoperative pain, flare ups, and delayed healing.Objectives:Of this meta-analysis was to collect and analyze in vitro studies quantifying apically extruded debris while using Hand ProTaper (manual), ProTaper Universal (rotary), Wave One (reciprocating), and self-adjusting file (SAF; vibratory) endodontic instrumentation systems and to determine methods which produced lesser extrusion of debris apically.Methodology:An extensive electronic database search was done in PubMed, Scopus, Cochrane, LILACS, and Google Scholar from inception until February 2016 using the key terms “Apical Debris Extrusion, extruded material, and manual/rotary/reciprocating/SAF systems.” A systematic search strategy was followed to extract 12 potential articles from a total of 1352 articles. The overall effect size was calculated from the raw mean difference of weight of apically extruded debris.Results:Statistically significant difference was seen in the following comparisons: SAF < Wave One, SAF < Rotary ProTaper.Conclusions:Apical extrusion of debris was invariably present in all the instrumentation systems analyzed. SAF system seemed to be periapical tissue friendly as it caused reduced apical extrusion compared to Rotary ProTaper and Wave One.

Effects of Different Final Irrigating Solutions on Depth of Sealer Penetration into Dentinal Tubules: An in vitro Confocal Laser Microscopic Study

ABSTRACT Aim To evaluate the maximum depth of sealer penetration into dentinal tubules at the coronal, middle, and apical third of root canals, following the use of different final irrigation solutions. Materials and methods Eighty freshly extracted mandibular premolars were selected for the study. After decoronation, instrumentation of samples was done using Protaper universal rotary file system till F4. During shaping and cleaning of root canal, 5.25% concentration of sodium hypochlorite (NaOCl) was used for irrigation. The samples were then randomly divided into four groups (n = 20) depending on the final irrigating solution used. Group I: 17% aqueous ethylenediaminetetraacetic acid (MA) (aq. EDTA); group II: 10% citric acid (CA); group III: 5% maleic acid; group IV: 5.25% conc. NaOCl. Passive ultrasonic irrigation (PUI) was used to activate each final irrigating solution. The samples were obturated using warm lateral condensation technique with guttapercha coated with AH plus sealer mixed with rhodamine B dye. Confocal laser scanning microscopy (CLSM) examined the sealer penetration depth. Results The Kruskal-Wallis analysis results showed that there was a significant difference in the maximum depth of sealer penetration among all groups in all sections (p &lt; 0.05). The coronal sections of the root canals in each group showed a significantly higher depth of sealer penetration than did the apical and middle sections (p &lt; 0.05). Conclusion A combination of 17% aq. EDTA and PUI used for final irrigation proved to be more effective for sealer penetration into the dentinal tubules. Clinical significance Final irrigation protocol followed is of paramount importance in achieving complete disinfection within the root canal, and also the penetration of sealer serves as an indicator of the extent to which the smear layer was removed. How to cite this article Shetty MA, Hegde V. Effects of Different Final Irrigating Solutions on Depth of Sealer Penetration into Dentinal Tubules: An in vitro Confocal Laser Microscopic Study. J Oper Dent Endod 2017;2(2):69-73.

Comparative evaluation of postoperative pain after single visit endodontic treatment using ProTaper Universal and ProTaper Next rotary file systems: A randomized clinical trial

Introduction: Root canal preparation may cause inadvertent apical extrusion of debris causing postoperative pain. This debris varies with the instrumentation technique and design characteristics. One of the major revolutions in the design of the instruments is the introduction of files with an offset center of mass or/and rotation, which causes asymmetric rotary motion in the canal. An example is the ProTaper Next (PTN) rotary file system. In vitro studies have shown that this system extrudes lesser debris than more commonly used ProTaper Universal (PTU). However, in clinical circumstances, periapical tissues may act as a natural barrier and host immune response may affect the response. Hence, the aim of the present study was to evaluate and compare the postoperative pain after single visit endodontic treatment using PTU and PTN rotary file systems. Study Design: A total of 80 patients were assigned to two groups according to the root canal instrumentation technique used, PTU or PTN. Root canal treatment was carried out in a single appointment, and the severity of postoperative pain was assessed using visual analog scale score after 6, 24, 48, and 72 h. The association of variables (age and sex) and root canal preparation time were also evaluated and compared between the groups. Results: Postoperative pain was significantly higher in PTU group than PTN group. The highest pain was observed at 6 h interval which reduced with each time with no pain at 72 h interval in both the groups. Significantly, more amount of time was involved with PTU as compared to PTN. A significantly higher pain was observed with advancing age and in females. Conclusion: The postoperative pain was significantly higher in patients undergoing canal instrumentation with PTU rotary instruments as compared to the PTN rotary instruments.

EVALUAREA MATERIALULUI DE OBTURAŢIE DE CANAL RESTANT DUPĂ DEZOBTURARE, FOLOSIND PROTAPER ROTATIV CU SAU FĂRĂ SOLVENŢI

The purposes of retreatment are to eliminate the cause for failure of initial endodontic treatment and to preserve the tooth as well. The aim of this study is a comparative evaluation of efficacy of Protaper rotaty retreatment instruments for gutta-percha removal with or without solvents specific both to the sealer and gutta-percha. Materials and methods: Forty single-rooted extracted teeth were randomly divided into 4 groups according to different methods of retreatment. The teeth were prepared with Protaper Universal system (Dentsply-Maillefer, Ballaigues, Switzerland) and filled using lateral condensation of gutta-percha and AH Plus (Dentsply DeTrey, Konstanz, Germany). All root canal fillings were removed using Protaper Universal Retreatment system (Dentsply-Maillefer, Ballaigues, Switzerland). During the retreatment procedure, in group 1 Resosolv (Pierre Rolland, Merignac, France) was used; in group 2 eucalyptol was used, in group 3 Endosolv E (Septodont, Paris, France) was used and in group 4 no solvent was used. The times required for retreatments and radiographycal evaluation after retreatment were recorded. Results: All root canals showed filling material remnants and group 1 with specific solvent for AH Plus recorded the shortest time. Conclusions: Although it is not possible to eliminate the entire filling material on the canal walls, the duration of retreatment was reduced by the use of a solvent specific to the sealer compared with a gutta-percha solvent or no solvent.

ENDODONTICS PROCEDURAL ERRORS

The rationale of this study was to assess the results of training endodontic topostgraduates. This study was assumed to evaluate the procedural quality of root canalobturation and occurrence of ritual errors in the root canal treatment cases performed bypostgraduates in the department of Operative Dentistry. Study Design: Cross sectional caseseries study. Setting: Department Operative Dentistry, Liaquat University of Medical HealthScience, Jamshoro. Period: May 2014 to Apr 2016. Methodology: Total two hundreds eightyeight cases were evaluated, out of which 144 were prepared using Pro-taper universal (Dentsply)rotary system and 144 were prepared using conventional hand file system. Each group of teethwas evaluated by radiograph for the occurrence or lacking of procedural errors i-e overfill, underfill, instrument separation. Results: Among 288 cases, out of 144 conventionally treated teeth58 (49%) had procedural errors. Whereas out of 144 teeth treated with Pro-taper next rotarysystem, 61 (51%) had technical errors. Most of errors seen in both groups but farthest wereoverfill. Chi square test showed P value &gt; 0.05 (0.416) which illustrate an irrelevant relationshipamong the systems applied &amp; the incidence of errors. Conclusion: There was variation amongoverfill &amp; under fill prevalence of practical errors in both systems; nonetheless, there was adisparity in the nature of error produced. It is accomplished that even though rotary systems arenot as simple to use as formerly alleged.

Comparative Analysis of Dentinal Erosion after Passive Ultrasonic Irrigation versus Irrigation with Reciprocating Activation: An Environmental Scanning Electron Study

IntroductionThe aim of this study was to assess ex vivo the erosive effects of passive ultrasonic irrigation versus irrigation with reciprocating activation on the dentinal surface of the root canal at 3 predetermined levels using environmental scanning electron microscopy. MethodsTen roots of mandibular premolars were prepared using the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland). The specimens were embedded in flasks cleaved longitudinally, and indentations were made 3.0, 6.0, and 9.0 mm from the apex. The specimens in the control group (n = 10) were cleaned in an ultrasonic bath containing 2.5% sodium hypochlorite and 17% EDTA and then dried. Then, environmental scanning electron microscopic images were obtained at magnification × 800. The specimens were then reassembled in their flasks, and the NaOCl and EDTA solutions were activated according to the conditions established for the experimental groups (ie, the passive ultrasonic irrigation group [n = 5] and the EasyClean (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brazil) group, irrigation with reciprocating activation with the EasyClean instrument [n = 5]). The specimens of both experimental groups were analyzed in the same manner as in the control group. Analysis of the dentinal surface topography was conducted using the 3D Roughness Reconstruction program (Phenom-World BV, Eindhoven, the Netherlands) as a means for assessing erosion. The data were evaluated by means of the Kruskal-Wallis, Student-Newman-Keuls, and Mann-Whitney tests. ResultsIn the EasyClean group, the degree of dentinal erosion at 3.0 mm was significantly higher than at 9.0 mm. In the other comparisons, there was no statistically significant difference (P < .05). ConclusionsThe final irrigation techniques tested were equivalent in relation to the degree of erosion caused to the dentinal surface.

On the Causality Between Dentinal Defects and Root Canal Preparation: A Micro-CT Assessment.

This study aimed to evaluate the cause-effect relationship between canal preparation with ProTaper Universal (PTU) system and dentinal defects formation using micro-computed tomography (micro-CT) analysis. Forty mesial canals of mandibular molars with a type II Vertucci's canal configuration were scanned at an isotropic resolution of 14.16 µm. The sample was assigned to an experimental (n = 30) and a control (n = 10) groups, and the mesial canals were prepared with PTU system up to F2 instrument. The specimens from the experimental group were scanned and the cross-section images of the mesial roots, before and after preparation, were screened to identify the presence of dentinal defects. In the control group, the specimens were sectioned perpendicularly to the long axis of the root into 1-mm-thick slices (n = 80) and examined under optical microscope. Once a dentinal defect was detected, the slice was scanned through micro-CT. In the experimental group, dentinal micro-cracks were observed in 4,828 slices (24.04%). In all cross-section images, dentinal defects identified in the postoperative images were already present in the corresponding preoperative image. In the control group, 13 out of 80 slices (16.25%) had at least one dentinal defect visualized under stereomicroscopy, which was identified after a further micro-CT scanning. Micro-CT showed reliability as similar as optical microscopy in detecting dentinal defects, adding the possibility of tracking the dentinal tissue, before and after canal preparation, and providing a clear visualization of micro-cracks. Root canal preparation with PTU system did not induce the formation of new dentinal defects.

Vertical Load Induced with Twisted File Adaptive System during Canal Shaping

IntroductionTo evaluate the vertical load induced with the Twisted File Adaptive (TFA; SybronEndo, Orange, CA) system during canal shaping of extracted teeth by comparing it with the Twisted File (TF, SybronEndo), ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), and ProTaper Universal (PTU, Dentsply Maillefer) systems. MethodsFifty-two root canals were shaped using the TFA, TF, PTN, or PTU systems (n = 13 for each system). They were shaped gently according to the manufacturers' instructions. During canal shaping, vertical loads were recorded and shown in 2 directions, apically and coronally directed loads. The vertical peak loads of 3 instrumentation stages were used for comparison. The effects of rotary systems on the mean positive and negative peak loads were analyzed statistically using the Kruskal-Wallis and Mann-Whitney tests at a confidence level of 95%. ResultsThe overall pattern of the instantaneous loads appeared to increase with the use of successive instruments within the system. During canal shaping in all groups, the apically and coronally directed peak loads ranged from 0.84–7.55 N and 2.16–2.79 N, respectively. There were significant differences in both peak loads among the tested systems at each instrumentation stage. TFA had the lowest apically directed peak loads. In terms of coronally directed peak loads, the TFA and TF had a significantly lower amount of loads developed with their instruments than PTN and PTU. ConclusionsThe choice of instrument system had an influence on the loads developed during canal shaping. TFA instruments were associated favorably with the lowest values of peak loads followed by TF, PTN, and PTU.

Influence of Operator's Experience on the Shaping Ability of Protaper Universal and Waveone Systems: A Comparative Study on Simulated Root Canals.

Objective:To assess the influence of operator experience on: shaping and centering ability, mean preparation time and presence of canal aberrations of ProTaper Universal and WaveOne systems on simulated root canals.Materials and Methods:Sixty S-shaped canals in resin blocks were assigned to four groups (n=15 for each group). Group1 (Experienced operator, ProTaper), Group2 (Experienced operator, WaveOne), Group3 (Inexperienced operator, ProTaper), Group4 (Inexperienced operator, WaveOne). Photographic method was used to record pre- and post-instrumentations images. After superimposition, it has been evaluated presence of canal aberrations and differences in shaping and centering ability between groups.Results:WaveOne system produced a lower amount of canal aberrations both in the hand of expert than inexpert operators. However, a WaveOne instrument breakage occurred in the hands of an inexperienced operator. No differences have been found in the evaluation of shaping ability with both systematics. Operator’s experience doesn't influence the shaping ability of ProTaper and WaveOne systems.Conclusion:Experience factor could influence the centering ability in the use of both the systematics. However, WaveOne Primary reduce the mean preparation time and the presence of canal aberrations.

Effect of Intracanal Irrigants on Bond Strength of Fiber Posts Cemented With a Self-adhesive Resin Cement

The aim of this study was to evaluate the effect of five intracanal irrigants on bond strength of fiber posts cemented with newer self-adhesive resin cement. A total of 60 extracted, single-rooted human premolars, sectioned at 14 mm, were prepared with the ProTaper Universal system with a size F3 instrument and filled with an F3 master cone and AH Plus. The root canal filling was partially removed, leaving 4 mm of apical gutta-percha. Specimens were randomly assigned to five groups (n=12), according to the solution used for dentin surface treatment before fiber post cementation, as follows: EDTA 17% (EDTA); QMix (QM); SmearClear (SC); 2.5% sodium hypochlorite (NaOCl), and 0.9% saline solution (SS). Ultrasonic activation was performed (three times, 20 seconds each), and root canals were dried with paper points. Fiber posts were cemented with RelyX U200. In one specimen per group, rhodamine B dye was mixed with RelyX U200 to provide adequate fluorescence for confocal laser scanning microscopy (CLSM) assessment. Specimens were transversally sectioned and three slices were obtained, one for each root third. Next, a push-out test was performed. A stereomicroscope and CLSM were used to analyze the failure modes and to illustrate the pattern of infiltration of RelyX U200 into dentinal tubules, respectively. Bond strength means were calculated, and analysis of variance and Bonferroni tests were used for statistical analysis. SS showed the highest mean bond strength values (11.5±5.3), superior to QM (5.1±3.1) and SC (5.1±3.3). NaOCl presented intermediary bond strength values (9.7±5.0), similar to EDTA (7.7±2.9) and SS. QM and SC showed the lowest mean bond strength (p<0.05). Adhesive failures between cement/dentin were predominant (53.9%). SS and NaOCl associated with ultrasonic activation seem to be adequate solutions for root canal cleaning before fiber post cementation with self-adhesive resin cement, whereas chelating solutions, such as EDTA, QM, and SC, cause a decrease in bond strength.

Effect of different gutta-percha solvents on the microtensile bond strength of various adhesive systems to pulp chamber dentin.

The aim of this study was to evaluate the effect of different endodontic solvents on the microtensile bond strength (μTBS) of various adhesives to pulp chamber dentin. A total of 120 human third molars were selected. Canals were prepared with the ProTaper Universal system and obturated. The access cavities were then restored with resin composite. After 1week, a retreatment procedure was applied as follows: control, no solvent was applied to the pulp chamber and experimental groups, three different solvents (chloroform, eucalyptol, and orange oil) were applied to the pulp chamber for 2min. The canal filling was removed and calcium hydroxide (Ca[OH]2) was placed into the canals. After 7days, the Ca(OH)2 was removed from the canals and the canals were re-obturated. Teeth were then divided into three subgroups according to the adhesive used. The samples were restored with a nanohybrid resin composite using three different adhesives: Clearfil SE Bond (CSE), Adper Easy One (AEO), and Single Bond 2 (SB2). The samples were aged with thermocycling. Teeth were sectioned, and a total of 20 dentin sticks were obtained for each subgroup. μTBS testing was then performed. The debonded surfaces were evaluated using scanning electron microscopy (SEM) analysis. Data were analyzed using two-way ANOVA and Tukey's post hoc tests. Chloroform showed statistically lower mean μTBS values (14±7.2MPa) than control group did (19.2±6.1MPa) (p<0.05). Orange oil (18.1±6.3MPa) and eucalyptol (16.9±6.8MPa) did not reduce the mean μTBS statistically (p>0.05). Chloroform showed significantly lower bond strength for all adhesives (p<0.05). Whereas orange oil did not reduce the mean μTBS values of all adhesive systems significantly (p>0.05), eucalyptol reduced the μTBS values of all the groups, but the results were only statistically significant for SB2 (p<0.05). CSE showed statistically higher bond strength (20.4±6.8MPa) than AEO (14.6±5.3MPa) and SB2 (16.3±7.2MPa) did (p<0.05). There were no statistical differences between AEO and SB2 (p>0.05). According to the SEM analysis of the debonded surfaces, adhesive failures were the most common type in all the groups, followed by mixed failures. While chloroform reduced the mean bond strength of the adhesive resins, orange oil did not affect the bond strength of the adhesives. The effect of eucalyptol on bond strength depended on the type of adhesive system. This study shows that endodontic solvents could affect the microtensile bond strength of adhesives to pulp chamber dentin.

Comparative analysis of simulated root canals shaping, using ProTaper Universal, Next and Gold

ObjectivesEvaluation of the changes to the initial simulated root canal anatomy when comparing the preparation made by three different rotary systems: ProTaper Universal, ProTaper Next and ProTaper Gold. MethodsThe quantitative analysis was made by measuring the canal width of 36 S-shaped canals, distributed by three groups of twelve samples each (Group A – ProTaper Universal, Group B – ProTaper Next, Group C – ProTaper Gold). To measure canal width, pre and post instrumentation images were superimposed and studied using Rhinoceros Software. The statistical analysis was obtained using Kolmogorov–Smirnov test, Mann–Whitney post hoc multiple comparisons U test and One-Way ANOVA, with a significance of p<0.05. ResultsConsidering the inner side of both apical and coronal curvatures, differences between files were statistically significant (p<0.05). ProTaper Universal system was responsible for a bigger widening, while ProTaper Gold presented the smaller mean value. ConclusionsProTaper Gold was the rotary system that most respected the initial S-shaped canal anatomy. ProTaper Universal was the system that originated the greatest modification of the initial canal, presenting a significant tendency to straighten the apical curvature.

Apically extruded debris during root canal preparation using ProTaper Gold, ProTaper Universal, ProTaper Next, and RECIPROC instruments.

The aim of this study was to determine the amount of apically extruded debris during root canal preparation with ProTaper Gold (PTG) (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Universal (PTU) (Dentsply Maillefer), ProTaper Next (PTN) (Dentsply Maillefer), and RECIPROC (VDW, Munich, Germany) in curved canals. Eighty human mandibular molar teeth were divided into 4 groups according to the system used for root canal preparation: PTG, PTU, PTN, and RECİPROC groups. The mean weight of extruded debris was statistically analyzed using one-way analysis of variance and post-hoc Tukey's test (α = 0.05). The PTU was associated with significantly more extruded debris than the PTG, PTN, and RECIPROC (p&lt;0.05). The PTG was associated with significantly more extruded debris than the PTN and RECIPROC (p&lt;0.05), whereas no significant difference was found between the RECIPROC and PTN (p&gt;0.05). All systems caused apical debris extrusion during curved canal preparations. However, the PTG, PTN, and RECIPROC systems resulted in significantly less debris extrusion than the PTU system.

Influence of Instruments Used in Root Canal Preparation on Amount of Apically Extruded Debris.

The aim of the present study was to compare the effects of ProTaper Gold, WaveOne Gold, ProTaper Universal, and WaveOne instruments on the amount of apically extruded debris. Eighty mandibular premolar teeth with straight root canals were selected and assigned to four groups (n = 20). The root canals were instrumented using ProTaper Gold, WaveOne Gold, ProTaper Universal, and WaveOne systems. Eppendorf tubes containing apically extruded debris were weighed three times, and mean values were calculated. The net mass of the extruded debris was calculated by subtracting the initial mass from the final mass. The groups were compared using one-way analysis of variance and Tukey's post hoc tests at a significance level of P < 0.05. The PTG group extruded less debris than the PTU group, and the WOG group extruded less debris than the WO group (P < 0.05). All the instrumentation systems tested in the present study were associated with apical extrusion of debris.

Comparison of curved root canals preparation using reciprocating, continuous and an association of motions

The aim of this study was to compare the rotary ProTaper Universal system, the single-file reciprocating WaveOne system and an association of motions assessing shaping ability, cleanliness, preparation time and instrument failures after preparation of curved root canals. Sixty root canals of extracted human molar teeth, with curvatures ranging between 20° and 40°, were divided into three groups, according with preparation system. Canals were prepared until apical size 25 using the ProTaper Universal system (G1), WaveOne (G2), or a hybrid technique (G3) associating reciprocating preparation with rotary glide path and cervical pre-enlargement. Teeth were scanned pre and post-operatively using computed tomography. Direction of transportation and centering ability of canals were measured using a computer image analysis program, and the results were analyzed statistically using one-way ANOVA. Preparation time was analyzed by one-way ANOVA and the Tukey post hoc test. Instrument failures were recorded. The amounts of debris and smear layer were quantified based on a numerical evaluation scale by scanning electron microscopy and were analyzed statistically using the Kruskal-Wallis test. No difference in transportation and centering ratio was found between the systems. Instrumentation with WaveOne was significantly faster than with other instruments (p < 0.05). During preparation, no instruments fractured and three suffered deformations. For debris removal and remaining smear layer, the results for the three groups were similar. The single-file reciprocating instrument was capable of providing faster root canal preparation with similar transporting, centralization and cleaning ability when compared with continuous and an association of motions in curved canals. SCANNING 38:462-468, 2016. © 2016 Wiley Periodicals, Inc.

EFFECT OF DIFFERENT IRRIGATING SOLUTIONS AND MECHANICAL AIDS ON THE REMOVAL OF CALCIUM HYDROXIDE INTRA-CANAL MEDICATION FROM STRAIGHT AND CURVED CANALS

aim: to study effect of different irrigating solutions and mechanical aids on Ca(OH)2 removal from straight and curved canals. materials and methods: Forty five maxillary central incisors with straight roots (group I) were prepared with step back technique until apical size 55 and forty five mandibular first molars with curved mesio buccal canals (group II) prepared with Pro Taper universal system up to apical size F2. Calcium hydroxide was applied into all canals and the accesses were sealed with temporary dressing. All teeth were placed in wax mould and digital radiographs were taken to confirm canal filling with Ca(OH)2 to length. Every group was subdivided into 3 subgroups according to the irrigating solution used; subgroup A irrigated with 5.25% NaOCl only, subgroup B irrigated with 5.25% NaOCl and 10% H2O2, and subgroup C irrigated with 5.25% NaOCl and 17% EDTA. Every subgroup was further subdivided into 3 subgroups (1, 2, and 3) according to the mechanical aid for Ca(OH)2 removal; in subgroup 1 used master apical file, in subgroup 2 used master apical file and apical patency, in subgroup 3 used master apical file, apical patency and increase in canal size. Post removal digital radiographs were taken for all teeth in their wax mould. Any traces of Ca(OH)2 were traced by “Image J” software and estimated as a percentage to the total canal space and statistically analyzed. results: There was no significant difference between the subgroups A, B, and C in anterior and posterior teeth either in subgroup 1, 2, or 3. In anterior teeth group, there were significant differences between subgroups 1, 2, and 3 in subgroup B and C but, in subgroup A, there was no significant difference. In posterior teeth group, there was a significant difference between subgroups 1, 2, and 3. in subgroup A but, in subgroup B and C, there was no significant difference. Anterior and posterior teeth were compared and the results were significant differences in subgroups A1 and A2 but, in subgroup A3 there was no significant difference. In subgroup B, there were significant differences in subgroups B1, B2 and B3. In subgroup C, there was no significant difference in subgroups C1, C2 and C3. conclusions: Under the tested conditions of this study, the most successful method of Ca(OH)2 removal was the use of master apical file (hand or rotary), apical patency and increase one size filing with the combination of EDTA and NaOCl irrigation in both anterior & posterior teeth.

Comparison of the amount of apical debris extrusion associated with different retreatment systems and supplementary file application during retreatment process

Background:The type of instrument affects the amount of debris extruded. The aim of this study was to compare the effect of retreatment systems and supplementary file application on the amount of apical debris extrusion.Materials and Methods:Forty-eight extracted mandibular premolars with a single canal and similar length were selected. The root canals were prepared with the ProTaper Universal system with a torque-controlled engine. The root canals were dried and were obturated using Gutta-percha and sealer. The specimens were randomly divided into four equal groups according to the retreatment procedures (Group 1, Mtwo retreatment files; Group 2, Mtwo retreatment files + Mtwo rotary file #30 supplementary file; Group 3, ProTaper Universal retreatment (PTUR) files; and Group 4, PTUR files + ProTaper F3 supplementary file). The extruded debris during instrumentation were collected into preweighed Eppendorf tubes. The amount of apically extruded debris was calculated by subtracting the initial weight of the tube from the final weight. Three consecutive weights were obtained for each tube.Results:No statistically significant difference was found in the amount of apically extruded debris between Groups 1 and 3 (P = 0.590). A significant difference was observed between Groups 1 and 2 (P < 0.05), and between Groups 3 and 4 (P < 0.05).Conclusions:The use of supplementary file significantly increased the amount of apically extruded debris.

Shaping ability of ProTaper Gold and ProTaper Universal files by using cone-beam computed tomography.

This study evaluated and compared the shaping ability of ProTaper Gold (PG) (PG; Dentsply, Tulsa Dental Specialties, Tulsa, OK, USA) system with ProTaper Universal (PU) (PU; Dentsply Maillefer, Ballaigues, Switzerland) using cone-beam computed tomography (CBCT) imaging. Forty mesiobuccal canals of mandibular first molars with curvatures of 25-30° were divided into two experimental groups (n = 20) according to the rotary nickel-titanium (NiTi) file system used in canal instrumentation as follows: Group PG and group PU. Canals were scanned before and after instrumentation using CBCT scanner to evaluate root canal transportation and centering ratio at 3, 5, and 7 mm from the apex and volumetric changes. Data were statistically analyzed using independent t-tests and the significance level was set at P < 0.05. There was no significant difference between PG and PU systems in the mean volume of removed dentine, canal transportation, and centering ratio (P > 0.05). The PG and PU NiTi rotary systems showed similar root canal shaping abilities in the preparation of mesial canals of mandibular first molars.