ProTaper Universal Files Research Articles

Cone-beam assessment of gutta percha removal by Reciproc versus ProTaper Universal re-treatment

This study intended: to assess use cone-beam analysis‏ of gutta percha removal by Reciproc versus ProTaper Universal retreatment systems. Methods: Thirty extracted humanoid lower first molars were collected. The mesiobuccal canal was selected from each tooth. The mesiobuccal canals were mechanically prepared in a crown-down approach using the “TF Adaptive” setting on Elements Motor. TF Adaptive Green ML1 file (Medium Large) and Yellow ML2 size 35 taper 4% till the file gets to the effective length. the obturation was done by lateral condensation technique with gutta pearch size 35 taper 6%, and AH plus in the same visit, and using gutta pearch size 25 taper 2% as auxiliary cones with spreader size 25. samples were unintentionally split into two investigational groups concurring to the re-treatment method used (n = 15). Group I: Reciproc system, and Group II: ProTaper Universal re-treatment. Cone beam (CBCT) was used to evaluate the gutta percha removal in both groups. Results: less remaining filling material following the wastage of the Reciproc system (0.169mm3) followed by the ProTaper Universal retreatment (1.459 mm3). There was less remaining filling material following the use of the Reciproc system (The rate of decrease was 96.82 %) followed by the ProTaper Universal re-treatment kit (The rate of decrease was 76.17 %). Conclusions: Reciproc was more effective than Protaper Universal files in the elimination of gutta‐percha and epoxy resin‐based sealer during the re-treatment.

The effect of triple antibiotic paste as an intracanal medication with an anti-inflammatory drug on post-operative pain of asymptomatic uniradicular necrotic teeth: a double blind randomized clinical trial

Background:Flare-ups may occur after root canal treatment which consist of acute exacerbation of asymptomatic pulpal and/or periradicular pathologic condition. The causative factors of interappointment pain include mechanical, chemical or microbial irritation to the pulp or periradicular tissues. The potential role of microorganisms in interappointment pain is why the success of endodontic treatment depends on complete eradication of microorganisms capable of causing an intraradicular or extraradicular infection. This can be achieved by mechanical cleaning and shaping, in conjunction with irrigation and antibacterial agents. The aim of this study was to assess the ability of triple antibiotic paste with the anti-inflammatory drug diclofenac potassium versus calcium hydroxide used as an intra-canal medication in reducing post-operative pain.Methods:84 patients with asymptomatic uniradicular necrotic teeth were randomly assigned into two groups according to the intra-canal medication used: calcium hydroxide group (CH) and triple antibiotic paste with diclofenac potassium group (TAPC). In the first treatment session, intracoronal cavity preparation was performed after rubber dam isolation followed by chemo-mechanical preparation using rotary Protaper Universal files with saline irrigation followed by intra-canal medication placement then postoperative pain was assessed at 24, 48 and 72 hours postoperatively using Visual Analogue Scale (VAS). In the second treatment session, intracanal medications were removed by irrigation using saline followed by obturation.Results:Both intracanal medicaments resulted in a statistically significant decrease in mean pain value from 24 to 48 and 72 hours postoperatively. While when comparing both groups, TAPC intracanal medication showed less post-operative pain compared to that of the CH group at 24, 48 and 72 hours with a statistically significant difference at 48 hours only.Conclusion:Both intracanal medicaments were efficient in reducing post-operative pain in asymptomatic uniradicular necrotic teeth.Trial registration:Clinicaltrial.govNCT02907489, 20/09/2016.

The Effect of Different Organic Solvents of Filling Removal during Endodontic Retreatment

Abstract: Objectives The aim of the study was Evaluation of the effectiveness of three different solvents (orange oil solvent, eucalyptol oil solvent, and chloroform) during retreatment regarding: root canal filling removal Methods were 33 premolar root canals were prepared by using protaper universal files for cleaning and shaping, obturation was done by lateral compaction technique. Samples were divided (n=11) Group A Chloroform, Group B orange oil, and Group C Eucalyptus oil according to the solvent used into three groups. Retreatment was done by combining two methods for filling removal as chemical by using organic solvents and mechanical by utilizing rotary retreatment files (protaper retreatment files). Roots were split longitudinally, canals were observed using a stereomicroscope at 6x. The images were subjected to morphometric analysis to assess the amount of remaining root filling material. Data were explored for normality using Kolmogorov-Smirnov and Shapiro-Wilk tests, data showed parametric (normal) distribution. Repeated measure ANOVA was used to compare between more than two groups in related samples. Results: The highest mean value was found in (Group A) followed by (Group B), while the least mean value was found in (Group C). A statistically significant difference was found between (Group C) and each of (Group A) and (Group B) (p < 0.001). No statistically significant difference was found between (Group A) and (Group B) (p=0.853). Conclusion: Chloroform and orange oil are preferable to be used in retreatment.

Evaluation of microcrack formation during root canal preparation using hand, rotary files and self-adjusting file in primary teeth: An in vitro study.

Background. Pediatric endodontics is a field with constant evolution, resulting in the shifting of paradigms from the use of conventional hand files to rotary files for biomechanical preparation in primary teeth. Biomechanical preparation plays a crucial role in the success of root canal treatment. Primary teeth need special attention since they differ from permanent teeth in root canal morphology. Cleaning and shaping of the canals damage the root dentin, leading to dentinal cracks. Newer techniques for root canal preparation, including Ni-Ti rotary files and SAF system, have been developed for use in pediatric endodontics to overcome the drawbacks of conventional methods. The present study compared dentinal defects formed by rotary systems in primary teeth.Methods. Eighty primary teeth were included. The teeth were decoronated with a diamond disc. All the roots were inspected for any pre-existing cracks or craze lines under transmitted light under a stereomicroscope. The specimens were then divided into four groups (n=20): group 1: control, group 2: hand files (HF), group 3: ProTaper files, and group IV: SAF files. The samples were instrumented according to the group they were assigned to. Results. The HF and SAF groups exhibited fewer microcracks. Dentinal microcracks were observed in roots prepared with rotary ProTaper files. There were significant differences between HF/SAF and rotary files (P <0.05). Conclusion. Stainless steel hand K-files and SAF instruments resulted in fewer dentinal damage than the ProTaper Universal files. SAF exhibited satisfactory results with minimal or no crack formation.

Retreatability of bioceramic and GuttaFlow bioseal root canal sealers using ProTaper universal system retreatment files: An Ex vivo study

Introduction: To evaluate the retreatability of Bioceramic and GuttaFlow Bioseal sealers using ProTaper Universal System Retreatment files aided by dental microscope analysis. Materials and Methods: Root canals of forty single-rooted human mandibular premolar teeth were prepared with ProTaper Next rotary system and obturated with single-cone obturation technique (n = 20 each) using EndoSequence Bioceramic root canal sealer (Group 1) and GuttaFlow Bioseal root canal sealer (Group 2). All specimens were retreated with ProTaper Universal Retreatment System files. The working time of retreatment procedure was calculated. Samples were sectioned, and the residual filling remnants were observed under dental operating microscope. Statistical analysis was performed using SPSS software. Results: The least total working time was observed in GuttaFlow Bioseal group (2.35 min). Overall, less residual filling materials was found in Bioceramic sealer group specimens in all root levels compared to GuttaFlow Bioseal group (P = 0.000, 0.022, and 0.000, respectively). Conclusion: The retreatment technique used was incapable of complete removal of filling material within root canal walls.

Endodontic Retreatment Using a Single Instrument from four Nickel-Titanium Systems - A Micro-CT Study.

This study evaluated the efficiency of using a single instrument from three different rotary multi-file systems and compared them with that of a reciprocating single-file for endodontic retreatment by means of micro-CT. Sixty extracted canines were prepared using a size F2 ProTaper Universal file and obturated. After 30 days of storage at 37ºC and 100% humidity, the teeth were randomly divided into four groups (n=15) based on the type of instrument used to retreatment: ProTaper Next (PTN), ProTaper Gold (PTG), TRUShape 3D (TS), and WaveOne (WO). The canals were retreated using only the size 40 instrument from each system according to the manufacturer's recommendations for torque and speed. The time required to remove the filling material was recorded in seconds. The amount of initial and residual filling material and the quantity of dentin removed were assessed by means of micro-CT. Data were statistically analyzed (ANOVA and Kruskal-Wallis) at a 5% significance level. TS instruments required the highest (p<0.05) amount of time (mean, 384.80 ±144.92) compared with the WO (229.67±68.16) and PTG (248.67±64.22) and not so different from PTN instruments (327.67±133.3). No differences in the amount of dentin removed, initial and residual filling volume, and percentages of filling material were observed among the groups. The use of a single rotary instrument from the PTG, TS, and PTN systems was as effective as that of the single-file reciprocating WO system. However, none of the instruments was able to remove the filling materials completely.

Evaluation of four final irrigation protocols for cleaning root canal walls

The aim of this study was to compare the efficiency of four final irrigation protocols in smear layer removal and bacterial inhibition in root canal systems. Thirty roots inoculated with Enterococcus faecalis were prepared with ProTaper Universal files. The teeth were disinfected by conventional needle irrigation, sonic agitation using the EndoActivator device, passive ultrasonic irrigation, or an M3 Max file. Teeth with no root canal preparation served as blank controls for the establishment of the infection baseline. Teeth with preparation but no final irrigation served as a post-instrumentation baseline. After the final irrigation, the teeth were sectioned in half. One half of each tooth was examined by scanning electron microscopy (SEM) to assess smear layer removal using a five-point scale. The other half was examined by confocal laser scanning microscopy (CLSM) using the LIVE/DEAD BackLight bacterial viability kit to evaluate the depth of bacterial survival in dentinal tubules. SEM analysis revealed no significant difference in smear layer removal throughout the whole canal among the EA, PUI, and M3 Max groups (P > 0.05). CLSM revealed that PUI achieved the greatest bacterial inhibition depth in the coronal ((174.27 ± 31.63) μm), middle ((160.94 ± 37.77) μm), and apical ((119.53 ± 28.49) μm) thirds of the canal (all P < 0.05 vs. other groups). According to this comprehensive SEM and CLSM evaluation, PUI appears to have the best infection control ability in root canal systems.

Influence of root canal filling techniques on sealer penetration and gutta percha/sealer ratio: a confocal laser scanning microscopy analysis

Objective: The influence of four root canal filling techniques on the penetration of an endodontic sealer into dentinal tubules and the gutta percha/ sealer ratio (GP/SR) in root canals was evaluated using confocal laser scanning microscopy (CLSM). Material and Methods: Roots of the maxillary central incisors (n=40) were prepared with ProTaper Universal files up to file F5 and assigned to five groups: continuous wave condensation, lateral condensation, single cone, Thermafill®, and negative control group. After root canal filling with gutta-percha and AH26, along with the addition of 0.01% fluorescein, the roots were cut into 2-mm slices. Using CLSM, the specimens were transversely sectioned at 3, 6, and 10 mm from the apex. Results: Sealer penetration was deeper and more frequent at 10 mm than at the 6mm and 3mm for all obturation technique. Penetration was not significantly affected by obturation techniques except single master cone tecnique. Single cone technique demonstrated the lowest sealer penetration at all levels. However, sealer thickness was strongly dependent on obturation technique. Termafill® demostrated superior GP ratio followed by continuous wave condensation, lateral condensation and single cone. Conclusion: In conclusion, the single cone technique resulted in lower sealer penetration than the other techniques, which did not differ significantly from each other. However, sealer thickness was strongly dependent on obturation technique. Termafill® demostrated superior GP ratio followed by continuous wave condensation, lateral condensation and single cone.KeywordsObturation techniques; Dentinal tubule penetration; Gutta percha, sealer ratio; Confocal laser scanning microscopy.

COMPARATIVE QUALITY ASSESSMENT OF ROOT CANAL PREPARATION WITH DIFFERENT SYSTEMS OF ENDODONTIC INSTRUMENTS

The aim: To compare the quality of root canal system preparation with the use of manual K-files, machine Protaper Universal and Silk files by in vitro studies. Materials and methods: Root canals preparation in 45 extracted premolars was performed in three groups with 15 teeth in each with K-files, Protaper Universal and Silk files. Transverse sections of the dental root were prepared. Histologically were assessed: amount of sawdust and predentin remaining, the purity degree of root canal walls. Results: When calculating the sawdust amount at the distance of 3 mm from an apex, a high degree of contamination was observed in the manual K-file group: 53.3% versus 33.3% in the Protaper Universal group and against 20.0% in the Silk file group. The amount of predentin after root canal treatment with manual files reached 25-30%. At the distance of 5 mm from the apex the root canals with high and medium purity degree were detected in 86.7% with Silk files and 80.0% with Protaper Universal files used. All predentin was removed when working with Protaper Universal and Silk files. Conclusions: In the histological sections of the root canals treated with K-files, the larger amount of dentine particles and predentin has been revealed than when using machine tools. The largest amount of predentin and dentine were removed with Protaper Universal files. Silk endodontic system is better for treatment of the root canals dentine surface in the apical area compared to Protaper Universal and K-files.

Performance Evaluation on Rotary Preparation of Root Canal by Beginner Operators.

This study aims to analyze the performance of rotary root canal preparation, conducted by beginner operators (students). After acquiring the necessary skills involved in applying endodontic preparation techniques on extracted teeth, all students from a cohort learned to use ProTaper Universal files (Dentsply Maillefer). The preclinical training had several stages. Experience 1: instrumentation on extracted single-root teeth; Experience 2: instrumentation on EndoTraining blocks (Dentsply Maillefer); Experience 3: instrumentation on EndoTraining blocks (Dia Dent Group International); Experience 4: Instrumentation on extracted multiradicular teeth. Preparation was done according to the manufacturer’s instructions, the initial file is Sx, followed by S1, S2, F1, F2 and the last file is F3. A batch of 50 teeth (E1, E2, E3, E4) was randomly selected to evaluate the onset of the rotary preparation of young operators. Two independent evaluators analyzed the array radiologically by stereomicroscope evaluation (E1, E4) and photo-analysis of the resulting Endo Training blocks (E2, E3). The success rate was 80% for E1, 72% for E2, 64% for E3 and 76% for E4 (p<0.05). The following were considered a failure: ledge formation and apical transportation in 10.66%, over instrumentation in 6.66%, zipping in 3.33%, and instrument fracture in 4% of cases.Endodontic instrumentation techniques require training to acquire the necessary skills. Rotary root canal instrumentation techniques used almost exclusively in modern endodontics require adequate preclinical training.

Comparative evaluation of apical extrusion of intracanal bacteria using ProTaper Next, Mtwo, and ProTaper rotary systems: An in vitro study.

Aim:The aim of this study was to evaluate the number of intracanal bacteria extruded apically after instrumentation with three different nickel–titanium rotary instruments.Materials and Methodology:Forty freshly extracted mandibular premolars were selected, access cavities were prepared, and the teeth were mounted in the bacterial collection apparatus. Root canals were contaminated with a suspension of Enterococcus faecalis and incubated for 24 h at 37°C. The contaminated teeth were divided into four groups of 10 teeth each according to the rotary system used for instrumentation: Group 1: ProTaper universal files, Group 2: MTwo files, Group 3: ProTaper Next files, and Group 4: Control group (no instrumentation). Bacteria extruded after preparations were collected into vials. The number of colony-forming units (CFUs) was determined for each sample.Statistical Analysis:The data obtained were analyzed using the one-way analysis of variance followed by post hoc Tukey’s test with a P = 0.05 as the level for statistical significance.Results:The results suggested a statistically significant difference in the number of CFUs between four experimental groups (P < 0.001).Conclusion:Least amount of bacterial extrusion was seen in ProTaper Next Group while more bacterial extrusion was seen in MTwo Group.

Efficacy of Two Nickel-Titanium Rotary Root Canal Instruments compared with Different Instruments in Endodontic Treatment: A Systematic Review

The success of endodontic treatment depends on root canal preparation which is extremely important during the root canal treatment. The root canal instrumentation phase by using nickel-titanium instruments will help in the effectiveness of other procedures, such as facilitating irrigation and aspiration and three-dimensional obturation of canals. The objective of this review reviews all the data in regards to the efficiency of two nickel-titanium rotary instruments which are pro-taper next files and pro-taper universal files compared with different instruments in endodontics and which conducts are most used and appropriate for optimal root canal instrumentation. For such, we carried out a systematic review of the literature, using all the databases included in PubMed and Google Scholar. The search retrieved 401 articles, of which, after applying the exclusion/inclusion and quality criteria, 12 articles were selected for an in-depth analysis. Among the main results, we highlight two nickel-titanium rotary instruments that were used to aid the cleaning and shaping in root canal treatment, in addition to presenting several aspects such as different types of instrument systems, the efficiency of instruments during cleaning and shaping, and updating studies of their effect in the root canal treatment and re-treatment. This review concluded the rotary instrumentations especially pro-taper next files and pro-taper universal files illustrated great cleaning efficiency during root canal treatment and root canal re-treatment compared with hand stainless steel files and different instruments.

The incidence of nickel-titanium endodontic hand file fractures: A 7-year retrospective study in a tertiary care hospital.

Aim:The present retrospective cross-sectional study aims to evaluate the incidence and factors associated with nickel-titanium hand file fractures in root canal-treated teeth in a tertiary care hospital of western India.Methodology:The diagnostic records of intraoral periapical (IOPA) radiographs were analyzed to check for file fractures in the root canal-treated teeth. As a part of standardized departmental protocol, Hand ProTaper Universal file system (Dentsply, India) was used for chemomechanical preparation for root canal treatment. The file fractures were analyzed with reference to age group, type of teeth, curvature of the canal, site of file fracture in the canal, length of file fracture, level of file fracture, distance of the file fracture from the apex, and obturation status of the file-fractured tooth. Chi-square test was applied to assess the significance difference between the tested groups.Results:A total of 19,810 IOPA X-rays were screened and 2728 root canal-treated teeth were found and of these 2728 cases, 109 file-fractured teeth were observed.Conclusion:The total incidence of file fractures was 3.9/100 root canal-treated cases, and mandibular molars with severely curved canals (>25°) had shown the maximum incidence of file fractures.

In vitro Comparison of Apically Extruded Debris during Root Canal Retreatment with Rotary and Reciprocating Systems

Introduction:The extrusion of apical detritus during the retracting procedure is very important, as, besides eliminating materials of radicular obturation, aggressive agents and products such as the remains of dentin taken out, and microorganisms are generally located in tissue around the roots, producing undesired effects, such as inflammation, acute pain, post-operatory pain and delays in the periapical treatment.Objective:To determine the amount of apically extruded detritus using rotary and reciprocating retreatment systems.Methodology:An experimental comparative study as conducted in which 40 single-rooted human first premolars were analyzed. The instruments used were ProTaper Universal files up to F3 and sodium hypochlorite, and the sealing was made through the hybrid technique Tager. They were then kept at 37ºC and 100% of humidity for 15 days so that the sealing material would seal. For the retracting procedure, experimental tubes previously weighted were used. The sample was divided randomly into two groups of 20 pieces. Group A: ProTaper R, and group B: Reciproc. Then, the irrigating material (distilled water) was evaporated from the tubes for 12 hours in a stove at 105ºC, and the experimental tubes were weighted in an analytical precision weighing scale 10-5g. The data was analyzed through the T Student with a significance level of 5%.Results:Results indicated that groups A and B, retreatment with rotational ProTaper R and reciprocating retreatment system (Reciproc) showed a similar difference of initial and final weights, indicating similar apical extrusion of detritus.Conclusion:Both systems extruded a similar amount of detritus during the retreatment procedures.

Comparative analysis of the cleaning ability of single file versus multiple file system (An in vitro study)

Aim: The purpose of this study was to assess smear layer removal following canal preparation with single file (One Shape file) and multiple file system (Protaper Universal files).Methodology: Sixteen freshly extracted mandibular molars were tested and divided into two experimental groups (n=8): group 1, cleaning and shaping was done using One Shape file (8 canals); and group 2, cleaning and shaping was done using a kit of Protaper Universal Files till file F2 (8 canals). Two grooves were prepared on the lingual and buccal surfaces of the instrumented roots by disc to facilitate vertical splitting with a chisel after canal instrumentation. The presence of smear layer was evaluated under SEM in the apical, middle and coronal thirds of the canals. Blind evaluation was done by two trained evaluators and scores were complied separately. Data were then collected, tabulated and statistically analyzed.Results: Smear layer scores showed no statistically significant difference either in comparison between the two systems or between different root levels in each group.Conclusions: Under the condition of the current study, both rotary systems failed to remove smear layer at different root canal levels using saline only as an irrigant.

The effect of triple antibiotic paste as an intracanal medication with an anti-inflammatory drug on post-operative pain of asymptomatic uniradicular necrotic teeth: a double blind randomized clinical trial

Background:Flare-ups may occur after root canal treatment which consist of acute exacerbation of asymptomatic pulpal and/or periradicular pathologic condition. The causative factors of interappointment pain include mechanical, chemical or microbial irritation to the pulp or periradicular tissues. The potential role of microorganisms in interappointment pain is why the success of endodontic treatment depends on complete eradication of microorganisms capable of causing an intraradicular or extraradicular infection. This can be achieved by mechanical cleaning and shaping, in conjunction with irrigation and antibacterial agents. The aim of this study was to assess the ability of triple antibiotic paste with the anti-inflammatory drug diclofenac potassium versus calcium hydroxide used as an intra-canal medication in reducing post-operative pain.Methods:84 patients with asymptomatic uniradicular necrotic teeth were randomly assigned into two groups according to the intra-canal medication used: calcium hydroxide group (CH) and triple antibiotic paste with diclofenac potassium group (TAPC). In the first treatment session, intracoronal cavity preparation was performed after rubber dam isolation followed by chemo-mechanical preparation using rotary Protaper Universal files with saline irrigation followed by intra-canal medication placement then postoperative pain was assessed at 24, 48 and 72 hours postoperatively using Visual Analogue Scale (VAS). In the second treatment session, intracanal medications were removed by irrigation using saline followed by obturation.Results:Both intracanal medicaments resulted in a statistically significant decrease in mean pain value from 24 to 48 and 72 hours postoperatively. While when comparing both groups, TAPC intracanal medication showed less post-operative pain compared to that of the CH group at 24, 48 and 72 hours with a statistically significant difference at 48 hours only.Conclusion:Both intracanal medicaments were efficient in reducing post-operative pain in asymptomatic uniradicular necrotic teeth.Trial registration:Clinicaltrial.govNCT02907489, 20/09/2016.

Fatigue resistance of ProTaper gold exposed to high-concentration sodium hypochlorite in double curvature artificial canal

This study aimed to evaluate and compare the fatigue resistance of ProTaper Gold (PTG) and ProTaper Universal (PTU) in artificial single and double curvature canals in 5% sodium hypochlorite (NaOCl) at body temperature (37 °C). PTG and PTU files (size F1) were subjected to fatigue tests in two different artificial ceramic canals. The single curvature model had a 60° curvature angle with a 5 mm radius. The double curvature model had a 60° curvature angle with a 5 mm radius and a second 30° curvature with a 2 mm radius. A file segment was introduced into the artificial canal and immersed in water or 5% NaOCl at 37 °C. The total number of cycles to fracture (NCF) was recorded. Data were analyzed using t-test and linear regression analysis. The NCF of all files was significantly influenced by the type of NiTi metal alloy (P < .01), canal curvatures (P < .01), and the environmental conditions (P < .05). PTG had higher fatigue resistance than PTU files in both single and double curvature canals (P < .05). The NCF of PTU files in 5% NaOCl was shorter than that in water (P < .05). The mean length of broken PTG was significantly shorter than those of PTU files in both single and double curvature canals (P < .01). The fatigue performance of PTG is better than that of PTU in both single and double curvature. Environmental conditions may affect the fatigue behavior of PTU files with single curvature.

Influence of Thermomechanical Treatment on the Mechanical Behavior of Protaper Gold versus Protaper Universal (A Finite Element Study).

AIM:To compare and evaluate the influence of thermomechanical treatment of Protaper Gold file versus Protaper Universal file during testing of bending and torsion using finite-element analysis.METHODS:Two nickel-titanium NiTi rotary files (ProTaper Gold and ProTaper Universal) were used in this study. The files were imaged using stereomicroscope to produce 3D models. The behaviour of the instrument during bending and torsion was numerically analysed in CAD/CAM software package.RESULTS:Under bending, ProTaper, Gold showed higher flexibility and flexural resistance than ProTaper Universal. The highest stress was related at the cutting edge of both files. While during testing of torsion, the maximum amount of stresses was related to the base of the flutes in both files. ProTaper Gold showed higher torsional resistance than the ProTaper Universal file.CONCLUSION:Thermomechanical treatment improved the mechanical response (bending and torsional resistance) of NiTi files.

Effect of NaOCl solution on the cyclic fatigue resistance of traditional and heat-treated file systems

Aim: To compare the cyclic fatigue resistance at distilled water and %5.25 NaOCl of immersed ProTaper Gold (Dentsply Sirona, Ballaigues, Switzerland) and ProTaper Universal (Dentsply Sirona, Ballaigues, Switzerland) file systems.Material and Methods: The ProTaper Gold F2 (25.06v taper) and ProTaper Universal F2 (25.06v taper) file systems were immersed in distilled water andNaOCl for 5 minutes. After immersion process files were rotated at artificial canal with 60O curvature and a 5-mm radius until fracture occurred. Time to fracture and fractured lengths were recorded. Data were analyzed statistically using independent t-tests. Statistical significance was set at P .05. Results: ProTaper Gold files had a significantly higher resistance to cyclic fatigue than ProTaper Universal files (P .05). When ProTaper Universal immersed in distilled water showed higher resistance to cyclic fatigue than immersed in NaOCl solution (P .05).Conclusion: ProTaper Gold system more resistant than ProTaper Universal system to cyclic failure. The effect of NaOCl were higher on the ProTaper Universal system.Keywords: Corrosion, cyclic fatigue; NaOCl; ProTaper Gold; ProTaper Universal.

Evaluation of dentinal micro-cracks caused by the Protaper Universal, Protaper Next and Reciproc rotary file systems used in root canal preparation

Objective: In this study, we compared the occurrence of dentinal micro-cracks after use of the ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Next (Dentsply Maillefer), and Reciproc (VDW, Munich, Germany) nickel–titanium rotary file systems in root canal preparation.&#x0D; Method: One hundred mandibular anterior teeth were divided into five groups of 20 specimens each. Group 1 served as a control, with no intervention. In group 2, preparation was performed using the step-back technique and K files. In groups 3–5, root canal preparation was performed using the ProTaper Universal, ProTaper Next, and Reciproc file systems, respectively. Following preparation, specimens were sectioned at 3, 6, and 9 mm using a Minitom precision cut-off machine. The sections were evaluated under a stereomicroscope. The following scoring system was used to rate specimens: 1, no micro-crack; 2, incomplete micro-crack; and 3, vertical root fracture. The results were statistically assessed (p ≤ 0.05).&#x0D; Results: No micro-crack formation was observed in groups 1 and 2. The highest rate of micro-crack formation was observed in specimens prepared with the ProTaper Universal file system (20%), followed by those prepared with the Reciproc (11.7%) and ProTaper Next (6.7%) file systems. However, no significant difference was detected among groups (p &gt; 0.05). In the groups ProTaper Universal and Reciproc files were used, 1 vertical root fracture was found in 9 mm sections for each.&#x0D; Conclusion: Considering the limitations of in vitro studies, we can conclude that all rotary file systems used in this study led to dentinal micro-crack formation in roots. The ProTaper Universal file system caused more dentinal micro-cracking than did the ProTaper Next and Reciproc file systems.