İbrahim Ersoy

Variations in cyclic fatigue resistance among ProTaper Gold, ProTaper Next and ProTaper Universal instruments at different levels

AIM To compare the cyclic fatigue resistance of ProTaper Gold (PTG, Dentsply Tulsa Dental Specialities, Tulsa, OK, USA), ProTaper Next (PTN, Dentsply Tulsa Dental Specialities) and ProTaper Universal (PTU, Dentsply Tulsa Dental Specialities) instruments at different levels. METHODOLOGY A total of 72 files were used to evaluate the cyclic fatigue of PTU (F2), PTN (X2) and PTG (F2) at 5 mm (n = 12) and 8 mm (n = 12) from the tip in 3-mm-radius steel canals with a 60° angle of curvature. The time to fracture was recorded. The Kolmogorov-Smirnov test was used to assess the normality of the samples distribution, and the statistical analysis was performed using the independent sample t-test (P < 0.01). RESULTS Significant differences were found amongst the instruments 5 mm from the tip (P < 0.01). The PTG files had the highest CF resistance, and the PTN files displayed greater CF resistance than the PTU files. No significant differences were found between the PTG and PTN files 8 mm from the tip (P > 0.01). The PTG and PTN files demonstrated greater CF resistance than the PTU files (P < 0.01). CONCLUSIONS The PTG instruments were the most resistant 5 and 8 mm from the tip; however, at 8 mm, there was no difference between the PTG and PTN instruments. The PTU files had the lowest CF resistance at all levels.

Comparison of fracture resistance between cast, CAD/CAM milling, and direct metal laser sintering metal post systems

PURPOSE The purpose of this study was to compare the fracture resistance of Co-Cr post-cores fabricated with 3 different techniques: traditional casting (TC), computer-aided design and manufacturing (CAD/CAM) milling (CCM) and direct metal laser sintering (DMLS). METHODS Forty intact human mandibular premolar were endodontically treated. The roots were then randomly divided into four groups according to the post systems: the control group was only filled with gutta percha. Co-Cr metal posts were fabricated with TC, CCM and DMLS in the other three groups. The posts were luted with a resin cement and subjected to compression test at a crosshead speed of 1mm/min. The statistical analysis of the data was performed using one-way analysis of variance (ANOVA) and multiple comparison post hoc Tukey tests (α=.05). The samples were examined under a stereomicroscope with ×20 magnification for the evaluation of the fracture types. RESULTS The mean fracture loads were 432.69 N for control, 608.89 N for TC, 689.40 N for DMLS and 959.26 N for CCM. One-way ANOVA revealed significant difference between the groups (p<0.01). In the post hoc Tukey test, there were significant differences between groups except DMLS and TC. CONCLUSION While Co-Cr posts fabricated by TC and DMLS systems performed similarly in terms of fracture resistance, posts fabricated by CCM techniques showed higher fracture resistance values. SIGNIFICANCE Co-Cr metal posts fabricated by CCM and DMLS could be an alternative to TC processing in daily clinical application.

Incidence of Dentinal Cracks after Root Canal Preparation with Twisted File Adaptive Instruments Using Different Kinematics

INTRODUCTION The purpose of the present study was to assess the effect of root canal instrumentation using Twisted File Adaptive instruments (Axis/SybronEndo, Orange, CA) with different kinematics (adaptive motion, 90° clockwise [CW]-30° counterclockwise [CCW], 150° CW-30° CCW, 210° CW-30° CCW, and continuous rotation) on crack formation. METHODS One hundred five mandibular central incisor teeth were selected. Fifteen teeth were left unprepared (control group), and the remaining 90 teeth were assigned to the 5 root canal shaping groups as follows (n = 15): adaptive motion, 90° CW-30° CCW, 150° CW-30° CCW, 210° CW-30° CCW, continuous rotation, and hand file. All the roots were sectioned horizontally at 3, 6, and 9 mm from the apex with a low-speed saw under water cooling, and the slices were then viewed through a stereomicroscope at 25× magnification. Digital images of each slice were captured using a camera to determine the presence of dentinal cracks. RESULTS No cracks were observed in the control group, and the continuous rotation group had more cracks than the reciprocation groups (90° CW-30° CCW, 150° CW-30° CCW, and 210° CW-30° CCW) (P < .05). Both the continuous rotation and adaptive motion groups had significantly more dentinal cracks than the hand file group (P < .05). Regarding the different sections (3, 6, and 9 mm), there was a significant difference between the experimental groups at the 9-mm level (P < .05). CONCLUSIONS The incidence of dentinal cracks is less with TF Adaptive instruments working in 210° CW-30° CCW reciprocating motion compared with working in continuous rotation and adaptive motion.

Efficiency of the Self Adjusting File, WaveOne, Reciproc, ProTaper and hand files in root canal debridement

Objectives: The aim of this study was to compare the canal debridement capabilities of three single file systems, ProTaper, and K-files in oval-shaped canals. Materials and Methods: Seventy-five extracted human mandibular central incisors with oval-shaped root canals were selected. A radiopaque contrast medium (Metapex; Meta Biomed Co. Ltd., Chungcheongbuk-do, Korea) was introduced into the canal systems and the self-adjusting file (SAF), WaveOne, Reciproc, ProTaper, and K-files were used for the instrumentation of the canals. The percentage of removed contrast medium was calculated using pre- and post-operative radiographs. Results: An overall comparison between the groups revealed that the hand file (HF) and SAF groups presented the lowest percentage of removed contrast medium, whereas the WaveOne group showed the highest percentage (P < 0.001). The ProTaper group removed more contrast medium than the SAF and HF groups (P < 0.05). Conclusions: None of the instruments was able to remove the contrast medium completely. WaveOne performed significantly better than other groups.

Effect of citric acid irrigation on the fracture resistance of endodontically treated roots

Objective: The aim of this study was to evaluate the effect of citric acid irrigation on root fracture in different concentrations and at various time exposures on root fracture. Materials and Methods: Forty-eight human mandibular incisors with similar dimensions were selected. The specimens were decoronated, then divided into 6 groups as follows: A group without instrumentation and filling (G1) and the 5 other groups with canal preparation and irrigation of distilled water (G2), 10% citric acid for 1 min (G3), 50% citric acid for 1 min (G4), 10% citric acid for 10 min (G5), and 50% citric acid for 10 min (G6). In the experimental groups, the canals were obturated and subjected to the strength test. Statistical analysis was performed using Kruskal-Wallis test (P = 0.05). Results: G6 showed the highest fracture resistance (629.97 N), and G3 showed the lowest fracture resistance (507.76 N). However, there was no statistically significant difference among the groups. Conclusions: The results of this study suggest that use of citric acid is safe in terms of fracture resistance.

Evaluation of the effect of different root canal obturation techniques using two root canal sealers on the fracture resistance of endodontically treated roots

Aim: The aim of this study was to compare the fracture resistance of teeth filled with AH Plus and MTA Fillapex root canal sealers by using different root canal obturation techniques. Materials and Methods: One hundred and twenty pieces of single‐rooted‐and‐canalled mandibular premolar teeth were selected. After the crowns were removed from the cemento‐enamel junction, they were divided into 10 groups (n = 12). All the root canals except for the Group 1 were shaped until F4 file with ProTaper Nickel‐ Titanyum (Ni‐Ti) rotary system. Group 1: was not instrumented. Group 2: the root canals were shaped but not filled. Group 3: roots were filled with cold lateral condensation technique (CLC) by using AH Plus. Group 4: roots were filled with CLC by using MTA Fillapex. Group 5: roots were filled with single cone technique by using AH Plus. Group 6: roots were filled with single cone technique by using MTA Fillapex. Group 7: roots were filled with AH Plus by using vertical compaction method with continuous heat. Group 8: roots were filled with MTA Fillapex by using vertical compaction method with continuous heat. Group 9: roots were filled with AH Plus by using thermoplastic core carrier method. Group 10: roots were filled with MTA Fillapex by using thermoplastic core carrier method. Before embedding the samples in acrylic resin after standing in an oven at 37°C for 2 weeks for the hardening of the root canal sealers the 5 mm apical portion of the roots were immersed in wax in order to imitate the surrounding tissues. Polyvinyl siloxane impression material was used for the samples which were embedded in acrylic resin in a way that the coronal 8 mm remained outside in order to imitate the periodontal ligament. Lateral force was applied to the samples with 1 mm/min speed in the Universal Tester. The maximum force values (F‐max) which cause fractures in the examples were determined and the results were subjected to statistical evaluation by using one‐way Anova and Tukey HSD tests with the significance set at (P < 0.05). Results: The control group showed the maximum fracture resistance (P < 0.05). Thermafil group showed higher fracture resistance than single cone technique, cold lateral condensation technique, and system B (P < 0.05). Conclusions: It was concluded that shaping and widening of the root canals reduced the fracture resistance of teeth while Thermafil increased the resistance of roots against fracture. Microsc. Res. Tech., 2015.

Efficacy of XP-endo finisher and TRUShape 3D conforming file compared to conventional and ultrasonic irrigation in removing calcium hydroxide

The aim of this study was to compare the efficacy of the XP-endo Finisher and TRUShape 3D Conforming File to conventional and ultrasonic irrigation techniques for removing calcium hydroxide from artificially created grooves on root canals. The study used 32 human mandibular premolar teeth, which were decoronated and instrumented up to ProTaper Universal F5 (Dentsply Maillefer; Ballagiues, Switzerland). The teeth were split longitudinally, two standardised grooves were prepared in the apical and coronal portions and filled with calcium hydroxide. Each tooth was reassembled with wax. The samples were stored at 100% humidity at 37°C for 1 week, after which the specimens were grouped and irrigated using needle irrigation, ultrasonic irrigation, XP-endo Finisher via continuous irrigation or TRUShape 3D Conforming File via continuous irrigation. Two calibrated observers scored the amount of calcium hydroxide remaining, and the data were statistically analysed using the Kruskal-Wallis and Mann-Whitney U-tests, (P < 0.05). Needle irrigation had the poorest scores (P < .001), while the XP-endo Finisher, TRUShape 3D Conforming File via continuous irrigation and ultrasonic irrigation groups had similar results in removing calcium hydroxide.

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 Tukeys 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 cyclic fatigue resistance between different NiTi instruments with 4% taper

The aim of this study was to make a comparison between the cyclic fatigue (CF) resistance of F360, twisted files (TF), FlexMaster (FM) and RaCE instruments with 4% taper. A total of 40 instruments were evaluated 8 mm from the tip. A stainless steel block with a simulated canal of 1.5 mm diameter, and a 60° angle of curvature was tested using CF testing. One‐way ANOVA and posthoc Tukeys test (P < 0.05) were used. The F 360 files showed the highest CF resistance while the TF files had greater CF resistance than the FM and RaCE (P < 0.05). There was no significant difference between the FM and RaCE (P > 0.05). F360 instruments with a double S cross‐section had the highest CF resistance among the group. The TF led the NiTi rotary files to be more resistant to fatigue than the FM and RaCE instruments. Microsc. Res. Tech. 79:345–348, 2016.