ABSTRACT
Background and Aim: The aim of this study is to evaluate the apical debris extrusion amounts and preparation times of four different nickel-titanium systems with a similar cross-section design-Mtwo, RECIPROC, RECIPROC blue, and VDW.ROTATE. Materials and Methods: Eighty human mandibular central incisors were divided into four equal groups (n = 20). The test apparatus was inserted into an assembly that provided root canal temperature. Preparation times were recorded using a stopwatch, and the amount of extruded debris was collected in pre-weighed Eppendorf tubes. After drying, the net amount was determined by subtracting the previously measured Eppendorf tube weights from the total weight. Results: The Mtwo had the largest amount of debris, but there was no significant difference among the other groups. The VDW.ROTATE completed the preparation in a significantly shorter time than the RECIPROC blue and Mtwo. Conclusion: Compared to other files, the Mtwo sequence produced significantly more debris and required significantly more time to complete the whole root canal preparation.
Subject(s)
Nickel , Titanium , Humans , Root Canal Preparation , Incisor , Tooth Apex , Dental Pulp CavityABSTRACT
OBJECTIVE: This in vitro study aimed to compare the cyclic fatigue resistance of HyFlex EDM (HEDM), Vortex Blue (VB), ProTaper Gold (PG), and OneCurve (OC) nickel-titanium (NiTi) instruments. MATERIALS AND METHODS: About 12 HEDM (25/.~), 12 VB (25/.06), 12 PG (25/.08), and 12°C (25/.06) instruments were included in this study. All the instruments were tested with a 60° angle of curvature and a 3-mm radius of curvature. All the instruments were utilized until fracture occurred, and then the number of cycles to failure (NCF) was calculated. The data were analyzed statistically using Kruskal-Wallis H and Mann-Whitney U-tests. The statistical significance level was set at P < 0.05. RESULTS: HEDM instruments had the highest cyclic fatigue resistance among all the other instruments (P < 0.05). The OC instruments had a significantly higher fatigue resistance than the PG and VB instruments (P < 0.05); however, there was no significant difference between PG and VB instruments in the NCF (P > 0.05). CONCLUSION: Within the limitations of this in vitro study, it was found that the cyclic fatigue resistance was higher for the HEDM instruments than for the VB, PG, and OC instruments.
Subject(s)
Dental Alloys/chemistry , Dental Instruments , Equipment Failure , Materials Testing , Root Canal Preparation/instrumentation , Alloys , Equipment Design , Gold , Humans , Nickel/chemistry , Titanium/chemistryABSTRACT
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.
Subject(s)
Gold , Root Canal Preparation , Equipment Failure , Humans , Nickel , TitaniumABSTRACT
AIMS: (i) To compare chlorhexidine and QMix(TM) in terms of orange-brown precipitate generation in root canals and (ii) to analyse the precipitate produced by mixing chlorhexidine and QMix(™) with NaOCl to determine whether para-chloroaniline was produced. METHODOLOGY: The root canals of 57 single-rooted anterior teeth were prepared using ProTaper Universal rotary instruments up to size F4. Two millilitres of 2.5% NaOCl was used between each instrument change. The specimens were then divided randomly into three groups (n = 19) and irrigated as follows: group 1, 5 mL of distilled water (control group) for 60 s; group 2, 5 mL of 2% chlorhexidine for 60 s; and group 3, 5 mL of QMix for 60 s. The roots were split longitudinally, and one of the halves was photographed using a stereomicroscope. The amount of orange-brown precipitate was evaluated using a four-grade scoring system. The data were analysed statistically using the Kruskal-Wallis and Mann-Whitney U-tests (P = 0.05). To evaluate whether the precipitates included para-chloroaniline, 5 mL of 2% chlorhexidine and 5 mL QMix were separately mixed with 5 mL of 2.5% NaOCl in two flasks. After centrifugation, precipitates were obtained and analysed using (1) H NMR spectra. The data were subjected to statistical analysis using the Kruskal-Wallis and Mann-Whitney tests at a 95% confidence level (P = 0.05). RESULTS: Chlorhexidine had significantly higher scores than QMix(™) in terms of orange-brown precipitate formed in the root canals (P < 0.001). According to the 1H NMR spectra, para-chloroaniline was present in the mixture of chlorhexidine and NaOCl. However, the mixture of QMix(™) and NaOCl did not result in para-chloroaniline formation. CONCLUSION: QMix(™) does not form para-chloroaniline when associated with NaOCl.
