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Objectives: The objectives of the study were to evaluate the radiographic technical quality of root canal treatment before and after the implementation of a nickel-titanium rotary (NiTiR) preparation followed by a matching-taper single-cone (mSC) obturation and to detect the procedural errors associated with this technique. Materials and methods: A random sample of 535 patients received root canal treatment at the Department of Conservative Dentistry and Periodontology at the University of Würzburg: 254 teeth were treated in 2002-2003 by using stainless steel instruments (SSI) for preparation and a lateral compaction (LC) technique (classic group (CG)). Two hundred eighty-one teeth were root filled in 2012-2013 employing NiTiR instruments for the root canal shaping and a mSC technique (advanced group (AG)). The quality assessments were based on the radiographic criteria of the European Society of Endodontology. The presence of voids was recorded separately for the apical, central and cervical thirds of the root canals. Procedural errors, such as ledges, apical transportations, perforations and fractured instruments, were detected. The root canal fillings in the CG and AG were compared using chi-squared and Fisher's exact tests. Multivariable logistic regression was performed to investigate the association between the independent variables (patient age, tooth type and type of treatment) and the dependent variables (density and length). Results: Adequate length was achieved significantly more often in the AG compared to the CG for molars ( p = 0.017), mandibular teeth ( p = 0.013) and primary root canal treatments ( p = 0.024). No significant difference was detected between the AG and CG regarding adequate length in general ( p = 0.051) or adequate overall quality of root canal filling ( p = 0.1). In the AG, a significant decrease in procedural errors was evident ( p = 0.019) and decreases in the densities of the root canal fillings in the cervical ( p = 0.01) and central ( p = 0.01) thirds of the root canals were also observed. Moreover, root canals in elderly patients exhibited fewer voids ( p = 0.009). Conclusions: Rotary root canal preparation followed by a matching-taper single-cone filling technique provides a reliable shaping of the root canal, with fewer procedural errors and a more acceptable filling quality in terms of length and homogeneity in the apical third. Less favourable results were achieved in the central and cervical parts of the root canals. Clinical relevance: The matching-taper single-cone technique seems to effectively obturate well-tapered root canals after adequate rotary instrumentation. Irregularly shaped canals require additional lateral or warm vertical condensation to avoid voids. [ABSTRACT FROM AUTHOR]

Introduction: This study compared the cleaning efficiency of Mtwo, Race and Medin Nickel-Titanium (NiTi) rotary instruments. Materials and Methods: Sixty mandibular molar mesial roots were selected with angle curvatures between 25-35 degrees and divided into three groups; each containing 20 teeth. Canals were prepared with the rotary files and irrigated with 2.5% NaOCl solution after each instrument. Total of 5mL of normal saline was used as the final rinse; subsequently the canals were dried with paper points. The amount of debris and smear layer in three parts of the root canal walls was evaluated using SEM and the data were analyzed by using the Kruskal-Wallis test and the Mann-Whitney U test. Results: The results for remnant debris in the coronal part of root canals were similar, whereas in the middle third, Mtwo instruments achieved significantly better results compared to Race and Medin instruments. In the apical third of the root canals more debris was created by Race instruments. Conclusion: Overall, Mtwo instruments had greater success in producing clean canals.

This study is an attempt to compare the NiTi rotary and K-files hand instrumentation on root canal preparation of primary and permanent molars for their efficiency in preparation time, instrument failure and shaping the canals. About 20 primary mandibular second molar (I) and 20 permanent mandibular first molar (II) were selected. Each was further divided into 10 for K-files (a) and 10 for NiTi (b) groups, respectively. Results showed that preparation time Ib

Objective: To evaluate the effects of deionised water, blood, phosphate-buffered saline (PBS) and a new anti-corrosive solution based on methoxy propyl amine (MOPA) on the cyclic fatigue resistance of endodontic NiTi rotary instruments under in vitro conditions., Methods: Forty ProTaper F1 files were provided and divided to four groups (n=10). Samples were first autoclaved and then stored in deionised water, blood, PBS or MOPA for 24 hours. Cyclic fatigue was tested with a custom-made stainless-steel block including artificial canals (curvature angle=30 degree, radius of curvature=5 mm). After immersion in test solutions, samples were rotated 300 rpm until fracture occurred. The number of cycles to failure (NCF) was calculated using recorded fracture time., Results: Data were analysed by the Kolmogorov-Smirnov, Levene, ANOVA and Scheffe statistical tests. Samples in blood group showed the lowest and samples in MOPA group showed the highest NCF values. Significant difference was observed between groups (P=0.001). NCF value of PBS group was significantly more than the NCF values of samples in blood and deionised water groups (P<0.05)., Conclusion: The tested novel anti-corrosive solution significantly increased the fracture resistance of the endodontic NiTi rotary instruments by reducing the cyclic fatigue. In contrast, blood and deionised water caused more corrosion and resulted in earlier file fracture., Competing Interests: Conflict of interest: No conflict of interest was declared by the authors., (Copyright: © 2018 European Endodontic Journal.)

Introduction: This study compared the cleaning efficiency of Mtwo, Race and Medin Nickel-Titanium (NiTi) rotary instruments., Materials and Methods: Sixty mandibular molar mesial roots were selected with angle curvatures between 25-35 degrees and divided into three groups; each containing 20 teeth. Canals were prepared with the rotary files and irrigated with 2.5% NaOCl solution after each instrument. Total of 5mL of normal saline was used as the final rinse; subsequently the canals were dried with paper points. The amount of debris and smear layer in three parts of the root canal walls was evaluated using SEM and the data were analyzed by using the Kruskal-Wallis test and the Mann-Whitney U test., Results: The results for remnant debris in the coronal part of root canals were similar, whereas in the middle third, Mtwo instruments achieved significantly better results compared to Race and Medin instruments. In the apical third of the root canals more debris was created by Race instruments., Conclusion: Overall, Mtwo instruments had greater success in producing clean canals.