Shaping ability of ProTaper Gold, One Curve, and Self-Adjusting File systems in severely curved canals: A cone-beam computed tomography study.

AIM: The aim of the study was to evaluate and compare canal transportation (CT), centering ability (CA), and volumetric changes in severely curved canals prepared using ProTaper Gold (PTG), One Curve (OC), and Self-Adjusting File (SAF) systems via cone-beam computed tomography (CBCT). MATERIALS AND METHODS: Sixty mesiobuccal canals of maxillary molars were selected. Pre- and postinstrumentation CBCT scans were taken in the same position. CT and CA were calculated at 1 mm, 4 mm, and 7 mm from the apex; change in volume for whole canal was measured and analyzed statistically. RESULTS: SAF showed the least mean CT at all the levels with no statistically significant differences at 1 mm and 4 mm when compared to other groups while statistically significant differences were observed at 7 mm with PTG and OC. Regarding CA, SAF better maintained canal centricity than PTG and OC at all the levels assessed, though the differences were not statistically significant except at 7 mm where statistically significant difference was observed between SAF and OC. SAF removed less volume of dentin followed by PTG and the highest removal was shown by OC. CONCLUSION: SAF showed promising behavior with the least CT, most centered preparation, and minimal dentin removal.

A Comparison of Apical Bacterial Extrusion in Manual, ProTaper Rotary, and One Shape Rotary Instrumentation Techniques.

INTRODUCTION: Apical extrusion of irrigants and debris is an inherent limitation associated with cleaning and shaping of root canals and has been studied extensively because of its clinical relevance as a cause of flare-ups. Many factors affect the amount of extruded intracanal materials. The purpose of this study was to assess the bacterial extrusion by using manual, multiple-file continuous rotary system (ProTaper) and single-file continuous rotary system (One Shape). METHODS: Forty-two human mandibular premolars were inoculated with Enterococcus faecalis by using a bacterial extrusion model. The teeth were divided into 3 experimental groups (n = 12) and 1 control group (n = 6). The root canals of experimental groups were instrumented according to the manufacturers' instructions by using manual technique, ProTaper rotary system, or One Shape rotary system. Sterilized saline was used as an irrigant, and bacterial extrusion was quantified as colony-forming units/milliliter. The results obtained were statistically analyzed by using one-way analysis of variance for intergroup comparison and post hoc Tukey test for pair-wise comparison. The level for accepting statistical significance was set at P < .05. RESULTS: All the instrumentation techniques resulted in bacterial extrusion, with manual step-back technique exhibiting significantly more bacterial extrusion than the engine-driven systems. Of the 2 engine-driven systems, ProTaper rotary extruded significantly more bacteria than One Shape rotary system (P < .05). CONCLUSIONS: The engine-driven nickel-titanium systems were associated with less apical extrusion. The instrument design may play a role in amount of extrusion.

MTAD in endodontics: an update review.

The major objective in endodontic therapy is to achieve complete chemomechanical debridement of the entire root canal system. This can be accomplished with biomechanical instrumentation and chemical irrigation. Various endodontic irrigants, such as sodium hypochlorite, chlorhexidene, and iodine potassium iodide, are available, each having its own advantages with some limitations. MTAD, a new endodontic irrigant, has been introduced to fulfill these limitations. MTAD is a mixture of doxycycline, citric acid, and a detergent (Tween 80). Since its introduction, it is a material that has been researched extensively for its properties. This article presents a review on the numerous properties of MTAD, such as antimicrobial activity, smear layer- and pulp-dissolving capability, effect on dentin and adhesion, and biocompatibility.