OBJECTIVE The objective of this study was to compare the smear layer formed on root canal walls during canal preparation of extracted human teeth by Twisted, Mtwo, and ProTaper rotary nickel titanium instruments. MATERIALS AND METHODS Sixty single rooted human premolar teeth with root curvature <25(0) were selected and randomly divided into three Groups (n= 20 teeth per Group). Three types of...

AIM To determine how instrument design affects the fatigue life of two nickel-titanium (Ni-Ti) rotary systems (Mtwo and ProTaper) under cyclic fatigue stress in simulated root canals. METHODOLOGY Cyclic fatigue testing of instruments was performed in stainless steel artificial canals with radii of curvature of 2 or 5 mm and an angle of curvature of 60 degrees . A total of 260 instruments were...

AIM To investigate the morphological changes in the apical third of the root canal after preparation with three techniques. METHODOLOGY Forty molar teeth were scanned using micro-computed tomography before and after instrumentation with: Group 1 - stainless steel K-files using the balanced force technique; Group 2 - stainless steel K-files (balanced force) and then refining the apical prepara...

This study investigated the incidence of hand and rotary instrument separation (IS) in the endodontics graduate program at the University of Pennsylvania between 2000 and 2004. In 4,865 endodontic resident cases the incidence of hand and rotary IS was 0.25% and 1.68%, respectively. The odds for rotary IS were seven times more than for hand IS. The probability of separating a file in apical thir...

AIMS Visual and microscopic evaluation of defects caused by torsional fatigue in hand and rotary nickel titanium (NiTi) instruments. MATERIALS AND METHODS Ninety-six NiTi greater taper instruments which were routinely used for root canal treatment only in anterior teeth were selected for the study. The files taken include ProTaper for hand use, ProTaper Rotary files and Endowave rotary files....

INTRODUCTION Single use of endodontic nickel-titanium (NiTi) instruments has been recommended to reduce instrument fatigue and the possibility of cross-contamination. The purpose of this study was to evaluate the defects of three NiTi rotary systems (ProFile series 29 [Dentsply Tulsa Dental Products, Tulsa, OK], ProFile [Dentsply Tulsa Dental Products], and ProTaper [Dentsply Maillefer, Ballaig...

AIM The aim of the study is to compare the maximum stress distribution on the rotary retreatment instruments within the root canal at cervical, middle, and the apical one-third during retreatment of gutta-percha. MATERIALS AND METHODS A human mandibular premolar was scanned, and three-dimensional geometry of the root was reconstructed using finite element analysis (FEA) software package (ANSY...

background: nickel-titanium (ni-ti) rotary instrument files are important devices in endodontics in root canal preparation. ni-ti file breakage is a critical and problematic issue and irrigation techniques were applied to decrease risk of file failure root. the aim of the present study was to compare the temperature gradient change of different irrigation solutions with ni-ti rotary instrument ...

The aim of root canal preparation is to clean and shape the root canal system while maintaining the original configuration. However, traditional hand instruments often failed in achieving these objectives, especially when used in severely curved canals. Over the years, many nickel-titanium rotary instruments have been developed to improve root canal preparation. More flexible files made of nick...