introduction: the aim of the present in vitro study was to evaluate the efficacy of d-race, protaper retreatment kit and hand h-files in removal of obturating materials (om) from the curved root canals using cone-beam computed tomography (cbct). materials and methods: sixty extracted molars were prepared and obturated. the samples were divided into three groups ( n =20). in each group the om wa...

OBJECTIVE This study assessed the muscular activity during root canal preparation through kinematics, kinetics, and electromyography (EMG). MATERIAL AND METHODS The operators prepared one canal with RaCe rotary instruments and another with Flexo-files. The kinematics of the major joints was reconstructed using an optoelectronic system and electromyographic responses of the flexor carpi radial...

The aim of this study was to assess cyclic fatigue resistance in rotary nickel-titanium instruments after simulated clinical use in curved root canals (40-degree, 5-mm radius curve). Thirty-six RaCe rotary NiTi files, size #5, taper 0.04, were divided into 3 groups: Groups A, B and C with one, three and five cycles of use, respectively. Time to failure was recorded with a stopwatch in seconds a...

introduction: this study aimed to perform a rigorous sample standardization and also evaluate the preparation of mesiobuccal (mb) root canals of maxillary molars with severe curvatures using two single-file engine-driven systems (waveone with reciprocating motion and oneshape with rotary movement), using micro-computed tomography (micro-ct). methods and materials: ten mb roots with single canal...

introduction: this study investigated the fatigue and fracture modes of race and protaper rotary instruments. materials & methods: fatigue resistance was evaluated by rotating the files 30 ° or 60 ° and with 2 or 5mm radius of curvature. race taper 06 size 25 and protaper f1 files (n=40) were used. the number of rotations to failure was analyzed by two-way anova and independent sample     t-tes...

INTRODUCTION Gutta-percha must be removed from the root canal space during retreatment to ensure a more favorable outcome. The aim of this study was to compare the efficacy of hand instruments, RaCe and RaCe plus XP-endo finisher instruments in removal of gutta-percha from root canal walls during retreatment. METHODS AND MATERIALS Thirty single-rooted premolars were prepared, obturated, and d...

INTRODUCTION Disinfection and subsequent obturation of the root canal space require adequate mechanical enlargement of the canals. The purpose of this in vitro study was to compare the shaping ability of Mtwo, RaCe and Medin rotary instruments during the preparation of curved root canals. MATERIALS AND METHODS Sixty mesiobuccal root canals of mandibular molars with severe curvatures between 2...

introduction : removal of root filling materials is one of the key steps in success of root canal retreatment. the purpose of this study was to evaluate the efficacy of h-file and protaper with or without chloroform in the removal of gutta-percha during retreatment of mandibular premolars. materials and methods: sixty mandibular premolars with one canal, and curvatures less than 30 degrees were...

AIM To compare ex vivo various parameters of root canal preparation using a manual technique and six different rotary nickel-titanium (Ni-Ti) instruments (FlexMaster, System GT, HERO 642, K3, ProTaper, and RaCe). METHODOLOGY A total of 147 extracted mandibular molars were divided into seven groups (n = 21) with equal mean mesio-buccal root canal curvatures (up to 70 degrees), and embedded in ...

introduction: root fracture is not an instant phenomenon but a result of gradual development of tiny craze lines in tooth structure. recent studies have shown that canal instrumentation has the potential to cause dentinal cracks. the purpose of this study was to evaluate and compare the formation of dentinal cracks caused by protaper rotary system to hand instrumentation. materials and methods:...