OBJECTIVE Use of rotary Nickel-Titanium (NiTi) instruments for endodontic preparation has introduced a new era in endodontic practice, but this issue has undergone dramatic modifications in order to achieve improved shaping abilities. Cone-beam computed tomography (CBCT) has made it possible to accurately evaluate geometrical changes following canal preparation. This study was carried out to co...

introduction: the aim of this in vitro study was to compare the effect of hand and rotary instruments on fracture strength of tooth roots. materials & methods: thirty two teeth were randomly divided into two experimental groups of 15 each and one negative control group with two samples. in group 1, step-back technique with conventional stainless steel k-files was used, and in group 2, instrumen...

introduction: preparation techniques and instruments produce and push debris out of canals. this can induce inflammation within the periapical area. therefore, instrumentation that causes less extrusion of debris is more desirable. the purpose of this in vitro study was to evaluate the quantity of debris extruded from the apical foramen during root canal preparation by using one hand, and two r...

INTRODUCTION The aim of this study was to assess the shaping potential of a novel nickel-titanium instrument, the self-adjusting file (SAF), in long oval root canals in distal roots in mandibular molars. METHODS Twenty mandibular molars with long oval distal root canals were selected and scanned preoperatively and postoperatively by using micro-computed tomography at an original resolution of...

the aim of this study was to assess the efficacy of apical negative pressure (anp), manual dynamic agitation (mda), passive ultrasonic irrigation (pui) and needle irrigation (ni) as final irrigation activation techniques for smear layer removal in curved root canals.mesiobuccal root canals of 80 freshly extracted maxillary first molars with curvatures ranging between 25° and 35° were used. a gl...

objectives: different chelators may be used during root canal treatment, offering various advantages including lubricant effect inside the canal and smear layer removal. however, chelator residues in narrow root canals can lead to apical microleakage. the aim of this in-vitro study was to compare apical microleakage following the use of three root canal chelators via fluid filtration method 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:...

introduction: the aim of the present study was to compare hand stainless steel k-files and nickel-titanium profile 0.04 taper 29 series rotary instruments for their efficiency, procedural errors and time consumed in preparation of root canal system. materials and methods: a total of 46 maxillary and mandibular first premolars extracted for orthodontic purposes were collected (two contralateral ...

introduction: in this experimental study, the amount of smear layer (sl) remnants in curved root canals after chemomechanical instrumentation with two engine-driven systems or hand instrumentation was evaluated. methods and materials: forty-eight mesiobuccal roots of mandibular first molars with curvatures ranging between 25 and 35 degrees (according to schneider’s method) were divided into thr...