Nickel-titanium (NiTi) instruments are commonly used for shaping the root canal system in endodontic practice. They are more flexible and have better cutting efficiency than conventional stainless steel files. The superelasticity of NiTi rotary files allows the clinicians to produce the desirable tapered root canal form with a reduced tendency to canal transportation and instrument fracture. Hy...

INTRODUCTION The aim of this study was to compare different obturation techniques in terms of the percentage of gutta-percha filled areas (PGFA), sealer filled areas (PSFA), and voids in straight root canals prepared with different instruments. METHODS One hundred sixty extracted single-rooted mandibular premolars with straight canals were allocated into 10 groups (n = 16 teeth per group): A,...

Screw-in effect is one of the unintended phenomena that occurs during the root canal preparation with nickel-titanium rotary files. The aim of this study was to compare the screw-in effect among various nickel-titanium rotary file systems. Six different nickel-titanium rotary instruments (ISO 20/.06 taper) were used: K3 (SybronEndo, Glendora, CA, USA), Mtwo (VDW GmbH, München, Germany), NRT wit...

introduction: the aim of this study was to compare the formation of dentinal crack and craze lines in the root dentin during root canal preparation with three different niti endodontic systems, naming reciproc (rcp), protaper universal (ptu) and mtwo. methods and materials: one hundred extracted mandibular premolars with single canals were selected and decoronated. the teeth were randomly divid...

AIM To evaluate the cyclic fatigue resistance of five NiTi rotary systems in an abrupt apical curvature. METHODOLOGY Cyclic fatigue testing was performed in stainless-steel artificial canals with a 2-mm radius of curvature and an angle of curvature of 90 degrees constructed to the dimensions of the instruments tested. The middle of the simulated curvature was 2.5 mm from the tip of the instru...

introduction: the preparation of the root canal space includes debridement, shaping and apical preparation. these procedures are challenging and constitute. the recent introduction of automated techniques for canal preparation has created considerable interest. the aim of this study was to test shaping ability of one hand instrumentation (passive step-back technique) and new rotary niti system ...

introduction: the success of endodontic retreatment is related to the complete removal of the obturation material from the root canal system. the aim of this study was to evaluate the efficacy of mtwo r and protaper retreatment files in removing the resilon/epiphany system with or without chloroform during retreatment. materials and methods: sixty distal roots of first mandibular molars were pr...

introduction: file fracture is one of the main procedural mishaps in endodontic treatment. the aim of this in vitro study was to compare the fracture rate of three niti rotary systems; hero 642, mtwo and flexmaster in artificial canals. methods and materials: in this study, bovine long bone was used. after primary preparation of bones, longitudinal sections with 4-cm diameter were cut and encod...

introduction: the aim of this in vitro study was to compare the efficacy of protaper retreatment (protaper r) and mtwo retreatment (mtwo r) files in removing gutta-percha and guttaflow from endodontically treated straight root canals. methods and materials: the root canals of 60 human mandibular single-rooted premolars were prepared and randomly divided into two groups ( n =30). in groups a and...

AIM   To compare the effectiveness of two Ni-Ti systems and hand files for removing gutta-percha and sealer from root canals. METHODOLOGY   The root canals of 60 single-rooted human teeth were prepared, filled with gutta-percha and sealer (Pulp Canal Sealer; SybronEndo, Orange, CA, USA). Specimens were then divided into three groups (n=20), and root filling material was removed using MTwo Ret...