The effect of obturation technique on the push-out bond strength of calcium silicate sealers.

INTRODUCTION: Calcium silicate-based sealers are known to have excellent sealing ability and bioactivities. They are typically recommended to be used in a single-cone (SC) technique. No studies have evaluated the effects of the thermoplastic obturation technique on the dentin interface of these sealers. The purpose of this study was to evaluate the push-out bond strengths of MTA Plus Sealer (Avalon Biomed Inc, Bradenton, FL) and EndoSequence BC Sealer (BC; Brasseler USA, Savannah, GA) when they were used in a thermoplastic technique. METHODS: Fifty single-rooted human extracted teeth were randomly divided into 5 groups (n = 10), instrumented, and obturated with the SC technique or continuous wave (CW) technique: group 1, BC-SC; group 2, BC-CW; group 3, MTA Plus-SC; group 4, MTA Plus-CW; and group 5, AH Plus (Dentsply DeTrey, Konstanz, Germany)-CW. The roots were sectioned into 1.0-mm-thick slices, and bond strengths were measured using a standardized push-out test. The mode of failure was determined by visual inspection under magnification. RESULTS: The MTA Plus-CW had statistically significant lower bond strengths than all other groups. The BC-SC group had statistically higher bond strengths than the MTA Plus-SC and AH Plus-CW groups. No significant differences were seen among the other groups. Modes of failure were predominately cohesive or mixed except for group 4 (ie, MTA Plus-CW) in which nearly half the specimens had no visible sealer. CONCLUSIONS: BC and MTA Plus sealer showed favorable bond strengths when used in an SC technique. The CW obturation technique decreased the bond strengths of these sealers.

Resistance to cyclic fatigue failure of a new endodontic rotary file.

INTRODUCTION: A new nickel-titanium (NiTi) rotary file called the ProFile Vortex (PV; Denstply, Tulsa Dental Specialties, Tulsa, OK) has recently been released for endodontic use. The purpose of this study was to compare cyclic fatigue resistance of the new size 30 PV files with size 30 files of other popular brands. Other files tested include Twisted File (TF; Sybron Dental Specialties, Orange, CA), ProFile (PF; Denstply Tulsa Dental Specialties, Tulsa, OK), GTX (GTX, Denstply Tulsa Dental Specialties), and EndoSequence (ES; Brasseler, Savannah, GA). METHODS: Size 30 files with a constant .06-mm/mm taper were rotated at manufacturer-recommended speed and torque settings in a simulated canal until failure. RESULTS: Significant differences were found between the various brands of files. The differences between file brands may be because of a different manufacturing process or differences in file design. CONCLUSIONS: Based on a simulated canal model, the PV, TF, and GTX files appear to offer greater cyclic fatigue resistance than ES and PF files.