Effect of specimen gripping device, geometry and fixation method on microtensile bond strength, failure mode and stress distribution: laboratory and finite element analyses.

摘要: Abstract Objectives Innumerous modifications have been proposed for the microtensile test since its introduction; however, testing parameters are not often well described and wide variations in bond strength commonly reported. The aim of this study was to evaluate effect specimen's gripping device, specimen geometry fixation method on strength, failure mode, stress distribution when using an etch-and-rinse 2-step adhesive system bonded human dentin. Methods Resin-based composite occlusal dentin from 21 molars used fabricate dumbbell- stick-shaped specimens which were divided into three groups: Di – dumbbell-specimens placed a Dircks device; GeS stick-specimens gripped Geraldeli's device with Superglue; GeZ Zapit. Specimens tested tensile mode examined under stereomicroscopy fracture initiation sites verified by scanning electron microscopy energy dispersive X-ray spectroscopy. Three-dimensional models each device/specimen created finite element calculations performed. Results devices significant, unless areas normalized. influenced type device. less sensitive error than Geraldeli's, produced more uniform at dumbbell layer did stick layer. Significance Microtensile can directly influence results consequently inter-study comparisons.