The Influence of Specimen Grips on the Measurement of Micro-Tensile Bond Strength to Human Dentin
To evaluate the effects of specimen grips on the measurement of the micro-tensile bond strength (mTBS) to dentin. Methods: Twelve extracted human molars were sectioned to expose mid-coronal dentin. Each surface was ground with 600-grit SiC paper. Four adhesives: Prime & Bond NT (Dentsply, USA), Contex (DMG, German), Adper Prompt (3M/ESPE, USA) and Clearfil S3 Bond (Kuraray, Japan) were applied to the polished surfaces followed by creation of composite buildups. After 24 hr storage in 37°C water, the teeth were sectioned perpendicular to the adhesive interface to produce multiple beams of composite-bonded dentin, approximately 0.8 mm2 in cross-sectioned area. Half of the specimens were attached to testing grips A which did not contain positioning pins and another half were attached to the testing grips B which contained positioning pins. All specimens were tested using a universal testing machine at a crosshead speed of 1.0 mm/min. Results: Specimens tested using the grips A presented lower mTBS than using the grips B (P<0.01). Many specimens tested using the grips A showed mix failure or cohesive failure within composite, and most of the failures were adhesive for specimens tested using the grips A. Conclusion: Specimen grips without positioning pins cannot accurately present mTBS and the grips with positioning pins can more accurately present mTBS.
Yiwang Bao, Danyu Jiang, Li Tian and Jianghong Gong
X. Y. Zhao et al., "The Influence of Specimen Grips on the Measurement of Micro-Tensile Bond Strength to Human Dentin", Key Engineering Materials, Vol. 492, pp. 18-23, 2012