Influence of specimens' design and manufacturing process on microtensile bond strength to enamel: laboratory and FEA comparison

Materials Research

Fernanda Tranchesi Sadek²  Antônio Muench²  Isis Andréa Poiate¹  Edgard Poiate Junior¹  Paulo Eduardo Capel Cardoso² 

[1] ,University of São Paulo Department of Dental Materials São Paulo SP ,Brazil

关键词: microtensile bond strength;    enamel;    sample geometry;    failure mode;    FEA;   

DOI  :  10.1590/S1516-14392010000200021

来源: SciELO

【 摘 要 】

This study evaluated the effect of specimens' design and manufacturing process on microtensile bond strength, internal stress distributions (Finite Element Analysis - FEA) and specimens' integrity by means of Scanning Electron Microscopy (SEM) and Laser Scanning Confocal Microscopy (LCM). Excite was applied to flat enamel surface and a resin composite build-ups were made incrementally with 1-mm increments of Tetric Ceram. Teeth were cut using a diamond disc or a diamond wire, obtaining 0.8 mm² stick-shaped specimens, or were shaped with a Micro Specimen Former, obtaining dumbbell-shaped specimens (n = 10). Samples were randomly selected for SEM and LCM analysis. Remaining samples underwent microtensile test, and results were analyzed with ANOVA and Tukey test. FEA dumbbell-shaped model resulted in a more homogeneous stress distribution. Nonetheless, they failed under lower bond strengths (21.83 ± 5.44 MPa)c than stick-shaped specimens (sectioned with wire: 42.93 ± 4.77 MPaª; sectioned with disc: 36.62 ± 3.63 MPa b), due to geometric irregularities related to manufacturing process, as noted in microscopic analyzes. It could be concluded that stick-shaped, nontrimmed specimens, sectioned with diamond wire, are preferred for enamel specimens as they can be prepared in a less destructive, easier, and more precise way.

【 授权许可】

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