Relationship between microtensile bond strength and nanoleakage at the composite-dentin interface.

Objectives: This study evaluated the relationship between microtensile bond strength (microTBS) and occurrence of nanoleakage at the resin-dentin interface using the same specimens.
Methods: Resin-dentin-bonded micro-specimens (sticks with a size of 300 microm x 300 microm x 8mm) were prepared using one of two material combinations (group I: Syntac classic/Tetric Ceram Cavifil: n=57; group II: Prime & Bond NT/Spectrum TPH: n=52). After immersion of the micro-specimens in 0.1% rhodamine-B solution for 1h, nanoleakage was imaged nondestructively using a confocal laser scanning microscope (CLSM). Then the specimens were subjected to a microTBS test.
Results: For the influence of nanoleakage on microTBS with the Syntac classic/Tetric Ceram Cavifil group, the nonparametric Spearman correlation was 0.033 at p=0.805. For the Prime & Bond NT/Spectrum TPH group, the nonparametric Spearman correlation was 0.077 at p=0.584.
Significance: The degree of nanoleakage had no influence on microtensile bond strength for the Syntac classic/Tetric Ceram Cavifil or for the Prime & Bond NT/Spectrum TPH group.