Microleakage at the composite-repair interface: effect of different surface treatment methods

This study evaluated microleakage at the composite-repair interface after using different methods of surface treatment. Eighty resin composite specimens (Filtek Z250, 3M Dental Products) aged in artificial saliva for three months were divided into four groups (n=20) according to the following surface treatment methods: untreated control-no roughening or abrasion of the surface; roughening with diamond burs; jet prophylaxis with sodium bicarbonate particles and air abrasion with 50 microm aluminum oxide particles. Each method was examined using scanning electron microscopy (SEM) to evaluate changes in surface topography. All groups were then etched with 37% phosphoric acid, coated with a bonding agent (Single Bond, 3M Dental Products) and received new resin applications. The samples were then thermocycled (800 cycles/5 degrees C to 55 degrees C [+/- 2]) and immersed in 2% methylene blue buffered dye solution (7.0 pH) for four hours. Three examiners measured the extent of microleakage in a stereoscope microscope using four representative scores. For all experimental groups, no significant difference in repair microleakage was identified by the Kruskal-Wallis test (p>0.05). Therefore, different testing methods of surface treatment showed the same effect on dye penetration along the repair interface.