The effect of surface treatments and bonding regimens on microtensile bond strengths of repaired composite: An in vitro study

AIM: To assess the microtensile bond strength of repaired composite resin that was surface treated by diamond point or silicon carbide followed by bonding using either only total- etch bonding regimen or silane coupling agent with adhesive resin. MATERIALS AND METHODS: Fourteen composite blocks were aged under deionized water for 14 days. The bonding surface was prepared with coarse diamond point or silicon carbide. Two blocks with no surface treatment were used as control groups. The bonding regimen was either total-etch bonding regimen or silane coupling agent and bonding agent. The aged samples were then bonded to new composite. Five sections per block (each 1mm thick) were prepared; cut to obtain an adhesive zone of approximately 1mm(2) and subjected to microtensile bond strength testing. RESULTS: The highest bond strength was obtained by surface treatment by coarse diamond point and total etch bonding regimen and least by silicon carbide and silane. A statistically significant difference was seen in all the four groups. CONCLUSIONS: Surface treatment by a coarse diamond point and total-etch bonding regimen provides highest bond strength. Thus, a simpler treatment regimen can contribute to a better bond strength in repaired composites.