Surface treatment techniques for resin composite repair

Purpose: To compare bond strengths of fresh resin composites to previously polymerized ("aged") composites following various surface treatments. Materials and Methods: Eighty Pertac Hybrid (PH) and an equal number of Silux Plus (SLX) specimens were fabricated and stored for 1 week prior to surface treatment. The specimens were then polished and stored for an additional 24 hours prior to final surface treatment. The surface treatments included use of one of the following: (1) diamond bur (DB), (2) microetcher with 50 μm Al₂O₃ @ 80 psi pressure (ME), (3) high-pressure air abrasion with 27 μm Al₂O₃ @ 160 psi, (KCP), or (4) low-pressure silicate ceramic deposition using 30 μm particles @ 34 psi (CJ-S) with a microetcher. Half of the samples were treated with a silanating agent. Fresh resin composite (same type as used for the aged specimen) was bonded to the treated surfaces, and specimens were then stored 24 h and thermocycled 300x at 5° and 55°C prior to testing for shear bond strength. Two-way ANOVA was used to determine significant differences between mean shear bond strengths for both composite materials. Results: Significant differences were found between the groups for both surface treatment and silane use (P< 0.05). The interaction between the two main effects was also significant (P< 0.05). Overall, the highest bond strengths were found when the low-pressure silicate ceramic deposition system (CI-S) was used, with or without silane.