SURFACE-TREATMENT TECHNIQUES FOR RESIN COMPOSITE REPAIR

Purpose: To compare bond strengths of fresh resin composites to previo usly polymerized (''aged'') composites following various surface treat ments. Materials and Methods: Eighty Pertac Hybrid (PH) and an equal n umber of Silux Plus (SLX) specimens were fabricated and stored for 1 w eek prior to surface treatment. The specimens were then polished and s tored 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 mu m Al2O3 @ 80 psi pressure (ME), ( 3) high-pressure air abrasion with 27 mu m Al2O3 @ 160 psi, (KCP), or (4) low-pressure silicate ceramic deposition using 30 mu m particles @ 34 psi (CJ-S) with a microetcher. Half of the samples were treated wi th a silanating agent. Fresh resin composite (same type as used for th e aged specimen) was bonded to the treated surfaces, and specimens wer e then stored 24 h and thermocycled 300x at 5 degrees and 55 degrees C prior to testing for shear bond strength. Two-way ANOVA was used to d etermine 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 < 0.0 5). The interaction between the two main effects was also significant (P < 0.05). Overall, the high est bond strengths were found when the l ow-pressure silicate ceramic deposition system (CJ-S) was used, with o r without silane.