Class I occlusal composite resin restorations: In vivo post-operative sensitivity, wall adaptation, and microleakage

Purpose: To investigate the effect of restoration technique and adhesive sy stem on the post-operative sensitivity and marginal adaptation of Class I o cclusal composite resin restorations placed in vivo. Materials and Methods: 48 Class I cavities were restored in vivo according to one of three protoc ols: (1) Scotchbond MultiPurpose/P50 placed in increments; (2) Scotchbond M ulti-Burpose/P50 placed in bulk, and (3) Clearfil Liner Bond 2/Clearfil Ray Posterior placed in bulk. Post-operative sensitivity and sensitivity on lo ading were recorded 5-7 weeks after placement of the restorations; the teet h were cautiously extracted, immersed in a dye solution and sectioned. SEM observations were made from epoxy resin replicas. Microleakage and gap form ation was assessed. Results: No differences among adhesive systems or resto ration procedures were found for microleakage. Post-operative sensitivity w as reported in 14% of all teeth but was absent in the Clearfil Liner Bond 2 group. Sensitivity on loading was experienced by patients in 56% of the re storations. Group 1: nine teeth; Group 2: 15 teeth; Group 3: three teeth. D ifferences were statistically significant for all three groups. The SEM ana lysis showed that restorations placed in two layers showed less gaps than r estorations placed in bulk.