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 system on the post-operative sensitivity and marginal adaptation of Class I occlusal composite resin restorations placed in vivo.

Materials And Methods: 48 Class I cavities were restored in vivo according to one of three protocols: (1) Scotchbond Multi-Purpose/P50 placed in increments; (2) Scotchbond Multi-Purpose/P50 placed in bulk, and (3) Clearfil Liner Bond 2/Clearfil Ray Posterior placed in bulk. Post-operative sensitivity and sensitivity on loading were recorded 5-7 weeks after placement of the restorations; the teeth were cautiously extracted, immersed in a dye solution and sectioned. SEM observations were made from epoxy resin replicas. Microleakage and gap formation was assessed.

Results: No differences among adhesive systems or restoration procedures were found for microleakage. Post-operative sensitivity was 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 restorations. Group 1: nine teeth; Group 2: 15 teeth; Group 3: three teeth. Differences were statistically significant for all three groups. The SEM analysis showed that restorations placed in two layers showed less gaps than restorations placed in bulk.