Objective: To compare the clinical performance of composite restorations polymerized by two methods. Methods: Ninety-eight, Class I and II, restorations (Z100, 3M) were cured with the following methods: 1) High Intensity light (HI): 40''@1000 mW/cm²; 2) Pulse Activation (PA): 3''@300mW/cm² + 4' to 5' delay + 40''@300mW/cm². Modified USPHS criteria, were used to evaluate Marginal Discoloration (MD), Marginal Adaptation (MA), Restoration Fracture (RF), Secondary Caries (SC) and Post-Operative Sensitivity (POS). Rating scale was based on three levels of performance: A-clinically ideal, B-clinically acceptable and C-clinically unacceptable. Results: Baseline (BL) and 2 years (2Y) results are listed in percentages (%):

At 2-year recall, 85 (87%) restorations were reevaluated. Results were analyzed using a non-parametric test (Mann-Whitney U). After two years, there was significantly less restoration fracture observed in the HI group, compared to the PA group (p£0.05). Seven restorations were considered clinically unacceptable, 4 belonging to the PA group (8.3%) and 3 to the HI group (6%). Conclusions: Even though the HI group showed slightly better overall performance, no significant differences were found between the tested techniques, with the exception of more restoration fracture in the PA group. Additional recalls are necessary to determine if this will lead to differences in overall failure rates. (Partially supported by NIH).