RESUMO
AIM: The aim of the present study was to determine the effects of immersion time and 10% carbamide peroxide treatment using a Hertzian indentation test after placing resin-based cements into 37°C distilled water, with and without 10% carbamide peroxide. METHODS: Disc-shaped specimens (10-mm diameter × 1-mm thick), were prepared from five resin-based cements; seT PP, Maxcem Elite, RelyX Unicem, Panavia F, and G-Cem. The specimens of each material were randomly divided into three groups of six. The study groups were bleached with 10% carbamide peroxide on one surface for 21 days for 2 h per day. Two control groups were kept in distilled water for either 24 h or 21 days. A load was applied to the center of the disc using a hard, steel ball. The load at the first crack was recorded. RESULTS: Significant differences were observed between the cements. seT PP showed the highest strength, and G-Cem the lowest. Differences between the treatment and control groups were statistically significant for all cements, except Panavia F. CONCLUSIONS: The effect of 10% carbamide peroxide treatment reduces cement strength, which could be important for patients undergoing bleaching who have crowns.
