Effect of home bleaching on the mechanical properties of resin luting cements using Hertzian indentation test
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.
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.
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.
The effect of 10% carbamide peroxide treatment reduces cement strength, which could be important for patients undergoing bleaching who have crowns.