Effects of 35% Versus 10% Carbamide Peroxide At-Home Bleaching Agents with or without MI Paste Plus on Enamel Properties

Abstract

This study compared the effects of 35% with 10% carbamideperoxide (CP) home used bleaching agents on enamel colorchange, microhardness, and surface changes in association withMI paste plus (CPP-ACPF). Forty buccal and lingual enamelsamples from twenty human third molars were prepared anddivided into four groups (n=10). The groups were bleached fortwo weeks according to different bleaching regimens as follow;G1 bleached with 10%CP, G2 bleached with 35%CP, G3 bleachedwith a mixture of 10%CP and MI paste plus, and G4 bleachedwith a mixture of 35%CP and MI paste plus. Color change wasrecorded with a colorimeter before and after bleaching and totalcolor differences (ΔE*) was calculated. Vickers microhardnesstest was recorded for all the samples before and after treatment.One sample from each group was evaluated for surface changes byscan electron microscopy (SEM). The data were analyzed withrepeated measure of variance and student's t-test at p<0.05. Nosignificant difference in ΔE* was recorded among the four groups(p>0.05). Significant reduction in enamel microhardness was onlyrecorded for G2 (p=0.003). SEM for G3 and G4 showed obviousmineral deposition. Similar teeth color whitening can be resultedafter two weeks of bleaching with both 10%CP and 35%CP whenused as recommended by the manufacturer with and without theaddition of MI paste plus. Using 35%CP decreased enamelmicrohardness significantly, whereas MI paste plus when mixedwith both bleaching agents could compensate for themicrohardness reduction.