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Clinical Evaluation of the Efficacy of 10% Carbamide Peroxide Bleaching Agent Used During Night-Time and Day-Time

This split-arch clinical study was performed to compare the effects of using 10% carbamide peroxide bleaching agent for one hour twice a day with its use for 8 hours/night on tooth color change, color stability and sensitivity. Method: Bleaching trays, with reservoirs for the six maxillary anterior teeth, were fabricated for 12 volunteers. The trays were cut into two halves between the left and right central incisors (day-side vs. night-side) to be used with 10% carbamide peroxide for two weeks. The day-side tray was applied for one hour twice a day, while the night-side was applied for 8 hours overnight. Objective color measurements, using a colorimeter, were adopted to measure the color of the teeth of the two sides at the baseline appointment and at 1, 2, 3, 6 and 12 weeks. Total color difference (ΔE*) between two color measurements was calculated for all periods. Teeth and soft-tissue sensitivity were self-recorded for both sides during the bleaching weeks and the following week. Both Student's t-test and Tukey's test were used to compare ΔE* between the two sides and with time at p