Objectives:The purpose of this clinical study is to compare three different whitening treatments, at-home with 10 % KP, over-the-counter with 5.3 % HP and in-office with 35 % HP, for the degree of color change in the teeth, the amount of color relapse 1 and 6 months after the end of the treatment and the level of tooth sensitivity. Methods:Thirty-six healthy volunteers who met the inclusion/exclusion criteria participated in the study and were allocated randomly to one of the three groups. Group A (n=12) used Voco Perfect Bleach 10 % Kp 8 hours a day for 14 days. Group B (n=12) used Crest Whitestrips 5.3% HP 1 hour a day for 14 days. Group C (n=12) were applied Pola Office 35 % HP in office during two appointments for three 5 minutes at each. Baseline tooth color, degree of color change at the end of the treatment and color relapse at 1 and 6 months were evaluated by the dentist using a colorimeter. Tooth sensitivity was self-evaluated by the subjects using a visual analog scale ranging from 0 to 10. Results:All three methods resulted in significant improvements in yellowness (
Db*), brightness (
DL*) and overall color (
DE*). Group B had significantly higher whitening response than groups A and C. However there was a greater color relapse in groups B and C compared to Group A at 1 and 6 months, Group C being the worst. Side effects were minimal in all groups and not significant statistically. Conclusions:All three bleaching systems seemed to be effective on the color change of teeth.