Color differences of canines and incisors in a comparative long-term clinical trial of three bleaching systems

This study was a long-term clinical trial of home and in-office LED and laser bleaching systems comparing for the first time interdental color differences (differences between the central labial surfaces of the canine and the central incisor). A total of 90 patients were divided into three groups of 30 each. One group received day guard vital bleaching, and the other two groups received one bleaching session for 20 min accelerated by a diode laser for 30 s per tooth or a blue LED for 3 min per tooth, and both groups received additionally day guard for 7 days. A total of four color measurements were carried out during the study period of 3 months and 3 weeks. The group treated with the LED tended to show the highest degree of equalization of lightness, chroma and hue. A significantly stronger overall increase in lightness was observed for canines after treatment when compared with incisors resulting in more homogeneous lightness values.