[Effectiveness of various whitening techniques and their effects on the enamel surface].

The objective of this in vitro study was to compare three different bleaching techniques with respect to the bleaching times required to achieve six grades of whitening in human teeth, i.e. from shade A4 to A3 of the VITAPAN classical shade guide. Additionally, the enamel surfaces were analyzed by SEM after each bleaching procedure to detect potential surface changes. A total of 24 anterior teeth extracted for periodontal reasons (baseline shade A4) were randomized to three different bleaching treatments (n=8): Group A Illuminé home (home-bleaching technique); group B Whitestrips (over-the-counter technique); and group C Opalescence Xtra (in-office technique). The bleaching cycles were carried out according to the manufacturers' instructions, with one bleaching cycle taking eight hours for product A, 30 minutes for product B, and 15 minutes for product C. The mean treatment time required to achieve a defined shade (A3) was 6.88 cycles (=3300 minutes) in group A, 36.25 cycles (=1087 minutes) in group B, and 4.25 cycles (63.75 minutes) in group C. None of the teeth studied showed detectable surface changes in the subsequent SEM (2000 X) analysis of the enamel surface. In this in vitro study all three techniques studied resulted in the desired tooth whitening within the recommended application time periods, and none of the three products tested created any detectable enamel surface changes.