The effect of light on tooth whitening: a split-mouth design

Abstract

Objectives: Conflicting research exists on the effect that various lights have on in-office tooth whitening. The aim of this study was to determine whether a sodium arc bulb lamp used with 25% hydrogen peroxide shows significant differences in shade using a split-mouth design.

Methods: Forty-nine subjects meeting study criteria had anterior teeth whitened with a 25% hydrogen peroxide in-office whitening system. The light was used on a randomly selected right or left half of the mouth. The opposing side was whitening only with gel. Shades were recorded using a spectrophotometer before, immediately after, 1 and 2 weeks post-whitening. Sensitivity was also recorded using a visual analogue scale. Values were analysed with a Friedman test with a stepdown Bonferroni adjustment for multiple comparisons.

Results: All teeth increased in lightness after whitening procedures. The only significant differences between use of the light and without use of the light were on the maxillary arch 1 week after whitening (P = 0.010). Sensitivity was greatest immediately after whitening but subsided within 1 week of whitening.

Conclusions: The use of a sodium arc bulb lamp with 25% hydrogen peroxide in-office whitening produces better results on maxillary teeth up to 1 week after whitening is completed. Subjects could not distinguish differences on each side of the mouth.