Whitening-dependent changes of fluorescence of extracted human teeth

Abstract

Objective: To evaluate in vitro the fluorescence properties of extracted human teeth whitened with 40% hydrogen peroxide. Materials and Methods: A total of 28 extracted human teeth were pumiced for 1 minute using a low-speed dental handpiece and a disposable rubber cup. Pre-whitening fluorescence measurements (T0), maximum excitation (Ex(max)), maximum emission (Em(max)), and maximum intensity (I(max)10(8)), were performed using a spectrofluorometer. After T0 measurements, the teeth were whitened using the in-office method with 40% hydrogen peroxide, three times for 20 minutes. The fluorescence parameters were measured under the same conditions 7 and 14 days after bleaching (T1 and T2, respectively). Results: Ex(max) exhibited a broader range 7 days after whitening and decreased after 14 days. The Em(max) and I(max)10(8) displayed a narrower range after whitening. The mean Ex(max) differed significantly between the time points (F = 20.09. P LT .001). The corresponding analysis for the mean Em(max) differed significantly between the time points (F=16.69, P LT .001). The same was true for the mean I(max)10(8) (F = 9.69, P LT .001). Conclusions: Within the limitations of this study, whitening provoked statistically significant changes in fluorescence of the intact teeth in vitro.