In vitro comparison of visual and computer-aided pre- and post-tooth shade determination using various home bleaching procedures.

Statement Of Problem: Due to inter- and intraexaminer differences, subjective evaluation of tooth color is deemed problematic.

Purpose: The purpose of this study was to evaluate the efficacy of home bleaching products, and to compare visual and computer-aided tooth shade determinations when various agents were applied.

Material And Methods: Human incisors (n=288) were stained (red wine, black tea) and allocated to 8 groups (n=36). Paint-on varnish (VivaStyle Paint On; 6% carbamide peroxide, CP) was used either for 1 x 20 min/d (VSP1), 2 x 20 min/d (VSP2), or 2 x 5 min/d (VSP25). Paint-on lacquer (Colgate Simply White, CSW; 5.9% hydrogen peroxide, HP) was applied for 2 x 30 min/d. Moreover, bleaching was performed using trays (VivaStyle, VS; 10% CP; 1 x 60 min/d, and Odol-med3 Beauty Kur, OBK; sodium chlorite; 2 x 10 min/d) or whitening strips (blend-a-med Whitestrips, BWS; 5.9% HP; 2 x 30 min/d). Water was used as control (1 x 60 min/d). Tooth shades were determined blindly (Chromascop Complete) after staining and 24 hours after final bleaching (visual and computer-aided assessment). Change in shade was analyzed using nonparametric methods (Kruskal-Wallis) and post hoc tests (Tukey and Kramer) (alpha=.05).

Results: Color changed significantly to lighter shades for all active agents. Analysis revealed significant differences among the control and all other groups, and among CSW/BWS versus VSP25/OBK, and VS versus OBK, for both evaluation methods. Additionally, significant differences were spectrophotometrically observed for VSP1/VSP2 versus BWS, and VSP2 versus OBK, with comparable reliabilities (0.995 at baseline; 0.994 after bleaching).

Conclusions: Increased bleaching efficacy was observed with high peroxide concentrations; application time did not alter efficacy. Spectrophotometry was reproducible and objective. The 2 assessment methods matched 45.8% of the time.