Bleaching Gels and Light-Emitting Diodes: Comparison of Tooth Color Change.

Abstract

To measure difference in tooth shade and color achieved via two different over-the-counter bleaching agents with and without their associated light-emitting diodes (LEDs). A total of 84 extracted human anterior teeth were randomly divided into seven groups. Gypsum models were made with 6 extracted teeth in an arch form (n = 12; 2 arches/group). Samples were kept hydrated throughout treatment (25°C). Bleaching treatment followed manufacturers' instructions with at least 1-h of rehydration between treatments. Control tooth arches were left untreated. L*a*b* values were measured with a Vita Easyshade (VITA North America, Yorba Linda, CA) three times per tooth using white and black backgrounds. ∆E (CIE 2000) was compared between and within treatment groups over time with ANOVA and post hoc Tukey (a = 0.05). Subgroup testing confirmed the data were normally distributed. Two-way ANOVA showed significant interaction between product (Control, Crest, Snow) and treatment (light only, product only, light and product) on ∆E values for black (p-value < 0.001, F = 15.28) and white (p-value < 0.001, F = 13.62) backgrounds. Post hoc pairwise Tukey tests showed a significant effect of light-and-product treatments in contrast to light- or product-only treatments. Repeated measures ANOVA of between-treatment change (∆E) by product showed significant interaction between time and treatment for Snow products (p < 0.001, F = 10.9) and independent effects of time and treatment for Crest products (Time: p-value < 0.001, Treatment: p-value < 0.01, F = 7.21) on a black background. On white backgrounds, only a significant effect of treatment was reported for both Snow (p-value < 0.01, F = 5.427) and Crest (p-value < 0.001, F = 5.61). Overall, a combination of light and gel produces significantly higher tooth color and shade change over time, with the highest change seen for Snow products. Many patients use over-the-counter tooth bleaching products because they are more cost effective and easier to access than in-office bleaching. However, these products may have adverse effects, such as increased sensitivity with repeated use, in addition to increased consumption of time and money. This project measured tooth shade between treatments which can help determine which product is most effective for at home use.