481 Chemical Activation Versus Light activation on Bleaching Efficacy

Thursday, March 22, 2012: 3:30 p.m. - 4:45 p.m.
Presentation Type: Poster Session
C.R.G. TORRES, C.A. GUIMARAES, Z.E.A. RIBEIRO, and A.B. BORGES, Department of Restorative Dentistry, UNESP - São Paulo State University, São José dos Campos School of Dentistry, São José dos Campos - São Paulo, Brazil
Objectives: The aim of this study was to evaluate the efficacy of different types and concentrations of chemical activators on bleaching efficiency of 35% hydrogen peroxide gel in relation to light activation (LA).

Methods: 540 enamel-dentin disks were obtained from bovine incisors using a 3mm diameter trephine mill. The initial colors of specimens were measured with a spectrophotometer (CM2600d – Konica Minolta) using the CIELab system. An experimental 35% hydrogen peroxide gel was used. A positive (without activator) and a negative (no bleached) control groups were prepared (n=20). Each one of the five chemical activators groups (n= 60) received a different substance: MG - Manganese Gluconate; MC - Manganese Chlorite, FG - Ferrous Gluconate, FC – Ferric Chlorite, FS – Ferrous Sulphate. Each activator group was divided into 3 different subgroups (n=20), according to the concentrations tested (1 - 0.01%, 2 - 0.02% e 3 - 0.03%). In the LA group, the gel was activated with blue light from a LED device (Bright Max II - MM Optics). Three applications of 10 min were performed for each gel, being repeated after 7 days. In intermediate periods, the specimens were stored in artificial saliva. The final color was measured one week after the final bleaching. The data were analyzed using one-way ANOVA and Tukey´s tests (a=5%).

Results: Significant differences were observed among the groups (p=0.0035 for ANOVA). The results of Tukey´s test for Delta E were: MC1-4.48(±1.10)a; MG3-4.69(±1.22)a; PC-4.70(±1.02)a; FC3-4.82(±1.01)ab; FG1-4.88(±1.39)ab; FG3-4.89(±1.25)ab; FS1-4.99(±1.30)ab; MG2-5.04(±1.19)ab; MC3-5.12(±1.29)ab; FG2-5.13(±1.13)ab; FS2-5.18(±1.42)ab; FS3-5.20(±1.13)ab; FC2-5.23(±1.00)ab; MG1-5.31(±1.41)ab; FC1-5.35(±1.18)ab; MC2-5.47(±1.32)ab; LA-5,83(±1,36)b. The groups followed by the same letter did not show significant differences.

Conclusions: Only light activation increased significantly the color change. Significant differences were obtained for all bleached groups in relation to the negative control group.

This abstract is based on research that was funded entirely or partially by an outside source: FAPESP - Proc. 2010/50912-8

Keywords: Bleaching, Color and Esthetics