|Budget Amount *help
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥2,000,000 (Direct Cost: ¥2,000,000)
Research on Vital Bleach Techniques
The purpose or this study was to determine the bleaching efficacy with different light sources on artificially discolored bovine teeth. Extracted bovine mandibular anterior teeth were soaked in a Fuchsine Basic 0.5% solution for 3days to prepare artificially discolored teeth. Three chairside bleaching agents, Apollo Secret In-Office whitening (DMD, CA., USA), Hi-Lite (Shofu, Kyoto, JAPAN) and Quasar Brite (Inter Dent, CA., USA) were employed and two types or light unit, Wite-Lite (300mW/cmィイD12ィエD1, with halogen lamp) and Plasma Arc Curing: PAC (1400mW/cmィイD12ィエD1, with xenon lamp) were used. After baseline color measurement with a calorimeter, these teeth were divided into 5 groups. Group or Apollo Secret were irradiated with PAC for 30sec, Hi-Lite groups with PAC 30sec, or with White-Lite 60sec and l80sec and Quasar Brite with PAC for 30sec. The bleaching procedure were repeated 3 times. We also measured pH change or bleaching paste during irradiation and bleached surfaces were observed by SEM.
Hi-Lite had low pH value of 3.9 to 4.2, Apollo Secret and Quasar Brite has 7.2 to 8.0. No morphological difference was recognized by SEM observation before and after bleaching. Bleaching effect was determined by calculating delta E value (CIELab color system).
The highest color difference was achieved Quasar Brite with PAC 30sec. ANOVA revealed that Hi-Lite with PAC 30sec had significantly higher value comparing Hi-Lite with Wite-Lite 180sec. Apollo Secret with PAC30sec and Hi-Lite with Wite-Litel80sec had no significant difference.