Optimum Wavelength of 3.5% Hydrogen Peroxide Bleach containing TiO2

Objectives: 3.5% Hydrogen Peroxide (HP) containing 0.06wt% TiO2 office bleach agent (Mitsubishi Gas Chemical Pyrenees: MGC PY) is marketed in Japan claiming less hypersensitivity occurrence and easy to protect gums and safeness. Since TiO2 is activated by relatively lower visible light wavelength, we tried to check various light source unit. The purpose of this study was to compare wavelength of various light sources and to confirm bleaching efficacy and hypersensitivity occurrence of 3.5% HP and conventional 35% HP bleach in the clinic.

Method: Spectra-radio meter USR-40D (Ushio, JAPAN) was used for measuring wavelength and intensity, 1mm or 10mm distance between the measuring head and object, for multi arch unit the distance was 50mm. We tried 3 Halogen Units; CANDELUX (Morita, Japan), Hyperlightel (Morita), Wite Lite (Takara Belmont, JAPAN), 3 Xenon lamp units; Power PAC (American Dental Technology: ADT), Power PAC2 (ADT), APPOLO Elite 95E (DMD, USA), 3 LED units; Radius (Osada, JAPAN), Flash Light (Discus, USA), G-Light (GC, JAPAN) and 2 multi arch units; Beyond (Halogen; Beyond Technology), ZOOM! (Metal Haraide; Discuss). MGC PY 3.5%HP containing TiO2 bleach and conventional 35% bleach (Shofu Hi-Lite: HL) were used as bleaching agent. In the clinic, 15 volunteers were involved in this study, clinical bleaching effect of MGC PY with ZOOM! irradiation was determined by measuring the CIELab values and calculated dE.

Results: Effective 420nm wavelength was obtained with Hyperlightel and Zoom! unit. After 3 visits, the max dE value of MGC PY group was 5.9 and 7.6 by HL bleaching. And hypersensitivity of MGC PY was relatively lower than HL bleaching.

Conclusion: TiO2 is activated by continuous 420nm visible light irradiation. 3.5%HP+TiO2 bleach had its safeness and easy to protect gums, less possibility of hypersensitivity occurrence, however 420nm continuous close irradiation was limited select of light source unit.