Analysis of the bleaching efficacy and adverse effects caused by the use of violet light in dental bleaching

Author(s)

Marjorie Oliveira Gallinari

• Document type: Doctoral Thesis
• Press: Araçatuba. 2019-08-30.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Odontologia. Araçatuba
• Defense date: 2019-07-29
• Advisor: André Luiz Fraga Briso

Abstract

Researchers have proposed tooth whitening only with the irradiation of violet light (VIO), without the need for whitening gel. Therefore, the objective of this study was to evaluate in vitro and in vivo this new treatment associated with different concentrations of hydrogen peroxide (PH) for its bleaching efficacy and possible adverse effects. For the in vitro study, 567 (n = 67) teeth were selected and divided into 9 groups: No Gel (SG) -Without Light (SL), PH17.5% -SL, PH35% -SL, SG-LED / Laser (LED), PH17.5% -LED, PH35% -LED, SG-VIO, PH17.5% -VIO, and PH35% -VIO. The application of the gels followed the manufacturer's recommendations. The LED was applied3 times 3 minutes, the VIO was applied3 times 7 minutes. After the bleaching procedures, superficial chromatic alteration and fluorescence intensity analyzes were performed (n = 10), considering 5 analysis times (initial T0, T1-1st session, T2-2nd session, T3-3th session, T4-14 days later), depth color change (n = 15), hydraulic conductance (n = 10), PH diffusion (n = 10), cell viability (n = 8) and intrapulp temperature variation (n = 10) ). Data were submitted to appropriate statistical tests for each type of analysis. VIO when used alone provided superficial and deep color changes, but its effect was statistically smaller than that provided by the whitening gel. In fluorescence, the T1 and T3 of PH35% -SL were different. PH diffusion and dental permeability, the PH35% groups presented the highest values, being potentiated when associated with LED / Laser. In cell metabolism, the PH35% groups presented the lowest values, and the isolated VIO increased intrapulp temperature and decreased cell viability. For the in vivo part of the study, 6 patients were initially selected and assigned to 3 treatments for the pilot study (n = 2): 10% Carbamide Peroxide (PC) + IVI, IVI and PH17.5% + IVI. Only the right side associated the irradiation with VIO with whitening gel, while the left side received only the application of the whitening gel. Nine clinical sessions were held, and in each session, 20 1-minute irradiations were performed at 30-second intervals. Patients receiving PC10% + VIO presented greater difference between hemi-arches, with positiveresults for the side that received the association with light, but it was found greater tooth sensitivity in this association. In the second study, the treatment with the largest difference observed in the pilot study (PC10% + VIO) was selected. Then, 20 patients were selected, and the selection of hemi-arches and treatments were performed by lot. The whitening gel was applied for 8 hours daily by the patient and he returned to the office 2 times / week for 3 weeks for IV irradiation for 30 minutes in eachclinical session. Data were submitted to repeated-measures 2-way ANOVA statistical tests and it was observed that the hemi-arch that received the association showed favorable results in color change, but there was an increase in tooth sensitivity even after the end of treatment (14 days after). It is concluded that the use of IVC with less concentrated gels is satisfactory, but should be used with caution not to cause side effects. (AU)

• FAPESP's process: 16/19982-6 - Use of violet light in tooth whitening: study of efficacy whitener, tooth fluorescence, trans-dentinoenamel penetration H2O2, cytotoxicity, hydraulic conductance, heat generation and adhesion to resin materials
• Grantee: Marjorie de Oliveira Gallinari
• Support Opportunities: Scholarships in Brazil - Doctorate