Effectiveness and morphological changes induced by nanobleaching of 6% hydrogen peroxide light activated by led violet: an in vitro study

• Grant number: 13/15724-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): December 01, 2013
• Effective date (End): November 30, 2014
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Osmir Batista de Oliveira Júnior
• Grantee: Rafaela Nanami Handa Inada
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

This randomized, controlled, double-blinded study with repeated measurements will be realized to study the effectiveness of a new bleaching agent to in-office dental bleaching (6% hydrogen peroxide containing TiO_N nano particles) and a new equipment for light activation with LEDs 405-410nm and 808-818nm (violet and infrared). 112 bovine incisors will be cut to obtain dental fragments with 6.00 X 6.00mm of the middle third of the labial surface of the tooth and will be stained with black tea (camellia sinuses) to standardize the initial color. The 112 fragments will be randomly distribute in 7 experimental groups (n=16) according to the bleaching agent: 35% hydrogen peroxide (PH35) or 6% (PH6) and to the kind of light activation: blue LEDs - 470nm and infrared - 808nm (A) or violet LEDs - 405nm and infrared - 808nm (V). The control group won't receive any bleaching treatment (C). The test groups will be designed: PH35; PH35A; PH35V; PH6; PH6A e PH6V. It will be realized three bleaching sessions and in each session will be realized three applications of the bleaching agent. In each application, the bleaching agent will be kept in contact to the enamel for 16 minutes, light activated for 8 minutes. The total time of bleaching will be 144 minutes. The effectiveness of the treatment (E) will be measured by spectroscopy (Vita EasyShade) at the baseline T0, after the first (T1), second (T2) and third (T3) sessions of bleaching, 7 days (T4) and 30 days (T5) after the last application of the bleaching agent. Eletron Scanning Microscopy (SEM) will be realized to observe alterations on the structure of the enamel. The data will be analyzed by repeated measures mixed ANOVA, with significance of p<0,05. (AU)