Establishment of individualized bleaching protocols according to the thickness of dental substrate based on 10% hydrogen peroxide bleaching gel

• Grant number: 15/21294-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2016
• End date: July 31, 2017
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Diana Gabriela Soares dos Passos
• Grantee: Fernanda Rubio
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

It has been shown that the tooth sensitivity mediated by bleaching is related to the protocol as well as to the group of teeth subjected to this procedure. Therefore, the aim of this study is to evaluate the effectiveness and cytotoxicity of a 10% hydrogen peroxide (H2O2) bleaching gel, applied for different periods onto enamel/dentin discs varying the thickness. Discs obtained from bovine incisors, will have the enamel/dentin thickness standardized in order to simulate low incisors and upper central incisors, respectively. To analyze bleaching effectiveness, the discs will be stained and subjected to bleaching for 3x15, 1x15 or 1x5 min. No treatment will be performed on negative control group. Six bleaching sessions will be performed within a 72-hour interval, and color alteration will be measured with UV-Vis spectrophotometer according to CIE L*a*b* system. To evaluate the trans-enamel and trans-dentinal cytotoxicity, the discs will be adapted to trans-well devices, and this set will be placed onto previously cultured human dental pulp cells (80% confluence). Immediately after bleaching, the cell viability (MTT assay) and morphology (SEM) will be assessed. Finally, the H2O2 diffusion through the discs will be measured (leuco-crystal violet/peroxidase). Data will be subjected to statistical analysis. (AU)