Effects of experimental bleaching protocols on odontoblast-like cells phenotype

• Grant number: 14/08058-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2014
• End date: August 31, 2015
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Diana Gabriela Soares dos Passos
• Grantee: Natália Marcomini
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

It was recently demonstrated that the reduction on hydrogen peroxide (HP) concentration in bleaching gels minimizes the trans-enamel and trans-dentinal cytotoxicity to pulp cells, associated to an effective bleaching when additional sessions are performed. However, the capability of pulp cells to express its phenotype when exposed to these experimental protocols was not investigated. Therefore, in the present study, the odontoblastic markers expression and the deposition of mineralized matrix in vitro by odontoblast-like cells exposed to a 17.5% HP gel will be analyzed. Enamel/dentin discs, from bovine incisors, will be adapted to trans-wells devices. The MDPC-23 odontoblast-like cell will be seeded in 24-well plates, in an 80% confluence pattern. The disc/trans-well set will be placed onto the previously seeded cells, in such way that only dentin surface will be in direct contact with culture medium. The bleaching gel will be applied to the enamel surface for 3x 15, 1x 15 or 1x 5 min. Immediately thereafter, the cells will be cultivated for 7, 14 or 21 days in odontogenic medium. At each period of analysis, the ALP activity (thymolphtalein assay), mRNA gene expression of DSPP, DMP-1 and ALP (real time PCR), as well as the deposition of mineralized nodule (alizarin red) will be assessed. Numeric data will be subjected to statistical analysis.