Blue led phototherapy on odontoblast-like and dental pulp stem cells: effect on pulp repair-related proteins production

• Grant number: 12/17552-3
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: March 01, 2013
• End date: December 31, 2015
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Josimeri Hebling Costa
• Grantee: Leopoldina de Fátima Dantas de Almeida
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil
• Associated scholarship(s): 14/12017-8 - The ability of a chitosan-based scaffold in the induction of odontogenic differentiation of dental pulp cells in culture, BE.EP.DR

Abstract

The use of phototherapy has been widely investigated in medical sciences. Considering that the blue LED is already used in Dentistry to activate the polymerization of materials such as composite resins and adhesive systems and that it has been demonstrated that a light in that spectrum has the potential to biostimulate some cell lines it is interesting to investigate if the use of that light source could promote the pulp tissue repair. Therefore, the aim of this study is to evaluate the effect of a blue LED, at 455 nm wavelength, on both odontoblast-like (MDPC-23) and pulp stem cells regarding the production of pulp tissue repair-related proteins. Two energy doses will be investigated, 2 J/cm2 and 4/cm2, selected from previous studies. Initially, it will be determined the direct effect of a blue LED at the abovementioned energy doses, irradiance of 20 mW/cm2, on pulp stem cells and MDPC-23 cells. Subsequently, it will be investigated the transdentinal therapeutic effect of the blue LED, in the same energy doses, on MDPC-23 cells using an irradiance of 80 mW/cm2. For that specific experiment, 0.2 mm-thick dentin discs will be prepared. The phototherapeutic effect for both, direct and transdentinal irradiance, will be determined by a number of methodologies which include cellular metabolism (MTT assay), mineralization nodules formation (alizarin red), cellular viability (Trypan blue), production of total protein estimation (Lowre's protein assay) alkaline phosphatase activity (ALP kit), collagen deposition (Sircol red) and cellular morphology (SEM). Additionally, quantitative PCR will be used to determine the gene expression of Dentin sialophosphoprotein (DSPP), dentin matrix acidic phosphoprotein 1 (DMP-1) and OCT-4 (octamer-binding transcription factor 4). With the results of both initial experiments, a blue LED prototype will be developed with objectives, photopolimeralization and cellular biostimulation. In order to evaluate the photopolimerization efficiency of the prototype it will be determined the degree of conversion of a restorative composite resin by Fourier transform infrared spectroscopy (FTIR). The phototherapeutic effect of the prototype on MDPC-23 and pulp tissue stem cells will be validated by repeating the previously mentioned tests. For all experiments, the statistical analysis, that is, the selection of the statistical tests will be defined based on the characteristics of the response variable sets, such as, adherence to the normal distribution and homoscedasticity. All statistical inferences will be based at the level of significance of 5%. (AU)