Effect of hydrogen peroxide on antimicrobial photodynamic therapy on dynamic oral biofilm

• Grant number: 18/18906-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date until: April 01, 2019
• End date until: March 31, 2020
• Field of knowledge: Health Sciences - Dentistry - Pediatric Dentistry
• Principal Investigator: Carolina Steiner Oliveira Alarcon
• Grantee: Victoria Gabriela Carbonero Geraldino
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

Dental caries and periodontal disease are biofilm-dependent oral diseases. Thus, innovative biofilm control techniques are important for the prevention of these diseases. Studies on the effects of antimicrobial photodynamic therapy (aPDT) have already shown bacterial susceptibility to death when using photosensitive agents activated by a light source; however, the association of hydrogen peroxide with the photosensitive agent could potentiate this effect. Thus, the objective of this study will be to test the effect of aPDT on oral biofilm with the differential of including dissolved oxygen in the medium, in the form of hydrogen peroxide associated to the photosensitizer in dynamic biofilm through cell flow system and red laser or LED light sources (» = 660 nm). The groups will be divided into (n = 3, in triplicate): C (negative control), CX - chlorhexidine 0.2% (positive control), P (Photosensitizer), H (Hydrogen Peroxide), PH (Photosensitizer + Hydrogen Peroxide), L (Laser + Photosensitizer), LH (Laser + Hydrogen Peroxide), LPH (Laser + Photosensitizer + Hydrogen Peroxide), LED (light emitting diode), LEDP (LED + Photosensitizer), LEDH (LED + Hydrogen Peroxide) and LEDPH (LED + Photosensitizer + Hydrogen Peroxide). The cell flow system will comprise chambers for culturing the S. mutans biofilm under continuous hydrodynamic conditions with BHI supplemented with 10% sucrose (w/v). The reduction of the microorganisms will be evaluated by counting viable microorganisms of the biofilm before and after the aPDT in selective culture mediums and the proportion of living dead microorganisms will also be evaluated by laser confocal microscopy. The normality of the data will be checked by the Shapiro-Wilks test and the results will be submitted to analysis of variance ANOVA or Kruskal-Wallis. All statistical tests will have significance level of 5%.