Evaluation of Photodynamic Therapy associated with Auxiliary Chemical Substances and Irrigants in the control of endodontic biofilms in Multispecies Biofilm Models

• Grant number: 23/08789-4
• Support Opportunities: Scholarships in Brazil - Master
• Start date: April 01, 2024
• End date: February 28, 2025
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Brenda Paula Figueiredo de Almeida Gomes
• Grantee: Bianca Cardozo
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

Knowledge of endodontic biofilm as well as strategies to eradicate them from the root canal system is important for maintaining oral health and the teeth in the oral cavity. The use of multispecies biofilm models that mimic endodontic biofilms in situ allows for realistic and efficient investigations of new antimicrobial therapies, such as photodynamic therapy and the aid of chemical auxiliaries and irrigants, to be tested. The main aim of this in vitro study is to evaluate the association of photodynamic therapy (PDT) with the chemical auxiliaries substances and irrigants commonly used in endodontic treatment against a multispecies biofilm model composed of 9 bacteria: Actinomyces oris OMZ 745; Enterococcus faecalis OMZ 422; Fusobacterium nucleatum OMZ 598; Parvimonas micra OMZ 518; Porphyromonas gingivalis OMZ 925; Prevotella intermedia OMZ 278; Streptococcus mutans UA OMZ 159; Streptococcus oralis OMZ 607; Veillonella díspar OMZ 493. A total of 72 bovine dentin discs (dimensions 9 mm × 4 mm × 0.5 mm) will be made. Biofilms will be prepared and cultured in 24-well polystyrene cell culture plates conditioned in 1 mL saliva. They will be divided into 6 groups, as follows: (G1) Saline 0.9 (control 1); (G2); Saline 0.9% + PDT (control 2); (G3) Sodium hypochlorite 2.5% + Saline 0.9%; (G4) Sodium hypochlorite 2.5% + saline 0.9% + PDT; (G5) Chlorhexidine 2% + saline 0.9%; (G6) Chlorhexidine 2% + saline 0.9% + PDT. Biofilms will be analyzed by the microbial culture method of Colony Forming Units (CFUs) Count, stained using the LIVE/DEAD BacLight bacterial viability assay and examined by Vital Stain and Confocal Laser Scanning Microscopy (CLSM) at three selected positions randomly using a Leica TCS SP5. Supplemental microbiological analyzes will be carried out using the Checkerboard DNA-DNA hybridization. After the data are performed and processed, they will be tabulated and according to normality and appropriate tests, submitted to statistical analysis by SPSS for Windows software (SPSS Inc., Chicago, Illinois, USA).