Interactions between probiotics-pathogens-surfaces in oral biofilms formed on implant materials and prosthetic components.

• Grant number: 23/02796-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2023
• End date: December 31, 2024
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Valentim Adelino Ricardo Barão
• Grantee: Thais Terumi Sadamitsu Takeda
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

Oral probiotics appear to improve the treatment of peri-implant diseases, but there is limited evidence on the mechanisms involved in microbiological modulation on dental implant surfaces. Thus, this proof-of-concept study aims to evaluate the effect of topical oral supplementation with Lactobacillus reuteri (LR; BioGaia®) on the viability, metabolism, structure, pathogenicity and virulence of oral biofilm formed in situ on commercial implant surface and abutments. An in situ, double-blind, crossover model, with 2 phases of 14 days each, will be performed. A total of 8 volunteers will use intraoral palatal appliances that will allow the formation of oral biofilm in situ on the surface of implants (SLA®, Sandblasted, Large grit, Acid-etched) and abutments (polished surface; titanium grade 4). Daily, the biofilms will be treated with sucrose 20% (v/v) and 5 drops of LR probiotic solution or placebo solution. After 14 days of biofilm formation, the discs will be removed, randomized, and the biofilm collected blindly for analysis. The modulatory effect of LR on the count (CFU) of total bacteria, anaerobic bacteria, Lactobacilli spp., Streptococcus spp. and Candida albicans will be investigated using selective culture media. The effect of LR on bacterial metabolism (XTT assay), insoluble biomass (biofilm dry weight), Lactobacilli biovolume and live/dead cells (confocal), biofilm structure (scanning electron microscopy/confocal), and probiotic-pathogen-surface interaction (transmission electron microscopy) will also be investigated. A susceptibility assay to chlorhexidine 0.12% with biofilms treated with LR and placebo, on the different tested surfaces, will be evaluated by bacterial count (UFC) and live/dead cells (confocal). Finally, the indirect virulence potential of biofilms after probiotic supplementation with LR in reducing the viability of human gingival fibroblasts will be determined (MTT assay). Data will be subjected to the most appropriate statistical test (± = 5%).