Evaluation of enamel caries lesions caused by microcosm biofilm - analysis by optical coherence tomography and transverse microradiography: a comparative study

• Grant number: 25/02696-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2025
• End date: June 30, 2026
• Field of knowledge: Health Sciences - Dentistry - Social and Preventive Dentistry
• Principal Investigator: Ana Carolina Magalhães
• Grantee: Laís Guilhen Torres Figueira
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

The objective of the project will be to compare the mineral loss and depth of carious lesions in enamel by Spectral Domain Optical Coherence Tomography (SD-OCT) and cross-sectional microradiography (TMR), as well as to analyze the cariogenic bacteria present in the microcosm biofilm used for this purpose. Ninety-six bovine enamel samples (4 mm x 4 mm) will be cut and polished. For the formation of the microcosm biofilm, the pool of saliva collected from 10 healthy individuals will be used. In 24-well plates, the samples will be allocated according to two factors under study: Biofilm formation time (1, 3, 5 and 7 days) and treatment (0.12% CHX-positive control and PBS-negative control). The samples will be exposed to 1.5 mL of inoculum (human saliva-glycerol + McBain saliva, 1:50) for 8 h. After the initial 8 h, the inoculum will be removed, the samples will be washed with PBS (5 s), and will receive 1.5 mL of fresh medium (McBain artificial saliva with 0.2% sucrose) for 16 h, completing the initial 24 h. From the 1st to the 7th day, according to the formation time, the samples will be treated for 1 minute with CHX or PBS (n=12, biological triplicate n=4) and the medium containing sucrose will be changed. The response variables will be: CFU/mL count for cariogenic microorganisms (Streptococcus mutans/ S. sobrinus and Lactobacillus spp) present in the biofilm and quantification of caries lesions by OCT and TMR (mineral loss and lesion depth). The data will be subjected to appropriate statistical analysis (parametric or nonparametric test), considering p<0.05. (AU)