Effect of toothpaste containing Chitosan with TiF4 or NaF on the development of enamel caries under a microcosm biofilm model: an in vitro study

• Grant number: 22/07982-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2022
• End date: October 31, 2023
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Ana Carolina Magalhães
• Grantee: Mariana Carvalho de Barros
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

This work aims to compare an experimental toothpaste containing Chitosan, with TiF4 or NaF, to a specific commercial fluoride toothpaste and their effects on the development of dental caries under a microcosm biofilm model. A hundred and ninety-two bovine enamel samples (4x4mm) will be prepared and divided into the following groups of toothpastes: 1) TiF4 (1400 ppm F-) + 0.5% Chitosan (75% deacetylation, 500 mPa); 2) TiF4 (1400 ppm F-); 3) NaF (1400 ppm F-) + 0.5% Chitosan (75% deacetylation, 500 mPa); 4) NaF (1400 ppm F-); 5) 0.5% Chitosan (75% deacetylation, 500 mPas); 6) Elmex® caries protection commercial toothpaste (GABA, Switzerland, 1400 ppm F-, AmF, positive control for caries); 7) Placebo without F (negative control); 8) No treatment. In 24-well plates, each enamel sample 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), they will receive 1.5 mL of fresh medium (McBain artificial saliva) for 16 h, completing the initial 24 h. From the 2nd to the 5th day, the medium with sucrose will be replaced 1x/day, the samples will be treated with the different toothpastes 'slurries 1:3 water (1 ml per well, 1 min) and the plates will be incubated at 5% CO2 and 37° C. The cultivation will be carried out in biological quadruplicate (n=3 for each repetition, final n=12). The percentage of dead and alive bacteria, the biofilm thickness and the extracellular polysaccharide biovolumewill be determined. The response variables used will be: CFU count for Streptococcus mutans/ S. sobrinus and total Lactobacilli; and quantification of enamel demineralization by surface microhardness (baseline and final) and transverse microradiography (TMR). Data will be subjected to appropriate statistical analysis (parametric or non-parametric test), considering p<0.05.