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Effect of toothpaste containing TiF4 and Chitosan on the reduction of erosive tooth wear in situ and of the development of enamel caries under a microcosm biofilm model

Grant number: 22/07715-4
Support Opportunities:Scholarships in Brazil - Doctorate
Effective date (Start): July 01, 2023
Effective date (End): August 31, 2026
Field of knowledge:Health Sciences - Dentistry
Principal Investigator:Ana Carolina Magalhães
Grantee:Monique Malta Francese
Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

This work will be divided in two steps. The in situ step aims to test the preventive effect of an experimental TiF4 and Chitosan toothpaste compared to a specific commercial fluoride toothpaste on the erosive tooth wear; the second step aims to test in vitro the protective effect of the experimental toothpaste on the development of dental caries under a microcosm biofilm model. In the first stage, fifteen adult will participate in three cross-over and double-bind phases (5 days, washout of 10 days), in which palatal appliances containing 8 samples (4 enamel and 4 dentin samples) will be wore, half of them will be eroded and the other half, eroded-abraded. The treatments correspond to the following phases will be: 1) Phase A - Experimental dentifrice with TiF4 (1400 ppm F-) + 0.5% Chitosan (75% deacetylation, 500 mPas); 2) Phase B - Elmex® Protection against erosion commercial toothpaste (GABA, Switzerland, 1400 ppm F-, NaF and AmF, SnCl2 and chitosan); 3) Phase C - Placebo without F (negative control). One hundred and eighty enamel samples and 180 root dentin samples (4x4mm) will be prepared from bovine teeth and embedded in acrylic resin of the palatine apparatus. During the phases, volunteers will perform erosive challenges (4 x 90 s/day in 0.1% citric acid, pH 2.5) and abrasive challenges (2 x 15 s / day abrasion + 45 s of treatment, 30 min after the 1st and the last erosive challenge) using the conventional toothbrush and the toothpaste slurry. At the end of the abrasion, the volunteers must replace the device into the mouth and spit the excess of toothpaste. Afterwards, they must keep the device into the mouth for 30 minutes. The tooth alterations will be analyzed by profilometry (p<0.05) by comparing the baseline profile to the final profile, and the data will be statistically compared (p<0.05). The surface morphological changes and the elements will be analyzed by SEM-EDS. The acceptability of the participants will be evaluated by scale and questionnaire. In the second stage, seventy-two enamel and 72 bovine dentin samples (4x4mm) will be prepared and divided into the following groups of toothpastes: 1) TiF4 (1400 ppm F-) + Chitosan 0.5% (75% deacetylation, 500 mPa); 2) TiF4 (1400 ppm F-); 3) 0.5% Chitosan (75% deacetylation, 500 mPas); 4) Elmex® caries protection commercial toothpaste (GABA, Switzerland, 1400 ppm F-, AmF, positive control for caries); 5) Placebo without F (negative control); 6) No treatment. In 24-well plates, each enamel and dentin 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 triplicate (n=4 for each repetition, final n=12). The response variables used will be: CFU count for Streptococcus mutans/ S. sobrinus and total Lactobacilli; total fluoride in the biofilm and quantification of enamel and dentin demineralization by transverse microradiography (TMR). Data will be subjected to appropriate statistical analysis (parametric or non-parametric test), considering p<0.05. (AU)

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