Association of aminomethacrylate/fluoride-based formulations against enamel erosive wear

• Grant number: 24/21683-3
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: September 01, 2025
• End date: February 29, 2028
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Alessandra Buhler Borges
• Grantee: Victor Cavallaro Bottesini
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

Erosive tooth wear is an increasingly prevalent condition that affects a large portion of the global population. Considering, the limitations of commercially available products, new agents have been incorporated into fluoridated products. Among these, aminomethacrylate (AMC) has shown promising results when used in the form of varnish, toothpaste, and mouthwash, separately. This proposal aims to evaluate the efficacy of treatments combining AMC and NaF in the prevention of enamel erosive wear. The proposal will be divided into two stages. Stage 1 will consist of an in vitro study aimed at evaluating the effectiveness of different vehicles (toothpaste, mouthwash, and/or varnish) containing the AMC+NaF combination in controlling enamel initial erosion and enamel surface loss. Bovine enamel specimens will be prepared and stratified into five treatment groups (n = 15): placebo toothpaste - negative control (NC); toothpaste with AMC and NaF (T); toothpaste and mouthwash with AMC and NaF (T+M); toothpaste and varnish with AMC and NaF (V+T); toothpaste, varnish, and mouthwash with AMC and NaF (V+T+M). The erosive/abrasive cycling will occur over five days, with each day consisting of 5 min of exposure to human saliva, 4 exposures to citric acid (0.3% - pH 2.6) per day for 1 min, 6 exposures to human saliva (30 min before and after treatment, and 1 h between acid challenges). The treatments will be applied after the first and last acid challenges of the day. When used, the varnish will be applied at the beginning of the cycle. The toothpaste and mouthwash treatment will involve brushing for 15 s followed by suspension of toothpaste for 105 s, followed by 1 min of immersion in mouthwash. The concentration of calcium dissolved in acid (mg/ml) will be evaluated by spectrophotometry after the first treatment, at the beginning of the cycling process, to assess the potential protection against initial erosion. Surface loss (µm) will be evaluated by profilometry at the end of the cycling. Additionally, at the end of the cycling, the concentration of fluoride adsorbed to the enamel (µg/cm2) (n = 10) will be measured, and a qualitative surface analysis will be conducted using scanning electron microscopy and energy dispersive spectroscopy (n = 5). Stage 2 aims to evaluate whether the combination of treatments (in-office using varnish and at-home using toothpaste and mouthrinse) is more effective than separate treatments (either in-office or at-home) through a randomized crossover in situ study. For this, bovine enamel specimens will be fixed in an intraoral device used by volunteers selected according to eligibility criteria (n = 12). The specimens will be stratified into four groups: placebo toothpaste and mouthrinse (Negative Control - NC); AMC+NaF varnish associated with placebo toothpaste and mouthrinse (V); AMC+NaF toothpaste and mouthrinse (TM); and AMC+NaF varnish associated with AMC+NaF toothpaste and mouthrinse (VTM). The treatments will be evaluated against two challenges: erosion and erosion+abrasion. The cycling will follow the same principles as in Stage 1, but the specimens will be attached to an intraoral device, so the exposure to human saliva and treatments will occur inside the mouth, while exposure to citric acid will be done outside the mouth (5 min). The following response variables will be analyzed: surface loss (µm) by profilometry and the concentration of fluoride adsorbed on the enamel surface (µg/cm²) at the end of the cycling will be analyzed. Additionally, scanning electron microscopy and energy dispersive spectroscopy analysis will be performed at the end of the cycling. The collected data will be subjected to the normality test (Shapiro-Wilk) and homoscedasticity test (Brown-Forsythe). If they meet the assumptions of normal distribution and homoscedasticity, one-factor ANOVA test (Stage 1) and repeated measures ANOVA test (Stage 2) will be applied, follow by Tukey's test (5%) (AU)