Effect of fluoride varnishes supplemented with nanosized sodium trimetaphosphate on demineralization of enamel in vitro

• Grant number: 18/25860-6
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): May 01, 2019
• Effective date (End): December 31, 2019
• Field of knowledge: Health Sciences - Dentistry - Pediatric Dentistry
• Principal Investigator: Juliano Pelim Pessan
• Grantee: Kerllen Dayane Barbosa Alves
• Home Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

The aim of the present study will be to evaluate the effect of fluoride varnishes supplemented with sodium trimetaphosphate nanoparticles (TMP) on bovine enamel demineralization in vitro. Bovine dental enamel blocks (n = 48) will be selected by surface hardness (SH) and randomly divided into 4 experimental groups, according to the varnishes to be tested: (a) Placebo (without F or TMP - negative control), (b) 5% NaF (positive control), (c) 5% NaF + 5% micrometric TMP and (d) 5% NaF + 5% nano-sized TMP. The blocks will receive a single application of the varnishes and will be immersed in a remineralizing solution for 4 h, followed by a demineralizing solution for 2 h. After the removal of the varnishes, the blocks will be transferred to a remineralizing solution for 18 h. This cycle will be repeated for 5 days. The varnishes will then be removed and the blocks, transferred to a remineralizing solution for 18 h, totaling 5 days of pH cycling. On the 6th and 7th days, the blocks will be kept in a remineralizing solution. After the treatments, the final SH will be determined, allowing the calculation of the percentage of loss (%SHL). Following, the blocks will be longitudinally sectioned, for the analysis of cross-sectional surface hardness (”KHN) and micro-computed tomography (microCT) analysis. The results will be submitted to normality and homocedasticity tests. If the use of parametric tests is possible, %SHL and ”KHN data will be submitted to 1-way ANOVA and Student-Newman-Keuls' test. Otherwise, the corresponding non-parametric tests will be applied. The significance level will be set at 5%.