Preventive effect of Er:YAG laser irradiation and a bioactive varnish on enamel after erosive-abrasive challenge

• Grant number: 23/14710-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2024
• End date: December 31, 2024
• Field of knowledge: Health Sciences - Dentistry - Pediatric Dentistry
• Principal Investigator: Carolina Steiner Oliveira Alarcon
• Grantee: Laine Longuinho Gonçalves
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

With the increase in the prevalence of dental erosion in recent years, new preventive therapies are important to control this change and the bioactive technologies of pre-reacted surface glass ionomer (S-PRG) and high-power laser irradiation have been studied. . S-PRG particles have biological effects properties of pre-reacted multifunctional glass on the surface, with the ability to release and recharge fluoride ions, in addition to being a physical barrier and modulator of mineral loss/gain. Irradiation of tooth enamel with a high-power laser promotes chemical-structural changes that make the enamel more acid-resistant. Therefore, the objective of this work will be to evaluate the preventive effect of Er:YAG laser irradiation and a bioactive varnish on enamel in situations of erosive-abrasive challenge. Bovine enamel specimens (n=50) will be standardized and, after formation of the acquired film on each one, they will be randomly divided into 5 groups: negative control (C-) without treatment; positive control (C+) with fluoride varnish (NaF 5%); Laser (L) Er:YAG laser irradiation (»=2.94 nm, 80 mJ, 20 Hz, 10s); S-PRG (bioactive varnish); Laser + S-PRG (L+PRG) laser irradiation + S-PRG bioactive varnish. Then, all groups will be subjected to a 5-day erosive-abrasive cycling model (0.3% citric acid for 5 min, artificial saliva for 60 min, 4x/day). Tooth brushing will be performed twice/day for 15 s, after the first and last erosive challenge of each day. After the cycling period, the volumetric loss of the surface will be analyzed using surface roughness (Sa) and surface profile (Rv) parameters of the specimens, in addition to evaluating the fluoride concentration in the erosive cycling solutions. The response variables will be volumetric wear, calculated from Sa (in µm) and Rv (in mm) and quantitative fluoride analysis (µg F/mL). After checking the precepts of normal distribution (Shapiro-Wilk test) and homogeneity (Levene's test), the appropriate statistical tests will be selected with a significance level of 5%.