Influence of experimental bleaching gels containing biosilicate with titanium dioxide and activated by violet LED on enamel with initial erosion lesions

• Grant number: 25/15921-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2025
• End date: August 31, 2026
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Vanessa Cavalli Gobbo
• Grantee: Bruno dos Santos
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

This study aims to evaluate the bleaching efficacy and surface effects on enamel with initial erosion lesions using experimental gels containing 35% and 6% hydrogen peroxide (HP), incorporated with Biosilicate® (BioS) and titanium dioxide (TiO¿), and activated by violet LED irradiation. Bovine enamel-dentin discs will be stained and subjected (or not) to an erosive-abrasive cycling protocol to induce initial erosion lesions, and then randomly allocated into the following groups (n = 10): G1) 35%HP (Control - Whiteness HP, FGM); G2) 35%HP + BioS_TiO¿ + LED; G3) 35%HP + LED; G4) 6%HP + BioS_TiO¿ + LED; G5) 6%HP + LED. Sound enamel groups will undergo the same treatment protocols as described for G1-G5. Bleaching efficacy (¿E00 and ¿WID) will be assessed using a reflectance spectrophotometer. Surface microhardness (KHN; and percentage of recovery - %SHR) will be evaluated using a microhardness tester with a Knoop indenter. Two-dimensional mean surface roughness (Ra, ¿m) will be determined using a rugosimeter. Enamel surface morphology will be examined by scanning electron microscopy (SEM), and mineral content will be qualitatively analyzed using energy-dispersive X-ray spectroscopy (EDS). All evaluations will be performed at four timepoints: baseline (T0), after erosive cycling (T1), and 24 hours (T2) and 14 days (T3) after the final bleaching session. Throughout the experimental period, specimens will be stored in artificial saliva. Statistical analyses will be conducted following exploratory data evaluation, with a significance level set at ¿ = 5%.