Influence of a bleaching gel containing 35% hydrogen peroxide, calcium glycerophosphate and fluoride on tooth demineralization: in vitro study

• Grant number: 20/14770-6
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): April 01, 2021
• Effective date (End): March 31, 2022
• Field of knowledge: Health Sciences - Dentistry - Pediatric Dentistry
• Principal researcher: Marcelle Danelon
• Grantee: Helena Fujisaka Robles
• Home Institution: Universidade de Ribeirão Preto (UNAERP). Campus Ribeirão Preto. Ribeirão Preto , SP, Brazil

Abstract

The possibility to minimize enamel changes after tooth whitening would be a benefit to the patient. The aim of this study is to evaluate in vitro the addition of calcium glycerophosphate (CaGP) associated with 0.05% sodium fluoride and 35% hydrogen peroxide on the mechanical properties of enamel. Bovine enamel blocks (4 mm x 4 mm, n = 60) will be selected by initial surface hardness (SHI) and divided into six groups (n = 10) according to bleaching gels: 1)35% hydrogen peroxide (PH); 2) PH + 0.1% NaF (PH/F); 3) PH + 0.25% CaGP (PH/CaGP); 4) PH + 0.1% NaF + 0.25% CaGP (PH/F/CaGP) ; 5) HP Blue 35% (FGM - Produtos Odontológicos: HP Blue) and 6) Whiteness HP 35% (FGM - Produtos Odontológicos: HP). The gels will be applied only once, during 3 sessions of 40 minutes/session, every 7 days, totaling 21 days. Between treatment sessions the blocks will remain in artificial saliva, which will be changed daily. Then the final surface hardness (SHF) will be determined to calculate the percentage of surface hardness loss (%SH) and integrated subsurface hardness loss (”KHN). For physicochemical characterization of the bleaching gels, they will be evaluated for polydispersity index (Pdl) and zeta potential. The data will be submitted to ANOVA followed by the Student-Newman-Keuls test (p < 0.001) if they present normal and homogeneous distribution. Otherwise, Kruskal-Wallis analysis and the Student-Newman-Keuls test will be used (p < 0.001).