DENTAL ENAMEL PROPERTIES AFTER BLEACHING WITH 35% HYDROGEN PEROXIDE GEL CONTAINING STRONTIUM-SUBSTITUTED CALCIUM CARBONATE NANOPARTICLES

• Grant number: 25/20277-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2026
• End date: December 31, 2026
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Laura Nobre Ferraz Jardim
• Grantee: Adria Dalize Bueno
• Host Institution: Pró-Reitoria de Graduação. Centro Universitário Hermínio Ometto (UNIARARAS). Araras , SP, Brazil

Abstract

The aim of this in vitro study is to evaluate the effects of incorporating strontium-substituted calcium carbonate nanoparticles (Sr0.5Ca0.5CO3) into a 35% hydrogen peroxide-based bleaching gel on the physicochemical andmorphological properties of dental enamel. Bovine enamel specimens will be stained with a black tea solution for 6 days and randomly assigned into three groups according to the bleaching gel used (n=12): no bleaching (negative control), 35% hydrogen peroxide (positive control), and 35% hydrogen peroxide + strontium-substituted calcium carbonate nanoparticles (Sr0.5Ca0.5CO3). TheSr0.5Ca0.5CO3 nanoparticles will be prepared and incorporated into the bleachinggel immediately before application according to the experimental group. The samples will then be bleached for the duration recommended by the manufacturer. Three bleaching sessions will be performed, with a 7-day interval between each session. Color analyses will be carried out using reflectancespectroscopy (¿L, ¿a, ¿b, ¿E*ab, ¿E00), along with assessments of surface roughness (Ra), surface microhardness, chemical analysis usingFourier-transform infrared spectroscopy (FTIR), and wettability (¿) at baseline after staining (T0) and after each bleaching session (T1, T2, and T3).Additionally, the enamel surface will be qualitatively analyzed using scanning electron microscopy (SEM). Data will be subjected to appropriate statistical analysis with a significance level of 5%. (AU)