EFFECT OF DESENSITIZING AGENTS CONTAINING STRONTIUMSUBSTITUTED CALCIUM CARBONATE NANOPARTICLES APPLIED PRIOR TO BLEACHING ON DENTAL ENAMEL PROPERTIES.

• Grant number: 25/20319-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2026
• End date: December 31, 2026
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Laura Nobre Ferraz Jardim
• Grantee: Ana Julia Queiroz
• Host Institution: Instituto Superior de Educação (ISE). Centro Universitário Hermínio Ometto (UNIARARAS). Araras , SP, Brazil

Abstract

The aim of this in vitro study is to evaluate the application of different desensitizing agents containing calcium and strontium carbonate particles prior to bleaching with 35% hydrogen peroxide and their effects on the physicalchemicaland morphological properties of dental enamel. Bovine enamel specimens will be stained with a black tea solution for six days and randomlyassigned to five groups according to the desensitizing agent used (n=12): G1:no desensitizing agent (control); G2: 2% sodium fluoride (NaF); G3: 2% NaF with the addition of 2% strontium-substituted calcium carbonate nanoparticles (Sr0.5Ca0.5CO3); G4: 2% NaF with 5% Sr0.5Ca0.5CO3; G5: 2% NaF and 5%potassium nitrate (KNO3); G6: 2% NaF and 5% KNO3 with 2% Sr0.5Ca0.5CO3; G7: 2% NaF and 5% KNO3 with 5% Sr0.5Ca0.5CO3. The Sr0.5Ca0.5CO3 particleswill be incorporated into the desensitizing agents immediately prior to their application according to the experimental group. The samples will then be bleached with 35% hydrogen peroxide. Three sessions will be performed, eachconsisting of the application of the desensitizing agent followed by bleaching, with a 7-day interval between sessions. Color analysis will be conducted using reflectance spectroscopy (¿L, ¿a, ¿b, ¿E*ab, ¿E00), along with assessments of surface roughness (Ra), surface microhardness, Fourier-transform infrared spectroscopy (FTIR), and wettability (¿), measured after staining (T0) and aftereach bleaching session (T1, T2, and T3). Quantitative analysis of enamel surfaces will be performed using scanning electron microscopy (SEM) after the final bleaching session (T3). Data will be submitted to appropriate statisticalanalysis with a significance level set at 5%. (AU)