Effect of Toothbrushing Performed Before or After Whitening Mouthwash Use on Enamel Color Alteration, Microhardness and Surface Roughness

• Grant number: 25/18528-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2025
• End date: November 30, 2026
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Mariane Cintra Mailart
• Grantee: Victor Augusto de Oliveira Fogaça
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

Objectives: To evaluate the effect of toothbrushing performed before or after the use ofmouthrinses containing hydrogen peroxide, phosphate, or activated charcoal on color alteration,surface microhardness, and roughness of enamel.Material and Methods: Bovine enamel/dentin specimens (N=144) will be obtained andrandomly allocated to the groups (n=16): (2.5% hydrogen peroxide-based mouthrinse (ListerineWhitening Extreme - LWE); phosphate-based mouthrinse (Colgate Luminous White - CLW);activated charcoal-based mouthrinse (Colgate Total 12 Carvão - CTC); deionized water(negative control for staining - with staining and without toothbrushing - ADM); and deionizedwater (negative control for toothbrushing - with staining and toothbrushing - ADE). Thespecimens of each treatment will be subdivided according to the moment of use (before or aftertoothbrushing). The treatment cycling will consist of immersion of specimens in a stainingsolution for 30 min; followed by immersion in artificial saliva for 30 min; and then they will besubmitted to the treatments varying the moment of toothbrushing. The treatment will comprisethe immersion of specimens in 2 ml of solution for 60 s, followed by rinsing with distilled waterfor 5 s. The abrasion will be carried out in a toothbrushing machine with a slurry containingtoothpaste and remineralizing solution (1:3). The specimens will be brushed with soft bristleswith a 200 g load and 2 strokes for seconds, in a total of 15 s of toothbrushing. The specimenswill be in contact with the slurry until 2 min. Analyses of color (CIELAB), surfacemicrohardness (SMH), and roughness (Ra) will be performed initially and after the treatmentcycling. Data will be used to calculate alterations in color (¿E¿¿), in whiteness index fordentistry (¿WID), in microhardness (%SMH), and in roughness (%Ra), and then will besubmitted to the normality and homoscedasticity tests. The proper statistical analyses will beperformed considering a significance level of 5%Material and Methods: Bovine enamel/dentin specimens (N=144) will be obtained and randomly allocated to the groups (n=16): 2.5% hydrogen peroxide-based mouthrinse (Listerine Whitening Extreme - LWE); phosphate-based mouthrinse (Colgate Luminous White - CLW); activated charcoal-based mouthrinse (Colgate Total 12 Carvão - CTC); deionized water (negative control for staining - with staining and wihtout toothbrushing - ADM); and deionized water (negative control for toothbrushing - with staining and toothbrushing - ADE). The specimens of each treatment will be subdivided accoridng to the moment of use (before or after toothbrushing). The treatment cycling will consist of immersion of specimens in a staining solution for 30 min; followed by immersion in artificial saliva for 30 min; and then they will be submiited to the treatments varying the momemnt of toothbrushing. The treatment will comprise the immersion of specimens in 2 ml of solution for 60 s, followed by rinsing with destilled water for 5 s. The abrasion will be carried out in a toothbrushing machine with a slurry containing toothpaste and remineralizing solution (1:3). The specimens will be brushed with soft bristles with a 200 g load and 2 strokes for second, in a total of 15 s of toothbrushing. The specimens will be in contact with the slurry until 2 min. Analyses of surface microhardness (SMH) and roughness (Ra) will be performed initially and after the treatment cycling. Data will be used to calculate the percentage of alteration in microhardness (%SMH) and in roughness (%Ra) and will be submitted to the normality and homocedaticity tests. The proper statiscal analyses will be performed considering a significal level of 5%. (AU)