Effect of Application Method and pH of Bleaching Gels on Color Change, Viscosity, Diffusion and Degradation of H2O2, Microhardness, and Enamel Roughness

• Grant number: 24/23265-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2025
• End date: April 30, 2026
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: André Luiz Fraga Briso
• Grantee: Maria Eduarda Zonta
• Host Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

In-office dental bleaching with Hydrogen Peroxide is often the preferred choice among dental practitioners. Although this procedure is well-established in dentistry and considered safe, certain aspects, such as the need for gel agitation during the application time, remain without consensus among professionals and lack clear answers in the literature.This study aims to comparatively evaluate the use of bleaching gels with acidic and basic pH, as well as different application methods, analyzing variables such as color change, trans-enamel-dentin diffusion, peroxide degradation, enamel surface microhardness and roughness, pH, and gel viscosity. For this purpose, discs of stained bovine teeth will be treated with two types of bleaching gels: an acidic gel (Mix One - pH 3.5) and a basic gel (Whiteness HP Blue - pH 8.1), applied using three protocols: three 15-minute applications without agitation, a single 45-minute application, and a 45-minute application with agitation every 15 minutes for 30 seconds.This study will provide dental practitioners with the necessary data to support their treatment choices, particularly regarding the need for agitation or replacement of the bleaching gel and the effects of pH on dental structure.