CYTOTOXIC AND OXIDATIVE STRESS RESPONSES OF PULP CELLS EXPOSED TO EXPERIMENTAL AND COMMERCIAL BLEACHING GELS

• Grant number: 25/23150-5
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)
• Start date: April 01, 2026
• End date: March 31, 2027
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Alessandra Buhler Borges
• Grantee: Juliana Benace Fernandes
• Supervisor: Satoshi Imazato
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil
• Institution abroad: University Of Osaka, Japan
• Associated to the scholarship: 24/07091-6 - Effect of different variables on the effectiveness of experimental dental bleaching gels, BP.DD

Abstract

This study aims to evaluate the cytotoxic effects of different hydrogen peroxide-based bleaching gels on odontoblast-like cells (MDPC-23), using an in vitro enamel-dentin barrier model. Bovine enamel-dentin specimens will be prepared and polished to standardized dimensions and positioned in custom spacers simulating pulpal chambers filled with DMEM medium without fetal bovine serum, allowing collection of substances diffused during bleaching. Experimental bleaching formulations with previously proven whitening efficacy will be tested, incorporating strategies to reduce cytotoxicity and protect dental tissues, including reduced hydrogen peroxide concentrations combined with chemical catalysts, elevated pH, and incorporation of bioactive glasses such as S-PRG and 45S5. Commercial in-office bleaching gels (Whiteness HP Automix and Pola Office+) will serve as positive controls, while ultrapure water will serve as the negative control. Collected extracts will be applied to MDPC-23 cells for 60 minutes. Cell viability will be assessed using the MTT assay, intracellular oxidative stress will be quantified using DCF fluorescence (carboxy-H¿DCFDA), and morphological alterations will be evaluated by scanning electron microscopy (SEM). Data will be statistically analyzed using parametric or non-parametric tests according to their distribution, with a significance level of 5%. The study is expected to identify experimental formulations with reduced cytotoxicity and improved biological safety compared with commercial bleaching products. (AU)