Anti-proteolytic action of bioactive toothpastes and physical-mechanical profile on sound and eroded dentin: an in situ study

• Grant number: 24/08227-9
• Support Opportunities: Scholarships in Brazil - Master
• Start date: April 01, 2025
• End date: March 31, 2027
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Linda Wang
• Grantee: Camily Bocardo Rodrigues
• Host Institution: Faculdade de Odontologia de Bauru (FOB). Universidade de São Paulo (USP). Bauru , SP, Brazil

Abstract

Erosive Tooth Wear results from episodes that cause dental demineralization, loss of structure, and changes to the organic matrix when affecting the dentin. Many strategies, including innovations in the form of toothpastes, have been developed to enhance the resistance to demineralization of dentin tissue when exposed. The consolidation of these effects involves the need for organized nucleation of minerals into an intact collagen network and inactivation of the proteolytic action of enzymes such as matrix metalloproteinases (MMPs) present in the dentin substrate. In this regard, toothpaste serves as one of the most commonly used vehicles among the population, offering better handling and accessibility for the patient. Thus, the purpose of this study aims to explore the anti-proteolytic action of bioactive toothpaste based on distinct technologies on sound and eroded dentin, conducting an in situ study. The analysis will involve two factors: 1 - material at 4 levels: Sorriso Fresh Hortelã Explosion (control), Elmex OptiEnamel, Biomin F, and 5% S-PRG paste; 2 - dentin condition at 2 levels: sound dentin (control) and eroded dentin (0.1% citric acid - 4 daily immersions/15mL/ 90s/7 days). For this purpose, bovine teeth will be sectioned and polished to obtain 384 root dentin specimens (4mm x 4mm x 3mm), with half undergoing erosive cycling. The specimens will be randomized and distributed, through surface by contact profilometry analysis, among 12 healthy volunteers for 4 in situ phases corresponding to each tested material. Eight dentin blocks will be fixed onto a palatal device (4 sound and 4 eroded), with one device per participant for each phase/material. Participants will wear the devices 5 days associated with 2x/1 min toothbrushing per day for each phase. Overnight, the device will be stored in moisture at 4°C. After the fifth day, the samples will be removed from the devices and quantitatively analyzed by means of profilometer and assessment of anti-proteolytic activity using in situ zymography (n=6) and qualitative surface analysis by laser confocal scanning microscopy. In addition, analysis of the wettability (n=10) of the toothpastes on the two different dentin and their viscosity (n=5) will be processed. The data will be analyzed using 2, 2, 2 and 1-way ANOVA, respectively for contact profilometry, in situ zymography, wettability and viscosity with multiple comparisons (Tukey) and a significance level of 5%.