EVALUATION OF Er:YAG LASER FOR DISINFECTION OF INFECTED CARIOUS DENTIN: MICROBIOLOGICAL AND SCANNING ELECTRON MICROSCOPY EVALUATION

• Grant number: 24/20988-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: December 31, 2025
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Sérgio Luiz Pinheiro
• Grantee: Maria Olívia Marcondes Pinto
• Host Institution: Escola de Ciências da Vida (ECV). Pontifícia Universidade Católica de Campinas (PUC-CAMP). Campinas , SP, Brazil

Abstract

Current literature does not provide strong scientific evidence for the use of Er:YAG laser for disinfection of dentin infected by caries without any tissue removal effect, only with the function of decontamination, which is the objective of this study. Ninety permanent third molars will be selected and flat dentin surfaces will be obtained. The samples will be waterproofed except for the coronal dentin and subjected to cariogenic challenge with a standard strain of S. mutans. The specimens will be randomly distributed into 5 sample groups according to the cavity disinfection procedure that will be applied (n = 15): Group C (positive control): carious lesion, no carious tissue disinfection procedure will be performed; aPDT group (negative control): will be performed with the active application of methylene blue 0.005% (Chimiolux) for 5 minutes on the dentin caries lesion and irradiation with a low-power diode laser with 9 J of energy, for 90 seconds; Er:YAG group, parameter A; ER:YAG group, parameter B and ER:YAG group, parameter C. All infected carious dentin will be collected with the aid of a sterile dentin spoon and will be immediately transferred to the BHI for subsequent microbiological processing. S. mutans counts will be performed in the sample groups. Three samples from each group will be analyzed in the scanning electron microscope for qualitative observation of the caries-infected dentin of the sample groups. The results will be analyzed in the Biostat 5.0 program and submitted to the Shapiro-Wilk normality test. If the sample presents normal behavior, the ANOVA test (Tukey) will be applied. If the sample presents non-normal behavior, the non-parametric Kruskal-Wallis (Student-Newman-Keuls) test will be applied with a significance level of 5%.