Exploring the Effects of aPDT and Laser Ablation on the Antioxidant Capacity of Enterococcus faecalis Biofilm

• Grant number: 24/18250-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2025
• End date: January 31, 2026
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Rogerio de Castilho Jacinto
• Grantee: Heloise Martins dos Santos
• Host Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

For the elimination of microorganisms, new adjuvant techniques for decontaminatingroot canal systems have emerged, and one of these techniques is antimicrobialphotodynamic therapy (aPDT). This in vitro study aims to evaluate the antioxidantcapacity induced in Enterococcus faecalis cells by laser ablation with indocyanine green(ICG) and by aPDT using methylene blue (MB) and curcumin (CUR). For theexperiment, E. faecalis inocula will be produced, incubated overnight at 37°C, with celldensity adjusted to 3 x 10^8 CFU/ml. After incubation, the inocula will be centrifugedto form pellets, which will be resuspended in sterile saline solution and fractionated into1.5 ml plastic tubes (n=60). The pellets will be divided into five groups of 12 sampleseach: MB+RL group (0.01% Methylene Blue + Red Laser), CUR+BL group (0.05%Curcumin + Blue LED), ICG+DL group (0.05% Indocyanine Green + Infrared DiodeLaser, 2.5 W, 300 ms interval, 100 ms duration), sterile saline solution group (negativecontrol), and 2.5% NaOCl group (positive control). The photosensitizers will be applieduntil they completely cover the pellets (50 ¿l), and each sample will be vortexed beforeactivation by laser at the specific wavelength. For redox state analysis, homogenateswill be prepared in 50 mmol/L sodium phosphate buffer and subjected to total oxidantcapacity (TOC), total antioxidant capacity (FRAP), superoxide dismutase (SOD),catalase (CAT), and glutathione peroxidase (GPx) analysis. Data will be subjected toANOVA analysis, followed by the Student-Newman-Keuls post hoc test, with asignificance level of 0.05.