Influence of brushing combined with immersion in organic solvents on the surface and adhesion of microorganisms to PMMA for CAD/CAM, polished with diamond-coated silicone tips

• Grant number: 24/11125-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2024
• End date: February 28, 2025
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Aldiéris Alves Pesqueira
• Grantee: Amanda Martinelli Moretti
• Host Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

In the oral environment, temporary acrylic resin restorations are subject to chemical changes and frequent tooth brushing. Therefore, it is essential to assess the combined aging effects on these restorations to ensure patient comfort and effectiveness. Therefore, the general objective of this study will be to characterize the surface and analyze the microbiological characteristics of PMMA CAD/CAM blocks, polished with diamond-coated silicone tips, and subjected to simulated brushing (SB) associated with immersion (I) in organic solvents simulating food (SB+IAD- distilled water, SB+IEA - absolute ethanol SB+IHE - heptane). The study will involve four factors: (1) use of prefabricated polymer blocks (PMMA) for CAD/CAM systems; (2) Surface treatment (POG: universal polishing system comprising diamond-coated silicone tips (OptraGloss/Ivoclar)); (3) Aging through 10,000 cycles of simulated brushing (SB) combined with 7 days of immersion (I) in three organic solvents simulating food: distilled water (SB+IA), absolute ethanol (SB+IE), and heptane (SB+IHE); and (4) Analysis times at 2 levels (TB - after 24 hours of surface treatment, stored in dry conditions at 37°C (baseline) and T1, after simulated brushing combined with immersion in solutions SB+IAD, SB+IEA, and SB+IHE). Parameters will be evaluated by: (1) Surface characterization through surface roughness (Ra); (2) Microbiological analysis of mixed biofilm of S. mutans and C. albicans through (2.1) quantification of cultivable cells (CFUs) and (2.2) analysis of biofilm structure by scanning electron microscopy (SEM). Quantitative data obtained in each analysis will be subjected to normality testing and subsequently to the most appropriate statistical test, with a significance level of 5%. Qualitative data aims to visualize the structure of biofilm formed, comparing among the different proposed groups.