Effect of hydrothermal on surface roughness and microorganism adhesion of PMMA blocks for CAD/CAM polished with surface sealants

• Grant number: 22/08201-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): August 01, 2022
• Effective date (End): July 31, 2023
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Aldiéris Alves Pesqueira
• Grantee: Marcos Eduardo Gomes Alves
• Host Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

Bacteria retention is directly associated with surface roughness, therefore, it is essential that the restorative material is properly polished so that it preserves its surface properties over time of use. Although there are several published studies on the mechanical properties of PMMA polymers for CAD/CAM, no study has evaluated whether surface sealants have the effect of preserving surface smoothness and preventing or limiting the adhesion of microorganisms to these materials when subjected to hydrothermal stress. In view of the above, the aim of the present study will be to characterize the surface and analyze the microbiological characteristics of PMMA blocks for CAD/CAM, polished with abrasive rubbers associated with different surface sealants and hydrothermal stress (thermocycling). The study will have four factors under analysis: (1) prefabricated polymer block (PMMA) for the CAD/CAM system; (2) Surface treatments (PA: Astropol tips, SB: Biscover surface sealant and SP: Palaseal surface sealant); (3) thermocycling (TC1 - 5,000 cycles, at 5 and 55oC; TC2 - 10,000 cycles, at 5 and 55oC) and (4) analysis times at 3 levels (T0 - after storage in distilled water for 24 hours, after TC1, and TC2). Three response variables will be considered: (1) to characterize the surface by means of surface roughness (Ra); (2) Microbiological analysis of mixed biofilm of S. mutans and C. albicans by means of (2.1) Quantification of cells (CFUs), (2.2) 3D analysis of the biofilm by confocal laser microscopy (MC) and (2.3) analysis of the structure of biofilms by scanning electron microscopy (SEM). The quantitative data obtained in each analysis will be submitted to the normality test and later to the most appropriate statistical test, with a significance level of 5%. Qualitative data will visualize the biofilm structure formed, comparing the different proposed groups.(AU)