Effect of hygiene protocols on the mechanical and physical properties and on the mixed biofilm formed on the surface of two resins to fabricate complete denture by 3D printing and characterized by extrinsic pigmentation.

• Grant number: 20/11054-8
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): January 01, 2021
• Effective date (End): December 31, 2021
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Cláudia Helena Lovato da Silva
• Grantee: Beatriz Marcatto Tinelli
• Home Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The purpose of this study will be to evaluate the effect of three hygiene protocols on mechanical and physical properties and on the mixed biofilm formed on the surface of two resins to fabricate complete denture by 3D printing (Resin Yller Cosmos Denture, Resin SmartPrint Bio Denture) and characterized by extrinsic pigmentation of the surface (Pala Cre active) and compare to a conventional heat-polymerized acrylic resin (Clássico). Disc-shaped specimens (12 x 3 mm) for color change and hardness and rectangular-shaped specimens (65 x 10 x 3 mm) for roughness and flexural strenght will be randomized in the following groups (n = 20): 1. brushing; 2. brushing and immersion in 0.25% sodium hypochlorite; 3. brushing and immersion in 0.15% Triclosan. Brushing (brushing machine) daily of 6 minutes (three brushings of 2 minutes) with soft brush and neutral soap and daily immersions of 20 minutes will be used. The measurements will be carried out immediately after obtaining the specimens (T0) and after the simulation of 01 (T1), 03 (T2) and 05 (T3) years of exposure to hygiene protocols. The effect of hygiene protocols on mixed biofilm of Candida albicans, Staphylococos aureus and Streptococos mutans (n = 9/group) will be measured by counting Colony-forming Units (CFU) after brushing for 2 minutes and immersion for 20 minutes. Surface evaluation using confocal microscopy (n = 4) will be performed on the surface of the specimens at T0 and after each simulated period. The data will be evaluated for normal distribution (Shapiro-Wilk Test) and homoscedasticity (Levene Test) to define the statistical tests to be used, considering a 95% confidence interval (SPSS 21.0 software).