Effect of thermocycling and surface characterization on color change, hardness, roughness, flexural strength, sorption and solubility of a resin for manufacturing complete dentures obtained by additive manufacturing (3D printing)

• Grant number: 24/17035-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2025
• End date: December 31, 2025
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Cláudia Helena Lovato da Silva
• Grantee: Vanderlei Cesar Brandão Junior
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The effect of thermocycling on three-dimensional (3D) printing resins for complete dentures has been studied. However, the literature is scarce regarding the behavior of these materials after surface pigmentation. The objective of this study is to evaluate the effect of thermocycling and surface pigmentation on changes in color, hardness, roughness, flexural strength, and sorption and solubility of 3D printing resin specimens, compared to thermopolymerizable resin (conventional). Specimens (n=15) will be made in the following dimensions: 12 mm x 2 mm for color, hardness and roughness; 65 x 10 x 3,3 mm for flexural strength and 50 mm x 0,5 mm for sorption and solubility. The printed specimens will be pigmented with priZma Makeup (red color) and priZma Glaze. A total of 3,000 thermocycling cycles will be performed (simulation of 3 years), with alternating immersions of 1 minute in distilled water at 5¿1ºC and 55¿1ºC. The color will be evaluated with a portable spectrophotometer and Standard Commission Internationale de L'Eclairage system (CIELab), the Knoop microhardness with a microdurometer, and the roughness (Sa) by Confocal Laser Microscopy. The flexural strength, sorption and solubility tests will follow the ISO 20795-1:2008 and ANSI/ASA Specification nº 12 (1975) standards, respectively. All variables will be evaluated immediately after obtaining the specimens (T0) and after thermocycling (T3). The data will be evaluated for normality (Shapiro-Wilk test) and homoscedasticity (Levene test) to define the statistical tests to be used, considering a 95% confidence interval (SPSS 21.0 software).