Propriedades físico-mecânicas e adesão microbiológica de resina para impressão 3D de bases e dentes de próteses totais

Abstract

Introduction: Three-dimensional printing has been gaining prominence in dentistry, offering a variety of benefits. Currently, for the manufacture of removable total dentures, the material of choice is polymethylmethacrylate (PMMA). But with the advent of digital flow, a lightweight, thermopolymerizable polymer is processed by stratification and curing, presenting advantages in clinical practice. Thus, it is essential to know the physical, mechanical and biological properties of these materials for greater predictability and applicability. Objective: To evaluate flexural strength, topography, surface roughness, Vickers hardness, porosity and microbiological adhesion. Method: A total of 34 specimens were made in bars (25 x 2 x 2 mm) and blocks (8 x 8 x 2 mm), divided into four groups: conventional acrylic resin for prosthesis base (RC), resin for base 3D printing (IR), 3D printed tooth (DI) and prefabricated tooth (DP). The bars were submitted to the mini flexural strength test, and the blocks were analyzed for roughness (Ra/Rq/Rz), microhardness, porosity and microbiological adhesion. Descriptive analysis and the Shapiro-Wilk normality test were performed, followed by the Mann-Whitney U test or Student's t-test. Results: The IR (0.91%) and DI (0.24%) groups showed lower porosity, with a significant difference in relation to the conventional groups (p=0.047 and p=0.004, respectively). Microbiological adhesion showed a lower number of colonies for the IR group (CFU/mL: 6.8) with p=0.01. There was no statistically significant difference between CR and IR for roughness, mini flexural strength and microhardness, nor between DP and DI for microhardness and microbiological adhesion. Conclusion: The printed resin used for the base of the prosthesis showed surface and mechanical properties similar to conventional materials for roughness, flexural strength and hardness, a lower percentage of porosity and lower biofilm formation of Candida Albicans. For the groups of teeth, the printed resin showed similar properties for hardness and microbiological adhesion and a lower percentage of porosity.