Effect of polishing techniques on a 3D printed resin for provisional dentures: an in vitro study on surface roughness and mechanical strength

Objective This study aimed to evaluate the effect of polishing techniques on a 3D-printed resin for provisional prosthesis through an in vitro assessment of surface roughness and mechanical strength. Methods Bar-shaped specimens (25 × 12 × 2 mm) were fabricated using a 3D-printed provisional resin at a 0° angle to the platform and divided into three experimental groups (n=10): no polishing (AP), mechanical polishing (PM), and chemical polishing (PQ). Surface analysis was performed with a stereomicroscope, and roughness parameters (Ra, Rq, Rz) were obtained with a confocal microscope. Flexural strength and modulus were also determined, followed by qualitative evaluation of the fracture pattern. Data were analyzed with one-way ANOVA (p<0.05) and Tukey’s test when appropriate. Results Distinct surface characteristics were observed among groups, with statistically significant differences for Ra (p=0.003) and Rq (p=0.002), while Rz showed no significance (p=0.063). Flexural strength (p<0.001) and flexural modulus (p=0.002) also differed significantly between groups. Conclusion Polishing techniques tested on a 3D-printed resin for provisional prosthesis significantly influenced Ra, Rq, flexural strength, and flexural modulus, but showed no significant effect on Rz.