Effects of different polishing systems on the surface roughness, microhardness and gloss of 3D-printed resins

The aim of this study was to investigate the surface roughness, gloss and microhardness values ​​of 3D-printed permanent resins after the use of polishing systems.

In this study, a total of 112 specimens were prepared from permanent resin using SLA and DLP 3D printers, with each material group comprising 56 specimens of 10 mm in diameter and 2 mm in thickness. One-step, two-step and multi-step polishing systems were applied to the prepared samples. Polishing systems were classified into two subgroups according to the use of diamond polishing paste. Surface roughness, microhardness, and gloss values were measured for all specimens following the polishing procedures. Statistical analysis was conducted using a two-way analysis of variance (ANOVA) (p < 0.05).

Application of one-step, two-step and multi-step polishing systems to 3D-printed resin specimens resulted in significantly lower surface roughness and higher gloss values (p < 0.05). The use of polishing paste following all systems further reduced surface roughness and increased gloss (p < 0.05). After two-step and multi-step polishing systems, the surface roughness of the paste-applied groups decreased below 0.2 μm and the gloss increased above 80 GU. Polishing procedures also enhanced the microhardness of the specimens (p < 0.05). However, the application of polishing paste after one-step, two-step, and multi-step systems did not result in a statistically significant difference in microhardness values (p > 0.05).

Application of two-step and multi-step polishing systems to 3D-printed permanent resin specimens significantly reduces surface roughness while enhancing microhardness and gloss values. While the application of polishing paste after polishing systems did not influence microhardness, it positively affected surface roughness and gloss, thereby potentially enhancing clinical success.