Marginal and internal fit of permanent crowns produced by different three-dimensional printing systems: A micro-computed tomography and digital three-dimensional analysis.

Abstract

Purpose: This study aimed to evaluate and compare the marginal and internal fit of permanent crowns fabricated using three different DLP 3D printers and their corresponding permanent resin materials. The fit was quantitatively assessed using micro-computed tomography (micro-CT) and digital 3D analysis.

Materials and methods: A premolar tooth was prepared according to conventional ceramic tooth preparation protocols and scanned with an intraoral scanner (TRIOS 5). The resulting standard tessellation language (STL) file was imported into the software for design. A total of 24 crowns were fabricated using three different printer and resin combinations (n = 8): an Asiga printer with Saremco Crowntec permanent resin (Group S), a Denta Fab printer with Power Resin C&B permanent resin (Group C), and a SprintRay printer with Crown permanent resin (Group SP). These crowns were then re-scanned with an intraoral scanner to obtain STL files. Marginal, axial, and occlusal alignment were calculated and compared using 3D analysis software and micro-CT software. As the data were normally distributed, comparisons were made using one-way ANOVA. The significance level was set at p < 0.05.

Results: In the marginal area, Group SP demonstrated significantly superior fit compared to Group S (p = 0.002) and Group C (p = 0.0005). No statistically significant difference was observed between Group S and Group C (p = 0.245). The findings obtained from both micro-CT and 3D superimposition analyses were consistent, confirming the reliability and agreement of the two evaluation methods.

Conclusion: This study demonstrates that crown restorations fabricated using 3D printers exhibit significant variations in fit depending on the type of resin employed. In particular, the resin used in Group SP tended to show improved marginal adaptation compared to Groups S and C, which exhibited comparable results. These findings may offer guidance for clinical decision-making regarding the selection of 3D printing systems and resins for crown fabrication in prosthodontic applications.