Fit comparison of interim crowns manufactured with open and proprietary 3D printing modes versus milling technology: An in vitro study

Objectives

This study aimed to assess the fit of interim crowns produced using DLP-based 3D printing with different manufacturing workflows—open and proprietary—versus milling technology.

Methods

A total of 120 crowns were evaluated using the replica technique. The control group (Mill, n = 30) was manufactured via subtractive technology. Experimental groups were printed using a DLP printer (SprintRay Pro95). In the proprietary mode (SR100, n = 30), manufacturer resin was used with a 100-μm layer thickness (LT) and a splashing cleaning postprocessing. In the open mode, validated resin was used. Group B100 (n = 30) had a 100-μm LT, and group B50 (n = 30) had a 50-μm followed by postprocessing in an ultrasonic bath with full immersion in isopropyl alcohol. Kruskal–Wallis tests with Bonferroni correction was applied after normal analysis (α = 0.05).

Results

Group B50 exhibited the best overall fit (123.87 ± 67.42 μm), which was comparable to the gold standard Milling group, which demonstrated the lowest marginal fit (p = 0.760). SR100 showed significantly poorer performance compared to Mill, B50, and B100 (p < 0.001).

Conclusions

3D printed and milled interim crowns generally demonstrated clinically acceptable fit, with the exception of the SR100 group. Postprocessing notably influenced crown fit, with the open mode with total immersion in isopropyl alcohol being superior.

Clinical Significance

The present study demonstrates that the selection of an optimal manufacturing and postprocessing workflow results in superior fit for interim crowns. This enables dental professionals to evaluate protocols and ensure reliable outcomes with improved clinical outcomes in interim crown fabrication.