To evaluate the effects of post-processing protocols on the accuracy and internal fit of 3D-printed definitive implant-supported single crowns (ISCs).

An ISC was digitally designed based on a 3D-printed model with an incorporated one-piece zirconia implant. 120 definitive ISCs were fabricated by additive manufacturing (AM) using a resin-based material. The crowns were divided into 12 experimental groups, and each group was subjected to combinations of post-washing and post-polymerization conditions. Variations included washing solution (96 % isopropyl alcohol (IPA) or pure ethanol), washing equipment (ultrasonic bath or rotary washer), and photopolymerization conditions (air-contact, nitrogen-contact, or low-vacuum). Ten ISCs were fabricated by subtractive manufacturing (SM) as the control group. The root mean square values (RMS) between the design and acquired scan data, and internal gap dimensions were calculated. Statistics involved the Mann-Whitney U test and three-way ANOVA.

Using a rotary washer with IPA led to significantly higher accuracy in external and overall regions. In contrast, post-curing did not significantly affect the RMS of ISCs regardless of the analyzed region. No significant differences in internal gap dimensions were found among the various post-processing strategies. SM crowns demonstrated significantly lower accuracy in the intaglio surfaces and smaller internal gaps than AM ones.

Post-processing strategies affected the printing accuracy of AM ISCs but had no significant influence on internal fit. SM ISCs exhibited smaller internal gaps despite lower dimensional accuracy of the intaglio surface, which may lead to early contact during crown seating, which requires more attention to intaglio adjustments.

AM can be recommended for producing ISCs, while post-processing protocols should be carefully considered.

Internal fit

Implant-supported restoration

Accuracy

Additive manufacturing

3D printing

© 2025 The Authors. Published by Elsevier Ltd.