Clinical efficacy of a novel 3D-printed zirconia single crown: A randomized controlled trial

This randomized controlled trial (RCT) aims to evaluate the clinical efficacy of Nano Particle Jetting (NPJ)-printed zirconia single crowns compared to Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM)-milled crowns over a 12-month follow-up period.

A total of 43 participants with 48 posterior teeth (vital or endodontically treated) were included. Randomization and allocation concealment were conducted using a computer-generated list and sealed envelopes, assigning 24 teeth to each group. Assessed parameters included the World Dental Federation (FDI) criteria as the primary outcome, Pink Esthetic Score (PES), White Esthetic Score (WES), periodontal parameters, and patient satisfaction.

The FDI criteria showed no significant differences between NPJ-printed and CAD/CAM-milled crowns in aesthetic, functional, and biological parameters (p > 0.05). NPJ-printed crowns demonstrated excellent marginal adaptation, achieving a clinical success rate of 95.8 % versus 91.6 % in the CAD/CAM group. One fracture was recorded in each group. No significant differences were demonstrated in most PES/WES and periodontal parameters (p > 0.05). However, NPJ-printed crowns had a higher PES at baseline and 12-month follow-up visit (p = 0.02), and a statistically significant increase in plaque index was observed in CAD/CAM-milled crowns during the 6-month follow-up (p = 0.04). Patients in both groups reported a significant improvement in oral health-related quality of life (p < 0.01) and maintained high levels of satisfaction (p > 0.05).

This 12-month RCT demonstrates that NPJ-printed zirconia single crowns are clinically comparable to CAD/CAM-milled crowns, suggesting that NPJ printing could be a viable alternative for dental crown fabrication. Future research should focus on long-term follow-up studies to further validate these findings. (Registration number: ChiCTR2400089790).