Purpose: To evaluate the 12- and 24-month clinical results of overlay and one-piece endodontic crown restorations applied with additively manufactured, 3D-printed, permanent ceramic-filled resin (PCR) according to the modified US Public Health Service (USPHS) criteria. Materials and Methods: A total of 33 indirect restorations (16 overlay, 17 endocrown; 4 premolar, 29 molar) produced using PCR (Formlabs) were applied in 30 patients by a single dentist. The restorations were evaluated according to the modified USPHS criteria at baseline (1 week), 12 months, and 24 months by two independent evaluators. For comparisons of the dependent criteria scores, related samples Cochran Q test was used, and in post-hoc paired comparisons, Bonferroni test was used. Fisher-Freeman-Halton test was applied in the comparisons of categoric variables according to the restoration type groups (α = .05). Results: No statistically significant difference was determined between the evaluation criteria scores at baseline, 12 months, and 24 months for marginal adaptation (P = .05), retention (P = 1), interproximal contact (P = .368), color match (P = 1), surface texture (P = 1), and patient satisfaction (P = 1). The only score criterion that showed a statistically significant difference between baseline and 24 months (P = .001) was marginal discoloration. This criterion’s score change was from 100% A score to 69.7% A score. Conclusions: In the 2-year follow-up of indirect single-tooth restorations produced with 3D-printed PCR, all restorations showed acceptable clinical performance (≥ 99.5% A + B score at 2 years).
