Intaglio Surface Accuracy of Temporary Crowns Fabricated by Additive Versus Subtractive CAD/CAM Methods

The success of temporary restorations depends on their marginal and internal adaptation, which are influenced by the manufacturing method. This study evaluated the intaglio surface accuracy, internal fit, and marginal fit of provisional crowns fabricated via subtractive (milling) and additive (3D printing) CAD/CAM technologies. Three milling systems-CEREC Primemill (4-axis), PrograMill Dry (5-axis), and Zirkonzahn M1 (5-axis)-and three 3D printers-Phrozen Mini 4K (LCD), SprintRay Pro95S (DLP), and Stratasys Objet30 (PolyJet)-were evaluated. For 3D printing, five build orientations (0°, 30°, 45°, 60°, and 90°) were tested. A total of 360 crowns were fabricated. Accuracy was quantified by Root Mean Square (RMS) deviation, and fit was assessed using the triple-scan method. Results indicated that build angles of 0° and 30° yielded the best performance for printed crowns (p < 0.05). While milling systems showed significantly superior intaglio accuracy and marginal fit compared to 3D printing (p < 0.05), no significant differences were found in internal fit between the two methods (p > 0.05). Milling offers higher dimensional predictability, but both approaches are clinically viable when optimized parameters are utilized.