Trueness, 3D Deviation, Time and Cost Comparisons Between Milled and 3D-Printed Resin Single Crowns

The purpose of this in-vitro study was to compare trueness, 3D deviation, production time and costs of milled and 3D-printed resin single crowns. A total of 20 CAD-CAM resin single crowns were fabricated from 10 digital wax patterns designed on 10 tooth preparations available in a reference model. Standardized control linear measurements were performed with a CAD software. Each STL file was then used to fabricate two resins crowns - one milled and one 3D-printed. All crowns underwent physical linear measurements using a digital caliper. The crowns were then scanned using an intraoral scanner for assessing 3D deviation. Finally, time to produce a single crown, as well as costs and production rates of both methods were also compared. Both CAM methods did not present statistically significant differences in linear measurements, as compared to controls (P⟩.05). Furthermore, 3D-printed crowns had significantly greater deviations in cervical margins (P=.032) and occlusal surfaces (P=.041), as compared with milled crowns. Finally, 3D-printing took significantly longer to produce one single crown (P=.001), but with a cheaper and higher production rate than milling. These findings suggest that milling devices produce resin single crowns with smaller 3D deviations but more expensive costs, as compared with low-cost 3D printers.