Trueness analysis of zirconia crowns fabricated with 3-dimensional printing

Statement of problem. The primary manufacturing method of zirconia ceramic crowns is computer-aided design and computer-aided manufacture (CAD-CAM), but a disadvantage of this technique is material waste. Three-dimensional (3D) printing, which has been recently introduced into dentistry, has improved the processing of polymers and metals, but not yet of ceramic crowns. Purpose. The purpose of this in vitro study was to evaluate the 3D trueness of zirconia crowns fabricated by 3D printing to investigate the potential application of this technology in dental ceramic restorations. Material and methods. A typodont tooth was prepared for a ceramic crown, and a digital crown was designed using the CAD software. The digital crown was processed either with a 3D-printing system or with a dental milling system. The crowns were scanned using a dental laboratory scanner, and the data collected for each crown were divided into 4 parts (the external surface, intaglio surface, marginal area, and intaglio occlusal surface). Finally, the trueness of each part was determined using the 3D inspection software. The 3D trueness of the crowns fabricated by either 3D printing or milling was compared by a 1-sided test (alpha=.05). Results. The trueness of the external surface, intaglio surface, marginal area, and intaglio occlusal surface of the 3D-printed crowns was no worse than the corresponding trueness of the CAD-CAM crowns (P<.05). Conclusion. Zirconia crowns produced by 3D printing meet the trueness requirements, and 3D printing may be suitable for fabricating zirconia crowns.