Digital Wear Analysis of Different CAD/CAM-Fabricated Monolithic Ceramic Implant-Supported Single Crowns Using Two Optical Scanners

Purpose: To digitally evaluate the volumetric wear of four different implant crown materials and their antagonists after artificial aging using an intraoral scanner (IOS) device and a laboratory desktop scanner. Materials and Methods: A total of 48 implants were restored with monolithic crowns and divided into groups according to restorative material: lithium disilicate (LDS); zirconia (ZR); polymer-infiltrated ceramic network (PICN); and porcelain fused to metal (PFM). Each specimen was scanned using a desktop scanner (LAB group; iScan D104, (metric 3D) and an IOS device (IOS group; Trios 3, 3Shape) before and after chewing simulation (1,200,000 cycles, 49 N, steatite antagonist, 5 degrees C to 50 degrees C). The obtained STL files were superimposed, and the volumetric loss of substance of the crowns and their antagonists was quantified. Kruskal-Wallis, Spearman p, and paired t tests were used to analyze the data (alpha = .05). Results: The mean volume loss for each restorative material varied between 0.05 +/- 0.06 mm(3) (ZR/IOS) and 3.42 +/- 1.65 mm(3) (LDS/LAB). The wear of the antagonists was significantly lower (P < .05) for ZR than the other groups. Increased wear of the crowns was highly correlated with increased wear of their antagonists (r(s) = 0.859). When comparing the wear measurement using the two scanning devices, no difference in mean volume loss was found (IOS: 1.81 +/- 1.81 mm(3); LAB: 1.82 +/- 1.78 mm(3)) (P = .596). Conclusion: Polished ZR was the most wear-resistant material and the least abrasive to the respective antagonist among the tested ceramics. For quantification of wear, this IOS device can be used as an alternative to desktop scanners.