Statement of problem: With the advancement of digital technology, extraoral digital scanners have become popular among dental laboratories and dentists. The literature concerning accuracy of restorations fabricated from digital images of extraoral scanners is non conclusive.
Aim: The the aim of the study is to compare the accuracy of single crowns generated from CAD/CAM Systems using digital images of two extra-oral scanners.
Materials and Methods: Twenty 3D printed dies were scanned using the investigated extraoral scanners (InEos X5 and Ceramill map 400). The digital images were used to produce a 3D virtual crown design on the systems' respective CAD softwares. Crowns were milled of lithium disilicate blocks. The milled crowns were divided into two groups according to the type of CAD/CAM system used; Group I/M (Cerec system: In Eos X5 and MCX5) and Group C/C (Amanngirbach System: Ceramill map 400 and Ceramill motion2), 10 crowns each. The marginal gap distance between the crown and the 3D printed resin die was measured using a digital microscope and replica technique was used to measure the internal gap between the crowns and their respective 3D printed resin dies.
Results: Group I/M demonstrated statistically significant smaller median marginal gap distance 95 μm while Group C/C demonstrated a median marginal gap distance of 113 μm.
The was no statistically significant difference between both systems with regards to internal fitness. The accuracy of crowns of both systems was within clinically acceptable range.
Conclusions: Crowns generated from CEREC system (In Eos X5/ MCX5) showed better marginal accuracy than AmannGirrbach system. (Ceramill map 400 / Ceramill motion 2).
Both systems produced marginal accuracy and internal fitness within the clinically accepted range.