Confocal 3D Optical Intraoral Scanners and Comparison of Image Capturing Accuracy

Several capture techniques are used in intraoral optical scanners in the dental market,such as Triangulation(Cerec Omnicam,Dentsply Sirona),Activewave front sampling(3M ESPE)and confocal technology(iTero,Align).The accuracy of intraoral scanners is the most significant focal point for developers to research.This in-vitro study studied the accuracy of confocal scanners launched from 2015-2020(Trios 3,Trios 4,iTero Element;3Shape Trios A/S,Copenhagen,Denmark,and iTero Element2,and iTero Element5D;Align Technologies,San Jose,CA,USA).A 3D printing model modified from the American National Standard No.132 was scanned five times each scanner.Both Trios3 and Trios4 were scanned using regular scan mode(N)and high-resolution mode(HR).All scanning methods followed the recommendations from the manufacturers.Then the digital models were exported and saved as STL files.Various measurements were determined in the digital model from each scan using Rhinoceros 3D Software(Rhino,Robert McNeel&Associates for Windows,Washington DC,USA).Measurements from the 3D printed model were used as control.All data were recorded in Microsoft Excel and then transferred to SPSS.Descriptive statistics were recorded.Multiple comparisons of various measurements were made among the different scanners and with the control using One-way ANOVA and post hoc using Sheffe(p<0.01).The surface area in the X and Y axis ranged from 2–60 mm,while the depth(Z-axis)ranged from 2–8 mm.The Trios and iTero families showed similar accuracy.However,for the diagonal,the Trios series showed better results compared with the iTero series.Within the same brand,different versions showed no significant change regarding accuracy.

Replacement of Unesthetic Posterior Metal Crowns with Monolithic Zirconia Crowns: A Case Report

Advances in metal-free materials and the popularization of Computer-Aided Design and Manufacturing (CAD/CAM) have led to the wide clinical use of all-ceramic crowns for esthetic restorations. A 72-year-old woman presented to our hospital with unesthetic restorations on the right upper and lower posterior teeth. Intraoral examination revealed poorly fitting metal crown margins. Defective prostheses were removed, and provisional restorations were provided to stabilize the mandibular position. Optical impressions and the maxillomandibular relationship were recorded using an intraoral scanner, and monolithic zirconia crowns were fabricated using CAD/CAM technology for complete veneer crown restorative treatment. Occlusal examination revealed an improvement in occlusal force distribution at initial examination (right side: 33.5%, left side: 66.5%) after placement of the zirconia crowns (right side: 54.9%, left side: 45.1%). Occlusal force and occlusal force distribution area also showed an increasing trend. The Oral Health Impact Profile short form (OHIP-14) score decreased from 7 points at initial examination to 0 points after prosthodontic treatment. Appropriate diagnosis and treatment planning contributed to the increased occlusal force and balanced occlusal force distribution. Therefore, the present case indicates the potential of monolithic zirconia crowns to achieve both esthetic and stable functional outcomes.