Evaluation of complete-arch implant scanning with 5 different intraoral scanners in terms of trueness and operator experience.

STATEMENT OF PROBLEM: The intraoral scanning of the edentulous arch might be challenging for an inexperienced operator because of the large mucosal area and the use of scan bodies. PURPOSE: The purpose of this ex vivo study was to compare the trueness of 5 intraoral scanners in replicating implant scan bodies and soft tissues in an edentulous maxilla and to investigate the effects of operator experience. MATERIAL AND METHODS: The maxilla was resected from a fresh cadaver, 5 implants placed, and a reference scan made. Eight scans were made by experienced operators and 8 by an inexperienced operator with each scanner (iTero Element 2, Medit i500, Primescan, TRIOS 3, TRIOS 4). The implant platform deviation was measured after complete surface alignment and after scan body alignment. Deviation data were analyzed with a generalized linear mixed model (α=.05). RESULTS: After complete surface alignment, the mean ±standard deviation implant platform deviation was higher for the inexperienced operator (421 ±25 µm) than for experienced ones (191 ±12 µm, P<.001) for all scanners. After scan body alignment, no significant differences were found between operators for Element 2, Primescan, and TRIOS 3. The experienced operators produced a lower deviation for TRIOS 4 (35 ±3.3 µm versus 54 ±3.1 µm, P<.001), but higher deviation for i500 (68 ±4.1 µm versus 57 ±3.6 µm, P<.05). The scanner ranking was Element 2 (63 ±4.1 µm), i500 (57 ±3.6 µm, P=.443), TRIOS 4 (54 ±3.1 µm, P=.591), TRIOS 3 (40 ±3.1 µm, P<.01), Primescan (27 ±1.6 µm, P<.001) for the inexperienced operator and i500 (68 ±4.1 µm), Element 2 (58 ±4.0 µm, P=.141), TRIOS 3 (41 ±2.8 µm, P<.001), TRIOS 4 (35 ±3.3 µm, P=.205), Primescan (28 ±1.8 µm, P=.141) for the experienced operators. CONCLUSIONS: Mucosal alignment greatly overestimated the platform deviation. The intraoral scanners showed different trueness during the complete-arch implant scanning. The operator experience improved the trueness of the edentulous mucosa but not implant platform deviation.

The effect of software updates on the trueness and precision of intraoral scanners.

OBJECTIVES: The goal of the study was to determine the effects of software updates on the trueness and precision of digital impressions obtained with a variety of intraoral scanner (IOS) systems. METHOD AND MATERIALS: Seven IOS systems were investigated. Each system was tested using two versions of software, with the second version being the latest at the time of conducting the study. Scans were performed on a custom mandibular typodont model with natural teeth that were either unrestored or restored with amalgam, composite, lithium disilicate, zirconia, and gold. Eight scans were obtained for each software version on any of the tested IOS systems. Experimental IOS scans were compared against an industry-standard master scan of the typodont obtained with an ATOS Capsule scanner proven to have a trueness of 3 µm and a precision of 2 µm. Isolation of each substrate material on the digital experimental and master scans was achieved using the Geomagic metrology software for subsequent analysis of the substrate influence on accuracy. A generalized linear mixed model was used to determine the influence of the software version on the trueness and precision of the impression scan. RESULTS: For some IOS systems, scans made with older software versions differ in accuracy compared with those obtained with the most recent software versions. Trueness was improved for most scanners following the software update, although the Element2 IOS performance deteriorated. Software updates had lesser effects on precision and showed variable trends among different systems. Software updates also influence different substrate materials scans' accuracy, although the results show variability among IOS systems. When comparisons were done among IOS systems updated with the latest software version, best performers for complete arch trueness were the Emerald S, Trios 3, and Primescan systems. CONCLUSION: Software updates have a statistically significant effect on the trueness and precision of different IOS systems. These updates can have both positive and negative effects on scan accuracy, although it appears that these variations are within the clinical acceptability levels.

The digital denture replication method (DRM): a simplified method to fabricate a complete removable prosthesis.

The proposed denture replication method shows a predictable workflow for fabricating complete dentures for patients with existing dentures. The replication technique is a method of fabricating new removable complete dentures utilizing the existing prosthesis as the foundation for a new denture. The technique has some advantages such as allowing the clinician to copy the tooth shape and contours of the existing prosthesis while modifying borders and intaglio surfaces. The denture replication method links proven methods of obtaining functional impressions using soft reline materials to a straightforward digital process. Utilizing the new "copy-denture" feature in the 3Shape software, it is possible to significantly reduce the number of appointments and laboratory labor involved in denture fabrication. The denture replication method protocol is increasing efficiency by reducing the amount of clinical procedures and visits, resulting in decreased treatment time and costs while providing a satisfactory clinical solution.