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Objective: In dental restorations, color determination is very important for achieving esthetic results. The aim of this study was to compare visual shade selection using digital methods and to assess the repeatability of the utilized intraoral scanners. Materials and methods: In 31 probands, tooth color was determined on teeth 11, 13, and 16. Shade selection was performed visually by a dentist and digitally using Trios 3 and Cerec Omnicam. Three measurements were performed to determine the repeatability of intraoral scanners. Fleiss' κ was used for statistical evaluation of the repeatability and Cohen's κ was used for comparison of methods. Results: The visual method showed only slight agreement with Trios 3 (Cohen's κ: 0.198) and Cerec Omnicam (Cohen's κ: 0.115). Moderate agreement was found between Trios 3 and Cerec Omnicam (Cohen's κ: 0.452). In terms of repeatability, Trios 3 scored higher overall than Cerec Omnicam (Fleiss' κ: 0.612 vs. 0.474). Conclusion: Intraoral scanners can facilitate the workflow in clinical practice. They are a good supplement for color determination, but should additionally be confirmed by the visual method. Clinical significance: The use of digital instruments is increasingly being preferred over conventional treatments. Therefore, it is essential to continuously improve the accuracy of intraoral scanners for color selection in order to offer an alternative to visual methods. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the trueness of complete- and partial-arch impressions obtained using conventional impression materials and intraoral scanners in vivo. Full-arch impressions were taken using polyether and polyvinylsiloxane. Gypsum casts were digitized using a laboratory scanner (IM, AF). Casts obtained from polyether impressions were also scanned using an industrial blue light scanner to construct 3D reference models. Intraoral scanning was performed using CEREC Omnicam (CO) and Trios 3 (TR). Surface matching software (Atos Professional) enabled to determine the mean deviations (mean distances) from the reference casts. Statistically significant discrepancies were calculated using the Wilcoxon signed-rank test. The mean distance for trueness ranged from 0.005 mm (TR) to 0.023 mm (IM) for the full arch, from 0.001 mm (CO) to 0.068 mm (IM) for the anterior segment, and from 0.019 mm (AF) to 0.042 mm (IM) for the posterior segment. Comparing the anterior vs. the posterior segment, significantly less deviations were observed for anterior with CO (p < 0.001) and TR (p < 0.001). Full-arch comparisons revealed significant differences between AF vs. IM (p = 0.014), IM vs. CO (p = 0.002), and IM vs. TR (p = 0.001). Full-arch trueness was comparable when using Affinis and the two intraoral scanners CEREC Omnicam and Trios 3. The digital impression devices yielded higher local deviations within the complete arch. Digital impressions of the complete arch are a suitable and reliable alternative to conventional impressions. However, they should be used with caution in the posterior region. Trial registration: Registration number at the German Clinical Trial Register (04.02.2022): DRKS00027988 (https://trialsearch.who.int/). [ABSTRACT FROM AUTHOR]

Purpose: Sufficient data are not currently available on how the various geometries of scan bodies and different scan strategies affect the quality of digital impressions of implants. The purpose of this study was to present new data on these two topics and give clinicians a basis for decision making. Materials and Methods: A titanium master model containing three Nobelreplace Select™ implants (Nobelbiocare Services AG, Zurich, Switzerland) was digitized using an ATOS industrial noncontact scanner. Digitization was repeated three times with different types of scan bodies integrated into the implants: ELOS A/S, nt‐trading GmbH, and TEAMZIEREIS GmbH. These three scans served as virtual master models. The titanium master model was then scanned with the TRIOS3© digital intraoral scanner (ELOS A/S, Copenhagen, Denmark), which was used for two different scanning strategies. Strategy A was a one‐step procedure that included both the titanium master model and the integrated scan bodies. Strategy B comprised two steps. First, a digital overlay was performed with a scan of the titanium master model without integrated scan bodies. A second scan was performed with the titanium master model and integrated scan bodies. By repeating both strategies 10 times for each type of scan body, 60 scans were generated and the corresponding standard tessellation language data sets overlaid with the corresponding virtual master model. Deviations in the resulting superimpositions were calculated and evaluated separately in the individual axes (x, y, z) and in three‐dimensional space (Euclidean distance). Statistical evaluation was performed using the R‐project software. Level of significance was determined at p ≤ 0.05. Results: With regard to the geometry of the scan bodies, strategy A significantly influenced the accuracy of the digital implant impression in regards to Euclidean distance (p = 0.003). No significant difference was found for strategy B in this context. Comparing the two scan strategies revealed that strategy A achieved significantly higher accuracy overall (p = 0.031). Conclusion: The quality of digital intraoral impressions seems to be influenced by both the geometry of the scan body and the scan strategy. For clinical practice, the one‐step scan strategy seems beneficial. Furthermore, the scan bodies of ELOS A/S showed a potential clinical advantage. [ABSTRACT FROM AUTHOR]

Objective: Assessing the level of precision entailed by the virtual fit of dental restorations is a very challenging issue. A cement space between an abutment tooth and a dental restoration is a clinical requisite that precludes the application of conventional best-fit registration protocols routinely applied in industrial precision measurements. Since two-dimensional fit assessment techniques currently used in dentistry miss important information about the third dimension, a new protocol was developed to provide threedimensional information for the virtual registration of the digitized restoration with respect to the abutment. Method and Materials: CAD/CAM was used to produce 10 titanium single crown copings for five gypsum master casts each, representing a molar prepared for a full crown. An industrial noncontact scanner was used for digitizing the components. Registration of surface data sets was achieved by a new triple-scan protocol. For statistical analysis and repeatability testing of the triple-scan protocol, mean distances of the cement space of all copings on their respective abutments were measured three times. Results: The validity of the approach is verified by intraclass correlation coefficients that revealed an almost perfect coefficient for repeatability (ICC = 0.981, P < .001) with a 95% confidence range between 0.970 and 0.989. Conclusion: The triple-scan protocol represents a reliable registration approach for surface data sets in dental applications and eliminates the limitations of conventional best-fit registration protocols when a cement space or gap is present between a restoration and its underlying abutment. Future fit assessment investigations can implement this approach of obtaining detailed information of component precision in all spatial orientation. (Quintessence Int 2011;42:651-657) [ABSTRACT FROM AUTHOR]

Background: The abrasion behavior of various ceramics is rarely investigated, though it is relevant for the clinical success of such restorations. The aim of this in vivo study was to evaluate the wear of feldspathic-ceramic-veneered zirconium oxide frameworks over a period of at least 10 years. Methods: The abrasion behavior of 15 bridge constructions from 15 different participants was examined after a period of 3, 5, and 10 years using plaster models, which were then subjected to a scanning process on the Atos II industrial scanner and digitized for three-dimensional evaluation of the abrasion by the corresponding software (ATOS Professional 7.6). The individual post-examination models were compared to the baseline model and deviations calculated in the sense of the largest, punctual loss of material in millimeters ("minimal distance"), the average abrasion in millimeters ("mean distance"), and the volume decrease in cubic millimeters ("integrated distance"). Statistical analyses were performed using the Wilcoxon sign rank test or mixed regression models. Multiple testing was considered by Benjamini-Hochberg correction. The significance level was set at 0.05. Results: We found steadily increasing wear of the ceramic. The average volume decrease was significant (P < 0.001) at 3 years and 10 years (− 3.25 mm3 and − 8.11 mm3, respectively). Conclusions: The results of this study indicate that the rate of volume loss in feldspathic-ceramic-veneered zirconia frameworks in the posterior region increases significantly over time. An increasing frequency of parameters was observed, particularly in the second half of the study period. However, the use of this class of materials can be considered clinically acceptable. Trial registration This study is registered in DRKS - German Clinical Trials Register with the register number DRKS00021743. https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00021743 [ABSTRACT FROM AUTHOR]