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This study aimed to investigate the transfer accuracy and required time for digital full-arch impressions obtained from intraoral scanners (IOSs) versus conventional alginate impressions (CAIs) in patients with multibracket appliances (MBA). Thirty patients with buccal MBAs (metal brackets, archwire removed) were examined using an established reference aid method. Impression-taking using four IOSs (Primescan, Trios 4, Medit i700, Emerald S) and one CAI with subsequent plaster casting were conducted. One-hundred-twenty (n = 30 x 4) scans were analyzed with 3D software (GOM Inspect) and 30 (n = 30 x 1) casts were assessed using a coordinate measurement machine. Six distances and six angles were measured and compared to the reference aid values (ANOVA; p < 0.05). Except for the intermolar distance, transfer accuracy was significantly higher with IOSs than with CAIs (p < 0.05). No such difference was found regarding the six angles. In patients with MBAs, digital impression-taking using IOSs can be recommended. For all measured variables except one, the transfer accuracy of IOSs was better than or at least equivalent to the data from CAIs. In addition, significantly (p < 0.001) less time was necessary for all IOSs in comparison to CAIs plus plaster casting.

This study aimed to investigate the transfer accuracy (trueness and precision) of three different intraoral scanning families using different hardware and software versions over the last decade from 2012 to 2021, compared to a conventional impression. Therefore, an implant master model with a reference cube was digitized and served as a reference dataset. Digital impressions of all three scanning families (True definition, TRIOS, CEREC) were recorded (n = 10 per group), and conventional implant impressions were taken (n = 10). The conventional models were digitized, and all models (conventional and digital) were measured. Therefore, it was possible to obtain the deviations between the master model and the scans or conventional models in terms of absolute three-dimensional (3D) deviations, deviations in rotation, and angulation. The results for deviations between the older and newer scanning systems were analyzed using pairwise comparisons (p &lt, 0.05, SPSS 26). The absolute 3D deviations increased with increasing scan path length, particularly for the older hardware and software versions (old vs. new (MW ± SD) True Definition: 355 ± 62 µm vs. 483 ± 110 µm, TRIOS: 574 ± 274 µm vs. 258 ± 100 µm, and CEREC: 1356 ± 1023 µm vs. 110 ± 49 µm). This was also true for deviations in rotation and angulation. The conventional impression showed an advantage only regarding the absolute 3D deviation compared to the older systems. Based on the data of the present study, the accuracy of intraoral scanners is decisively related to hardware and software, though, newer systems or software do not necessarily warrant improvement. Nevertheless, to achieve high transfer accuracy, regular updating of digital systems is recommended. The challenge of increasing errors with increasing scan paths is overcome in the most recent systems. The combination of two different scanning principles in a single device seems to be beneficial.

Dental care has been affected by SARS-CoV-2 (COVID-19) worldwide. In contrast to other dental clinics, the Justus-Liebig-University Giessen (Germany) decided not to limit dental treatment to emergencies alone, but to continue dental care for all patients, with increased safety measures. As such, health care professionals may be exposed to additional physical and mental stress. The aim of this study was to assess the perspectives of all persons involved in dental care (dentists, dental assistants, students, and patients) regarding the aspects of safety measures, anxiety about self-infection and infecting others, and other prospects in the period March to December 2020 using a questionnaire. Data collection was performed between 14 December 2020 and 23 January 2021. A total of 35 dentists (response rate of 79.5%), 23 dental assistants (65.7%), 84 students (80%), and 51 patients (21.8%) completed the survey. The patients did not notice any changes in the care received. Dentists and dental assistants reported a higher workload due to additional safety measures. The majority of dentists, students, and patients agreed that normal patient care was maintained. One-third of dental assistants would have preferred emergency treatment alone and expressed significantly higher anxiety about COVID-19 infection than all other groups (p &lt, 0.05). In conclusion, all groups showed a predominantly positive perspective on dental care, and anxiety about self-infection and infecting others was especially low. However, additional measures are time-consuming and compound daily patient care. This concept, based on well-established infection control, might be a viable proposal for current and future pandemics.