## 5 Conclusions  
Based on the results of the present study, the following conclusions can be drawn. The scanning accuracy of IOS is decisively related to hardware and software version; though, newer systems or software versions 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. Based on the data of the present study, it can be concluded that the potential of future intraoral scanner systems seems to be further improved and that digital impression techniques may replace conventional impression techniques in the near future. However, several other aspects, such as functional impression taking with intraoral scanners, need to be considered. These are still largely unresolved, so future investigations are necessary. Conceptualization, A.S. and M.A.S. ; methodology, B.W. ; software, A.S., H.S.K. and H.L. ; validation, M.A.S., A.S. and B.W. ; formal analysis, M.A.S. ; investigation, H.S.K. and H.L. ; resources, B.W. ; data curation, A.S.; writing--original draft preparation, A.S. and M.A.S. ; writing--review and editing, B.W. ; visualization, M.A.S. ; supervision, B.W. ; project administration, A.S. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. The datasets of this article are available from the corresponding author on a reasonable request. We gratefully acknowledge the support of our biostatistician, [PERSON], for the statistical analysis. The authors declare no conflict of interest related to this study. * [PERSON] et al. (2021) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Accuracy of full-arch digital implant impressions taken using intraoral scanners and related variables: A systematic review. _Int. J. Oral Implantol._**2021**, _14_, 157-179. * [PERSON] et al. (2014) [PERSON]; [PERSON]; [PERSON]; [PERSON] [PERSON] Recent advances in dental optics--Part I: 3D intraoral scanners for restorative dentistry. _Opt. Laser. Eng._**2014**, _54_, 203-221. [CrossRef]
* [PERSON] et al. (2017) [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON] Intraoral Scanning Systems: Need for Maintenance. _Int. J. Prosthodont._**2017**, _30_, 27-29. [CrossRef] [PubMed]
* [PERSON] et al. (2016) [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON] [PERSON] Impact of digital intraoral scan strategies on the impression accuracy using the TRIOS Pod scanner. _Quintsence Int._**2016**, _47_, 343-349. [CrossRef]
* [PERSON] and [PERSON] (2013) [PERSON]; [PERSON] [PERSON] Influence of scanning strategies on the accuracy of digital intraoral scanning systems. _Int. J. Comput. Dent._**2013**, _16_, 11-21. * [PERSON] et al. (2017) [PERSON]; [PERSON] [PERSON]; [PERSON]; [PERSON] [PERSON] Accuracy of digital implant impressions with intraoral scanners. A systematic review. _Eur. J. Oral Implantol._**2017**, _10_ (Suppl. 1), 101-120. [PubMed]
* [PERSON] et al. (2015) [PERSON] [PERSON]; [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON] Accuracy of single-tooth restorations based on intraoral digital and conventional impressions in patients. _Clin. Oral Investig._**2015**, _19_, 2027-2034. [CrossRef] [PubMed]
* [PERSON] et al. (2016) [PERSON]; [PERSON]; [PERSON]; [PERSON] [PERSON] A new method for assessing the accuracy of full arch impressions in patients. _J. Dent._**2016**, _55_, 68-74. [CrossRef]
* [PERSON] et al. (2020) [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] Accuracy of Digital Impressions in Fixed Prosthodonics: A Systematic Review of Clinical Studies. _Int. J. Prosthodont._**2020**, _33_, 192-201. [CrossRef]
* [PERSON] and [PERSON] (2020) [PERSON]; [PERSON] Accuracy of full-arch digital impressions: An in vitro and in vivo comparison. _Clin. Oral Investig._**2020**, _24_, 735-745. [CrossRef]
* [PERSON] et al.