The Influence of Scanning Conditions of Digital Impressions on the Scan Precision of Lingually Bonded Arches – an In-vitro Study
Kim Müller1, Stefan Baumgartner2, *, Michel Dalstra1, Carlalberta Verna1
The aim of this study was to evaluate the influence of scanning conditions on the precision of digital impressions of lingually bonded arches.
Materials and Methods:
A maxillary and mandibular plastic cast bonded with lingual brackets (Incognito, Monrovia, USA) were scanned with three different scanning systems (3M True Definition Scanner, 3Shape TRIOS®, Carestream Dental CS 3600 scanner). The cast was scanned both fixed onto a flat surface (extraoral-EO) and mounted in a phantom head, and in dry (intraoral-IO-dry) and wet (intraoral-IO-wet) conditions. Standardized landmarks were positioned and distances between the landmarks were measured by using image-analysis (Materialise Mimics® 18.0). All measurements were repeated and the error of the methods was calculated using Dahlberg's formula. 2 by 2 comparisons of settings, scanners and anterior and posterior scanned areas were analysed using a t-test.
The double comparisons of measured distances showed statistically significant differences with all settings. In general, the 3-Shape scanning system showed the highest precision, both for the maxillary as well as for the mandibular scans. The True Definition and the Carestream scanners showed similar results for the mandibular scans, but the Carestream scanner exhibited more variability for the maxillary scans. Variations in the posterior areas were always larger than those anteriorly, for all IO-dry settings and the IO-wet setting of the Carestream scanning system.
The scan precision of arches with lingually bonded brackets depends on the type of scanner, the setting (dry or wet) and the region within the arch. Mandibular scans generally have a higher precision than maxillary scans, especially in the anterior region.
* Address Correspondence to this author at Private Practice, Promenade 134, 7260 Davos Dorf, Switzerland; Tel: +41 81 416 22 88; E-mail: firstname.lastname@example.org