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
1 Clinic of Orthodontics and Pediatric Dentistry, University Center for Dental Medicine, University of Basel, Basel, Switzerland
2 Private Practice, Davos, Switzerland



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.

Keywords: CAD/CAM-technique, Dental medicine, Digital impression, Lingual orthodontics, Precision, Scanning.

Abstract Information

Identifiers and Pagination:

Year: 2018
Volume: 12
Publisher Item Identifier: EA-TODENTJ-2018-119

Article History:

Received Date: 01/10/2018
Revision Received Date: 27/10/2018
Acceptance Date: 18/11/2018
Electronic publication date: 22/11/2018
Collection year: 2018

© 2018 Müller et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address Correspondence to this author at Private Practice, Promenade 134, 7260 Davos Dorf, Switzerland; Tel: +41 81 416 22 88; E-mail: