The Open Dentistry Journal

ISSN: 1874-2106 ― Volume 14, 2020

Accuracy and Reliability of Space Analysis Measurements in Digital Models with Different Degrees of Crowding

Antonino Lo Giudice1, *, Simone Muraglie1, Stefano Martina2, Vincenzo Ronsivalle1, Rosalia Leonardi1
1 Department of Orthodontics, School of Dentistry, University of Catania, Policlinico Universitario “Vittorio Emanuele”, Via Santa Sofia 78, 95123, Catania, Italy
2 Department of Neurosciences, Reproductive Science and Oral Sciences, Division of Orthodontics, University of Naples Federico II, Naples, 80131, Italy



With the introduction of digital systems in the orthodontic field, it is not still clear if such systems can accurately substitute analogical systems in the diagnosis and orthodontic treatment plane.


The study compared the Arch Length Discrepancy (TALD) and Bolton ratio obtained from plaster dental casts (gold standard) and digital models and tested the null hypothesis that TALD and Bolton ratio measurements in digital models are affected by the degree of crowding.


The sample included 40 dental models divided into five sub-groups, according to the American Board of Orthodontists (ABO) score of crowding. Plaster casts were scanned by a 3D laser scanner to obtain digital models. In digital and plaster models, the mesiodistal width of each tooth and arch lengths (maxillary and mandibular) were measured to calculate anterior and total Bolton ratios and TALD. Three operators performed measurements on plaster and digital models using a digital caliper and OrthoAnalyzerTM 3D software (3Shape A/S, Copenhagen, Denmark).


No statistically significant differences were obtained for intra and inter-examiner reliability (p > 0.05). When comparing plaster and digital findings, statistically significant differences were obtained for all measurements except for mandibular arch length and anterior Bolton ratio. In general, there was an overestimation of tooth size and arch length discrepancy in digital models. Moreover, the mean difference of measurements between both the methods increased in more crowded models.


Crowding affects, the accuracy of Bolton ratio, and the arch length measurements. since the overestimation is relatively small, it should not be considered of clinical significance.

Keywords: Space analysis, Digital models, Bolton ratio, Arch length discrepancy, Dental crowding, Digital dentistry.

Article Information

Identifiers and Pagination:

Year: 2019
Volume: 13
First Page: 505
Last Page: 511
Publisher Id: TODENTJ-13-505
DOI: 10.2174/1874210601913010505

Article History:

Received Date: 25/09/2019
Revision Received Date: 20/11/2019
Acceptance Date: 18/12/2019
Electronic publication date: 31/12/2019
Collection year: 2019

© 2019 Lo Giudice 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 the Department of Orthodontics, Policlinico Universitario “Vittorio Emanuele”, University of Catania, Via Santa Sofia 78, Catania, Italy; Tel: + 39 3498674523 Email:


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