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Updated: Jun 9, 2026
Force System with Vertical V-Bends: A 3D In Vitro Assessment of Elastic and Rigid Rectangular Archwires
Published on: July 24, 2018
Effect of arch form on the fabrication of working archwires
Clare McNamara1, Jonathan R Sandy, Anthony J Ireland
1Orthodontic Department, Gloucestershire Royal Hospital, Gloucester, United Kingdom. Clare.McNamara@bristol.ac.uk
Introduction:
Previous studies have shown that most practitioners plan to maintain intercanine and intermolar widths during orthodontic treatment with fixed appliances. The aim of this study was to determine whether this was put into practice by clinicians during the latter stages of orthodontic treatment with fixed appliances.
Methods:
This 2-part investigation was a laboratory-based measurement study at Bristol Dental Hospital, United Kingdom, from 2005 to 2007. Using standardized maxillary and mandibular study models with identical intermolar and intercanine widths but with differing degrees of tooth misalignment, 30 clinicians were asked to fabricate final working archwires according to their normal clinical practice. Then the intercanine and intermolar widths of the archwires were measured. In the second part of the study, the same intra-arch dimensions were measured directly from 50 pretreatment and posttreatment patient study models obtained from a subsample of 10 of the clinicians.
Results:
The intercanine and intermolar widths measured on the adapted archwires from the standardized study models showed wide variations in the results, even though the intercanine and intermolar widths of the models were identical. Data from 50 treated patients also showed that, in most, there were wide variations in intercanine and intermolar widths between the patients' pretreatment and posttreatment study models.
Conclusions:
Although most clinicians aim to maintain the pretreatment arch form, this study shows that this is often not transferred to clinical practice.
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