Effects of levelling of the curve of Spee on the proclination of mandibular incisors and expansion of dental arches: a prospective clinical trial
Publié en ligne: 14 déc. 2023
Pages: 61 - 65
Reçu: 01 août 2009
Accepté: 01 janv. 2010
DOI: https://doi.org/10.2478/aoj-2010-0011
© 2010 Nikolaos Pandis et al., published by Sciendo
This work is licensed under the Creative Commons Attribution 4.0 International License.
Objectives
To investigate the effects of levelling the curve of Spee (COS) on the inclination of the mandibular incisors and the width of the mandibular arch.
Methods
Fifty patients, 10–18 years of age, were selected using the following inclusion criteria: nonextraction treatment in the mandibular arch; eruption of all mandibular teeth; no spaces in the mandibular arch; no crowding in the posterior mandibular segments; a mandibular irregularity index greater than 2.5. The depth of the COS, the amount of crowding of the mandibular anterior dentition and the intercanine and intermolar widths were measured on standardised photographs of the casts. The inclinations of the mandibular incisors were measured on cephalometric radiographs. The paired
Results
The COS showed a median decrease of 0.9 mm, with 50 per cent of the cases ranging between 0.4 mm and 1.4 mm. The sole predictor of curve flattening was the lower incisor to mandibular plane angle.
Conclusions
The COS is mainly ‘flattened’ by proclining the mandibular incisors. For 1 mm of levelling the mandibular incisors were proclined 4 degrees, without increasing arch width.