Effectiveness of the passive lingual arch for E space maintenance in subjects with anterior or posterior rotation of the mandible: a retrospective study.

OBJECTIVE The aim of this study was to determine whether or not lingual arches in subjects with anterior or posterior mandible rotation can produce different effects in the prevention of first permanent molar mesial migration. SUBJECTS AND METHODS Forty-two patients with a mean age of 9 ± 0.8 years were selected from the Department of Orthodontics, University of Catania, Italy. These subjects were treated with a passive mandibular fixed lingual arch. The sample was divided into 3 groups according to the gonial angle in order to establish the pattern of mandible growth: mandibular posterior rotation (MPR), mandibular growth in straight-downward direction (MSD) and mandibular anterior rotation (MAR). Lateral cephalograms and study models of the patients before and after treatment were examined to determine any positional changes of the mandibular first molars and incisors. RESULTS Statistically significant differences between the MPR group and the other 2 (MSD and MAR) were found as regards mandibular first molar and incisor positional changes. No significant differences were found between the MSD and MAR groups. CONCLUSION The results indicate that the effect of lingual arch is influenced by mandibular growth patterns. In patients with MPR, the lingual arch preserves arch length but the mesial migration of first permanent molars is not completely blocked.