Early diagnosed impacted maxillary canines and the morphology of the maxilla: a three-dimensional study.

BACKGROUND: The aetiology of the canine displacement still remains controversial. Some authors implicated a deficiency in maxillary width as a local mechanical cause for impacted canines. The aim of the study was to examine whether there is a relationship between impacted maxillary canines, early diagnosed by using panoramic radiographs, and the morphology of the maxilla on 3D model casts. METHODS: The displaced maxillary canines (DMC) group consisted of 24 patients (mean age, 9.1 +/- 1.1 years), while the control group consisted of 25 subjects (mean age, 8.7 +/- 0.9 years). Seven measurements were calculated on the digital casts of each subject: intermolar width (IMW), arch length (AL), depth of the palatal vault (PVD), available arch space (AAS), the sum of the anterior segments (SAS), the right/affected (R-Af) and left/unaffected (L-Un) available spaces. RESULTS: Both IMW and AL in the DMC group were significantly decreased relative to the control group (P < 0.01), indicating that patients with displaced canines presented a shorter and narrower palate than subjects without eruption problems. Moreover, the values of the SAS and AAS were significantly decreased (P < 0.01) in the DMC group relative to the controls. CONCLUSIONS: The shape of the maxillary arch was narrower and shorter in the displaced maxillary canines group compared with the control group.