RELATIONSHIP BETWEEN DISPLACED MAXILLARY CANINES AND THE MORPHOLOGY OF THE MAXILLA: A 3D MODEL ANALYSIS

AIM: 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. SUBJECTS AND METHODS: Subjects were divided into two groups: the displaced maxillary canines (DMC) group and the control group. The DMC group consisted of 24 patients, with a mean age of 9.1±1.1 years, while the control group consisted of 25 subjects, with a mean age of 8.7±0.9 years. Fourteen patients had bilateral maxillary canine impactions. Early prediction of maxillary canine impaction was made by using three geometric measurements on panoramic radiographs: the position (sector) of the displaced canine relative to the surrounding teeth, the angle made by the long axis of the tooth with the midline, and the distance from the occlusal plane. 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 widths of the four maxillary incisors (SWI), the right/affected (R-Af) and left/unaffected (L-Un) available spaces. Differences between the DMC group and the control group were calculated by means of Student’s t-test for independent samples. RESULTS: Both IMW and AL in the DMC group resulted statistically significant decreased relative to the control group (P<0.01). No statistically significant differences between the two groups were found in the PVD. Moreover, the values of the SWI and AAS were significantly decreased (P<0.01) in the DMC group relative to the controls. These findings are consistent with those found for AL and IMW. The right/affected and left/unaffected sides were shorter in the DMC group as well (P<0.01), although there were no statistically significant differences between the two sides (right/affected, left/unaffected) in both groups. CONCLUSION: The shape of the maxillary arch was narrower and shorter in the displaced maxillary canines group compared with the control group. Further researches are needed to investigate the differences between unilateral and bilateral impactions.