SUBJECTS AND METHOD: Forty-six patients (18 males, 28 females; mean age 13.8±1.2 years) with palatally displaced of one or both canine (PDC) were compared with a control group (CG) of 25 subjects (11 males, 14 females, mean age 14,6±4.7years) presenting no eruption disorders. The PDC were divided in two groups: unilateral palatally displaced canine (UPDC; 14 males, 17 females; mean age 14.4±2.1 years) and bilateral palatally displaced canine (BPDC; 4 males, 11 females; mean age 13.7±1.9 years). For each subject, dental casts were taken and the upper arch was scanned using a 3D scanner. To study the entirety of the shape of the palate in any point of the surface, 3D geometric morphometric analysis was applied. On each digital model, 3D and linear measurements were performed to analyse maxillary arch morphology. Procrustes analysis and principal component analysis (PCA) were performed to reveal the main patterns of palatal shape. Linear measurements differences were tested with the Anova multicomparison test and the independent sample Student’s t-test (P < 0.05).
RESULTS: For the morphology of the palate, the three principal components considered (PCs) for the maxillary casts were width, height and length. There was no statistically significant difference between the groups PDC vs CG, UPDC vs CG, BPDC vs CG, UPDC vs BPDC with regard to the three components. Regarding the linear measurements, there was no statistically difference between the groups except the intercanine width that was significantly smaller in PDC, UPDC, BPDC subjects when compared with the controls. Moreover, maxillary linear measurements comparison between the UPDC vs BPDC has no statistically significant differences.
CONCLUSION: The morphometric variation of the palatine vault or the alteration of maxillary arch dimensions can not be considered as etiological factors in palatally displaced canines. Therefore, these results confirm the genetic theory that says canine positional anomaly appears to be a product of polygenic, multifactorial inheritance.
FUSAROLI D*, MILAZZO A, PALMACCI D, TIBERTI G