Correlation Between Points of Interest of the Two Upper Thirds of the Face and Mandibular Landmarks: A Statistical Study
Résumé
Aims: To determine whether the shape and dimensions of the mandible could be predicted from certain landmarks located at the middle and upper thirds of the facial bones and thus establish whether the mandibular morphology is correlated or not to the rest of the facial skeleton.
Methods: 153 three-dimensional CT-scans of the facial bones (77 men and 76 women) were included. Seventeen standard cephalometric points located in the 3 thirds of the face were selected. Thirty anthropometric measurements, presumed to be representative of the global facial morphology, were taken from these points and analyzed using the Spearman Correlation Coefficient (SCC) to establish whether there was a statistically significant correlation between measurements describing the upper and middle thirds of the face and the mandible.
Results: There was a moderate correlation between the distance between the porions and the intercondylar distance (SCC women = 0,54; SCC men = 0,43 ; p ˂ 0,05) and between the distance separating the porion from the nasal spine and the mandibular depth defined as the sagittal distance between the condyle point and the chin point (SCC women (right and left) = 0.47 and 0.64; men CCS (right and left) = 0.32 and 0.42; p˂0,05).
Conclusion: The size and shape of the mandible are overall weakly correlated with the rest of the facial bones in an average population. Only the transverse width at le condylar level and the sagittal length of the mandible are moderately correlated. These results challenge the facial growth theories and most of the cephalometric analyses.