The Measurement Study Of Canine Alveolar Morphology In Skeletal Class Ⅱ Malocclusion Adult Patients With Different Vertical Facial Types

Objective:This is a measurement about different vertical facial skeletal class II adult patients with canine alveolar bone through CBCT technology combined with Mimics17.0 software,analyzing the relationship between the canine and the corresponding jaw morphology among different vertical skeletal types.The aim was to provide a reference for clinical orthodontics.Methods: A total of 60 cases of skeletal class II before treatment were selected,including 18 males and 42 females,aged from 19 to 34 years old.They were divided according to SN/MP angle and FH/MP angle,totally into three groups.The Mimics17.0 software were used to reconstruct the DICOM data and build the measurement plane,and it was used to define the measurement points and lines at the same time.The parameters including alveolar height,alveolar thickness and root movement range were measured on sagittal section of upper and lower canines.Paired test,one-way ANOVA and LSD-t test were used to determine the differences among three different vertical skeletal types.Results:1.Labial and lingual alveolar bone thickness of the short skeletal type patients was larger than the long skeletal type patients on both maxillary and mandibular canine.2.Maxillary canine’s labial palatal root central alveolar bone thickness of the short skeletal type patients was larger than the long skeletal type patients;Mandibular canine’s lingual root central alveolar bone thickness of the short skeletal type patients was larger than the long skeletal type patients.3.Maxillary canine’s palatal crestal thickness of the short skeletal type patients was larger than the long skeletal type patients.4.Mandibular canine’s labial-lingual alveolar bone height of the short skeletal type patients was higher than that of the long skeletal type patients.5.Maxillary canine’s palatal cotical angle of the short skeletal type patients was larger than the long skeletal type patients,and the short skeletal type patients was smaller than the normal skeletal type patients at the same time.Mandibular canine’s lingual cortical bone angle of of the short skeletal type patients was larger than that of the long skeletal type patients.6.Both of the short skeletal type and the normal skeletal type patients’ canine labiallingual root rotation angle,rotation distance,total rotation angle and total rotation distance were larger than that of the long skeletal type patients.7.The canine’s cortical angle,alveolar bone thickness,rotation angle and rotation distance at the center and apex of root based on the same vertical facial type had significant difference.In this case,labial sides were smaller than lingual sides.Conclusions:1.The short skeletal type patients’ canine root had the largest range of motion in the corresponding alveolar bone in skeletal class Ⅱ adult patients,which was contrary to the same project of the long skeletal type patients.2.Compared with the short skeletal type patients,the mandibular canine’s alveolar bone height of the long skeletal type patients was lower,and the impedance center of the long skeletal type patients was closer to the apical part in skeletal class Ⅱadult patients.3.The moving range of the canine root tip to the lingual side was larger than that to the lip side in the same vertical facial type among skeletal class Ⅱ adult patients.