Morphology And Position Of Condyle In Different Skeletal Malocclusions Assessed By CBCT

Objective: The aim of this experiment was to study malocclusion effect on temporomandibular joint(TMJ) using cone-beam computed tomography(CBCT)furthermore, to investigate the differences in the condylar morphology of skeletal II1 patients in different vertical skeletal features, so as to provide information for clinical treatment.Methods: Thirty subjects selected respectively for different skeletal malocclusions were chosen from the CBCT database of Qingdao Stomatological Hospital, and then divided skeletal II1 patients into three groups according to Go Gn-SN and S-Go/N-Me:(low angle group,middle angle group and high angle group). Condylar measuring project mainly includes condylar volume, condylar surface, morphological index, anteroposterior diameter, medialateral diameter,superior joint space, anterior joint space and posterior joint space. The condylar volume and other indexs were measured on the sagittal and coronal sections by Mimics 10.01. The positional parameters of condyle were reconstructed on oblique position perpendicular to the long axis of condyle. Data were analyzed by SPSS 17.0.Results:1. The characteristics of condyle in different skeletal malocclusions:(1) No statistically significant differences were observed between the right and left sides in three groups(p < 0.05).(2) The differences not only between skeletal III malocclusions and skeletal I malocclusions but also skeletal class III malocclusions and skeletal II1 malocclusions were statistically significant in condyle volume and condyle surface(P<0.05), the condyle volume and surface of skeletal III were bigger than both skeletal I and skeletal II1 by comparing means.(3) The anteroposterior and medialateral diameter of skeletal II1 malocclusions were smaller than skeletal III and skeletal I malocclusions by comparing means, the differences had statistic meaning(p < 0.05).(4) There were significant differences in all joint spaces expect for the superior joint space between skeletal I and skeletal II1, the differences had statistic meaning(P<0.05).(5) In the whole sample condylar morphology parameters(condylar volume, condylar surface, anteroposterior diameter and medialateral diameter) were significantly higher in males than in females(p < 0.05).2. The characteristics of condyle in skeletal II1 patients of different vertical skeletal features :(1) The analysis of all projects between low and middle mandibular plane angles revealed a significant difference(p < 0.05).(2) The analysis of condylar parameters between low and high angle groups showed a significant difference(p < 0.05).(3) There were significiant differences on the condylar anteroposterior diameter,medialateral diameter,anterior joint space and superior joint space between middle angle group and high angle group.Conclusions:(1) No significant differences were observed between the right and left sides in temporomandibular joint parameters of healthy adult patients.(2) There are significant differences in condylar morphology and spatial position among the three malocclusion groups, which stable and repeatable data will form the basis for future studies on craniofacial development.1)Volume and surface of condyle in skeletal III patients are greater than both skeletal II1 and skeletal I patients.2)The temporomandibular joint area of skeletal II1 patients has small volume and width joint space.(3) Condylar volume and surface in low angle subjects is greater than normal and high mandibular plane angle subjects.The condyle is located posteriorly in glenoid fossa.