[Cone-beam CT evaluation of the changes in the temporomandibular joint of patients with class II division 1 subdivision malocclusion before and after twin-block treatment].
OBJECTIVE
This study aims to evaluate the temporomandibular joint (TMJ) changes in patients with class II division 1 subdivision malocclusions before and after Twin-block treatment using a cone-beam CT (CBCT).


METHODS
Twenty subjects with class II division 1 subdivision malocclusions were included in this study. Hand-wrist radiographs were conducted in the FG-G stage. CBCT was performed to determine the changes in the TMJ before and after the Twin-block treatment. The InVivoDental software was used to calculate the relevant parameters from the three-dimensional CBCT images. The acquired data were then analyzed.


RESULTS
After treatment, the sagittal condylar anterior spaces were reduced, whereas the sagittal condylar superior and posterior spaces as well as the coronal condylar superior space increased (P < 0.01). The condylar height, sagittal condylar angles, and condylar anteroposterior diameters also increased (P < 0.01).


CONCLUSIONS
After the Twin-block treatment, new bone deposition was observed on the condyle. The condyle height also increased and resulted in adjustments in the condyle position within the glenoid fossa to more downward and forward positions. CBCT can quantify TMJ changes and provide an objective assessment to orthodontic treatment.
State Key Laboratory of Oral Diseases, Dept. of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
Bowen
B
Liu
State Key Laboratory of Oral Diseases, Dept. of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
Yanmin
Y
Wang
State Key Laboratory of Oral Diseases, Dept. of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
Fang
F
Song
State Key Laboratory of Oral Diseases, Dept. of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
Min
M
Liu
State Key Laboratory of Oral Diseases, Dept. of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
Ying
Y
Duan
State Key Laboratory of Oral Diseases, Dept. of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China.
Li
L
Zhou
D000293:Adolescent; D054893:Cone-Beam Computed Tomography; D006801:Humans; D008310:Malocclusion; D008312:Malocclusion, Angle Class II; D008335:Mandibular Condyle; D013704:Temporomandibular Joint