Evaluation of the dimensional changes in the mandible, condyles, and the temporomandibular joint following skeletal class III treatment with chin cup and bonded maxillary bite block using low-dose computed tomography: A single-center, randomized controlled trial

Amr H Husson; Ahmad S Burhan; Mohammad Younis Hajeer; Fehmieh R Nawaya

doi:10.12688/f1000research.130941.1

Evaluation of the dimensional changes in the mandible, condyles, and the temporomandibular joint following skeletal class III treatment with chin cup and bonded maxillary bite block using low-dose computed tomography: A single-center, randomized controlled trial

F1000Res. 2023 Mar 13:12:264. doi: 10.12688/f1000research.130941.1. eCollection 2023.

Authors

Amr H Husson¹, Ahmad S Burhan¹, Mohammad Younis Hajeer¹, Fehmieh R Nawaya²

Affiliations

¹ Department of Orthodontics, University of Damascus Faculty of Dentistry, Damascus, Damascus, Syria.
² Department of Pediatric Dentistry, Faculty of Dentistry, Syrian Private University, Damascus countryside, Syria.

Abstract

Background: Insufficient evidence regarding the effects of chincup therapy on the mandibular dimensions and temporomandibular joint (TMJ) structures requires high-quality studies using three-dimensional (3D) imaging. This trial aimed to evaluate the 3D changes in the mandible, condyles, and glenoid fossa after chin cup therapy for skeletal Class III children compared to untreated controls. Methods: A 2-arm parallel-group randomized controlled trial on 38 prognathic children (21 boys and 17 girls), with mean ages 6.63±0.84 years. Patients were recruited and randomized into two equal groups; the experimental group (CC) was treated with occipital-traction chin cups in conjunction with bonded maxillary bite blocks. No treatment was provided in the control group (CON). Low-dose CT images were acquired before (T1) and after achieving (2-4 mm) positive overjet (T2), and after 16 months apart in both groups. The outcome measures of the condyle-mandibular 3D distances, the condyles-glenoid fossa postional changes, and the quantitative displacement parameters of superimposed 3D models were compared statistically. Paired- and two-sample t-tests were used for intra- and inter-group comparisons, respectively. Results: Overall, 35 patients (18 and 17 in the CC and the CON groups, respetively) were enrolled in the statistical analysis. The mean mandibular and condylar volumes increased significantly by 777.24 mm ³ and 1,221.62 mm ³, 94.57 mm ³, and 132.54 mm ³ in the CC and CON groups, respectively. No statistically significant differences were observed between the groups regarding the volumes, superficial areas, and linear changes of the mandible and condyles, and part analysis measurements, except the changes of the relative sagittal and vertical positions of condyles, glenoid fossa, and posterior joint space, which were significantly smaller in the CC group (p<0.05) than the CON group. Conclusions: The chin cup did not affect the mandibular dimensions. Its primary action was confined to the condyles and the TMJ internal dimensions. Clinicaltrials.gov registration: NCT05350306 (28/04/2022).

Keywords: Skeletal Class III malocclusion; chin cup; lose-dose CT; low-dose computed tomography; volumetric assessment.

Publication types

Randomized Controlled Trial
Research Support, Non-U.S. Gov't

MeSH terms

Child
Child, Preschool
Female
Humans
Male
Malocclusion, Angle Class III* / therapy
Mandible
Mandibular Condyle*
Temporomandibular Joint / diagnostic imaging
Tomography, X-Ray Computed

Associated data

figshare/10.6084/m9.figshare.21973517.v3
ClinicalTrials.gov/NCT05350306

Grants and funding

This study was supported by the University of Damascus Postgraduate Research Budget with the grant allocated to the principal researcher (A.H.H.; Ref no: 73072019132DEN).