Impact of Camouflage Treatment with Class III Elastics on Temporomandibular Joint and Dentoskeletal Relationships: A Pilot CBCT and MRI-Based Clinical Trial.

Abstract

Objective: Orthodontic camouflage effectively addresses mild to moderate skeletal Class III malocclusion by repositioning the mandible and anterior teeth. However, recent findings suggest potential temporomandibular joint (TMJ) impact of the intermaxillary elastics frequently used in this treatment. This study aims to comprehensively assess changes in the TMJ and dentoskeletal relationship following Class III camouflage treatment, using a combination of CBCT and MRI.

Methods: This clinical trial enrolled skeletal Class III malocclusion patients meeting eligibility criteria. Non-extraction camouflage treatment was administered, employing the straight wire technique with conventional Class III intermaxillary elastics. CBCT and MRI were conducted at baseline (T0) and after achieving normal occlusion (T1). Condylar position in three dimensions and dentoskeletal relationship were assessed from CBCT images using Dolphin^® imaging software, while TMJ disc position and length were measured from MR images using MicroDicom software. Statistical analyses were performed with IBM^® SPSS^® software.

Results: The dataset comprised nine subjects, with a mean age of 24.3±7.0 years. CBCT analyses indicated significant changes in dentoskeletal relationship, especially those of the mandible (increased ANB 2.32±0.51°, increased SN-MP 2.61±1.05°, decreased profile angle 5.40±1.07°), but nonsignificant changes in condylar position post-treatment (0.11±0.15 mm). Similarly, MRI measurements demonstrated non-significant changes in both position (0.91±1.61°) and length (0.07±0.37 mm) of the articular disc post-treatment.

Conclusion: Class III camouflage treatment using conventional intermaxillary elastics significantly improves the dentoskeletal relationship without significant adverse effects on the condyle and articular disc of the TMJ.