Class II Division 2 Condyles Changed More Than Division 1 After Orthodontics

Edited by Dentaltown staff

Adults with Class II Division 2 malocclusion showed significant condylar and joint space changes after comprehensive orthodontic treatment while Division 1 patients showed structural stability, according to a retrospective study published Aug. 15 in Clinical Oral Investigations.

Investigators enrolled 82 adults aged 18 to 35, 43 women and 39 men, including 54 with Division 1 and 28 with Division 2 malocclusion. Cone beam computed tomography before and after treatment measured coronal and sagittal joint spaces, axial condylar angle, condylar height and length, condylar sagittal inclination, and glenoid fossa morphology. An electronic articulator recorded incisal protrusive movement, lateral excursion, mouth opening and closing, condylar movement trajectory, and protrusive condylar inclination.

In Division 1 patients, no significant overall changes appeared in condylar size, sagittal inclination, joint space, or fossa morphology. One functional measure did shift: incisal protrusive movement distance decreased significantly, at P = .020.

Division 2 patients changed more broadly. Bilateral condylar length, height, and sagittal inclination all increased after treatment. The left anterior, right anterior, and left superior joint spaces decreased while posterior joint spaces increased bilaterally. The right posterior slope angle decreased, as did the condylar protrusive trajectory angle bilaterally. Incisal protrusion, lateral excursion, and mouth opening and closing distances did not change significantly.

The authors concluded that orthodontic treatment was associated with adaptive temporomandibular joint remodeling, that Division 1 patients showed overall structural stability with limited functional change, and that Division 2 patients showed more pronounced changes across condylar dimensions, inclination, joint spaces, and protrusive trajectory. Changes in mandibular functional movement were limited overall.

Xin Li, J. Luo, J. Zhang, and S. Fang conducted the study, which was registered with the Chinese Clinical Trial Registry as ChiCTR2000034222.

Among Division 1 patients, 20 were treated without extraction, 13 with single-arch extraction, and 21 with double-arch extraction; all Division 2 patients were treated without extraction. The authors classify their extraction-pattern comparisons as exploratory and caution against reading them as evidence of extraction-related remodeling. The design was retrospective with no untreated control, so the changes cannot be attributed to treatment itself.

Sources:
Clinical Oral Investigations, “Changes in temporomandibular joint morphology, condylar position, and mandibular functional movement induced by orthodontic treatment in class II malocclusion: a retrospective study based on CBCT and electronic articulator technology,” published online Aug. 15, 2026: link.springer.com/10.1007/s00784-026-07082-5
PubMed, PMID 42601547: pubmed.ncbi.nlm.nih.gov/42601547