Relationship between interincisal angles and TMJ morphology/position and trabecular structure: a retrospective study.

Area of Science:

• Orthodontics
• Craniofacial Morphology
• Temporomandibular Joint (TMJ) Imaging

Background:

• The influence of the interincisal angle on TMJ morphology and trabecular structure is not well understood.
• Skeletal class II malocclusions present unique challenges for TMJ development and function.

Purpose of the Study:

• To investigate TMJ morphology, condylar position, and glenoid fossa characteristics in skeletal class II individuals with varying interincisal angles.
• To determine the relationship between interincisal angle variations and TMJ structural changes.

Main Methods:

• Cone-beam computed tomography (CBCT) scans of 150 skeletal class II patients were analyzed.
• Patients were categorized into normal, small, and large interincisal angle groups.
• TMJ parameters were measured using specialized imaging software (Dolphin Imaging, Mimics, ImageJ).

Main Results:

• Significant differences in condylar dimensions (anteroposterior, mediolateral diameters) and bone volume were observed between groups.
• Altered trabecular bone structure (thickness and number) was noted in small and large interincisal angle groups.
• Variations in condylar rotation (axial and coronal planes) and glenoid fossa dimensions (height, width) correlated with interincisal angle size.

Conclusions:

• Both small and large interincisal angles are associated with distinct TMJ morphological and structural alterations.
• Condylar position and glenoid fossa depth/width are significantly affected by interincisal angle.
• Orthodontic treatment should consider interincisal angle correction to optimize TMJ health and morphology.