Soft tissue changes in patients with Class II Division 1 malocclusions treated using Twin Block appliances:...

Area of Science:

• Orthodontics
• Craniofacial morphology
• Dental aesthetics

Background:

• Class II division 1 malocclusions present challenges in achieving ideal facial aesthetics and function.
• Orthodontic treatment aims to correct skeletal and dental discrepancies, influencing soft tissue profile.
• The Twin Block appliance (TBA) is a common functional appliance used for treating Class II malocclusions.

Purpose of the Study:

• To quantify changes in the soft tissue profile of patients with Class II division 1 malocclusions treated with the Twin Block appliance (TBA).
• To analyze size and shape alterations in specific facial regions following TBA treatment.

Main Methods:

• Analysis of 99 pairs of lateral cephalographs before and after TBA treatment.
• Digitization of 25 soft tissue landmarks and Procrustes superimposition for average profile generation.
• Application of finite element scaling analysis (FESA) to localize and quantify size and shape changes.

Main Results:

• Significant differences in soft tissue profiles were observed pre- and post-treatment in both prepubertal and adolescent groups (P < 0.001).
• Localized increases in size were noted in the labiomental groove, nasal, and mental regions, with varying degrees of negative allometry in lip and symphyseal areas.
• Shape changes were largely isotropic, except for the labiomental region and labial fissure.

Conclusions:

• Twin Block appliance (TBA) treatment for Class II division 1 malocclusions leads to a reduction in the prominence of the labiomental groove.
• These profile changes may contribute to an improved anterior lip seal, enhancing functional outcomes.