Mandibular articular disk position changes during Herbst treatment: a prospective longitudinal MRI study

Area of Science:

• Orthodontics
• Temporomandibular Joint (TMJ) Disorders
• Biomedical Imaging

Background:

• Class II malocclusion is a common dental issue requiring orthodontic intervention.
• The Herbst appliance is frequently used to correct Class II malocclusions.
• Understanding TMJ disk behavior during orthodontic treatment is crucial for patient outcomes.

Purpose of the Study:

• To prospectively evaluate changes in temporomandibular joint (TMJ) articular disk position during Herbst therapy.
• To assess the relative position of the articular disk to the condyle throughout different treatment phases.

Main Methods:

• A prospective longitudinal study involving 15 patients with Class II malocclusions treated with the Herbst appliance.
• Parasagittal Magnetic Resonance Imaging (MRI) of the TMJ was performed at five time points: pre-treatment, start, 6 weeks, 13 weeks, and 7 months post-treatment.
• A disk position index was used to analyze the relative position of the articular disk and condyle.

Main Results:

• Herbst treatment successfully corrected Class II malocclusions to Class I or overcorrected Class I relationships.
• Condyle position remained largely unchanged throughout the Herbst therapy duration.
• The articular disk initially moved to a retrusive position upon mandibular advancement but returned to near its pretreatment position by treatment completion.

Conclusions:

• Herbst therapy does not appear to cause adverse changes in TMJ articular disk position.
• The findings suggest that the Herbst appliance may be beneficial in managing patients with anterior disk displacement.
• Further research is warranted to confirm the therapeutic potential of the Herbst appliance for TMJ disk issues.