Neuromuscular adaptations with flexible fixed functional appliance--a 2-year follow-up study.

AIM

To evaluate long-term neuromuscular adaptation with the flexible fixed functional appliance.

PATIENTS AND METHODS

Electromyography (EMG) was performed on 15 young, growing females with Class II Division 1 malocclusion treated with a flexible fixed functional appliance. Bilateral EMG activity from the anterior temporalis and masseter muscles was monitored longitudinally to determine changes in posture, swallowing, and maximum voluntary clenching during a 24-month observation period.

RESULTS

There was a significant decrease in EMG activity during saliva swallowing (p < 0.05) and maximum clenching (p < 0.05 at 3 months and p < 0.01 at 1 month after treatment); this persisted for up to 1 month but gradually returned to pre-appliance levels near the end of 6 months. It remained stable from then on until the end of the observation period (24 months).

CONCLUSION

The anterior temporalis and masseter muscles clearly responded to appliance therapy. The neuromuscular adaptation documented after 6 months of treatment remained stable over a 24-month observation period.