Incisor crossbite and repaired unilateral cleft lip and palate: changes in jaw movement and temporalis muscle activity before and after edgewise treatment--case report.

Abstract

To examine the changes in jaw movement and temporalis muscle activity of a patient with unilateral cleft lip and palate before and after edgewise treatment. Clinical case study. University dental hospital, department of orthodontics. A 12-year 3-month-old male with incisor crossbite, molar malocclusion, and repaired unilateral cleft lip and palate who had completed first-phase orthodontic treatment. This patient was treated with an edgewise appliance. Jaw movement and temporalis muscle activity during the chewing of a hard gummy jelly were recorded at 2 kHz from the sixth to the twentieth stroke before edgewise treatment and after a retention period of 2 years. Optimum intercuspation of teeth was achieved. The reversed crossing jaw-movement pattern before treatment changed to a normal grinding after treatment. The posterior temporalis muscle on the chewing side exhibited an earlier burst than the contralateral one during chewing at the post-treatment stage, as is observed in cases with good occlusion. Improvement in the occlusion using an edgewise appliance is necessary for acquiring a good masticatory function in patients with incisor crossbite, molar malocclusion, and cleft lip and palate.