Abstract
Chin caps and frontal pull appliances to the maxilla have been used for primary anterior crossbites, but previous studies of the treatment effect have highlighted problems, such as pressure on the temporomandibular joint (TMJ) and cranial bones. Therefore, to reduce these problems on the TMJ and cranial bones, a functional orthodontic appliance, Muh shield (YC3), was developed to improve the overjet and overbite in the primary dentition. However, there have been no reports on application of the Muh shield to cleft and lip palate patients although there are some reports on primary anterior crossbite orthodontic patients. Therefore, we applied the Muh shield in two young patients with cleft lip and palate. The aim of this study was to examine the treatment effects of the Muh shield in correcting cleft lip and palate in young patients.
Case 1 was a girl who was 5 years and 6 months old. The patient presented as follows: overjet 0 mm, overbite 0 mm, terminal plane: mesial step type, ANB + 4.0°. The patient was diagnosed as leftside cleft lip and palate. As a result of treatment, ANB of case 1 increased from 4.0° to 5.5°, and there was skeletal improvement. After using the Muh shield for 2 years and 6 months, only the lateral central incisor increased from overjet 0 mm to 2 mm.
Case 2 was also a girl who was 5 years and 7 months old. The patient presented as follows: overjet -1 mm, overbite +4 mm, terminal plane: mesial step type, ANB + 1.0°. The patient was diagnosed as isolated cleft plate. As a result of treatment, ANB of case 2 increased from 1.0° to 2.0°, and there was skeletal improvement. Both cases showed a clockwise rotation of the mandible and retrusion. Furthermore, case 1 indicated downward and forward growth and case 2 indicated only downward growth of maxillary.
These results indicate that the Muh shield improves functional effects on the skeletal system during primary dentition in cleft lip and plate patients. The Muh shield might be effective during primary dentition because it reduced the risks of caries and obstruction of teeth eruption. We will continue studies in the near future.
