上下顎骨に顎整形力を適用した骨格型反対咬合の治療例

抄録

Mandibular prognathism due to morphological and/or positional abnormality of the upper and lower jaws is often caused by narrowing and retrusion of the maxilla or hyperdevelopment and protrusion of the mandible. Orthopedic treatment has been regarded effective for patients with jaws in the developmental stage having this type of malocclusion. A girl,in the aged 10 years and 8 months, with jaws in the developmental stage with anterior protrusion of the mandible and narrowing of the maxillary dental arch, was treated by application of orthopedic force to the upper and lower jaws. Rapid maxillary expansion was applied to the upper jaw and a chin cap appliance to the lower jaw. Occlusion was then reconstructed using a multibracket appliance after tooth extraction. The following results were obtained:

1. Rapid maxillary expansion resulted in successful enlargement of the maxillary dental arch width. Even at 1 year and 6 months after expansion, the maxilla remained almost completely free from relapse. 2. There was no evidence of anterior displacement of the upper jaw due to rapid expansion of the maxilla. 3. Anterior crossbite associated with mandibular prognathism was corrected by swing back of the mandible mainly using a chin cap appliance. This treatment markedly improved the anteriorly protruding appearance of the lower lip and chin which had been obvious at the time of first examination. 4. Control of dental alignment and axis in the entire arch was facilitated by improvement of the maxillomandibular relationship.