Abstract
To investigate the relationship between skeletal morphology and muscle function in maxillofacial complex, and for the further understanding of mastication and/or biological basis of orthodontic treatment, we have been developing new analyzing systems with the help of advanced technology. In this article, we present some results from our studies.
From the results of our first study concerned with bone density and mechanical stress generated by muscle loading, mandibular skeletal growth was affected by the muscle development. In the second study, the vector of reaction force at the condylar head calculated by moment analysis, using EMG activity and muscle-loading direction, was coincident to the growth direction. Also, from the analysis of changes in the curve of Spee during orthodontic treatment, the dental arch showed sufficient reconstruction of their position to adapt the mechanical environment. This suggested that the biomechanical simulation method, including the measurement or muscle activity and bite foree, was necessary for treatment planning. Genetic analysis applied to the prediction of mandibular growth was introduced in a third study. The DNA pattern of growth hormone receptors demonstrated a strong correlation with mandibular size in cephalometrics. A more accurate growth prediction will be possible in the future. Furthermore, a computer-assisted orthodontic diagnosis system and a corn-beam CT scan were introduced.
These computer-assisted and advanced technologies could make it useful for us to derive clinically indisposable information about mechanical conditions in the mandible and mastication functions in individual subjects and lead scientific evaluation in orthodontic diagnosis.
