Orthodontics is commonly known as straightening of the teeth or correction of crooked teeth. To begin with, a tooth is an organ developed in and supported by the jaw bone. What makes orthodontic treatment possible is based on the fact known since the ancient Roman period that resorption and apposition of the adjoining bones are caused by giving teeth a weak external force that results in moving the teeth. The goal of orthodontic treatment is not only to make up natural teeth as beautifully aligned, but to reconstruct the functionally tight and excursive intercuspation of teeth so that food can be effectively chewed and speech can be made correctly. In addition, the treatment to control the growth and development of jaw bones is performed even in cases with malocclusion which result not from abnormal tooth alignment but from malformation or growth abnormality of the craniofacial structures. 　Orthodontics is a branch of clinical oral health sciences which explores factors that contribute to establishing the optimum occlusal relationship of the natural teeth for achieving good facial esthetics and stable occlusal function. The aim of orthodontics is to achieve an optimal spatial relationship between the teeth and craniofacial structures by guiding and controlling the growth and development of the dentiofacial complex in growing humans or by altering the form or spatial position of the natural teeth and jaws by exerting mechanical stimuli to the internal structure of the crariofacial complex. 　Research in orthodontics is extremely interdisciplinary because it covers a wide range of scientific studies such as cognitive science, neurology, mathematical engineering, genetic engineering and molecular biology for the research on the recognition of facial shapes and expressions, the formation of bones and teeth and control of jaw movement or that of pain. It is well known that these fields of studies have made a remarkable development in recent years. Accordingly and naturally, the contents of research in orthodontics has entered into more profound details. 　We cover following research concerns:
(1) Mathematical modeling of the masticatory system

(2) Development of knowledge database and mathematical understanding of inferencelogic structures for decision-making in orthodontics

(3) Biochemical studies on factors which are relevant to the growth and developmentof dentofacial structures

(4) Immunohistological studies on the influences of stress on the central nervous system

(5) 3D morphological analysis and modeling of growth and development of dento-cranio-facial structures