Real-time mandibular movement analysis system using four-dimensional cranial bone model

The analysis of jaw movement has long been used as a measure for clinical diagnosis and treatment of prosthodontics, orthodontics, and oral surgery. However, prior analysis methods focus on the trajectory of the mandible or nearby points, and involve analysis which assumes a standard human bone shape or analysis which takes into consideration a portion of the shape of the mandible or other bones. Anatomically accurate assessment of the shape and motion of the bones overall for each patient is problematic. The authors have combined the morphological information for the bones of each subject obtained from CTs and the information on the movement of the mandible obtained from infrared markers set up on the teeth, and developed a system that can visualize and analyze in real time the state of the temporomandibular joint using real-time imaging technology. As a result, the three-dimensional shape of the mandible overall and its movements over time can be analyzed in real time quantitatively; in other words, analysis of jaw movement in four dimensions is possible. This system can be used to clarify the cause of bone deformations thought to result in jaw movement abnormalities, to assess treatment options for patients with temporomandibu lar joint illness, and to provide explanations to patients. Moreover, through further validation of its precision, the system may also be used clinically as a navigation system for dental therapy.