Four-dimensional analysis of stomatognathic function.

Many researchers have attempted to clarify the complex relationships between stomatognathic function and craniofacial morphology. Most studies investigated the trajectories of incisal or condylar points and measured temporomandibular morphology projected onto 2-dimensional radiographic films. Although these methods provided valuable information, their diagnostic capabilities were limited. We introduce a new 4-dimensional (4D) analysis of stomatognathic function that combines the 3-dimensional (3D) computed tomography of the cranium and mandible, dental surface imaging with a noncontact 3D laser scanner, and mandibular movement data recorded with a 6 degrees of freedom jaw-movement analyzer. This method performs dynamic and precise simulations that can analyze and display condyle to fossa distances and occlusal contacts during mandibular function. These comprehensive relationships can be analyzed and displayed not only at intercuspal position, but also at any mandibular position during functional movements. We believe that our 4D analyzing system will be useful for diagnosing temporomandibular disorders of patients with jaw deformities and other malocclusions.