A new method for three-dimensional reconstruction and animation of the temporomandibular joint

The aim of this project was to develop a new method for the three-dimensional reconstruction and animation of the temporomandibular joint (TMJ). Magnetic resonance (MR) tomograms of the TMJ were combined, using an extraorally placed reference system, with jaw motion data, recorded with six degrees of freedom, by means of the opto-electronic tracking system Jaws-3D. The three-dimensional reconstruction of the TMJ was calculated and animated on a graphics workstation by means of kinematic transformations. A subject without any past or present history of myoarthropathies of the masticatory system, performed jaw opening and closing and chewed chewing gum. The animation provided a three-dimensional visualisation of the movements of the entire condyle within the fossa. The condyle-fossa distance was computed for every condylar point and represented by shading the surface of the condyle with pseudo-colours. The position of the minimum distance between condyle and fossa was calculated and displayed in a plane graph representing the condylar surface.