Automatic reconstruction of the human temporomandibular joint axis movement using optoelectronic sensors

There is a new measurement method of computerized temporomandibular joint axiography presented in the paper. In the article there is presented the results of the movement analysis of the optoelectronic markers coupled with mandible and the transformation method of camera views into the trajectory of invisible temporomandibular joint parts, especially in localization of invisible rotation axis. The new approach consists in a use of optoelectronic markers mechanically coupled with human mandible and tracking them in 3D space with the camera system. The proposed method, in opposition to other methods used nowadays, radically decreases the weight of elements directly coupled with teeth and therefore ensures more natural function of the temporomandibular joint during an examination. The recording and analysis of subject head image and optoelectronic markers views during joint movements allow estimating many useful medical parameters, e.g. geometric dimensions of the jawbone, localization and trajectory of invisible rotation axis of the temporomandibular joint. Presented method is competitive to the computer axiography based on ultrasonic measurement of distance between sensors located on the object head. The proposed method can be used in developing of quite simple optoelectronic axiographs and will allow recognizing dysfunctions of temporomandibular joint in early illness phase. It will also allow to make the joint diagnostics more objective and to objectively control the therapy progress.