A System of Measuring and Processing for Diagnosis of the Mandibular Movements

Analysing the mandibular movements is important in dentistry, as there are some problems in clinical application, this method has not been as popular as the EMG. The measuring equipment have so far included complex instruments to align the coordinates and have been difficult to operate. Furthermore, as is usual with biological information, it takes much time and effort to manage the measured data. For this reason, a non-invasive system has been developed for this purpose with a transducer composed of LEDs, and cemented to the upper and the lower incisor teeth, and a photo diode which senses the position (x, y) of the input light spot. This measuring equipment determines the lower jaw displacements relative to the upper jaw by electronic means ; it is, therefore, not necessary to provide instrumentation to fix the head. To estimate the accuracy of measurement, the errors resulting from the non-linearity of the sensor, the variation of the distance between LEDs and photo diode, from rotation, inclination and other movements of the subject's head are discussed. Our aim is the development of an examination system comprising a mini-computer, which analysis the masticatory system measured by our equipment and other devices for EMG and TMJ sound. The computer system for the processing of biological information is composed of a 64 kw CPU, a 16-channel, 12-bit A/D-converter, disk storage, graphic display, and other peripherals. It has capability to aquire a great amount of measured data and to store them on the disk at the same time. We have developed a software to process the measured data interactively and to display the movements as a function of time or in perspective using the 3 standard planes (frontal, sagittal, horizontal which could be partly magnified); velocity and acceleration of any component of themovements are also displayed. Furthermore, a section display that shows sectional diagrams of movements and a stereo display composed of a series of horizontal sections could be provided. Patient information such as name, age, sex, etc. and measured data relevant to the diagnosis will be selectively stored on a diskette (264 kB). Our system could be applied clinically for the analysis of mandibular movements and should be useful in the diagnosis of masticatory function for its ability to manage measured data conveniently