Abstract
A novel system for measuring nocturnal mandibular movements using a PIN photodiode sensor was devised in combination with EMG. The sensing portion of the sensor is divided into four parts, and two axis positions of LED faced to the sensing surface can be detected.
When the LED was moved on the X-Y stage with a micrometer gauge, linearity was kept in the relationship between the output voltage and amount of the movement. The maximum error in the central area of the sensor was about 91 micrometers and that in the peripheral area was about 241 micrometers. Metal splints fitting with the labial surfaces of upper and lower incisors were fabricated to fix the LED and the sensor respectively, and mandibular movements of the frontal view can be measured two-dimensionally in the area around the intercuspal position.
This system was found to be quite useful for measuring not only positions of the mandible but also movement patterns like grinding: these patterns could not be detected accurately by conventional systems.
