Abstract
Temporomandibular joint(TMJ)disorders accompanied by disk displacements and/or disk perforations have been considered to be the result of excessive TMJ loading.However, the precise values for loads acting on TMJ during mastication have not been measured.In this study, a micro pressure-sensor(3mmφ)composed of biocompatible HAP(hydroxyapatite)-piezoelectric PZT(Lead Zirconate Titanate)laminated ceramics was designed and then fabricated to measure directly the load acting on the local surface area of the condylar head of monkey during mastication.First, the pressure-sensor was calibrated under the cyclic loading conditions.The results of a calibration test showed a linear relationship(r=0.9981)between the integrated output of the sensor and the load up to 19.6N.Subsequently, the pressure-sensors were implanted into the anterior and superior surface of the condylar heads of monkeys, and then the loads acting on the sensors were recorded during the mastication of hard foods.The maximum load of 2.05N, 0.42N, and 0.18N was measured at the maximum opening of mandible, during chewing movement, and during grinding movement, respectively.Assuming that the load was distributed uniformly on the sensor, these maximum loads could be converted into the maximum pressure of 0.29MPa, 0.07MPa, and 0.03MPa, respectively.
