Direct measurement of loads at the temporomandibular joint in Macaca arctoides.

This paper describes a novel technique of directly measuring loads at the condyle in Macaca arctoides and provides recordings on one animal while measuring loads at the TMJ. This study is the first to actually measure loads directly at the articulating surfaces of the condyle. The data collected in this study confirm Hylander's data that the TMJ is a stress-bearing joint. With this pilot study, observations which can be made are: 1) The loads at the condyle are minimal during posterior chewing of both soft and hard foods (1-3 lb), and 2) during mastication of food the load (3-4 lb) at the condyle is larger than for posterior chewing. It was demonstrated during the calibration of the transducer that as the condyle translates forward over the articulating eminence during opening, a load is produced on it which is as large as the load present during incisal biting. Since recordings were only successfully taken on one animal, the above observations must be confirmed with further experiments.