INVIVO STRAIN-GAUGE ANALYSIS OF THE SQUAMOSAL-DENTARY JOINT REACTION FORCE DURING MASTICATION AND INCISAL BITING IN MACACA-MULATTA AND MACACA-FASCICULARIS

Rectangular rosette or single-element strain gauges were bonded to surgically-exposed mandibular cortical bone in the region immediately below the temporo-mandibular ligament in adult and sub-adult macaques. After recovery from the general anaesthetic, bone strain was recorded during incision and mastication of apples. The bone strain data demonstrate that the joint is loaded to varying degrees depending on the position of the bite point. Bone strain values were larger on the contralateral side than on the ipsilateral during mastication, demonstrating that the net compressive reaction force along the contralateral joint probably exceeds the net compressive reaction force along the ipsilateral one during these periods. The largest bone strain values were recorded during apple incision, demonstrating that the joint is also loaded during incisal biting. © 1979.