Mechanical Stresses at the Primate Skull Base Caused by the Temporomandibular Joint Force
The existence of a reaction force at the temporomandibular joint (TMJ) has been the subject of long debate. Among others, Gingerich (1971) and Roberts and Tattersall (1974) suggested the mammalian mandible to function not as a lever but as a link, so that the resultant forces produced by the masticatory muscles always pass through the bite point and in consequence the condyles are not loaded. In the meantime the existence of a reaction force at the TMJ has been convincingly proved by experiments and computations of the equilibrium of forces at the jaw (Crompton and Hiiemae, 1969; Hylander, 1975, 1979; Molitor, 1969; Pruim et al., 1980; Wolff, this volume). In a very recent experimental approach Brehnan et al. (1981) have directly measured the loads at the TMJ. They implanted a pressure sensitive foil at the head of the condyle of a stump-tailed macaque and recorded loads during molar chewing and incisal biting. Although they unfortunately did not distinguish between biting side and balancing side, it is very probable that the joint forces are higher on the balancing side than on the biting side (Hylander, 1975; Smith, 1978; Walker, 1978; Wolff, this volume).
KeywordsReaction Force Skull Base Temporomandibular Joint Joint Force Polarize Filter
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