Quantitative analysis of tempo~ornandibula~ joint adaptations to protmsive function

M uch has been published in the clinical and basic science literature on the growth of the temporomandibular joint. An area of significant controversy is the question of whether the growth of the temporomandibular joint, and of the mandibular condyle in particular, can be influenced to any significant degree through therapeutic or experimental intervention. Despite the number of clinical and experimental studies of this question, no universal agreement has been reached regarding the potential for adaptation in response to an alteration of the structural or functional environment by means of growth and/or remodeling of the temporomandibular joint. Part of the reason for this lack of agreement stems from the fact that competing dogmas exist concerning the growth and adaptability of the temporomandibular joint. A precise definition of the mechanisms by which condylar growth takes place also has been hindered, in many cases, by inadequate clinical and experimental samples and by incomparability of treatment plan or experimental design. Numerous persons have undertaken experimental investigations of temporomandibular joint growth in animal models. An evaluation of the findings from these studies reveals that the age or developmental stage of the animals used in these experiments is a critical factor in determining the potential for temporomandibular joint adaptability. There is little experimental evidence demonstrating that any significant adaptations can occur in the adult temporomandibular joint,13, 16, li, 34 and pathologic changes have been reported to occur in some instances. 6 In contrast, other studies have shown that the temporomandibular joint region, particularly the mandibular condyle of young, growing animals, can be a primary site of craniofacial adaptation to altered occlusal function.‘, 2. s, *L 28-33, 35 We lhave experimentally studied temporomandibular joint adaptability to alteration of the biomechanical environment, using the rhesus monkey (Macaca mulatta) as our animal