The occlusal theory further complicated

This paper reviews the critique presented against the occlusal theory of the temporomandibular disorders (TMD) and presents a new hypothesis. Although no empirical evidence has been found to refute the role of occlusion in the etiology of TMD, we argue that the occlusal theory in its present form is biased in that it is based on the findings in adults and assumes that the causal chain proceeds from structure to function. However, the close developmental relationship between function and structure and the recent changes in the functional environment of the stomatognathic organ indicate that the causal influences take place in both directions. We suggest that the occlusal theory should be reformulated in such a way that it includes mutual interactions between function and structure during growth. We assume that the structural adaptations taking place in the growing child in response to functional stimuli may play an important role in the etiology of TMD. Testing of our hypothesis requires longitudinal studies which focus on both functional and structural development.