Journal of Craniomandibular Function, 04/2009

Allostasis is defined as a set of adaptive processes that protect the body by responding to internal and external stress through the autonomic nervous system (ANS), the hypothalamic-pituitary-adrenal (HPA) axis, and the immune system. Allostatic load refers to the price the body pays for being forced to adapt to adverse psychosocial or physical situations, and it represents either the presence of too much allostasis or the inefficient operation of the allostasis response systems. Evidence has accumulated that masticatory activity, which includes bruxism, plays an important role in attenuating stress-induced psychosomatic disorders through downregulating the limbic system. In this field of study, two concepts play a central role: the concept of a centrally regulated feedback control system and the concept of the stress-bruxism axis. The role of the masticatory organ as a stress release valve must be recognized as the most important component of occlusion medicine. Keywords: Allostasis, allostatic load, homeostasis, masticatory organ

To date, it has not been clearly proven whether there is a direct correlation or no interaction at all between craniomandibular dysfunctions (CMD) and changes in head posture. It was the aim of the present paper to determine whether such a correlation has been described in the literature and whether a particular diagnosis of CMD (primarily arthrogenic, primarily myogenic or mixed forms) shows a significant correlation with changes in head posture. Another objective was to assess the measuring instruments used and in particular to investigate whether the studies specified any quality criteria for measuring instruments (reliability, objectivity, validity). A systematic literature review has been conducted on this basis, yielding 30 studies relevant to the topic, of which 26 were primary studies and four were secondary studies. The evaluation showed that the majority of papers observed a correlation between CMD and changes in head posture. They also found that a mixed diagnosis of CMD, ie, a combination of arthrogenic and myogenic CMD is commonly associated with this change. As there was no adequate information regarding the quality criteria of the measuring instruments used, no ideal measuring instrument could be determined. Currently, the most useful and scientifically substantiated results can be achieved with a combination of cephalometric analyses, inspections, and measurements complemented by clinical tests. More methodologically sound studies would be desirable to prove existing trends and to generate ideal measuring instruments. Keywords: CMD, head position, head posture, measuring instruments

A great variety of splints have been described in the literature but often their effectiveness and mechanisms of action are as yet unclear. The aim of the present paper was therefore to collect and evaluate studies published between 2005 and 2008, in which the effectiveness of different types of occlusal splint therapy for craniomandibular dysfunctions (CMD) was investigated. The literature review was based on the following databases: PubMed, Cochrane Library, and zm-online. A total of six studies were found that matched the search criteria for the effectiveness of occlusal splints for the treatment of CMD. Several studies assumed that it is rarely possible to demonstrate any effects that are attributable to a particular type of splint. In fact, the treatment success is influenced by many factors such as time, patient instruction, the clinician's skills, and a correct diagnosis. Keywords: centric splint, craniomandibular dysfunction, effectiveness, splint, temporomandibular disorders