Changes in head posture in craniomandibular dysfunctions (CMD) and the pertinent measuring instruments

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