The effect of craniovertebral fusion on occlusion.

The purpose of this study was to compare the effect of head posture on occlusion in subjects with craniovertebral fusion to that in normal unfused subjects. The experimental group consisted of five subjects (age range 30-76) who have all undergone previous surgical fusion of the craniovertebral region. The control group consisted of five unfused subjects matched by age, race and gender. Each subject's tooth contacts were recorded with a computerized dental instrument known as the T-scan. The tooth contacts were measured several times for each subject with the head tilted backwards (45 degrees) and forwards (30 degrees). A modification of Wilcoxon's rank sum test was used to compare the location of the tooth contacts and compare any variations between the craniovertebral-fused subjects' occlusal contact patterns and those of the normal nonfused patients. The results indicated that four of the five fused subjects had occlusal contact patterns that differed from their matched counterparts, thus suggesting that fusion of the craniovertebral region interferes with a normal mechanism that permits changes in head posture to shift tooth contact points. These results suggest that those who manage problems related to occlusion (craniofacial pain syndromes) need to consider the influence of the craniovertebral region on both occlusion and jaw position.