Methods: 15 male patients treated 28 - 35 years ago with a partial bite-raising splint, the Dahl appliance, were evaluated through new cephalometric tracings. Mean age was 64,1 years (range 53 – 82) at the end of observation time. The test group was also compared to a control group consisting of 37 patients that had cephalometric x-rays taken over a period of 20 – 23 years.
Results: Measured from start of the original study to the present day observation most patients had reverted to their original face height. Anterior face height and occlusal face height decreased significantly in the test group (p=0.006 and p<0.001 respectively). Posterior face height increased in both groups, but significantly more in the control group (p=0.004). An increase in the interincisal angle was seen in 9 of 15 cases.
Conclusions: An increase in the occlusal face height by eruption of the posterior teeth and intrusion the front teeth in adults, will lead to a relapse over time. As the dentoalveolar structures are an integral part of the craniofacial structure and changes to it will have widespread effects on overall facial morphology. There is, however, no data that implies that a clinical intervention using the Dahl concept is harmful to patients. The present study reveals that patients that undergo treatment of this type show significantly different growth adaptations in several cephalometric parameters over a thirty-year study period.