[A comparative study on the responses of blood vessels of oral mucosa to thermal stimulation in dentulous and edentulous subjects].

The purpose of this experiment was to clarify the characteristic changes of vasculature in edentulous alveolar mucosa and the effect of wearing a complete denture during sleep. Thermal stimulations were applied to the oral mucosa of five normal subjects and five completely edentulous patients and the responses of blood vessels were observed using both Impedance Plethysmography (IMP) and Reflection Photoelectric Plethysmography (RPP). Quantitative comparisons were made between edentulous patients and dentulous normal subjects, and between patients wearing complete dentures during sleep and those who do not. The following results were obtained. 1) The responses of blood vessels were divided into four groups. Type 1 showed dilatation in IMP and RPP. Type 2 showed dilatation but had late initial rising in IMP. Type 3 showed initial contraction in either or both IMP and RPP, and followed by dilatation few seconds later. Type 4 showed no changes in RPP but dilatation in IMP. 2) There was definite difference between edentulous and dentulous subjects in the frequency of exhibition of each type. Especially for the edentulous patients type 4 was observed in all stimulation temperature. 3) For the dentulous subjects there were more cases showing responses of RPP in digital apex than those do not. This was most conspicuous at the 50 degrees C stimulation. However for the edentulous patients there were about equal number of each cases. 4) The responses of blood vessels for both dentulous and edentulous subjects became greater and blood volume increased both with time at each temperature and as the stimulation temperature were raised. However the increase in the response was greater for the edentulous patients when the stimulation temperature was raised from 0 degrees C to 50 degrees C. 5) The responses of blood vessels became greater after two weeks when complete dentures were worn during sleep at night. And when dentures were not worn during sleep the responses decreased to a level lower than what it used to be after three weeks. 6) From the above results it was suggested that oral mucosa of the edentulous patients were losing their sensitivity due to wearing complete dentures and were not receiving as much effect of the contractile control from body as the dentulous subjects. It was also suggested that wearing denture during sleep at night cause inflammation of oral mucosa and increase the metabolism of tissue in edentulous patients.