The correlation between brain function activity and the occlusal contact area according to Eichner’s Classification is shown in Fig. 14. A positive correlation coefficient between the brain function activity and occlusal contact area was noted, but no correlation was recognized in each Eichner’s Classification.

The correlation between the brain function activity and occlusal force according to Eichner’s Classification is shown in Fig. 15. A positive correlation coefficient between the brain function activity and occlusal force was shown excluding Eichner’s Classification B-3, but no correlation Alpelisib cell line was shown in each Eichner’s Classification. A positive correlation coefficient between the brain function activity and comfort during chewing was shown only for B-3, but no correlation was shown in all classification. TSA HDAC A positive correlation

coefficient between brain function activity and the degree of satisfaction was shown in B-1 and B-2, but no correlation was shown in all classifications. The brain function is activated through various stimulations. Kodama et al. [48] reported that brain function was activated by music therapy, cooking, and craftwork. In this study, it was possible that the brain function of the subject was activated through conversation and treatment by the doctor. Therefore, in the preliminary examination, we confirmed that the brain function activity was not influenced by conversation and treatment by the doctor, by wearing and removing dentures, by visual stimulation, and by time through measuring brain function activity in a resting state. Furthermore, Temsirolimus when the measurement of the brain function activity was performed twice on the same day, the activity could have been influenced by the measurement order. So, brain

function activity was evaluated on changing the measurement order for gum chewing with and without dentures. As a result, brain function activity was barely influenced by the measurement order. In this study, brain function activation in subjects with dentures was significant compared to that in those without dentures after gum chewing (p < 0.05). It was suggested that trigeminal nerve sensory information transmitted through the periodontal ligament, masticatory muscles, temporomandibular joint, and residual mucous membrane increased when subjects could chew comfortably with appropriate dentures [49]. Ikebe et al. [50] and [51] reported that satisfactory dentures enriched the oral function and health of elderly patients. Therefore, the increase in the occlusal contact area and occlusal force appear to be important factors related to brain function activity. Thus, denture treatment in edentulous and partially edentulous patients dose not only improve the masticatory function, but it also restores the appropriate mechanism for conveying sensory information to the trigeminal nerve and eventually activate brain function activity.