Evaluation of salivary cortisol levels in relation to dento-maxillary prosthesis adjustment

The purpose of this study was to investigate the influence of dento-maxillary prosthesis adjustment procedure on levels of salivary cortisol. Nine participants (six men, three women, mean age 65.9 years) took part in this study. Saliva samples were collected before and after dento-maxillary prosthesis adjustment during the four different visits. Free cortisol levels were determined using a salivary cortisol immunoassay kit (expanded-range high-sensitivity salivary cortisol enzyme immunoassay kit, Salimetrics). Besides, original self-report sheets, a 35-item food intake questionnaire, the University of Washington Quality of Life (UW-QOL) questionnaire version 4, and the Geriatric Oral Health Assessment Index (GOHAI) questionnaire were also administered. The changes of salivary cortisol levels were analyzed using 2-level multilevel linear regression, with adjustment for age, sex, and time. Wilcoxon signed-rank test was used to compare scores of the food intake questionnaire, UW-QOL questionnaire, and GOHAI questionnaire. Salivary cortisol levels decreased significantly after carrying out the dento-maxillary prosthesis adjustment procedure. During the third adjustment, the salivary cortisol levels were significantly low. In addition, salivary cortisol levels of participants aged 70 years and over were significantly higher than other aged groups. The total scores for grade III–V of the food intake questionnaire increased significantly. Other questionnaires had a trend toward increasing scores, yet the differences were not significant. Within the limitations of this study, the results suggest that a reduction in symptoms of discomfort may have an influence on the decrease of salivary cortisol levels in dento-maxillary prosthesis wearers.