Correlation between health-care costs and salivary tests.

The burden of health-care costs relative to gross domestic product in Japan is increasing. A large percentage (7.6% in 2009) of the Japanese gross domestic product has been spent on health care, and this percentage has been increasing annually. Soaring health-care costs have been recognised as a serious social problem. In this study, we attempted to estimate the relationship between periodontal disease and health-care costs. Subjects consisted of teachers and staff members (35 men, 26 women; mean age, 45 ± 9 years) from two high schools. The salivary levels of lactate dehydrogenase and haemoglobin were adopted as biomarkers to assess periodontal disease. After salivary tests, data for the health-care costs over the subsequent 6 months were provided by the mutual association of the public schools on an individual basis. Curve-fit estimations were then performed where health-care costs were used as a dependent variable and age or salivary levels of haemoglobin or lactate dehydrogenase were used as independent variables. However, no good fitness was obtained. Subsequently, multilayer perceptron neural networks were applied. With the neural networks, good fitness was obtained by using lactate dehydrogenase as an independent variable. The results of this study show that oral health, particularly periodontal disease, is correlated with total health-care costs. The data presented in this study suggests that, from the perspective of both oral and systemic health, oral health can be a signpost in well-being and health promotion.

Comparison of salivary hemoglobin measurements for periodontitis screening.

Salivary hemoglobin (Hb) for screening of periodontitis is approved under the pharmaceutical affairs law of Japan. Two reagents are commercially available for the modified fecal occult blood test: Saliva Hemo Plus and OC-AUTO S Latex Reagent. We simultaneously measured split specimens from 561 samples by using these two methods and compared the differences and agreement between both methods. Moreover, saliva samples were collected from 10 subjects at five time points during the day for analysis of circadian variations and fluctuation. The Pearson's correlation coefficient for these two reagents was 0.794. The Bland-Altman plot of differences in salivary Hb levels measured by the two reagents indicated that the difference included fixed errors (0.55 µg/mL). On analysis of circadian variations, no statistically significant differences were observed using the Friedman test. However, fixed errors were observed between wake-up time and before dinner and before lunch and before dinner, and no random errors were observed by Bland-Altman analysis. In conclusion, the salivary Hb levels measured using OC-AUTO S Latex Reagent were lower than those measured using Saliva Hemo Plus, along with a tendency for higher levels in the morning. Thus, when performing salivary tests these observations must be considered.