Factors Related to the Number of Existing Teeth among Korean Adults Aged 55-79 Years.

This study aimed to determine the association between the number of existing teeth (NET) and socioeconomic status (SES), oral health-related behaviours, and metabolic syndrome in Korean adults aged 55-79 years. The study included 3255 adults who underwent oral health examinations and answered questionnaires regarding SES, oral health-related behaviours, and metabolic diseases in the Sixth Korea National Health and Nutrition Examination Survey (2013-2015). The dependent variable was the binary status based on the median NET in each age group. The independent variables were based on SES, oral health-related behaviours, and the presence of metabolic syndrome. The study findings showed that the factors associated with the NET were sex, household income, education level, region of residence, daily toothbrushing frequency, dental visit within 1 year, smoking, and metabolic syndrome. NET was lower in males (adjusted OR: 0.74), in low household income group (adjusted OR: 0.77), in primary school graduates (adjusted OR: 0.53), in rural residents (adjusted OR: 0.78), and in medicaid beneficiaries (adjusted OR: 0.78). The interventions aimed at preserving existing teeth in elderly population should consider their SES, oral health-related behaviours, and metabolic syndrome and overhauling current oral healthcare system and redefining the roles of oral health professionals.

Salivary bisphenol A levels and their association with composite resin restoration.

Composite resin has been increasingly used in an effort to remove minimal amount of tooth structure and are used for restoring not just carious cavities but also cervical abrasion. To synthesize composite resin, bisphenol A (BPA) is used. The aim of the study was to measure the changes in salivary BPA level related with composite resin restoration. ELISA was used to examine the BPA levels in the saliva collected from 30 volunteers whose teeth were filled with composite resin. Salivary samples were collected immediately before filling and 5 min and 7 d after filling. Wilcoxon signed-ranks test and linear regression were performed to test the significant differences of the changes in BPA levels in saliva. Before a new composite resin filling, there was no significant difference between with and without existing filling of composite resin and BPA level in the saliva was not correlated to the number of filled surfaces with composite resin. However, BPA level in the saliva increased to average 3.64 µg/L from average 0.15 µg/L after filling 5 min. BPA level increased in proportion with the number of filled surfaces. BPA level decreased to average 0.59 after filling 7 d. However it was higher than the BPA level before a new composite resin filling. Considering 50 µg/kg/day as the Tolerable Daily Intake of BPA suggested by European Food Safety Authority, the amount of BPA eluted in saliva after the composite resin filling is considered a safe level that is not a hazard to health at all.