How to Increase Number of Present Teeth in Elderly: Consideration of Percentile Curves for Present Teeth in Tokyo.

Maintaining dental and oral health and increasing healthy life expectancy are important issues for Japan as it deals with the rapid aging of its population. The purpose of this study was to determine effective dental health measures aimed at increasing the number of present teeth in the elderly. Change in the number of present teeth was determined based on data obtained from the 2009 and 2014 "Good Teeth Tokyo (Ii-ha Tokyo)" surveys carried out by the Tokyo Metropolitan Government.

Atmospheric polycyclic aromatic hydrocarbons: size distribution, estimation of their risk and their depositions to the human respiratory tract.

Polycyclic aromatic hydrocarbons (PAHs) in the atmosphere may be one of the causes of lung cancer. However, in many countries including Japan, only benzo[a]pyrene is regulated, though more toxic PAHs than benzo[a]pyrene have been reported. Therefore, it is necessary to characterize the risk of atmospheric PAHs and to find major contributing compounds that can act as suitable indicators for estimating and monitoring the risk of PAHs as a whole.