Abstract
Elderly people with less than ten missing teeth can masticate any food as well as younger people.
We found that the average number of missing teeth per persons increases in a sigmoid curve with age using the “Report on the survey of dental diseases (1987, Japan) ”.
Next we determined the theoretical average number of missing teeth per person by sex and age by means of cubic logit-log polynomial regression analysis.
To achieve less than ten missing teeth at the age of eighty, we estimate the intermediate objective number of missing teeth at the intervals of five years for the people who begin their effort at the age of thirty or forty.
Because the report “To maintain twenty present teeth at the age of eighty” was published by Ministry of Health and Welfare Japan, intermediate objective of number of present teeth per persons to achieve this objective (less than eight missing teeth) was evaluated using our theoretical curve.
