Application of the linear regression line to the oral health status of various groups

Abstract

We determined a method of evaluating the oral health status of various age groups in Japan. We attempted to analyze the relation between dental caries (DMFT) and age in two age groups (5 to 15 years and over 20 years). The basic data were obtained from the Report on the Survey of Dental Diseases for the years 1957 to 1999. For the 5 to 15 year age group the slope of the linear regression line increased during 24 years between 1957 and 1981, but then decreased for the next 18 years from 1981 to 1999. These results indicated caries increased during the first period but then decreased after that for the 5 to 15 year age group. For those over 20 years, the slope and y-intercept of the linear line increased from 1957 to 1999. The slope and Y-intercept of the linear regression line relating DMFT and age could be used to evaluate changes in caries experience in an age group. We concluded that the oral health status of a group could be evaluated by the slope and Y-intercept data of the linear regression line relating DMFT and age.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 270-278.