Patterns of tooth loss in young Hong Kong adults: a preliminary study based on Prince Philip Dental Hospital patients in 1984, 1998 and 2004

Abstract

Objective. To describe the change in the patterns of tooth loss among 21- to 25-year-old Hong Kong dental patients over the 20-year period from 1984 to 2004 inclusive. Materials and methods. The first panoramic radiographs of all young adult patients who registered at the Prince Philip Dental Hospital of Hong Kong in 1984, 1998 and 2004 were viewed and the presence of teeth by tooth type in each patient was recorded. Results. The proportions with a full dentition (32 teeth including the third molars) were 38.4% in 1984, 46.7% in 1998 and 48.2% in 2004; the mean numbers of teeth present were 30.5, 30.8 and 30.7, respectively. The change between 1984 and 2004 is significant (χ2=5.57, df=1, P<0.05), but the change between 1998 and 2004 is not (χ2=0.16, df=1, P=0.69). Differences in the proportions of teeth missing among 1984, 1998 and 2004 subjects were statistically significant (χ2 test, df=2, P<0.05) for all tooth types. The tooth missing rates have decreased over the years for all tooth types, except premolars and third molars, the missing rate of which has increased. A major portion of these changes occurred during the period between 1984 and 1998. The missing rate in upper premolars was higher for females than males in 1984, 1998 and 2004; the differences being statistically significant between 1998 and 2004. Conclusions. Significant changes in the pattern of tooth loss in the young adult patients seen at the dental hospital between 1984 and 2004 have been detected. There has been a reduction in tooth loss generally for all tooth types, except the premolars.