Risk for periodontal disease in a Swedish adult population. Cross-sectional and longitudinal studies over two decades

Sammanfattning: The overall aim of this thesis was to describe changes in the prevalence and severity of periodontal diseases and to identify risk factors for severe periodontal disease in adults living in Jönköping County, Sweden, by analysing the cross-sectional, epidemiological studies that had been carried out in the city of Jönköping in 1973, 1983, and 1993. Individuals were randomly selected from the following age groups: 20, 30, 40, 50, 60, and 70 years. The number of dentate subjects was 537 in 1973, 550 in 1983, and 552 in 1993. The cross-sectional study in 1993 was expanded to include an additional 1192 dentate individuals from the rest of the county. A longitudinal follow-up was also performed based on a re-examination in 1988-91 of 361 of the individuals examined in 1973. The main findings were as follows: Oral hygiene among 20-year-olds had deteriorated in 1993 compared with the 1983 results and the prevalence of gingivitis in this age group reverted to levels similar to those in 1973. The largest increase in mean number of teeth was found among the 70-year-olds who had an average of five more teeth per subject in 1993 than in 1973. Similar findings regarding tooth loss and levels of alveolar bone could be seen in individuals living in the city of Jönköping and in the rest of the county. The prevalence of individuals diagnosed with severe periodontal disease experience (13%) was unchanged between 1983 and 1993. These subjects had, on the average, two-four more teeth in 1993 than in 1983. Higher levels of supragingival plaque were significantly associated with severe periodontal disease/disease progression. A mean plaque level of <20% at baseline was identified as compatible with minimal loss of alveolar bone. Smoking was the most important explanatory variable for severe periodontal disease/disease progression. Moderate-heavy smoking (=>10 cigarettes/day) was strongly correlated with severe periodontal disease, but no association was found for light smoking (1-9 cigarettes/day). Female gender was found to be correlated with severe periodontal disease progression. The potential risk factors identified in the cross-sectional study were similar to the risk factors identified in the longitudinal study.