Secular trends over 40 years of periodontal health and disease in individuals aged 20-80 years in Jönköping, Sweden: Repeated cross-sectional studies.

The periodontal health has improved in the population over the 40 years. The number of teeth increased significantly in the population, and in 2013, this increase occurred entirely in the severe group. Finally, there was a trend toward diminished prevalence of severe periodontitis.