OBJECTIVE: Epidemiological studies of the prevalence of periodontitis over an extended time using the same methodology to investigate and classify periodontitis are sparse in the literature. Smoking and socio-economic factors have been proven to increase the risk for periodontal disease. The objective of this study was to investigate 30-year time trends, using the same methodology to classify the prevalence and severity in alveolar bone loss (ABL) and to investigate the influence of tobacco and socio-economic factors.

METHODS: Four cross-sectional epidemiological studies in an adult population were performed in the county of Dalarna, Sweden, in 1983, 2003, 2008 and 2013. Random samples of 787-1133 individuals aged 35-85 who answered a questionnaire about tobacco use and socio-economic factors were radiographically and clinically examined. A number of teeth, ABL and calculus visible on radiographs were registered. The severity of ABL as detected on radiographs was classified into no bone loss, moderate or severe.

RESULTS: The prevalence of moderate ABL decreased from 45% in 1983 to 16% in 2008, but increased to 33% in 2013 (P < 0.05). The prevalence of severe ABL remained the same from 1983 (7%) to 2013 (6%). Calculus visible on radiographs increased from 22% in 2008 to 32% in 2013 (P < 0.05). Socio-economic factors had limited impact on the severity of ABL.

CONCLUSION: Moderate ABL and calculus visible on radiographs significantly increased between 2008 and 2013. Smoking was the strongest factor associated with ABL overall.