The declining trend in the prevalence of manifest caries seems to be broken. In the oldest age group mean number of DS was higher in 2013 compared with 2008, indicating a possible beginning of an increase. This needs special attention as this group increases in the population, retaining natural teeth high up in age. Manifest caries was found to be associated with socio-economic and socio-behavioural factors.

ObjectiveEpidemiological 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.MethodsFour 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.ResultsThe 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.ConclusionModerate ABL and calculus visible on radiographs significantly increased between 2008 and 2013. Smoking was the strongest factor associated with ABL overall.