A large number of epidemiological studies of the incidence of periodontal disease has now been published. For example, the search terms "periodontal epidemiology" currently yield over 50 meta-analyses in Pubmed. Without limiting the search results, over 5000 studies are available for these two terms.
As noted above, a fundamental problem with epidemiological studies is the lack of comparability because of different study designs or study types.
Even if the results of these studies are difficult to compare because the investigation methods often differ markedly, two important epidemiological studies may be cited by way of example.
A very well-known longitudinal study by Löe et al. dealt with the periodontal status of Tamil tea plantation workers in Sri Lanka over a 15-year period. At the start of the study, the participants were between 14 and 31 years old. The special feature of this study is that the participants had not previously taken part in any prevention program for avoiding and treating dental disease.
The original study states: "Thick plaque, abundant calculus and tooth discoloration were the rule. Practically all gingival regions were inflamed." It is noteworthy that the study participants did not develop caries but lost their teeth only on account of periodontitis.
Three groups were formed:
(Löe et al. 1986)
|Group, percentage of study participants
||Mean attachment loss at the age of 35 years
|Mean attachment loss at the age of 45 years
|Attachment loss per year
|Rapid progression (RP), 8 %
Start of tooth loss at 20 years, 12 teeth lost at 35 years
20 teeth lost at 40 years, total loss of the teeth at 45 years
|Moderate progression (MP), 81 %
Start of tooth loss at 30 years
7 teeth lost
|No progression (NP)
||< 1 mm
No tooth loss
|< 1 mm
In Germany, the most important study of oral health is the Deutsche Mundgesundheitsstudie [German oral health study].
The results of the fourth German oral health study show that periodontal diseases are widespread and have increased since 1997. 52.7 % of adults suffer from moderately severe (CPI grade 3) and 20.5 % from severe forms of periodontitis (CPI grade 4). Among seniors 48.0 % are affected by moderately severe and 39.8 % by severe disease.
Particular risk factors for severe forms of periodontitis proved to be a low educational level and smoking. Smokers with a low educational level had a 3.3-fold increased risk of developing severe periodontitis compared with the average for their age group. Severe forms of periodontitis are more frequent in men than in women (German Society for Dental, Oral and Maxillofacial Medicine)