Studies within the past ten years have suggested an association between periodontal disease and the likelihood of delivering preterm, low-birthweight babies, developing cardiovascular disease, and having difficulty controlling blood sugar levels in people with diabetes. Some studies have also linked periodontal disease to respiratory infection in people with pulmonary problems.
It has been assumed that periodontal therapy would reduce the inflammatory response and thus atherosclerotic changes. A number of studies have demonstrated that treatment of periodontitis has lead to a significant reduction in the cardiovascular disease biomarkers and to improvement in endothelial function as assessed by measurement of the brachial artery during flow-mediated dilatation. However, in a systematic review and meta-analysis of studies investigating the effects of periodontal treatment on serum CRP levels, it was concluded that it is highly unlikely that CRP levels can be modulated by a single episode of non-surgical periodontal treatment in patients with severe periodontitis. Periodontal treatment seems to reduce systemic inflammation and endothelial dysfunction.
A number of studies have provided evidence that periodontal treatment aimed at maternal periodontal disease may reduce the likelihood of PLBW infants by up to 50% . The conflicting findings may be related to the variety in the ethnicity of the populations studied or the timing and type of the periodontal intervention. Overall, these interventional studies suggest that mechanical intervention in pregnant mothers with gingivitis or periodontitis can reduce the incidence of PLBW.
A number of studies were carried out to investigate the efficacy of a variety of periodontal interventions on diabetes mellitus. These studies were subjected to two meta-analyses. The primary outcome measure has been changes in levels of glycosylated haemoglobin (HbA1c). Results from both meta-analyses have indicated a decrease in HbA1c level, however, the reduction was more pronounced in Type II diabetes than Type I.
The evidence for the effect of periodontal therapy on bacterial pneumonia is promising. The 1996 study by DeRiso reported that the incidence of pneumonia was reduced by 60% with the use of pre and postoperative application of 0.12% chlorhexidine rinse in patients undergoing cardiac surgery. In another important study, Yoneyama and colleagues in 2002 investigated the role of supervised tooth brushing on the incidence of pneumonia in a group of elderly people living in nursing homes in Japan. There was a 39% reduction in pneumonia over a two year period compared to the control group. A recent review has shown that when the load of oral bacteria is reduced, the risk of pneumonia is also reduced . However, these findings are limited to special care populations.
The potential link between periodontitis and systemic conditions is now the focus for a wide range of research around the world. The potential for periodontal pathogens to gain access to the systemic circulation through ulcerated pocket walls is certainly present. Both in vitro and animal studies have clearly demonstrated the harmful effect of these pathogens on the cardiovascular, pregnancy, diabetes and some respiratory conditions. Moreover, inflammatory mediators commonly associated with periodontitis can also affect atheroma formation, pregnancy outcomes and insulin resistance. However, in order to show causality between periodontal disease and systemic condition, better designed large-scale longitudinal studies are required. In the meantime, a good oral health would be advocated among all patients with special emphasis on the additional systemic benefits for certain conditions such as coronary heart disease, Type II diabetes, bacterial pneumonia and pregnancy.
Dieter Deussen, DMD, PhD, MSc, MSc