Personal risk factors for generalized periodontitis

Periodontitis is generally considered to be a consequence of an unfavourable host-parasite interaction in which bacteria are the determinants of disease. An intense search continues for the bacteria, specific or non-specific, that are responsible for periodontitis and various forms of the periodontal diseases have been associated with, and are widely believed to be caused by, specific bacterial groups. However, the distribution of periodontopathic bacteria is far wider than the distribution of periodontitis, indicating that the association between bacteria and periodontitis is weak. This paper proposes a paradigm for the etiology of generalized periodontitis in which 'host' factors are not only those triggered by bacteria (the agent) but are also those personal factors that influence the outcome of the host/parasite relationship. The personal factors that diminish the efficiency of host defense may include psycho-social stress from the social environment, factors from the lifestyle such as diet, smoking and alcoholism and systemic factors such as intercurrent disease or deficiencies within the immune/inflammatory system. A model is described in which the interaction of personal factors with the social environment provides the potential for the initiation of periodontitis. Biological variation is significant and the combination of factors that cause generalized periodontitis or any other chronic disease in one individual may not result in dental or any other chronic disease in another.