The "sufficient cause" model framework applied to the periodontitis-systemic diseases link

The premise for the oral-systemic diseases relationship dates to the early 20th century with the introduction of the focal infection theory that posited that oral disease affects overall health and wellbeing. While the biological plausibility for the link has been supported by experimental animal models and observational studies in humans, findings from interventional studies in which periodontal therapy failed to alleviate systemic health outcomes have often been interpreted as evidence against periodontitis contribution to the etiology of systemic health conditions. One concept of causation assumes a one-to-one correspondence between cause and effect. Nevertheless, common chronic diseases to which periodontitis is associated have multifactorial etiologies. This commentary provides an overview of Rothman's "sufficient cause" model as a framework for consideration of the oral-systemic diseases link.