The approach to the diagnosis and treatment of periodontal disease is changing. The disease has not changed, but dentistry's understanding of the pathogenesis and appreciation for the influence of host factors has improved. As a result, the approach to the management of the disease is evolving. This paper reviews some of the host risk factors that have been linked to an increased severity of periodontal disease and briefly highlights some of the evidence that has led to the current belief that periodontal disease may be a risk factor for adverse systemic health conditions.