Relationships among clinical measures of periodontal disease and their associations with systemic markers.

BACKGROUND: Recent investigations of the relationship between periodontitis and systemic disease require that periodontal disease also must be thought of as a disease process that is an exposure for a systemic disease or condition (outcome), rather than as the outcome itself. When viewing periodontal disease as an exposure, investigators must consider the clinical, microbiological, and inflammatory components of periodontitis that potentially convey risk for the systemic outcome of interest, which may or may not be the same as those associated with the assessments used to define tooth-based disease. Another important consideration is the temporal relationship between the exposure and the outcome of interest.
METHODS: To explore which definitions of periodontal disease or clustering of clinical signs are important with regards to systemic exposure to inflammatory stress, we examined the relationship between clinical periodontal disease measures and 2 systemic inflammatory markers of increased risk for cardiovascular disease: serum soluble intercellular adhesion molecule (sICAM), which is a measure of vascular stress and serum C-reactive protein (CRP), which is a measure of hepatic acute-phase response. The Dental Arteriosclerosis Risk in Communities (ARIC) study, a cross-sectional study of the relationship between periodontal disease and cardiovascular disease, forms the basis for the examples used in this investigation.
RESULTS: Our findings demonstrated that while attachment loss, probing depth, (PD) and bleeding on probing (BOP) are individually associated with sICAM and CRP, only BOP remains significant for sICAM when all 3 are in the model and, for CRP, only PD remains significant. Both of these clinical parameters were more robust in estimating the degree of systemic inflammation than traditional classifications of mild, moderate, and severe periodontitis or other measures of disease severity such as attachment loss.
CONCLUSIONS: When selecting a definition of "systemic periodontitis" (periodontal disease that represents an exposure for a systemic condition), it is helpful to think of periodontal disease as a chronic oral infection with a number of clinical signs, rather than as the dento-centrically defined entity, periodontal disease. Thus, "systemic periodontitis" should be defined predicated upon those clinical signs that best represent the underlying mechanisms and temporal sequence that may affect that systemic outcome.