Serum IgG titers to selected periodontal species, combined with demographic and behavioral characteristics, resulted in a moderately accurate classification of periodontal status in epidemiologic studies. The external validity of these findings must be examined further.

Demographic, behavioural, and oral- and general health-related characteristics were strong determinants of systemic antibody responses to periodontal bacteria in a nationally representative sample of US adults.

A distinction between the two principal categories of the current periodontitis classification cannot be established by the study of infection patterns.