Methods: Logistic regression analysis was performed to assess associations between clinical diagnosis, IL6 genetic factors and presence of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis (assessed by PCR) in subgingival biofilms of a group of 142 patients diagnosed with severe forms of periodontitis (CP n=115, AgP n=27).
Results: A. actinomycetemcomitans was detected in 45.7% and 48% of CP and AgP subjects respectively. The corresponding figures for P. gingivalis were 80.2% and 68.0%. IL6 -6106 AA genotype was associated with detection of A. actinomycetemcomitans (p=0.009, O.R. = 3.5, 95% C.I. = 1.38- 9.16). IL6 -6106 AA and IL6 -174 GG were also associated with concomitant detection of A. actinomycetemcomitans and P. gingivalis (p=0.015, O.R. = 3.6, 95% C.I. = 1.28-10.04 and p=0.042, O.R. = 2.8, 95% C.I. = 1.04-7.75 respectively).
Conclusions: In this subject sample, genetic factors were more predictive of the presence of periodontopathogenic bacteria than clinical diagnosis.