Bacterial markers vs. clinical markers to predict progression of chronic periodontitis: a 2-yr prospective observational study.

The aim of this study was to identify sites at risk for future progression, during 2 yr of maintenance, in patients with chronic periodontitis (CP), based on longitudinal clinical and microbiological monitoring. At baseline (2003), clinical and microbiological features were recorded in 50 patients with CP. Two microbial samples were obtained from each patient (one from a clinically healthy site and one from a periodontitis site) and these were analyzed using DNA-DNA hybridization involving 25 bacterial species. After non-surgical periodontal therapy, clinical and microbiological re-examinations were performed at the same or similar sites at 2 yr (2006) and 4 yr (2008) of maintenance. Plaque, bleeding on probing (BoP), and the number of sites with periodontitis (≥4 mm) and severe periodontitis (≥6 mm) all showed a significant decrease at 2 and 4 yr of maintenance after non-surgical intervention. Checkerboard analysis revealed that various bacteria with a high colonization score (≥3) corroborated the clinical findings of pathology at 2003, 2006, and 2008. Different clusters of bacteria, not just the 'red complex', were able to predict progression of chronic periodontitis during 2 yr of maintenance (2006-2008). Therefore, quantified bacterial markers (reflecting bacterial load) and the clinical markers BoP and periodontal probing depth show comparable prediction of future disease condition.