Salivary biomarkers for predicting the progression of chronic periodontitis

Objective Predicting the progression of periodontitis would allow for targeted supportive periodontal therapy. The purpose of this study was to determine the usefulness of salivary biomarkers for predicting the progression of periodontitis. Design Eighty-five chronic periodontitis patients were enrolled in an 18-month longitudinal study. Amongst them, 57 experienced progression of periodontitis, indicated at the end of the 18 months by at least one site with >3 mm loss of attachment compared with baseline. We determined the levels of aspartate aminotransferase, alanine aminotransferase (ALT), lactate dehydrogenase, alkaline phosphatase and free haemoglobin as biomarkers, as well as the counts of Porphyromonas gingivalis, Prevotella intermedia and Tannerella forsythia, which represented the periodontal bacteria, in the stimulated saliva. The Mann–Whitney U test was used to compare patients with and without progression. After categorising the diagnostic values, the chi-square test was applied. Results Counts and ratios (ratio to total bacteria) of P. gingivalis and P. intermedia were found to be significant predictors of the progression of periodontitis. To increase prediction accuracy, combination analyses were performed. The combination of ALT level and the P. gingivalis ratio showed the highest likelihood (p < 0.001, sensitivity 0.40, specificity 0.96, likelihood 11.30). Conclusion Our findings suggest that salivary ALT level and the P. gingivalis ratio may be potential indicators for the progression of periodontitis. Such a salivary test could be a useful diagnostic tool for predicting periodontal disease progression.