Validation of an algorithm for chronic periodontitis risk assessment and prognostication: analysis of an inflammatory reactivity test and selected risk predictors.

Background: Patients with severe forms of chronic periodontitis present with varying degrees of decreased inflammatory reactivity. A previously reported algorithm for chronic periodontitis risk assessment and prognostication is based on the analysis of some 20 risk predictors. One of these predictors is a skin provocation test that assesses the individual patient's reactivity to a lipid A challenge. The aim of this report was to analyze results from validation data for the algorithm with respect to the contribution of results of the skin provocation test as a risk predictor for the progression of chronic periodontitis and to compare these results with the contribution from other predictors, namely smoking, angular bony destruction, furcation involvement, abutment teeth, and endodontic pathology. Methods: Data from a previously reported clinical validation sample were used for the analysis, including the calculation of quality measures and explanatory values using different types of regression analysis and non-parametric testing. Results: Smoking, endodontic pathology, abutment teeth, angular bony destruction, and furcation involvement presented with individual explanatory values for periodontitis progression between 4% and 13% and highly significant parameter estimates. Explanatory values for the results of the skin provocation test ranged between 2.6% and 5.1% depending on the disease severity group, with a positive predictive value of 82% for the identification of high-risk patients. Conclusion: The skin provocation test provided a clinically significant contribution to the quality of analysis with the periodontitis risk and prognostication algorithm, in particular in the selection of high-risk patients for in-depth individual tooth analysis. J Periodontol 2010;81:837-847.