The invention is a new method for predicting when subjects having chronic periodontitis will fail or succeed conventional standard therapy. The method uses measures of the plaque cadaverine fraction with additional measurements including age, fraction of gingival margins that bleed on probing (BOP), and clinical attachment level (CAL in mm) to calculate discriminant function equations for calculating individual score sets. When CF is above 0.45 in periodontitis patients, it is predicted that most available therapies with which the periodontitis patient can be treated will fail, including a conventional standard treatment or an aggressive combined antibiotic/oral hygiene therapy.