Quantitative real–time polymerase chain reaction versus culture: a comparison between two methods for the detection and quantification of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythensis in subgingival plaque samples. - Lau,L.; Sanz,M.; Herrera,D. (J Clin Periodontol, 2004)