Quantitative Analysis of Periodontal Pathogens Using Real-Time Polymerase Chain Reaction (PCR)

The quantitative polymerase chain reaction (qPCR) is a variant of PCR aimed to detect and quantify a targeted DNA molecule. This is made through the addition of probes labeled with fluorescent molecules that emit fluorescence within each amplification cycle, resulting in fluorescence values proportional to the amount of accumulated PCR product. This chapter presents the detailed procedures for quantification of different periodontal pathogens (Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Campylobacter rectus, Streptococcus oralis, and Fusobacterium spp.) using qPCR. It also includes the description of the most frequent problems encountered, how to solve them, and recommendations to minimize the risks for laboratory staff handling oral samples. In addition, a detailed protocol for multiplex qPCR to detect and quantify Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Tannerella forsythia is also included.