Quantitative Evaluation of Porphyromonas gingivalis in Indian Subjects With Chronic Periodontitis by Real-Time Polymerase Chain Reaction

Background and Aims: Porphyromonas gingivalis ( P. gingivalis) is considered as an important pathogen responsible for periodontal disease which is characterized by inflammation of gingiva and destruction of periodontal ligament and alveolar bone leading to loss of tooth. Along with clinical investigations, suitable microbiological analysis needs to be performed which could provide more insight into the disease severity. We aim to quantify P. gingivalis by real-time PCR (RT-PCR) and analyze its association with demographic data including clinical parameters. Materials and Methods: The study consisted of chronic periodontitis patients (CP group) and healthy subjects (H group) with 120 samples in each group. RT-PCR was carried out by the SYBR Green assay to target 16S ribosomal ribonucleic acid species-specific region of P. gingivalis. Standard strain of P. gingivalis ATCC 33277 was used as a control. Results: In the CP group, 79.16% samples were found positive for P. gingivalis, whereas 29.17% samples were positive in the H group. A significant difference was found when the prevalence was compared within males and females ( P < .001 for both). In the older age groups, we found a higher rate of detection of P. gingivalis. As analyzed by Spearman’s correlation test, the number of cells of P. gingivalis was significantly associated with probing depth ( P = .02) and clinical attachment level ( P = .01) in the CP group. The mean cell number of P. gingivalis was found to be increasing with increasing levels of probing depth and clinical attachment level ( P < .001 and P = .01, respectively). Conclusion: The present study reaffirms that the P. gingivalis microbe is significantly associated with the chronic periodontitis and that its level varies with the severity of the disease. Colonization of the bacterium is significantly associated with severe forms of the disease.