Real-Time PCR Quantification of Red Complex Bacterial DNA and Periodontal Status in Removable Partial Denture Wearers

The insertion of removable partial dentures (RPDs) in the oral cavity is associated with changes in the oral microflora over time. However, there is a paucity of literature examining the presence of red complex bacteria (RCB) in these patients. Given RCB's established role in the development of periodontitis, peri-implantitis, and various systemic diseases, investigating the impact of RPDs on these bacteria is crucial. This study aims to quantify the subgingival burden of RCB-Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola-in abutment teeth of partially edentulous patients rehabilitated with RPDs, using real-time polymerase chain reaction (RT-PCR). A secondary objective was to assess the periodontal status of abutment and non-abutment teeth and to determine the correlations between microbial load and clinical periodontal indices. Thirty participants requiring RPDs were enrolled. Deoxyribonucleic acid (DNA) was isolated from bacterial samples obtained from abutment teeth before (T0) and 3 months post-insertion (T3). RCB quantification was performed via RT-PCR and expressed as "Lg (genome equivalents/sample)". Clinical parameters-plaque index (PI), gingival index (GI), probing depth (PD), and tooth mobility (TM)-were recorded for abutment and non-abutment teeth at both timepoints. Abutment teeth demonstrated statistically significant increases in RCB loads across all three target species from T0 to T3: P. gingivalis (1.99 ± 2.01 vs 3.64 ± 2.21, p = 0.00003), T. forsythia (2.20 ± 2.17 vs 3.56 ± 2.33, p = 0.00009), and T. denticola (0.82 ± 1.41 vs 2.35 ± 2.21, p = 0.0001). While periodontal parameters were elevated in abutment versus non-abutment teeth post-treatment, differences did not reach statistical significance. Among pathogens, T. forsythia exhibited the strongest positive correlation with periodontal indices. Short-term use of RPDs is associated with a significant increase in RCB colonization of abutment teeth, suggesting early microbial and inflammatory shifts that may precede clinically evident periodontal breakdown.