Association of the Red Complex Bacteria in Endo-Perio Cases Before and After Endo-Perio Therapy: A Clinico-Microbiological Study

Introduction: Pulp and periodontal diseases are among the most frequent causes of tooth loss. Due to the anatomical continuum between the pulp and the periodontium, pathological shifts in one tissue frequently cause a secondary response in the other, manifesting as a combined endodontic-periodontal lesion. Treating endo-perio cases requires a systematic, staged, combined approach that addresses both the endodontic and periodontal components of the lesion. Traditional success criteria rely on clinical and radiographic assessments; however, these physical measurements do not always reflect the ongoing biological status of the disease. Comprehensive evaluation of therapeutic outcomes requires the integration of microbiological data and molecular biomarkers, which serve as critical indices for monitoring current disease activity and predicting long-term clinical stability. The strategic implementation of microbial assays at follow-up stages can help the clinician to improve the management of the case, ensuring that interventions are personalized to the individual case. Objectives: The objective of this study is to evaluate the presence of "red complex" bacteria (Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia) in endo-perio lesions and to compare the effect of endodontic therapy alone and the combined approach of endodontic and periodontal therapies on the levels of these bacteria. Materials and methods: This prospective clinico-microbiological study involved 40 research participants of the age group (20-60 years), all diagnosed with primary periodontal lesions with secondary endodontic involvement as per Simon’s classification (1972). Participants were randomly assigned to two treatment groups: Group A (n = 20) received endodontic treatment only. Group B (n = 20) received endodontic treatment followed by periodontal treatment at three months. N-benzoyl-DL-arginine-2-napthylamide-enzymatic™ (BANA) test and clinical parameters (gingival index (GI), probing pocket depth (PPD) and clinical attachment level (CAL)) were assessed at baseline, three months, and six months. Results: Before treatment, 75% of research participants were BANA-positive. After treatment, there was a significant reduction of red complex bacteria from baseline to six months (p < 0.001) in both groups. The Chi-square analysis showed no significant difference in the distribution of BANA status between the groups at three months (p = 0.692) and six months (p = 0.942). Both groups demonstrated an improvement of clinical parameters such as GI, PPD and CAL from baseline to six months (p < 0.05). However, the F-statistic for overall study progress was higher in Group B (F = 33.682) compared to Group A (F = 26.845). Conclusion: The combined therapeutic approach (Group B) results in a more statistically significant reduction in the red complex bacteria.