Presence of Methanogenic Archaea in Necrotic Root Canal Teeth Before and After Root Canal Instrumentation—An In Vivo Study

Methanogenic archaea facilitate metabolic activities of anaerobic bacteria, thereby amplifying infection dynamics. This study aimed to determine the prevalence of methanogenic archaea in necrotic root canals before and after irrigation, involving 81 patients with apical periodontitis. Pre-irrigation intracanal samples represented native microbial status. Positive samples were subjected to second-sample collection and allocated into Group I-control with saline and Group II-3% Sodium hypochlorite, Group III-5.25% Sodium hypochlorite, each followed by saline and ethylenediaminetetra-acetic acid. Samples underwent deoxyribonucleic acid extraction and real-time polymerase chain reaction. Among the 81 samples, 48.1% were positive for methanogenic archaea. Post-irrigation analysis showed no reduction in Group I; however, Groups II and III demonstrated samples below the detection threshold, with no statistically significant difference between the two groups (p > 0.05). The study confirmed the presence of methanogenic archaea in necrotic root canals, and conventional irrigation protocols were effective against methanogenic archaea.