[Anaerobes in infected canals: a preliminary study].

Area of Science:

• Microbiology
• Endodontics
• Oral Pathology

Context:

• Periapical periodontitis involves inflammation and infection of the tissues surrounding the root apex.
• Root canal flora composition, including anaerobic bacteria, plays a critical role in disease progression.
• Understanding the specific roles of predominant anaerobes is crucial for effective treatment strategies.

Purpose:

• To investigate the prevalence and characteristics of anaerobic bacteria in infected root canals associated with periapical periodontitis.
• To determine the relationship between specific anaerobic species and clinical/radiographic findings.
• To evaluate the pathogenic potential of isolated anaerobes, particularly their collagenase activity, in an animal model.

Summary:

• A study of 17 infected root canals revealed that while both aerobic and anaerobic bacteria were present, anaerobes predominated in chronic periapical periodontitis.
• Key isolates included Peptostreptococcus, Bacteroides melaninogenicus, and Bacteroides oralis. Peptostreptococcus correlated with apical radiolucency, and B. melaninogenicus with percussion sensitivity and odor.
• Animal experiments demonstrated that B. melaninogenicus, B. oralis, and mixed flora exhibited collagenase activity, leading to the degradation of collagen fibers and bone in periapical tissues.

Impact:

• Highlights the significant role of anaerobic bacteria, particularly Peptostreptococcus and Bacteroides species, in the pathogenesis of periapical periodontitis.
• Identifies collagenase activity as a key virulence factor contributing to the destruction of periodontal tissues and bone.
• Provides insights for developing targeted antimicrobial therapies to address anaerobic involvement in endodontic infections.