DNA-DNA hybridization demonstrates multiple bacteria in osteoradionecrosis

Area of Science:

• Oral and Maxillofacial Surgery
• Microbiology
• Oncology

Background:

• Osteoradionecrosis (ORN) of the jaw is a serious complication of radiation therapy.
• Previous understanding attributed ORN to trauma and sepsis, but conventional methods failed to detect significant microbial presence in affected bone.
• The hypoxic, hypovascular, and hypocellular nature of irradiated bone was thought to limit microbial colonization.

Purpose of the Study:

• To investigate the presence and types of bacteria within osteoradionecrotic mandibular bone.
• To utilize advanced molecular techniques for more comprehensive bacterial detection.
• To re-evaluate the role of microorganisms in the pathophysiology of ORN.

Main Methods:

• DNA-DNA hybridization was employed to detect bacterial species in deep medullary specimens.
• Twelve bone samples were obtained from resected radionecrotic mandibles.
• This molecular technique allowed for the identification of a broad range of bacteria, including anaerobes, which are difficult to culture.

Main Results:

• A diverse array of bacterial species was detected in all twelve osteoradionecrotic bone samples.
• Anaerobic bacteria were predominant, with Porphyromonas gingivalis and Fusobacterium nucleatum subspecies polymorphum being the most frequently identified.
• Actinomyces, Prevotella, and F. nucleatum were consistently present across all samples.

Conclusions:

• Bacteria, particularly anaerobic species, are significantly involved in the pathophysiology of osteoradionecrosis.
• The findings challenge the notion that ORN bone is sterile or only superficially contaminated.
• Microbial factors likely play a more fundamental role in ORN development than previously recognized.