When is metronidazole particularly useful in dentistry?

• A. Effective against viruses in the oral cavity.
• B. Effective against yeasts.
• C. Particularly useful for anaerobic periodontal pathogens and odontogenic infections; often used with penicillin.
• D. Used only as a local rinse.

Answer: (C)

Metronidazole is especially useful in dentistry because it targets the anaerobic bacteria that dominate many dental infections. In periodontal pockets and odontogenic infections, anaerobes such as certain Bacteroides/Prevotella/Porphyromonas species are common, and metronidazole is highly effective against these organisms. It works by entering the bacterial cell and, after reduction in anaerobic conditions, causing DNA damage that leads to cell death. It does not act on viruses or yeasts, and it is typically used systemically rather than as a local rinse (though topical forms exist for pockets). In mixed infections, it’s often combined with penicillin to cover both anaerobic and aerobic/facultative organisms, broadening the overall effectiveness.