Periodontics · single question
A patient has Periodontal-Endodontic (Perio-Endo) lesion (PUNA/NUP) with bone loss. What is the antibiotic of choice?
Show answer and explanation
Correct answer: B. Metronidazole
For necrotizing ulcerative periodontitis (NUP/PUNA) or aggressive periodontitis with bone loss, Metronidazole is the first-line antibiotic of choice. Metronidazole is highly effective against anaerobic Gram-negative bacteria (Fusobacterium, Treponema, Prevotella) — the key pathogens in NUP and aggressive periodontitis. It is often combined with amoxicillin for aggressive periodontitis (Slots & Ting protocol). For NUP alone, metronidazole monotherapy is standard.
- A. CORRECT. Metronidazole is the drug of choice for NUP/aggressive periodontitis — its anaerobic spectrum perfectly targets the key periodontal pathogens.
- B. Incorrect. Amoxicillin may be combined WITH metronidazole in aggressive periodontitis, but alone it is less effective against the anaerobic periodontal pathogens than metronidazole.
- C. Incorrect. Clindamycin is used as a penicillin alternative in dentistry but is not the first choice for NUP/perio-endo lesions.
- D. Incorrect. Azithromycin has some evidence for use in periodontitis but is not the established first-line for NUP.