What is the typical dosage of penicillin (antibiotic) for a broken tooth with suspected infection?

Penicillin Dosing for Broken Tooth with Suspected Infection

For a broken tooth with suspected infection, antibiotics are generally NOT indicated unless there is evidence of spreading infection (cellulitis, lymphadenopathy, diffuse swelling) or systemic involvement (fever, malaise), and definitive dental treatment (drainage, extraction, or endodontic therapy) should be the primary intervention. 1, 2

When Antibiotics Are NOT Recommended

• Uncomplicated tooth fractures (enamel only or enamel-dentin without pulp exposure) do not require systemic antibiotics 1
• Localized dental abscesses without systemic signs should be treated with surgical drainage alone (root canal therapy or extraction) 1, 2
• Acute apical periodontitis and acute apical abscess do not benefit from antibiotics when surgical drainage is performed 1, 2

When Antibiotics ARE Indicated

Systemic antibiotics should be prescribed when there is: 1

• Evidence of spreading infection (cellulitis, lymph node involvement, diffuse swelling)
• Systemic involvement (fever >38°C, malaise, tachycardia)
• Medically compromised patients or immunocompromised status
• Progressive infections where immediate surgical referral is necessary

Recommended Penicillin Dosing

For Adults (First-Line Treatment)

Penicillin V (Phenoxymethylpenicillin): 3, 4, 5

• Standard dose: 500 mg orally every 6 hours
• Alternative dose: 250-500 mg orally every 6-8 hours
• Duration: 5-7 days (though evidence suggests 3-5 days may be sufficient) 6

Amoxicillin (alternative penicillin): 4

• Dose: 500 mg orally every 8 hours
• Duration: 5-7 days

For Children <12 Years

Penicillin V: 1

• Dose: 25-50 mg/kg/day divided into 3-4 doses
• Duration: 5-7 days

For Penicillin-Allergic Patients

Clindamycin: 1, 4

• Adults: 300-450 mg orally 4 times daily
• Children: 10-20 mg/kg/day in 3 divided doses

Critical Clinical Considerations

Surgical Intervention is Primary

• Antibiotics are adjunctive only and should never replace definitive surgical treatment (drainage, extraction, or endodontic debridement) 1, 2
• Studies show no significant benefit of antibiotics over surgical drainage alone for localized infections 2

Second-Line Options if No Improvement in 2-3 Days

If the patient fails to improve within 48-72 hours on penicillin: 4

• Amoxicillin-clavulanate: 875/125 mg twice daily
• Metronidazole plus penicillin for anaerobic coverage
• Clindamycin: 300-450 mg four times daily

Common Pitfalls to Avoid

• Do not prescribe antibiotics without establishing drainage or definitive dental treatment 1, 2
• Do not use antibiotics for prophylaxis in routine dental extractions in healthy patients (only 19 patients need treatment to prevent one infection in third molar surgery) 7
• Avoid prolonged courses beyond 5-7 days without clear indication, as shorter courses (3-5 days) appear equally effective 6
• Do not prescribe antibiotics for irreversible pulpitis or uncomplicated crown fractures 1

Special Situations

Tooth avulsion (knocked-out tooth): 1

• Children >12 years: Doxycycline is preferred
• Children <12 years: Penicillin is indicated
• Penicillin-allergic: Clindamycin

Complicated crown fractures with pulp exposure: 1

• Immediate dental referral for pulp therapy is essential
• Antibiotics are not routinely indicated unless signs of spreading infection