What antibiotic regimen is recommended for acute gingivitis, including alternatives for penicillin‑allergic patients?

Antibiotic Therapy for Acute Gingivitis

Antibiotics are generally NOT recommended for routine acute gingivitis, as this condition is managed primarily with mechanical debridement and antiseptic rinses rather than systemic antimicrobials.

Understanding Acute Gingivitis vs. Conditions Requiring Antibiotics

• Acute gingivitis is a reversible inflammatory condition caused by dental plaque accumulation that responds to mechanical removal of biofilm and does not typically require systemic antibiotics. 1
• The evidence base for gingivitis management focuses on mechanical plaque control (scaling, root planing, toothbrushing) combined with antiseptic mouthrinses, not antibiotics. 1, 2
• Antibiotics are reserved for specific periodontal infections such as necrotizing ulcerative gingivitis (NUG), aggressive periodontitis, or acute dentoalveolar abscesses—not simple gingivitis. 3

When Antibiotics ARE Indicated: Necrotizing Ulcerative Gingivitis (NUG)

If the patient has necrotizing ulcerative gingivitis (characterized by painful necrosis of interdental papillae, ulceration, bleeding, and often fever/malaise), then antibiotics are appropriate:

First-Line Antibiotic for NUG

• Metronidazole is the preferred agent for NUG, which is caused by fusiform bacilli and spirochetes. 3
• Amoxicillin-clavulanate (Augmentin) is an alternative first-line option for NUG. 3

Alternative for Penicillin Allergy

• Macrolides (erythromycin, clarithromycin, azithromycin) can be used in patients with periodontal disease who are allergic to penicillin. 3
• However, note that macrolides have 20-25% resistance rates for common respiratory pathogens, though this data comes from sinusitis studies rather than periodontal infections. 4

First-Line Management of Routine Acute Gingivitis (No Antibiotics)

Mechanical Debridement

• Scaling and root planing are the cornerstone of gingivitis treatment and must be performed before considering any adjunctive therapy. 1, 5
• Professional tooth cleaning removes the bacterial biofilm that causes gingival inflammation. 2

Antiseptic Mouthrinse: Chlorhexidine

• 0.12% chlorhexidine gluconate mouthrinse is the most effective adjunct to mechanical plaque control, providing high-quality evidence of plaque and gingivitis reduction. 2
• Dosing: Rinse with 15 mL of 0.12% chlorhexidine twice daily for 30 seconds after brushing. 2
• Duration: Use for 4-6 weeks as an adjunct to mechanical oral hygiene. 2
• Efficacy: Chlorhexidine reduces gingivitis by 0.21 points on the 0-3 Gingival Index scale and produces a large reduction in plaque (SMD 1.45 standard deviations). 2

Expected Adverse Effects of Chlorhexidine

• Extrinsic tooth staining is the most common side effect, occurring with use ≥4 weeks (SMD 1.07 standard deviations higher staining). 2
• Taste disturbance/alteration is frequently reported. 2
• Oral mucosa effects including soreness, irritation, mild desquamation, and mucosal ulceration/erosions may occur. 2
• Burning sensation of the tongue or general oral burning is common. 2
• Calculus buildup may increase with prolonged use. 2

Alternative Antiseptic: Metronidazole Irrigation

• 0.05% metronidazole delivered via supragingival irrigation (pulsating water jet) can reduce plaque and gingivitis when combined with scaling, root planing, and Bass brushing technique. 5
• This is less effective than chlorhexidine for plaque control but may be considered when chlorhexidine is not tolerated. 5

Other Antiseptic Agents (Lower Evidence)

• Listerine has proven ability to reduce plaque and gingivitis in a moderate way (less effective than chlorhexidine). 6
• Hexetidine combined with zinc has greater antiplaque effect and can be compared with 0.1% chlorhexidine. 6
• Povidone-iodine cannot be used to keep plaque at low levels. 6
• Sanguinarine can reduce plaque accumulation when toothpaste and mouthrinse are used together. 6
• Hydrogen peroxide is an antiplaque agent but has negative effects such as ulcerations. 6

Critical Pitfalls to Avoid

• Do not prescribe antibiotics for routine acute gingivitis—this is inappropriate antibiotic stewardship and contributes to resistance. 3, 2
• Do not rely on chemical agents alone—mechanical plaque removal (brushing, flossing, professional cleaning) is essential and cannot be replaced by mouthrinses. 6
• Do not confuse acute gingivitis with necrotizing ulcerative gingivitis (NUG)—only NUG requires antibiotics. 3
• Warn patients about chlorhexidine staining—this is expected and reversible but can be cosmetically concerning, especially on anterior teeth. 2
• Ensure adequate mechanical debridement first—antiseptic rinses are adjuncts, not replacements, for scaling and oral hygiene. 1, 5

Treatment Algorithm

1. Confirm diagnosis: Is this simple acute gingivitis or necrotizing ulcerative gingivitis (NUG)?

   • Simple gingivitis: Redness, swelling, bleeding on probing, no necrosis → No antibiotics
   • NUG: Painful necrosis of papillae, ulceration, fever, malaise → Antibiotics indicated

2. For simple acute gingivitis:

   • Perform scaling and root planing 1, 5
   • Prescribe 0.12% chlorhexidine mouthrinse 15 mL twice daily for 4-6 weeks 2
   • Reinforce mechanical oral hygiene (Bass brushing technique) 5
   • No antibiotics 3, 2

3. For necrotizing ulcerative gingivitis (NUG):

   • Perform scaling and debridement 3
   • Prescribe metronidazole or amoxicillin-clavulanate 3
   • Add 0.12% chlorhexidine mouthrinse as adjunct 1
   • For penicillin allergy: use macrolides 3

4. Follow-up:

   • Reassess at 4-6 weeks to evaluate gingival inflammation and plaque control 2
   • If no improvement, consider undiagnosed periodontitis or systemic factors 1