This guidance is based on the Scottish Dental Clinical Effectiveness Programme guide to drug prescribing in dentistry.
To provide evidence for the guidance a literature review using Medline and Cochrane has been conducted, by Dr Joanne Hooker, up to October 2011 searching for Gingivitis; Antibiotics & dental abscess; Mucosal ulceration; Metronidazole; Oral Inflammation; Microbial flora & oral cavity; Oral hygiene; Oral microbial pathogens; Acute necrotising ulcerative gingivitis; Ludwig’s angina; Dentoalveolar abscess; Mucositis; Odontogenic infection; Antimicrobials & dentistry; Pericoronitis; Periodontal disease; Mouthwash/mouthrinse; Periodontitis; Chlorhexidine; Anti-plaque/anti-gingivival; Hydrogen peroxide; Antimicrobial susceptibility; Saline solution. The rationale was written by Dr Joanne Hooker under the guidance of Dr Cliodna McNulty and reviewed by stakeholders. Where only expert opinion was available, the guidance was based on the literature on the main pathogens and their antimicrobial susceptibility profiles in the UK.
Dosage of antimicrobials recommended in this guidance:
The Scottish Dental Clinical Effectiveness Programme 2011 recommends doses of 250mg amoxicillin or 200mg metronidazole when antimicrobials are appropriate. We recommend a higher dose of 500mg amoxicillin and 400mg metronidazole. The rationale for this is when antimicrobials are considered appropriate, it is important to have sufficient concentrations at the site of infection. For β-lactams such as amoxicillin this is time-dependent (i.e. the time period above the MIC) and 500mg TDS amoxicillin is more likely to attain this. For metronidazole, the killing effect is dose-dependent and the greater the concentrations above the MIC the better. AUC/MIC >70 is only attainable against Bacteroides fragilis with a 400mg dose.
The mainstay of treatment is local antiseptics and hygiene measures; adjunctive antibiotics are only required in cases of systemic involvement or where there is failure to improve following primary dental management. Metronidazole recommended; amoxicillin is an alternative.
Duckworth R, Waterhouse JP, Britton DE, Nuki K, Sheiham A, Winter R, Blake GC. Acute ulcerative gingivitis. A double-blind controlled clinical trial of metronidazole. Br Dent J 1966,21;120:599-602. In this double-blinded clinical trial 33 patients with ANUG were treated for 2 days with metronidazole (200mg TDS) and 33 patients with phenoxymethylpenicillin (250mg QDS). There was no placebo group. There was no difference in the initial response rate but at 12 month follow-up there were significantly more recurrencies in the phenoxymethylpenicillin group (8/21 vs. 0/20 of those who completed the
follow survey). This data supports the use of metronidazole in the treatment of ANUG.
Wade AB, Blake GC, Miza KB. Effectiveness of metronidazole in treating the acute phase of ulcerative gingivitis. Dent Pract 1966;16:440-444. In this double-blinded clinical trial 25 patients with ANUG were treated for 2 days with metronidazole(200mg TDS) and 25 patients used sodiumperborate mouth rinse (one sachet TDS). There was no placebo group. The initial response was significantly better in the metronidazole group but there was no long term follow up. This data may support the use of systemic metronidazole over topical mouth rinse in the treatment of ANUG.
Loesche WJ, Syed SA, Laughon BE, Stoll J. The bacteriology of acute necrotizing ulcerative gingivitis. J Perodontol 1982;53:223-230. In this small longitudinal study a total of eight patients with ANUG were included. Those systemically ill (n=3) were treated with metronidazole (200mg TDS) and those with local symptoms only received standard periodontal therapy. Those systematically ill had more microbiological findings initially. Metronidazole treatment reduced the number of anaerobes but at a 2-3-month follow-up these had reverted to pre-treatment levels. This study supports the efficacy of metronidazole on anaerobic pathogens in the treatment of ANUG and highlights the efficacy of standard periodontal treatment.
Preshaw PM. Antibiotics in the treatment of periodontitis. Dental Update 2004;31:448-456. Informal expert opinion (UK). This review recommends root surface instrumentation, chemical plaque control (chlorhexidine mouthwash) and oral hygiene advice as the gold standard treatment. Metronidazole (400 mg 3 times daily for 3 days) can be added in the acute stages.
Kuriyama T; Williams, DW; Yanagisawa, M; Iwahara, K; Shimizu, C; Kakagawa, K; Yamamoto, E; Karasawa, T. Antimicrobial susceptibility of 800 anaerobic isolates from patients with dentoalveolar infection to 13 oral antibiotics. Oral Microbiol Immunol 2007:22:285-288 (Japan & Wales). A clinical study looking at the antimicrobial susceptibility of 800 anaerobic isolates from dentoalveolar infections. Strict anaerobes predominate, P.intermedia (a common pathogen in ANUG) found to be 100% susceptible to metronidazole. This supports the use of metronidazole in this condition. Fusobacterium species has good susceptibility to amoxicillin/clavulanic acid, a wide range of cephalosporins, clindamycin and metronidazole.
Dahlen G. Microbiology and treatment of dental abscesses and periodontal-endodontic lesions. Peridontol 2000 2002;28:206-239. (Sweden) .Metronidazole is effective against strict anaerobes (the common pathogens seen in ANUG). Four studies demonstrated that Prevotella, Porphyromonas species and Fusobacterium species were 100% susceptible to metronidazole. This study highlighted the benefits of metronidazole in the face of β-lactamase-producing anaerobes and also the penicillin allergic patient.