Chronic periodontitis affects between 5-20% of the population. Scaling and root planing (SRP) is one of the most effective methods of treatment. The aim of this review was to assess whether  the adjunct of amoxicillin and metronidazole (AMX/MET) to SRP increased its effectiveness compared to SRP alone.

The authors searched eight databases and hand-searched a number of  international dental journals. The main outcomes of interest were  clinical attachment level gain (CAL) and reduction in probing depth (PD). A range of secondary outcomes, and adverse events were also analyzed. The data was pooled using a random-effect model. For continuous outcomes the weighted mean difference (WMD) with 95% confidence interval (CI) was calculated. Heterogeneity was assessed with the Cochrane χ² and I² tests. The level of significance was set at p < 0.05.

Four randomized clinical trials were included and the results of the meta-analysis showed:-

• Significant CAL gain (WMD: 0.21; 95% CI: 0.02-0.4; p < 0.05) and
• PD reduction (WMD: 0.43; 95% CI: 0.24-0.63; p < 0.05) in favour of SRP +AMX/MET.
• No significant differences were found for
• bleeding on probing (WMD:10.77; 95% CI: -3.43-24.97; p > 0.05) or
•  suppuration (MD: 1.77; 95% CI:-1.7-5.24; p > 0.05).

The authors concluded:-

The findings of this meta-analysis seem to support the effectiveness of SRP + AMX/MET; however, future studies are needed to confirm these results.

Sgolastra F, Gatto R, Petrucci A, Monaco A. Effectiveness of Systemic Amoxicillin/Metronidazole as Adjunctive Therapy to Scaling and Root Planing in the Treatment of Chronic Periodontitis: A Systematic Review and Meta-Analysis. J Periodontol. 2012 Jan 5. [Epub ahead of print] PubMed PMID: 22220767.

Related reviews

A review by  Angaji M et al  in 2010 looked at the use of adjunctive antibiotics  for the treatment of  periodontitis in smokers. Their review included 5 randomised trials and they concluded:-

 The present systematic review concludes that the evidence for an additional benefit of adjunctive antibiotic therapy in smokers with chronic periodontitis is insufficient and inconclusive. Additional well-designed RCTs are required to assess the effect of antibiotics in conjunction with periodontal treatments in smokers.

Angaji M, Gelskey S, Nogueira-Filho G, Brothwell D. A systematic review of clinical efficacy of adjunctive antibiotics in the treatment of smokers with periodontitis. J Periodontol. 2010 Nov;81(11):1518-28. Epub 2010 Jun 28. Review. PubMed PMID: 20583918.

The Cochrane Oral Health Group  has a systematic review protocol registered  looking at adjunctive systemic antibiotics for the treatment of chronic periodontitis.

Cazzaniga A, Galli C, Fiorini A, Cantini E, Lodi G. Systemic antibiotics as adjunctive treatment for chronic periodontitis (Protocol). Cochrane Database of Systematic Reviews 2005, Issue 1. Art. No.: CD005099. DOI: 10.1002/14651858.CD005099.

There is also a related Cochrane review by Eberhard J et al  originally published in 2008 that looks at the use of full mouth disinfection for the treatment of chronic periodontitis.

Eberhard J, Jepsen S, Jervøe-Storm PM, Needleman I, Worthington HV. Full-mouth disinfection for the treatment of adult chronic periodontitis. Cochrane Database of Systematic Reviews 2008, Issue 1. Art. No.: CD004622. DOI: 10.1002/14651858.CD004622.pub2.

That review concluded:-

In patients with chronic periodontitis in moderately deep pockets slightly more favourable outcomes for pocket reduction and gain in probing attachment were found following FMD compared to control. However, these additional improvements were only modest and there was only a very limited number of studies available for comparison, thus limiting general conclusions about the clinical benefit of full-mouth disinfection.