The clinical benefit of adjunctive antibiotics alongside non-surgical periodontal therapy with respect to periodontopathogenic bacteria?

Data sources The following electronic databases were searched with no language restrictions: MEDLINE, EMBASE and Cochrane library. Reference lists of included studies were searched, alongside the Open Grey database and hand searches in Journal of Dental Research, Journal of Periodontology, Journal of Clinical Periodontology and Journal of Periodontal Research. The editor of each journal was contacted to enquire about relevant accepted and forthcoming articles.Study selection Two independent reviewers screened for randomised controlled trials (RCTs) with a follow-up of at least six months. The main outcome was the change in periodontal pocket depths (PPD) and clinical attachment level (CAL) six months after treatment, where patients were divided according to adjunctive treatment (antimicrobial vs placebo) as well as the pre-treatment detection of periodontopathogenic bacteria.Data extraction and synthesis Data was extracted from all selected papers using a standardised form, including treatment methods, antimicrobial regime and bacterial detection methods. The Cochrane Collaborations tool was used to assess risk of bias. The weighted mean difference (WMD) of treatment effects between bacterial detection groups was obtained and pooled. A two-stage, fixed-effects meta-analysis was performed, and statistical heterogeneity was described using the Q-statistic and I2 index.Results Following the screening of 643 papers and author contact, five placebo-controlled studies were included in the systematic review. All had a low risk of bias. They varied in patient sample sizes, periodontal diagnoses, subgingival debridement protocols, antimicrobial regimes, as well as baseline microbial analysis methods. The meta-analysis of four studies, using amoxicillin and metronidazole as adjuncts, revealed a significant increase in the reduction of PPDs compared to placebo. It also showed no significant difference in the clinical effect on PPDs ≥5 mm when prescribing adjunctive amoxicillin and metronidazole based on the pre-treatment detection of A. actinomycetemcomitans (WMD = 1.16, 95% CI [-5.37, 7.68], I2 = 37.8%).Conclusions Although data on baseline periodontopathogenic bacteria was limited to A. actinomycetemcomitans, this systematic review suggests that there is not enough evidence to support the use of pre-treatment analysis of subgingival bacteria as a criterion for prescribing adjunctive antibiotics.