Systemic amoxicillin-metronidazole was proven to be effective in managing periodontitis in systemically healthy patients. It was demonstrated that systemic antibiotic therapy can effectively improve clinical periodontal parameters and reduce periodontopathogenic organisms in the subgingival biofilm. However, the evidence for prescribing this drug combination to patients with diabetes remains insufficient. This systematic review was designed to evaluate the effectiveness of a systemic amoxicillin-metronidazole combination as an adjunct to nonsurgical periodontal therapy in patients with diabetes presenting with chronic periodontitis. The PubMed, Scopus, and Web of Science databases were electronically searched for randomized clinical trials in January 2022. Randomized clinical trials evaluating systemic amoxicillin-metronidazole therapy as an adjunct to nonsurgical periodontal therapy in patients with type 2 diabetes presenting with periodontitis were selected for screening. The qualities of the studies were assessed using the Cochrane Collaboration's Tool for Assessing Risk of Bias Version 2.0 (ROB-2), and a GRADE assessment was applied to estimate the overall certainty of the evidence. Using predefined eligibility criteria, four clinical trials examining 209 patients were selected from the 611 articles identified in the search. Two studies reported a better reduction in clinical parameters when SRP was combined with systemic amoxicillin-metronidazole. Systemic amoxicillin-metronidazole was found to be as effective as clindamycin. Surgical therapy with systemic amoxicillin-metronidazole was more effective than nonsurgical therapy with systemic amoxicillin-metronidazole, even though both resulted in reduced clinical parameters. Combined amoxicillin-metronidazole was observed to reduce periodontal probing depth (PPD), clinical attachment level (CAL), and bleeding on probing (BOP) compared to no treatment or NSPT alone. However, the effect was not greater when compared to NSPT with clindamycin or surgical therapy with amoxicillin-metronidazole. Further randomized trials are required before clinical guidelines can be established for the use of systemic amoxicillin-metronidazole. Future randomized controlled clinical trials with long-term follow-ups are required to assess the efficacy of systemic antibiotic therapy in managing periodontitis in patients with diabetes.
Keywords: amoxicillin; diabetes mellitus; metronidazole; non-surgical therapy; periodontitis; systemic antibiotics.