Effect of non-surgical periodontal therapy on sub-gingival microbiome in type-2 diabetic patients with periodontitis—a systematic-review

Studies have shown a two-way link between periodontitis and Type 2 diabetes mellitus. This systematic review aimed to determine the effectiveness of nonsurgical periodontal therapy in changing the sub-gingival microbiome of Type 2 diabetic patients with periodontitis. The SCOPUS, WEB OF SCIENCE, PUBMED/MEDLINE and GOOGLE SCHOLAR databases were searched up to and including January 2024. Interventional trials assessing the sub-gingival microbiome of periodontitis patients with Type 2 diabetes mellitus [DM] undergoing nonsurgical periodontal therapy [NSPT] were eligible for inclusion. Risk of Bias assessment was done using the Cochrane Risk of Bias tool. Five studies were included for qualitative analysis comprising 285 patients: 166 in the test group [periodontitis with Type 2 DM] and 119 in the control group [periodontitis-only] followed up to 3–6 months. Microbiological findings, the primary outcome of this systematic review, presented a heterogeneous result. However, 100% of studies reported an improvement in clinical parameters after NSPT with a follow-up of 3 months. Aggregatibacter actinomycetecomitans (Aa), Prevotella intermedia (Pi), Porphyromonas gingivalis (Pg) Teneralla forsythia (Tf) and Treponema denticola (Td) were the most common species discussed in all studies. All studies documented a noticeable reduction in bacterial counts after 3 months of therapy in both groups. Despite heterogeneity in the findings of microbiological parameters, it is stated unequivocally that NSPT resulted in a reduction of bacterial counts and was influential in changing the microbiome of both periodontitis with Type 2 DM and periodontitis-only groups and remained stable for the short term regardless of microbiological assessment technique, sampling protocol or variable sample size. Periodontitis is a polymicrobial infection that plays a role in the onset and progression of systemic diseases like DM. NSPT, regarded as the gold standard for periodontal treatment, aids in shifting the pathogenic microbiome towards a healthier state in periodontitis patients with Type 2 DM. This systematic review highlights the need for healthcare workers to consider NSPT as an essential component of management protocol for DM patients with periodontitis.