Reports & Studies

Periodontal treatment improves more than just the periodontium in diabetics

PD Dr. Kristina Bertl, PhD MSc MBA

In 2021, it was estimated that 537 million people worldwide were suffering from diabetes mellitus. The correlations between diabetes mellitus and periodontal disease are much discussed and have also been explored here in previous reports:

Periodontal treatment improves more than just the periodontium in diabetics.
Periodontal treatment improves more than just the periodontium in diabetics.

Diabetes mellitus and periodontitis have a mutual negative effect on each other, i.e. diabetes mellitus increases the risk of periodontitis and worsens the outcome of periodontal treatment, but untreated periodontitis also has an equally negative impact on the progression of cases of diabetes mellitus. However, the negative influence of diabetes mellitus primarily depends on managing the blood glucose level and if a diabetic performs well in this area there is also no negative effect on the periodontal disease. This does inevitably raise the following question, however: Can periodontal treatment help to control blood glucose levels?

The existing literature covering this question was recently summarised by a Brazilian team of researchers (Oliveira et al. 2023). The group performed a systematic review on the subject and identified 12 studies that looked at the effect of periodontal treatment on the long-term blood glucose level (HbA1c) in type 2 diabetics. The results, based on data from 1,374 patients, showed that periodontal treatment was able to reduce the HbA1c value by 0.3% points and that this effect persisted even after six months! Another valuable piece of information to emerge from the study was that regular, non-surgical periodontal treatment was entirely sufficient to achieve this positive effect, with the result that neither antibiotics nor surgical treatment were required!

Ultimately, it is of course interesting to know how much 0.3% is – is it a small and negligible improvement or a significant, clinically relevant effect? In order to be able to answer this question, it is best considered in relation to the effect of medications that are used to control the blood glucose level. For example, in diabetics who are already taking metformin, an additional (second) diabetes drug (rosiglitazone) reduces the HbA1c value by 0.2% on average. This means that periodontal treatment can achieve a comparable effect to taking an additional drug, suggesting a clear clinically relevant effect.


  1. Oliveira, V. B., Costa, F. W. G., Haas, A. N., Júnior, R. M. M., & Rêgo, R. O. (2023). Effect of subgingival periodontal therapy on glycaemic control in type 2 diabetes patients: Meta-analysis and meta-regression of 6-month follow-up randomized clinical trials. Journal of Clinical Periodontology, 50(8), 1123–1137. jcpe.13830