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Does Treating Gum Disease Help Blood Sugar Control in Diabetes? What the Evidence Says

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Introduction

Periodontitis, the advanced form of gum disease, is the inflammation and destruction of the tissues that support the teeth, and glycaemic control is a key component of diabetes management [PMID 35420698]. Diabetes and periodontitis are chronic non-communicable diseases that are independently associated with mortality and have a bidirectional relationship [PMID 29280174]. For people living with diabetes in India, a practical question follows: if gum disease is treated, does blood sugar control improve, and by how much?

This article summarises the systematic review and trial evidence on that question, explains its limits, and sets out what a person with diabetes may reasonably do with it. It is written for patients and families and does not replace advice from your physician or dentist.

1. How gum disease and diabetes are linked

The association runs in both directions.

  • Diabetes and the risk of gum disease. A meta-analysis of 13 prospective studies comprising 49,262 individuals found that diabetes increased the risk of the incidence or progression of periodontitis by 86% (RR 1.86, 95% CI 1.3 to 2.8) [PMID 29502214].
  • Gum disease and the risk of diabetes. A meta-analysis of cohort studies found a summary relative risk for incident diabetes of 1.26 (95% CI 1.12 to 1.41) in people with periodontitis compared with those without it, and a summary relative risk for incident periodontitis of 1.24 (95% CI 1.13 to 1.37) in people with diabetes. The authors noted high unexplained heterogeneity between the studies [PMID 34211029].
  • Blood sugar in people who already have diabetes. The joint consensus report of the International Diabetes Federation (IDF) and the European Federation of Periodontology (EFP) stated that cohort studies among people with diabetes demonstrate significantly higher HbA1c levels in patients with periodontitis than in periodontally healthy patients, although data among people with type 1 diabetes are insufficient [PMID 29280174].

The same report described mechanistic links involving inflammatory mediators such as interleukin-1β, tumour necrosis factor-α and interleukin-6, together with oxidative stress [PMID 29280174]. In our reading, these associations show that the two conditions are connected; they do not, on their own, show that treating one improves the other. That question requires randomised trials.

2. What the randomised trial evidence shows

HbA1c (glycated haemoglobin) reflects average blood glucose over the preceding months and is the usual outcome in these trials.

The Cochrane review. Simpson and colleagues included 35 randomised trials that randomised 3249 participants with diabetes and periodontitis to periodontal treatment or to no treatment or usual care; almost all participants had type 2 diabetes [PMID 35420698]. The principal findings were as follows.

  • At 3 to 4 months: moderate-certainty evidence from 30 studies (2443 participants) showed an absolute reduction in HbA1c of 0.43% (4.7 mmol/mol; 95% CI −0.59% to −0.28%) [PMID 35420698].
  • At 6 months: an absolute reduction of 0.30% (3.3 mmol/mol; 95% CI −0.52% to −0.08%; 12 studies, 1457 participants) [PMID 35420698].
  • At 12 months: an absolute reduction of 0.50% (5.4 mmol/mol) in a single study of 264 participants [PMID 35420698].
  • Safety: studies that measured adverse effects generally reported no or only mild harms, although most studies did not evaluate adverse effects [PMID 35420698].

The authors concluded that there is now moderate-certainty evidence that periodontal treatment using subgingival instrumentation improves glycaemic control in people with both periodontitis and diabetes by a clinically significant amount, and that further trials of treatment versus no treatment are unlikely to change this conclusion [PMID 35420698].

Other systematic reviews point the same way.

  • A meta-analysis of 12 trials with at least six months of follow-up, which excluded antimicrobial therapies, found that subgingival instrumentation resulted in 0.29% lower HbA1c (95% CI 0.10 to 0.47) than non-active treatment in 1374 patients with type 2 diabetes, with moderate-grade evidence. None of the 12 studies was judged to be at low risk of bias [PMID 37257917].
  • An umbrella review of 16 systematic reviews pooled 27 studies and found HbA1c reductions of 0.49% at three months and 0.38% at six months with non-surgical periodontal therapy alone compared with no treatment. Adding antibiotics or laser did not produce a statistically significant further benefit [PMID 36261746].
  • An Indian meta-analysis restricted to scaling and root planing alone, in six trials of 812 patients, found a decrease in HbA1c of 0.26% at three to four months that was not statistically significant (P = 0.17), and described the improvement as modest [PMID 31367125].

3. Two landmark trials that reached different conclusions

A 12-month trial in the United Kingdom. D'Aiuto and colleagues randomly assigned 264 people with type 2 diabetes and moderate-to-severe periodontitis to intensive periodontal treatment (subgingival scaling, surgical therapy where appropriate, and supportive care every three months) or to control treatment (supragingival scaling and polishing). Mean baseline HbA1c was 8.1% in both groups. After 12 months, with adjustment for baseline HbA1c and other factors, HbA1c was 0.6% (95% CI 0.3 to 0.9) lower in the intensive treatment group [PMID 30472992].

A 6-month multicentre trial in the United States. In the Diabetes and Periodontal Therapy Trial, 514 participants with type 2 diabetes and HbA1c between 7% and 9% received either scaling and root planing with supportive therapy or no treatment for six months. Enrolment was stopped early for futility. Gum health improved in the treated group, but there was no significant difference in HbA1c between groups (mean difference −0.05%; 95% CI −0.23% to 0.12%), and the authors concluded that their findings did not support periodontal treatment for the purpose of lowering HbA1c [PMID 24346989].

In our reading, the difference may relate to the intensity and duration of treatment, the length of follow-up and the populations studied, but these explanations were not tested directly. The later Cochrane review, which pooled both kinds of trial, reached a positive conclusion with moderate certainty [PMID 35420698].

4. How large is the benefit, in practical terms?

The Cochrane authors judged a reduction of about 0.3% to 0.5% in HbA1c to be clinically significant [PMID 35420698], and the IDF–EFP consensus reported reductions of 0.27% to 0.48% after three months, while noting that studies with longer follow-up were inconclusive [PMID 29280174]. A systematic review of economic evaluations found low- to moderate-certainty evidence that periodontal treatment reduces total healthcare costs, including diabetes-related costs, and concluded that including it in the care of patients with type 2 diabetes and periodontitis is cost-effective; the authors noted that further research is needed on whether these findings transfer to other countries [PMID 39150000].

In our reading, this is a meaningful but supplementary benefit. It is not a reason to change or stop any diabetes medicine, which should only be adjusted by your physician.

A practical checklist for people with diabetes

The following steps are our interpretation of the evidence above and the consensus guidance; they are not a protocol tested in the studies cited.

  • Tell your dentist that you have diabetes, and share your most recent HbA1c result and medicines.
  • Tell your physician if you have bleeding, swollen or receding gums, loose teeth or persistent bad breath; the IDF–EFP report sets out guidance for physicians, oral healthcare professionals and patients on early diagnosis and co-management [PMID 29280174].
  • Ask for a gum (periodontal) examination, not only a check for cavities, because diabetes increases the risk of periodontitis onset and progression [PMID 29502214].
  • If periodontitis is diagnosed, complete the full course of treatment and attend follow-up visits; the trial with the largest 12-month effect included supportive care every three months [PMID 30472992].
  • Continue your diabetes medicines, diet and monitoring as advised by your physician; gum treatment adds to, and does not replace, medical care.
  • In our reading, recheck HbA1c at your usual interval after treatment and share the result with both your physician and your dentist.

How D4dent can help

D4dent's patient services let you find a dentist and book appointments online, with email or SMS reminders for appointments booked through the platform, which can help you keep the follow-up visits that periodontal care requires. You can browse dental clinics by city on our clinics page. A teleconsultation can help you discuss gum symptoms and your diabetes history with a dentist and decide how soon an in-person examination is needed; it does not replace a clinical periodontal examination. Our symptom checker is another starting point. D4dent connects patients, doctors, clinics, laboratories, dealers and X-ray centres in one ecosystem.

Frequently asked questions

Can treating gum disease lower my HbA1c?

In people who have both diabetes and periodontitis, the evidence suggests that it can, by a modest amount. A 2022 Cochrane review of 35 randomised trials found moderate-certainty evidence of an absolute reduction in HbA1c of 0.43% three to four months after periodontal treatment, and 0.30% after six months, compared with no treatment or usual care.

Is the effect large enough to matter?

The Cochrane authors described the improvement as clinically significant. In our reading, periodontal treatment should be regarded as an addition to medical diabetes care, not a substitute for it.

Do all studies agree?

No. A large multicentre trial published in JAMA in 2013 found no significant difference in HbA1c between treated and untreated groups at six months, although gum health improved. Later systematic reviews, which pooled many more trials, nevertheless concluded that treatment improves glycaemic control.

Does diabetes make gum disease more likely?

Yes. A meta-analysis of prospective studies found that diabetes increased the risk of the onset or progression of periodontitis (RR 1.86), and a meta-analysis of cohort studies found that people with periodontitis had a higher risk of developing diabetes (summary relative risk 1.26).

What does gum disease treatment involve?

The core treatment is subgingival instrumentation, the professional removal of plaque, calculus and debris from below the gumline with hand or ultrasonic instruments, also known as scaling and root planing or non-surgical periodontal treatment. It is sometimes accompanied by antimicrobials or, in severe disease, surgery. For guidance on home care, see our page on correct brushing and interdental cleaning.

Limitations to keep in mind

Most trials in the Cochrane review were at high or unclear risk of bias, only two were at low risk, most were carried out in secondary care, and almost all involved type 2 diabetes [PMID 35420698]. None of the 12 trials in the six-month meta-analysis was at low risk of bias [PMID 37257917]. Evidence beyond six months is limited to a small number of trials [PMID 35420698][PMID 29280174], one large trial found no effect [PMID 24346989], and the association studies showed high unexplained heterogeneity [PMID 34211029]. The economic evidence comes from other health systems and may not transfer directly to India [PMID 39150000]. Figures are taken from published abstracts; readers should consult the full texts before citing specific values.

Conclusion

The best available evidence indicates that treating periodontitis in people with diabetes may lower HbA1c by a modest but clinically significant amount, about 0.3% to 0.5%, over three to twelve months [PMID 35420698][PMID 37257917][PMID 36261746]. Not every trial agrees [PMID 24346989], and the benefit supplements rather than replaces medical diabetes care. Because diabetes also raises the risk of gum disease [PMID 29502214], in our reading a regular periodontal examination is a sensible part of living with diabetes.

More in this series

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References

  1. Simpson TC, Clarkson JE, Worthington HV, MacDonald L, Weldon JC, Needleman I, et al. Treatment of periodontitis for glycaemic control in people with diabetes mellitus. Cochrane Database Syst Rev. 2022 Apr 14;4(4):CD004714. PMID: 35420698
  2. Oliveira VB, Costa FWG, Haas AN, Júnior RMM, Rêgo RO. 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. J Clin Periodontol. 2023 Aug;50(8):1123-1137. PMID: 37257917
  3. Di Domenico GL, Minoli M, Discepoli N, Ambrosi A, de Sanctis M. Effectiveness of periodontal treatment to improve glycemic control: an umbrella review. Acta Diabetol. 2023 Jan;60(1):101-113. PMID: 36261746
  4. D'Aiuto F, Gkranias N, Bhowruth D, Khan T, Orlandi M, Suvan J, et al. Systemic effects of periodontitis treatment in patients with type 2 diabetes: a 12 month, single-centre, investigator-masked, randomised trial. Lancet Diabetes Endocrinol. 2018 Dec;6(12):954-965. PMID: 30472992
  5. Engebretson SP, Hyman LG, Michalowicz BS, Schoenfeld ER, Gelato MC, Hou W, et al. The effect of nonsurgical periodontal therapy on hemoglobin A1c levels in persons with type 2 diabetes and chronic periodontitis: a randomized clinical trial. JAMA. 2013 Dec 18;310(23):2523-32. PMID: 24346989
  6. Sanz M, Ceriello A, Buysschaert M, Chapple I, Demmer RT, Graziani F, et al. Scientific evidence on the links between periodontal diseases and diabetes: Consensus report and guidelines of the joint workshop on periodontal diseases and diabetes by the International Diabetes Federation and the European Federation of Periodontology. J Clin Periodontol. 2018 Feb;45(2):138-149. PMID: 29280174
  7. Stöhr J, Barbaresko J, Neuenschwander M, Schlesinger S. Bidirectional association between periodontal disease and diabetes mellitus: a systematic review and meta-analysis of cohort studies. Sci Rep. 2021 Jul 1;11(1):13686. PMID: 34211029
  8. Nascimento GG, Leite FRM, Vestergaard P, Scheutz F, López R. Does diabetes increase the risk of periodontitis? A systematic review and meta-regression analysis of longitudinal prospective studies. Acta Diabetol. 2018 Jul;55(7):653-667. PMID: 29502214
  9. Sáenz-Ravello G, Castillo-Riquelme M, Cuadrado C, Gamonal J, Baeza M. Efficiency of periodontal treatment to improve type 2 diabetes mellitus outcomes: A systematic review and meta-analysis of economic evaluations. Community Dent Oral Epidemiol. 2025 Apr;53(2):135-151. PMID: 39150000
  10. Jain A, Gupta J, Bansal D, Sood S, Gupta S, Jain A. Effect of scaling and root planing as monotherapy on glycemic control in patients of Type 2 diabetes with chronic periodontitis: A systematic review and meta-analysis. J Indian Soc Periodontol. 2019 Jul-Aug;23(4):303-310. PMID: 31367125