Does treatment for gum disease help people with diabetes control their blood sugar levels?

The level of sugar in the blood is too high in people with diabetes, so keeping blood sugar levels under control is a key issue. Glycemic control is a medical term referring to the typical levels of blood sugar (glucose) in a person with diabetes mellitus. Some research suggests a relationship exists between gum disease treatment and glycaemic control. Glycaemic control can be measured in different ways. For this review, we focused on HbA1c, which shows average blood glucose levels over the preceding 3 months. It can be reported as a percentage (of total haemoglobin) or as mmol/mol (millimoles per mole). Excellent glycaemic control in a diabetic person might be around 6.5% or 48 mmol/mol.

This review was carried out by authors working with the Cochrane Oral Health and is part one of an update of a review previously published in 2010 and 2015. This review evaluates gum disease treatment versus no active treatment or usual care for improving glycaemic control. The evidence is current up to 7 September 2021.

What was the research?

A systematic review to find out the effectiveness of gum disease (periodontitis) treatment for controlling blood sugar levels in people with diabetes, compared to no active treatment or usual care.

Who conducted the research?

The research was conducted by a team led by Terry C. Simpson of Edinburgh Dental Institute, University of Edinburgh, Edinburgh, UK on behalf of Cochrane Oral Health. Janet E. Clarkson, Helen V. Worthington, Laura MacDonald, Jo C. Weldon, Ian Needleman, Zipporah Iheozor-Ejiofor, Sarah H. Wild, Ambrina Qureshi, Andrew Walker, Veena A. Patel, Dwayne Boyers and Joshua Twigg were also on the team.

What evidence was included in the review?

35 randomised controlled trials with 3,249 participants were included.

The experimental groups received gum disease treatment called ‘subgingival instrumentation’, also known as scaling and root planing or deep cleaning. In some experimental groups, the deep cleaning was supplemented with instructions for cleaning teeth properly (‘oral hygiene instruction’), or other gum treatments, for example, antimicrobials, which are used to treat infections. Control groups received no active treatment or ‘usual care’, which was oral hygiene instruction, support with oral hygiene, and/or removal of plaque above the gumline. 

Almost all participants had type 2 diabetes, with a mix of good, fair, and poor diabetic control. Most of the studies were carried out in hospitals. The studies followed up participants for between 3 and 12 months.

What did the evidence say?

Evidence from 30 trials (results from 2,443 participants) showed that periodontitis treatment reduces blood sugar levels (measured by HbA1c) in diabetic patients on average by 0.43 percentage points (e.g. from 7.43% to 7%; 4.7 mmol/mol) 3 to 4 months after receiving the treatment compared with no active treatment or usual care. A difference of 0.30% (3.3 mmol/mol) was seen after 6 months (12 studies), and 0.50% (5.4 mmol/mol) at 12 months (one study).

There were not enough studies measuring side effects to be able to evaluate the risk of harm from gum disease treatments.

How good was the evidence?

There is moderate‐certainty evidence to support gum disease treatment (known as subgingival instrumentation) for controlling blood sugar levels in people with periodontitis (gum disease) and diabetes up to 12 months after the start of the periodontal treatment.

What are the implications for dentists and the general public?

There is moderate‐certainty evidence that the treatment of gum disease by subgingival instrumentation improves glycaemic control in people with diabetes, with a mean absolute reduction in HbA1c of 0.43% (4.7 millimoles per mole (mmol/mol)) at 3 to 4 months, maintained up to 12 months. There is not enough evidence to draw reliable conclusions about the potential of periodontal treatment to cause adverse effects or to impact quality of life or diabetic complications. 

What should researchers look at in the future?

We think it may be unnecessary to conduct future trials comparing periodontal treatment versus no treatment/usual care. Comparing different periodontal treatments against one another, or specialist‐led care versus treatment provided by non‐specialists will be researched in a future Cochrane review. Future research could consider costs and how the delivery of care for patients with diabetes is best integrated across healthcare settings

Link

Simpson TC, Clarkson JE, Worthington HV, MacDonald L, Weldon JC, Needleman I, Iheozor-Ejiofor Z, Wild SH, Qureshi A, Walker A, Patel VA, Boyers D, Twigg J. Treatment of periodontitis for glycaemic control in people with diabetes mellitus. Cochrane Database of Systematic Reviews 2022, Issue 4. Art. No.: CD004714. DOI: 10.1002/14651858.CD004714.pub4.

This post is an extended version of the review’s plain language summary, compiled by Anne Littlewood at the Cochrane Oral Health Editorial Base.