the Australian Dental Association
Written by the Australian Dental Association, Apr 21, 2023
Fact Checked

Diabetes is a serious complex condition that can affect the entire body. If complications from diabetes develop, they can impact day-to-day quality of life. The mouth is often overlooked as an area of the body that can experience complications associated with diabetes.


Diabetes can lead to multiple complications in the mouth. These complications can increase in severity when a person with diabetes has poor control of their blood glucose levels. Patients with complications of diabetes, particularly diabetic neuropathy, can be more likely to develop oral complications.

The most recognised oral complication related to diabetes is severe gum disease, known as periodontitis.
Other oral complications can include:

  • Tooth decay.
  • A decrease in saliva production causing a dry mouth.
  • Oral thrush.
  • Delayed or poor healing of wounds in the mouth, such as mouth ulcers.
  • Altered taste.

You may think you do not have any of the listed conditions because you are not experiencing any pain or discomfort. Many of these diseases are often painless, however, in cases of advanced disease or sudden flare-up, pain can occur. At this stage, it may be too late for treatment to save the tooth. This shows why it is important to look after your oral health.


Periodontitis is a chronic disease that requires life-long care and professional treatment. It causes recession of the gum and/or bone surrounding affected teeth. These changes are not able to be reversed. A dentist or gum specialist, known as a periodontist, can check for signs of periodontal disease and provide treatment. Signs of periodontal disease can include bleeding from the gums, bad breath, sensitive teeth, loose teeth, recession of the gums or longer-looking teeth, and gaps developing between the teeth which may lead to food becoming stuck. Severe untreated periodontal disease can result in teeth becoming loose, painful and eventually being lost from the mouth.

The risk of developing periodontitis is greater in people with diabetes, particularly when blood glucose levels are not within the recommended range of 4-7 mmol/L. However, with optimum blood glucose management the risk of developing periodontitis is the same as for a person without diabetes.

There is increasing evidence of a two-way relationship between periodontitis and diabetes. Periodontitis may negatively affect blood glucose levels. Studies have shown that people with periodontitis exhibit a higher chance of developing prediabetes and diabetes. People with periodontitis have poorer glycaemic status (higher level of HbA1C), compared to people without periodontitis.

Professional periodontal treatment has been shown to create a mild improvement in blood glucose levels. However, these results lasted for only a short three-month period of time (longer term studies are ongoing).

These relationships can differ for people with type 1 diabetes compared to type 2. It is important that people continue to remain in control of their oral health and their diabetes management over time.

Tooth decay

The root of a tooth anchors the tooth in the mouth and is covered by the bone and gums. Periodontitis can cause the bone and gum around the tooth to recede, where it pulls away from its original position. This uncovers and exposes the root surface, which is not as strong as the white tooth enamel covering the tooth crown.

Tooth decay affecting tooth's root surface can occur more often in people with diabetes. This decay is influenced by factors associated with diabetes including gum receding due to periodontitis exposing the root surfaces and a decrease in saliva production. Saliva helps to protect the teeth against decay, therefore, a decrease in saliva can cause a person to become more likely to develop tooth decay.

Dry mouth

People with diabetes more commonly experience a decrease in saliva production which can cause a dry feeling within the mouth. This is reported to be more common in patients with diabetes complications, in particular diabetic neuropathy.

Oral thrush

Oral thrush is a fungal infection that can occur in and around the mouth and throat. It is also known as oral candidiasis, and is mostly caused by an overgrowth of fungal yeast called candida albicans.
Symptoms of oral thrush can include white patches of plaque on soft tissues in the mouth, such as the tongue. The white patch can often be wiped off and will leave behind red areas that may bleed slightly. It can occur in people with diabetes due to multiple reasons:

  • A poor immune system.
  • A decrease in saliva being produced.
  • High blood glucose levels cause increased glucose in saliva which can cause more Candida bacteria to live and grow.

Delayed or poor wound healing

Due to changes in blood flow and a poorer body immune system in people with diabetes, this can cause wounds in the mouth to heal very slowly.

Altered taste

The ability to taste foods and drinks can be affected in people with diabetes. The underlying cause for this is not clear. It may be related to the taste receptors in the mouth renewing at a slower rate or is suggested to be associated with the presence of diabetic neuropathies.

Caring for your oral health

Key steps to look after the health of your mouth, including your teeth and gums, and to decrease the risk of complications associated with diabetes:

  • Brush your teeth twice a day using a soft toothbrush with a pea-size amount of fluoride-containing toothpaste.
  • Clean between your teeth daily using floss or interdental brushes.
  • Eat a diet low in sugar.
  • Drink fluoridated tap water where available.
  • Chewing sugar-free gum can help to stimulate saliva flow.
See a dentist regularly

The dentist will let you know how often to return for a routine check-up. This may be more often if you have any of the above complications from diabetes. Oral health education should also be provided when seeing the dentist. Patients with severe periodontal disease may be referred to a specialist periodontist.

It is important to tell your dentist if you have diabetes and how well the condition is controlled. Ensure your dentist knows the names of all prescribed and over-the-counter tablets and medicines you take as well as if you are a current or past smoker.

Avoid smoking

Other than diabetes, cigarette smoking is another key risk factor for developing periodontitis. If you are a current or previous smoker, it is recommended you tell this to your dentist.

Hypoglycemic episodes

After treating hypoglycemia with fast acting carbohydrates, such as jellybeans, soft drink, fruit juice or sugar directly, it is important to drink water once you feel well again. This helps to rinse the sugar and acids from your mouth. If you would like to brush your teeth, try to wait 60 minutes before doing so.

For more information on diabetes, go to Diabetes Australia