Diabetes Mellitus & Periodontal Disease: Education, Collaboration and Information Sharing between Doctors, Dentists & Patients


Diabetics are at 3 to 4 times higher risk of developing periodontal disease than non-diabetics and smokers 10 times, first recorded in 1928. However, many doctors are not aware of this. Diabetes mellitus and periodontal disease are biologically linked, the one affecting the other and vice versa although the mechanism is not fully understood. Periodontal disease has an adverse effect on glycaemic control. That improves when periodontitis is successfully treated. Doctors should consider periodontal disease when their patients have persistently high HbA1c levels, and dentists should consider diabetes or pre-diabetes when they have patients with refractory periodontitis. Doctors and dentists need to share results. This paper considers what that shared information should be. A system of red, yellow and green for both medical and dental risks is proposed. Until there are reliable methods of information exchanges, and a paradigm shift in inter-professional working, patients should obtain their medical and dental results and share them with their respective advisors. Those patients who do not attend for dental care should be advised by their doctor about the potential benefits of dental screening for periodontitis.


The relationship between diabetes mellitus (DM) and periodontal disease (PD) is well established as a two-way process with one disease affecting the other and vice versa (1). The diseases are biologically linked (2). Diabetics have a 3 to 4 times greater risk of developing PD than non-diabetics (3): for smokers the risk is 10 times (4). When the individual disease risks for diabetics are considered:

Cardiopathy and arterial disease

Poor oral health is associated with atherosclerotic cardiovascular disease (5). This interaction raises cardiovascular morbidity fourfold and is associated with chronic infection, mediators from which may lead to the initiation of endothelial dysfunction (6).


Diabetics on haemodialysis are at greater risk of developing PD (7). For severe PD there is a 2.6 times greater risk of macroglobulinaemia and 4.9 times for end stage renal disease (ESRD) (8). PD predicts the development of overt nephropathy and ESRD in a dose dependent manner in individuals with little or no pre-existing kidney disease (9). Periodontal management can contribute to the prevention of severe renal disease (9). Patients could be screened for PD before acceptance on dialysis programmes (9).


This complication is a microvascular complication (10) and is associated with xerostomia and can affect over 40 per cent of diabetics. As salivary flow reduces, the risk of developing caries increases due to a reduced buffering capacity. There is an inverse relationship between salivary flow and HbA1c levels that may be due to disturbances in glycaemic control (11).


There are few studies of this complication together with PD. However, an increase in the severity of diabetic retinopathy is associated with the components of PD (12).


While the pathophysiological mechanism of the relationship between the two diseases is still under investigation, there is a common pathogenesis between DM and PD involving an enhanced inflammatory response at both local and systemic level (13). This is caused by the chronic effects of hyperglycaemia and the formation of advanced glycation end-products that promote the inflammatory response (14). Levels of cytokines (15), tissue necrosis factor (14) and C-reactive protein (13) are raised in both diseases. Interleukin 8 is also raised and gives a potential contribution to cross-susceptibility (16). Polysaccharides in Gram-negative bacteria in dental plaque are known to stimulate the production of cytokines (17).

It has been concluded that the chronic bacteriological challenge of PD is a persistent source of inflammatory mediators leading to endothelial dysfunction (6, 18). It is the severity of hyperglycaemia that affects the periodontium most (3). Diabetes enhances periodontal bone loss through enhanced resorption and diminished bone formation (19) because its progression is associated with an increase in HbA1c levels in type 2 diabetes (20).

As PD and DM affect each other, there is some evidence that patients with PD are at risk of developing type 2 diabetes (21) and pre-eclampsia (22). PD has an adverse but modifiable effect on glycaemic control (23). Periodontal therapy improves metabolic control so the overall management of DM may improve (20).


PD had been described as the sixth complication of DM (24). Unfortunately, and through no fault of their own in a crowded curriculum many doctors have not been taught about the importance of PD for DM and the two-way relationship. In one study only 5.7 were aware of this link (25). Diabetics themselves are unaware of the link. While doctors may claim that dental problems are not their responsibility, who is going to advise those diabetics who do not have dental care about the increased risks they run, not only for PD but for their metabolic control?

For example, in the United Kingdom the Government’s Department of Health and Social Care’s diabetics website fails to mention PD, the National Institute for Clinical Excellence has refused to add dental care to the annual list of checks they require doctors to carry out for diabetics, and the principal charity Diabetes UK is more concerned with salivary sugar levels with merely a mention of PD.

A recent paper has called for better inter-professional education and collaboration between doctors and dentist for patients with DM and PD (26). It follows that both parties need to be aware of the significance of the others results and how relative risks may be quantified.

A. For Doctors

The gold standard is the serum level of glycated haemoglobin, the HbA1c which should be maintained below 6.5. For convenience this could be divided into the following bands 0 to 2, low risk, 3 to 5, medium risk, and 6 or above, high risk. They could be called respectively, green, yellow and red risks.

B. For Dentists

Various indices of periodontal health have been described. However, the measure of choice is the World Health Organisation’s Community Periodontal Index of Treatment Needs (CPITN) (27). In the UK dentists are required to examine patients using a specially designed dental pocket measuring probe and record scores, a Basic Periodontal Examination (BPE). These are six numbers, one in each of three sections comprising molars and premolars on each side and incisors and canines as the central number. This applies to both the mandible and the maxilla making six scores in all. Each score is called a sextant. These numbers range from 0 to 4*. The maximum score in each sextant is recorded.

  • 0 – no periodontal problems.
  • 1 – bleeding on probing (a sign of gingivitis and poor plaque control).
  • 2 – Calculus (indicating the need for scaling and root planning).
  • 3 – Pockets of 3.5 to 5.5mm (that is early periodontal breakdown).
  • 4 – Pockets of 5.5 to 8.5mm (that is moderately severe periodontal breakdown).
  • 4* – Pockets greater than 8.5mm (that is severe periodontal breakdown with an increased risk that teeth will require extraction).

Dentists need to share these results with their patients as a matter of routine, not least as a method of education and assistance in promoting better plaque control in those areas with high scores.

The basis of understanding the risks that these scores give has been described in relation to nephropathy (28) and recommended as the international standard to use (29). From the sextant scores the single highest score is taken and classified:

  • 0 or 1, low risk, but let’s call that green.
  • 2 or 3, medium, but let’s call that amber.
  • 4 or 4*, high, but let’s call that red.In this way it will provide an easily understood method of defining the relative risks for both doctors, dentists and diabetics.

Two consecutive scores should be used to establish trends in treatment progression or regression.

Case Report. Mrs D is aged 76 years, has lived all her life in the same English town, and has been a type I diabetic for 25 years. She is monitored frequently by her doctor and has just lost 2Kg in weight because her HbA1c score is 6.6, that is to say using the above definitions, in the red zone for her doctor.

She has attended the same dentist for forty years, has never had radiographs taken, and been advised that her dental health is satisfactory despite BPE scores of 3 and the loss of mandibular central incisor teeth to periodontal abscesses, replaced with a removable acrylic partial denture, the classis ‘gumstripper’ that will exacerbate her loss of periodontal attachment over time. Her dental risk is amber.

Neither her doctor or dentist know about each other’s results.

In an ideal world her doctor should be asking if her periodontal health is affecting glycaemic control29, and her dentist whether her red zone HbA1c scores are contributing to difficulties in controlling her periodontal disease.

This classic case reinforces the call for better sharing of results between the two professional groups. Dentists should be aware of the link between DM and PD (30). However, the majority of doctors, through no fault of their own in crowded teaching programmes, are not aware of the importance of periodontal disease for diabetics. In one recent survey only 5.7 per cent of doctors knew about the two-way link between the diseases (25). Doctors may claim that dental problems are not their responsibility. In relation to their diabetic patients this can no longer be acceptable. There is a need for a paradigm shift in training doctors about these risks, their thinking about diabetic’s risk factors, result sharing, and inter-professional co-operation.

The questions that need to be considered are how to inform doctors, dentists and their patients about the relationship between DM and PD, and especially those patients who have not attended for dental care for whatever reason. This is likely to be a long process although purchasers of healthcare could require these links to be made.

A simple questionnaire for doctors to determine the dental health of their diabetic patients could be a starting point29.


Fortunately PD is both a treatable and preventable disease the mainstay of which is daily efficient and effective control of plaque by patients (31). Pending the development of inter-professional links, patients could take charge of their own health by recording their HbA1c results from their doctor and, if they have dental care, their BPE scores from which they could find both their relative risks using the traffic light method described above and show both parties the results. The author declares that there are no conflicts of interest. Mrs D has given written permission for the publication of her case resumé.


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