Diabetes mellitus and periodontal disease: a new perspective in care

Turner C

Published on: 2023-12-13

Abstract

First recorded in 1928, people living with diabetes mellitus (DM) are at a 3–4 times higher risk of developing periodontal disease (PD) than non-diabetics; for those who smoke, this risk is up to 10 times higher. However, many doctors are not aware of this.

DM and PD are bidirectionally linked, with one affecting the other and vice versa, although the mechanism is not fully understood and may be linked to chronic infection. PD has an adverse effect on glycaemic control. That improves when periodontitis is successfully treated.

Doctors should consider PD when their patients have persistently high glycated haemoglobin (HbA1c) levels, and dentists should consider diabetes or pre-diabetes when they have patients with unstable or progressive periodontitis.

Doctors and dentists and their teams need to share results. A system of red, amber, and green for both medical and dental risks is proposed and pro forma designed so that diabetics themselves can share them with their professional advisors until such times as there are reliable methods of interprofessional communication and a paradigm shift in working practices is achieved.

Dentists need to find ways to teach their medical colleagues about the basics of PD, update their medical records, and understand more about medical risks. More research is required.

Keywords

Diabetes Mellitus; Periodontal Disease

Introduction

First described in 1928 [1] the relationship between diabetes mellitus (DM) and periodontal disease (PD) is well established as a two-way positive bi-directional interaction [2]. The diseases are linked [3]. People with DM have a 33–4times greater risk of developing PD than non-diabetics [4]. For smokers, the risk is 10 times greater, with a marked shift to the most serious stages of periodontitis when both smoking and DM are present [5].

Pathophysiology

While the pathophysiological mechanism of the relationship between the two diseases is still under investigation, there is a common pathogenesis between diabetes mellitus and PD involving an enhanced inflammatory response at both local and systemic levels [6]. This is caused by the chronic effects of hyperglycaemia and the formation of advanced glycation end-products that promote the inflammatory response [7]. Levels of cytokines [8], tissue necrosis factor [7], and C-reactive protein [6] are raised in both diseases. Interleukin [8] is also raised, contributing to potential cross-susceptibility [9]. Polysaccharides in gram-negative bacteria in mature dental plaque are known to stimulate the production of cytokines [10].

Alveolar bone loss

Toxic products from these gram-negative organisms, notably osteoclast activation factor, initiate tissue breakdown and increase osteoclastic bone resorption in the periodontium. Osteoclastic activity also increases along with enhanced glycation levels and poor glycaemic control [11], thus stimulating further bone resorption and diminished bone formation [7] in a vicious circle and contributing to the enhanced levels of periodontitis and alveolar bone loss seen in people with diabetes who also have a reduced healing capacity.

Periodontitis

When dental plaque is left, after 7 to 10 days [12], gingival inflammation ensues, and this is the precursor of periodontitis. PD is not a classical infection because no single causative organism has been identified, and it does not conform to Koch’s postulates. While multifactorial, it appears to be a chronic hypersensitivity reaction to inflammatory products predominantly from Gram-negative bacteria in dental plaque. It has been concluded that the chronic bacteriological challenge of PD is a persistent source of inflammatory mediators leading to endothelial dysfunction [13,14]. It is the severity of hyperglycemia that affects the periodontium most [4].

These diseases affect each other. Moreover, there is some evidence that patients with periodontitis are at greater risk of developing gestational type 2 diabetes [15] and pre-eclampsia [16]. PD has an adverse but modifiable effect on glycaemic control [17]. Periodontal therapy improves metabolic control, so the overall management of diabetes may improve [18,19]. Recently, HbA1c and blood sugar levels have been related to interdental cleaning habits [20]. No interdental plaque control gives poorer glycaemic control for Type 2 diabetics [20]. These factors underline the need for screening people with periodontal disease for diabetes mellitus and vice versa [2].

Medical Risks For People Living With DM

When the five well-recognized individual disease risks, checked annually by doctors in the UK, for people with diabetic patients are considered:

Cardiopathy and arterial disease

Poor oral health is associated with atherosclerotic cardiovascular disease [21]. This interaction raises cardiovascular morbidity fourfold and is associated with chronic infection, mediators from which may lead to the initiation of endothelial dysfunction [22].

Nephropathy

People living with diabetes on haemodialysis are at greater risk of developing PD [23]. For severe PD, there is a 2.6-fold greater risk of macroglobulinaemia and a 4.9-fold greater risk for end-stage renal disease (ESRD) [24]. Periodontal management may contribute to the prevention of renal disease because one study has shown that a low eGFR might be attributed to PD in Japanese middle-aged men [25]. Before acceptance into dialysis programs, patients could and should be screened for PD [25]. Further research may show that prior treatment of any existing periodontitis may reduce dialysis requirements and, therefore, ongoing health care costs.

Neuropathy

This is a microvascular complication [26], is associated with xerostomia, and can affect over 40 percent 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 [27].

Retinopathy

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 [28].

The odds ratios for people living with diabetes with periodontitis compared to those with diabetes but without PD are reported as follows [29]:

Table 1

Retinopathy	2.8 – 8.7
Neuropathy	3.2 – 6.6
Cardiovascular	10.2 – 17.7
Mortality	2.3 – 8.5

Although periodontal disease is now regarded as the sixth complication of diabetes mellitus [30], in one study, only 5.7% of doctors asked questions about their patients' dental histories [31]. People living with diabetes themselves are unaware of the link. While doctors may claim that dental problems are not their direct responsibility, who is going to advise those people with diabetes who do not have dental care about the increased risks they run, not only for dental problems but for their metabolic control?

In 2022, the UK’s National Institute for Clinical Excellence (NICE) has added a recommendation for dental history to be added to the annual check list they require doctors to carry out for their patients living with DM. In summary, the NICE recommendations to doctors for both people with type 1 and type 2 diabetes are:

They should advise patients that they are at greater risk of developing periodontal disease.
Controlling periodontal disease can improve glycaemic control [32].

However, doctors should record which dentist their patients are seeing and be prepared to refer those who do not have dental care and are in the higher risk categories, as defined by their HbA1c blood levels, for periodontal screening in the first instance and any necessary treatment.

Recent papers have called for better inter-professional education and collaboration between doctors and dentists for their patients with diabetes [33,34,35]. It follows that both parties need to be aware of the significance of the other results, how relative risks may be quantified, and to share information about existing treatments.

Dentists could benefit from an update about diabetes medications that, with the exception of insulin for type 1 diabetics, are orally administered hypoglycaemic or anti-hyperglycaemic agents that (a) increase the amount of insulin secreted by the pancreas, (b) increase the sensitivity of target organs to insulin, (c) decrease the rate at which glucose is absorbed from the gastrointestinal tract, and (d) increase the loss of glucose through urination. The principal drug groups are:

Table 2

Drug class	Mode of action
Sulphonylureas	Stimulate insulin release by pancreatic beta cells
Metformin	Acts on the liver to reduce gluconeogenesis
Alpha-glucoside inhibitors	Inhibit carbohydrate digestion in the small intestine
Thiazolidinediones	Reduce insulin resistance
GLP-1 agonists	Mimic the effects of a natural appetite suppressing hormone

For some patients, insulin injections are also prescribed.

Defining risk factors for doctors

The gold standard for diabetic monitoring is the serum level of glycated haemoglobin which is a 2-to-3-month retrospective measure called HbA1c. Initially, this was recorded as percentage levels that should be maintained below 6.5 percent, an easily understood figure for patients. More recently, the values have been expressed as either mmol/mol or mmol/liter (Table 3).

A traffic light classification of risk has been proposed as a simple way for doctors, dentists, and patients themselves to understand the risks that they face from the interaction of these two diseases [38]. For HbA1c levels below 6.5 percent, the band is green, an amber band for 6.5 to 8.5 percent, and a red band for greater than 8.5 percent in the first instance, although this could change with further research.

Table 3: HbA1c levels and medical risks.

RISK FACTOR	LOW, GREEN	MODERATE, AMBER	HIGH, RED
Percentage	<6.5	6.5 – 8.5	8.5 >
mmol/L	< 7.8	7.8 – 10.9	10.9 >
Mmol/mol	<48	48 - 69	69>

However, previously determined individualized targets could be more appropriate for some people with diabetes, particularly those who are frail or lack awareness of hypoglycaemia [36].

Defining risk factors 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) [37]. This method divides the mouth into molars and bicuspids for right and left, and incisors and canines to give three areas for each jaw or sextant. Using a specially designed measuring probe for pocket depths to create a score for each sextant from 0 to 4*. The maximum score in each sextant is recorded.

0 – Pockets less than 3.5mm periodontal health

1 – Pockets less than 3.5mm bleeding on probing (a sign of gingivitis and poor plaque control)

2 – Pockets less than 3.5mm Plaque retentive factors and the presence of calculus indicate the need for professional mechanical plaque removal.

3 – Pockets of 3.5 to 5.5mm (early or moderate periodontal breakdown)

4 – Pockets of greater than 5.5 mm (severe periodontal breakdown)

4*- Root furcation involvement or severe periodontal breakdown with an increased risk that teeth will require extraction with the proviso that both the number and the * should be recorded if a root furcation is detected.

Dentists should 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. More detail, such as plaque and bleeding scores and pocket charts, would not be required in the first instance for doctors and their teams to assess basic dental risks from periodontal screening and could be confusing.

The basis for understanding the risks that these scores give has been described and put forward as the international standard to use as a simple-to-understand report for doctors about their patients with diabetes [39]. From the sextant scores, the single highest score is taken and classified (Table 4).

Table 4: Periodontal risk factor.

RISK FACTOR	LOW, GREEN	MODERATE, AMBER	HIGH, RED
Highest sextant score	0 - 1	2 - 3	4 or 4*

Except that root furcation involvements scored with an * increase the risk to the next higher level; for example, 3* would raise the risk from amber to red.

This will provide an easily understood method of defining the relative risks for both doctors, dentists, and people living with diabetes.

Two consecutive scores should be used to establish trends. These results can be recorded in a suitable pro forma that includes the details of the periodontal scores as an educational tool for both patients and doctors, as this is likely to be new information for them.

Table 5: MY DIABETES RESULTS FOR 20……..

NAME…………………………………………………DOB…………

Doctors – HbA1c, this should be below 6.5%

Risk Factor: less than 6.5% low; 6.5-8.5%, medium; 8.5% or more high, or

Less than 48mmol/mol, low; 48-70mmol/mol, medium; 70mmol/mol or more, high

Date HbA1c……………… Risk level…………

Previous results

Date HbA1c……………… Risk level…………

Dentists: The Basic periodontal examination

Date………………….. Highest score……..

Risk Factor 0-1 low; 2-3 medium; 4 or 4* high

Previous results

Date………………….. Highest score……..

Risk Factor 0-1 low; 2-3 medium; 4 or 4* high

Notes: 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).

For the future, informing doctors and their teams about the basics of periodontitis and how it affects their overall care of their patients living with diabetes could include [38]:

Deans of dental schools are arranging with their medical counterparts to include a lecture about PD and its risks during the teaching of DM to medical students.
Chief Medical and Dental Officers working together to establish joint policies
Dental tutors arrange joint lectures with their medical colleagues.
Individual dentists share the above risk information for their DM patients with their doctor as a matter of routine.
Purchasers of healthcare require professional collaboration.

Discussion

Periodontitis has been recognized as the sixth complication of PD [30], and in the UK, doctors have been advised by NICE to discuss this at their annual reviews [32]. It makes no mention of identifying relative risks, what referrals to dentists would be beneficial to their DM patients, or how to help those patients who do not have dental care or professional cooperation. However, it is a start on what could be a long road to improving the overall care of people living with DM. A simple questionnaire for doctors and their teams to determine the dental health of their diabetic patients could be a starting point [34], asking if their patients have regular dental care and recording who is their dentist and their CPITN scores, if known, with the objective of identifying those patients who are at greatest risk with red zone scores for both diseases, as this group could have higher levels of other diabetic complications. This will require further research, especially in relation to treatment outcomes from collaborative care, as well as methods to ensure effective inter-professional result sharing dependent upon doctors being willing to listen to and accept dental opinions [39].

Fortunately, periodontitis is both a treatable and preventable disease with good clinical outcomes when detected at an early stage. Prevention depends on the efficient and effective control of plaque by patients on a daily basis [40]. In relation to other costs of care for the main diabetic complications, dental treatment is relatively cheap. Recent evidence has shown that periodontal treatment is cost-effective for people with type 2 diabetes, assuming improvements in HbA1c levels are maintained [19].

It follows that doctors and their teams who support patients living with diabetes will have to be taught about periodontitis, the most important of which should be direct contact between fellow professionals, dentists, and doctors, and vice versa. [38,39]

Dentists will have to change their medical history forms to show whether the diabetes is Type 1 or Type 2, what the HbA1c results are, and understand their significance as determinants of risk together with that of their patients' therapeutic regimes. They should ask questions about glycaemic stability and whether their patient has had hospitalization for hypo- or hyper-glycaemic episodes.

Pending further research and 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 CPITN scores, from which they could find both their relative risks using the traffic light method described above and show both parties the results.

A pro forma has been designed to simplify the objective of information sharing about relative risks between the three parties—doctors, dentists, and people living with diabetes—because the traffic light system is readily understandable by all [38] and is freely available at www.chooseabrush.com.

It should be regarded as a starting point in the process of helping those living with diabetes to be more aware of their risks of complications and more involved in their care [39].

However, it will require both doctors, dentists, and their teams to make their results readily available for their patients as a matter of routine rather than being asked to provide them through access to medical records requests. For dentists who are not routinely sharing their CPITN results, this will represent a significant change in their working practices.

Meanwhile, multi-professional teams should work together and involve their patients to facilitate and improve diabetes management and clinical outcomes in a rapidly changing environment where dental care has been shown to mitigate diabetic complications.

Conclusions

Periodontitis is a significant factor for people living with DM that has been overlooked by doctors. Dentists should take the lead by informing them about the periodontal status of their patients as a first step in information and care sharing. Diabetics themselves should be used to keep both their medical and dental records and share them with their respective professional advisors.

Dentists should share the BPE scores with their patients as a matter of routine and with their diabetic patients' doctor and update their medical history form.

Doctors need to inform their patients living with diabetes about periodontal risks, ask about dental care, and explain the dental risk factor as defined by the CPITN score.

A formal dental and medical combined standard of care protocol would be beneficial before the centenary of the first description of diabetic periodontopathy in 2028.

Declaration of interest

The author is the inventor of the Chooseabrush method of plaque control.

International Journal of Endocrinology and Diabetes