Diabetes and Oral Health

Diabetes and oral health

The scope of the problem 

According to data from the Centers for Disease Control and Prevention (CDC), 37.3 million people or 11.3% of the population of the United States has diabetes. 28.7 million people have been diagnosed, while 8.5 million people have undiagnosed diabetes (CDC, 2021). Type I (insulin-dependent) diabetes accounts for 5%-10% of all diabetic cases. Type II (non-insulin dependent) diabetes accounts for 90% to 95% of cases.  

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Diabetes is the leading cause of blindness, kidney failure, and replacement of lower limbs among adults. By 2023, experts project to be the seventh leading cause of death worldwide (WHO, 2021).  

Gestational diabetes develops in the second half of pregnancy and is caused by placental hormones which increase insulin resistance. This results in a relative insulin deficiency. These cases resolve after the postpartum period, but they place the patient at an increased risk of the development of Type II diabetes later in life. 

The pathophysiology of diabetes 

Type I diabetes is a chronic autoimmune disease in which the insulin-producing beta cells of the pancreas produce little to no insulin. Insulin is the only hormone in the body which lowers blood glucose. 

This condition usually develops in childhood or adolescence. It requires exogenous insulin to regulate the blood glucose levels. Diseases such as pancreatitis and pancreatic malignancies which cause destruction of the pancreatic beta cells can also cause the development of Type I diabetes.  

Type II diabetes features a condition known as insulin resistance. In such cases, the patient’s body produces insulin, but the target receptors for the insulin-mediated glucose deposition into muscle cells and fat cells are less receptive to this process. This leads to a rise in the blood glucose levels. Excess weight, a sedentary lifestyle, genetics and poor dietary habits often accompany Type II diabetes. 

Prediabetes refers to blood glucose levels which are higher than normal but are not of the magnitude by which a formal diagnosis of diabetes can be made. However, patients with prediabetes have an increasing risk of developing Type II diabetes.   

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Systemic complications of diabetes 

The chronic elevation of blood glucose levels (hyperglycemia) causes progressive damage to many of the body’s organs and systems. The extended hyperglycemic state causes plaque to accumulate within the arteries. Built-up plaque leads to a decreased perfusion of blood throughout the body.  

This altered state includes adverse changes to the vascular anatomy, structure and function. These changes cause damage to the organs and tissues of approximately one-half to one-third of diabetic patients (Sakran, et. al., 2022)  

Some common macrovascular complications range from cardiovascular disease inclusive of ischemic heart disease to cerebrovascular disease such as ischemic strokes to peripheral vascular disease. Microvascular complications include retinopathy, neuropathy and nephropathy. The significance of these complications is evident as diabetics are two to three times more likely to develop cardiovascular disease and have a tenfold increased chance of the development of end-stage renal disease (ESRD) (Glick, 2019). 

Oral health considerations for diabetic patients 

It is beyond the scope of this discussion to list all of the mechanisms and complications by which diabetes affects oral health. However, the following are some of the most frequent.  

The adverse microvascular changes of diabetes decrease salivary gland function and flow and results in xerostomia (dry mouth). This causes a decrease in the self-cleansing action which saliva provides for the teeth and an increase in the retention of bacterial-laden plaque. Consequently, this increases the risk of the development of carious lesions and of periodontal disease. 

Saliva contains several antimicrobial substances which inhibit the adhesion of bacterial and fungal species to the teeth and soft tissues. The decreased activity of this function can cause the development of opportunistic infections such as oral candidiasis. The desiccated oral mucosal tissues in a xerostomic environment are more prone to injury. They can challenge the ability to wear complete or partial dentures which rely on an adequately lubricated mucosal surface for comfort and function. Dry mouth also inhibits basic functions like phonation, mastication and deglutition. 

After extensive research and the publication of 90 epidemiological studies in the 1990s, research established a bidirectional link between diabetes and periodontal disease. It identified periodontitis as the sixth complication of diabetes (Void-Holmes, 2022). 

Diabetics have an increased production of Advanced Glycation end-products (AGEs) which interact with their receptors (RAGEs) in the periodontal tissues. This stimulates a localized inflammatory response, which then causes clinical attachment loss and loss of the alveolar bone (Santonocito, et.al., 2022). This response hinders the nutrient delivery to the periodontal tissues.  

It also hinders the arrival of polymorphonuclear (PMN) leukocytes such as the neutrophils to the periodontal tissues. Neutrophils are the (PMN) which play a predominate role in the defense against oral bacterial pathogens. These pathogens initiate and potentiate periodontal disease.   

Diabetes and oral health 

Diabetic patients also have impaired synthesis of collagen which is the major component of the matrix of the periodontal tissues. This is why diabetic patients with poor glycemic control have a prolonged duration of healing after oral or periodontal surgery. Additionally, this duration is exacerbated for those diabetic patients who smoke, have poor nutritional habits, and who have a poor oral hygiene regimen.  

The bidirectional relationship between diabetes and periodontal also postulates how periodontal disease has an adverse effect upon glycemic control. During periodontal disease, systemic mediators of inflammation such as Tumor Necrosis Factor Alpha and Interleukin 1 and 6 have access to systemic circulation via the increased vascularity within the periodontal pocket.

These substances can increase insulin resistance and cause the blood glucose levels to rise by decreasing the uptake of glucose by the receptors of the muscle cells and adipose cells. They can also decrease the conversion of glucose into its storage form of glycogen in the liver, which will also increase the blood glucose levels. The bidirectional relationship between periodontal disease and diabetes is complex and requires further research for the mechanisms which involve this relationship.  

Further studies 

The relationship between periodontal treatment and its effect upon glycemic control has also been the subject of several studies. Randomized controlled trials investigating this relationship have yielded inconsistent results. Some studies have found that periodontal treatment such as root planning and scaling have not improved glycemic control. Others have found that HbA1c levels were reduced at 3 months with further reductions at six months (ADA, 2022).  

More large-scale studies are needed to determine the initial and long-term benefits of periodontal treatment and its influence on glycemic control. The inherent difficulties of these studies are that variables such as patient compliance with an ideal oral hygiene regimen, habits such as smoking, differences in immunocompetence among study participants and variations in diet individually or collectively can influence the interpretation of the from these studies.  

At some point in their career, most dental clinicians will treat patients with Type I and Type II diabetes. It is critical that they have a working knowledge of diabetes and oral health implications so that they can provide dental treatment which promotes all aspects of ideal health.  

Selected references 

  • Centers for Disease Control and Prevention (CDC). Diabetes. National Diabetes Statistic Report. Last Reviewed June 29, 2022. https://www.cdc.gov>diabetes>data>statistics-report. 
  • Diabetes: key facts. World Health Organization. November 10,2021. https://www.who.int/news-room/fact-sheets/detail/diabetes 
  • Sakran Nasser, Graham Yitka, Pintar Tadeja, et. al. The many faces of diabetes. Is there a need for re-classification? A narrative review. BM<C Endocrine Disorders. (2022). 22:9. https://bmcendoctdisord.biomedcentral.com>articles 
  • Glick, Michael. (Editor). The Oral-Systemic Connection. Second Edition. © 2019 by Quintessence Publishing Co, Inc. Batavia, Illinois. 
  • Void-Holmes Joy D. Diabetes and oral health. The not-so-sweet relationship. RDH Magazine.  
  • June 20, 2022. https://www.rdhmag.com>patient-care>article>dia 
  • Santonocito Simona, Polizzi Alessandro, Marchetti Enrico, et.al. Impact of Periodontitis on Glycemic Control and Metabolic Status in Diabetes Patients: Current Knowledge on Early Disease Markers and 
  • Therapeutic Perspectives. Hindawi. Mediators of Inflammation. August 13, 2022. https://www.hindawi.com>journals 
  • American Dental Association. Diabetes. Last Updated January 24, 2022. https://ada.org>research>oral-health-topics>d