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 Table of Contents  
Year : 2021  |  Volume : 8  |  Issue : 1  |  Page : 2-8

A narrative review of Diabetes mellitus: An update for dentists

1 Department of Conservative Dentistry, The University of Jordan, Amman, Jordan
2 Department of Oral Surgery, Faculty of Dentistry, The University of Jordan, Amman, Jordan
3 Department of Biological Sciences, School of Science, The University of Jordan, Amman, Jordan

Date of Submission24-Jul-2020
Date of Decision18-Oct-2020
Date of Acceptance28-Nov-2020
Date of Web Publication17-Apr-2021

Correspondence Address:
Dr. Alaa AL-Haddad
Department of Conservative Dentistry, Faculty of Dentistry, The University of Jordan, Amman
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/sjos.SJOralSci_68_20

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Introduction: Diabetes mellitus (DM) is a common metabolic disorder and a leading cause of mortality and morbidity worldwide. Dentists are increasingly encountered with patients affected by this chronic condition.
Aim: To a review on updates in DM, dental management and emergencies.
Methods: Database search was carried out in PubMed and Google scholar limited to articles of English language from 1998 to 2021 and pertaining to the keywords diabetes, orofacial manifestations , dental management diabetic emergency. A narrative review of this search is presented in this article.
Results and Discussion: This article gives a concise update on DM and discuss the management of diabetic patients in a dental setting.
Conclusion: Discussion of the possible orofacial manifestations of DM and management of diabetic emergencies is emphasized for efficicient dental practice.

Keywords: Complications, dentistry, diabetes, medicine

How to cite this article:
AL-Haddad A, Hassona Y, Silawi A, Al Kayed A. A narrative review of Diabetes mellitus: An update for dentists. Saudi J Oral Sci 2021;8:2-8

How to cite this URL:
AL-Haddad A, Hassona Y, Silawi A, Al Kayed A. A narrative review of Diabetes mellitus: An update for dentists. Saudi J Oral Sci [serial online] 2021 [cited 2022 Dec 2];8:2-8. Available from: https://www.saudijos.org/text.asp?2021/8/1/2/313928

  Introduction Top

Diabetes mellitus (DM) is a complex metabolic disorder characterized by abnormal protein, lipid, and carbohydrate metabolism. The primary feature of this disorder is elevation in blood glucose level, resulting from either reduction in insulin secretion, increase in target tissue resistance to the action of insulin, or both.[1]

DM is a significant world health problem. Globally, it is estimated that the number of people with diabetes will increase to 300 million by the year 2025.[2] According to the National Centre for diabetes, Endocrinology and Genetics, the overall age-standardized prevalence rate in Jordan increased from 13.0% in 1994 to 17.1% in 2004, 22.2% in 2009, and 23.7% in 2017. Known diabetes in the 2017 survey accounted for 82.6% of people with diabetes. A HbA1c of <59 mmol/mol (7.5%) was observed in 41.4% of participants with known diabetes.[3] Consequently, dental practitioners will encounter an increasing number of patients with diabetes presenting for dental treatment in years to come.

This narrative review from selective literature will help dental practitioners to have an update on current literature. It also can provide enhanced quality of care for diabetes patients and preparedness for dental practice challenges.

Aim: This article aims to provide an overview of DM and discuss aspects of the condition relevant to the practice of dentistry. Objectives: To analyze updates on diabetes mellitus, determine dental management guidelines in diabetes care with a particular focus towards emergencies.

Methods: Database search was carried out in PubMed and Google scholar limited to articles of English language from 1998 to 2021 and pertaining to the keywords diabetes, orofacial manifestations , dental management diabetic emergency. A narrative review of selective literature is presented in this article. This review does not need ethical approval. Informed consent was obtained from the patient for the use of unidentifiable patient data.

  Pathogenesis and Classification Top

The hallmark of DM is elevation in blood glucose levels (hyperglycemia) resulting from either a defect in insulin secretion or a change in insulin action [Figure 1]. Consequently, there are two main types of DM; type 1 and type 2.[4]
Figure 1: Pathophysiology of diabetes mellitus

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Type 1 DM is a relatively uncommon disease characterized by an absolute insulin deficiency due to autoimmune destruction of pancreatic β cells in genetically predisposed individuals. The onset of signs and symptoms in type 1 DM is relatively abrupt and usually occurs at a young age (<30 years). Insulin administration is essential in patients with type 1 DM and without it, severe dehydration and diabetic ketoacidosis (DKA) can develop, which may result in coma or even death.[4]

Type 2 accounts for approximately 95% of all cases of DM. It is a disease of middle age and elderly people, caused principally by resistance to the peripheral action of insulin. Although inadequate secretion of insulin may occur later on, absolute insulin deficiency is not a feature of type 2 DM. The hyperglycemia in type 2 DM is not caused by autoimmune destruction of β cells, but it is rather a failure of these cells to meet an increased demand for insulin.[4] There is a strong genetic predisposition in type 2 DM. Sixty percent of type 2 patients have either a parent or a sibling with the disease, and it is estimated that the life time risk for a first degree relative of a patient who has type 2 DM is five to ten times higher than that of patients without a family history of DM.[4] Other risk factors for type 2 DM include obesity, lack of physical activity, hypercholesterolemia, low high-density lipoproteins, and hypertriglyceridemia.[4]

Impaired glucose tolerance and impaired fasting glycemia are intermediate conditions in the transition between normality and diabetes. Patients with these conditions are referred to as having “prediabetes” and are at high risk of progressing to type 2 DM, although this is not inevitable.[4]

  Diagnosis Top

According to the American Diabetic Association, at least one of the following conditions must exist to establish the diagnosis of DM:[5]

  1. Fasting plasma glucose ≥126 mg/dl (≥7 mmol/L)
  2. Presence of the classic symptoms of diabetes (polyuria, polyphagia, polydipsia, visual blurring, thrush, lethargy, and unexplained weight loss), with unequivocal hyperglycemia (random plasma glucose ≥200 mg/dl (11 mmol/L))
  3. Abnormal Oral Glucose Tolerance Test (OGTT): This involves giving the patient 75 g of glucose in 300 ml of water to drink the morning after an overnight fast. Blood glucose is measured every 30 min for 2 h. The test is positive if the 2-hour plasma glucose ≥200 mg/dl (11 mmol/L)
  4. Hemoglobin A1c (HbA1c) ≥6.5%: HbA1c is a form of hemoglobin that is measured primarily to identify the average plasma glucose concentration over a period of 2–3 months. This test therefore is useful to monitor glycemic control in diabetic patients.

Prediabetes is the state in which blood glucose level is higher than normal but not high enough to meet the diagnostic criteria of DM.[1] A patient is referred to as having prediabetes if:

  1. Fasting plasma glucose 100–125 mg/dl (6.1–6.9 mmol/L)
  2. Plasma glucose 140–199 mg/dl (7.8–11 mmol/L) following a 2 h OGTT
  3. HbA1c 5.7%–6.4%.

  Management Top

Medical management of patients with DM aims to allow a normal life, minimize symptoms, and avoid complications such as diabetic retinopathy, nephropathy, neuropathy, and cardiovascular disease.[6]

Dietary changes, life style modifications, patient education, and smoking cessation are essential to the management of DM.[6] Patients with type 1 DM invariably require insulin replacement therapy. Exogenous insulin is administered by subcutaneous injection or through an insulin pump. Insulin replacement therapy should mimic the physiologic release of insulin which is characterized by a continuous basal secretion, to prevent fasting hyperglycemia, as well as prandial insulin release to prevent postprandial hyperglycemia.[7] Insulin is classified as rapid, intermediate, and long acting depending on the duration of activity.[7]

The management of type 2 DM is a complex process that often involves a step wise regimen of diet modification, life style adjustments, oral hypoglycemic drugs, and ultimately in some individuals' insulin administration.[8] A wide range of oral hypoglycemic drugs to treat type 2 DM exist, and they either increase pancreatic insulin secretion or improve insulin action. Oral hypoglycemic drugs include insulin secretagogues (such as sulfonylureas and meglitinides), insulin sensitizers (such as biguanides and thiazolidinediones), α-glucosidase inhibitors, and incretins.[8] Oral hypoglycemic drugs can be used alone or in combination with one another and with insulin.

Tight glycemic control is essential to prevent complications and improve treatment outcome. The glycosylated hemoglobin test (HbA1c) is widely used to assess glycemic control. This test measures glucose that binds to blood hemoglobin within the circulating erythrocytes. It is the preferred test for the medical evaluation of diabetic control because it measures the blood glucose level over a period of 8–12 weeks (the life span of red blood cells).[9] For glycemic control, it is recommended that the level of HbA1c level (monitored every 3 months) be maintained at <7%.[10]

Poor glycemic control is associated with increased rate of complications, including poor wound healing and postoperative infections [Table 1].
Table 1: Chronic complications of DM

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  Orofacial Manifestations Top

There are no specific oral manifestations of DM [Table 2]; however, prolonged hyperglycemia has been associated with increased incidence, progression, and severity of gingivitis, periodontitis, and alveolar bone loss independent of the severity of plaque accumulation.[9] Evidence also indicates that periodontitis might contribute to insulin resistance and increase the risk of ischemic heart disease and diabetic nephropathy. The relationship between diabetes and periodontitis is bidirectional. The risk of periodontitis is increased 2–3 times in people with diabetes compared to individuals without, 9 and the level of glycemic control is key in determining risk.[11],[12] Similar to the other complications of diabetes, the risk for periodontitis increases with poorer glycemic control. The majority of the research on periodontitis and diabetes has focused on type 2 diabetes (possibly because these diseases tend to mainly present in middle-aged adults), but type 1 diabetes has also been associated with increased periodontal destruction in children and teenagers.[13]
Table 2: Effects of diabetes on orofacial tissues

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The pathogenic processes that link the two diseases are the focus of much research, and it is likely that upregulated inflammation arising from each condition adversely affects the other. Diabetes increases the risk for periodontitis by contributing to increased inflammation in the periodontal tissues. For example, in diabetes, there is increased deposition of advanced glycation end-products (AGEs) in the periodontal tissues, and interactions between AGEs and their receptor (the receptor for AGEs, found particularly on macrophages) lead to activation of local immune and inflammatory responses.[14] These upregulated responses result in increased secretion of cytokines such as interleukin-1 β (IL-1 β), tumor necrosis factor-α (TNF-α), and IL-6, increased oxidative stress, and disruption of the receptor activator of nuclear factor kappa-B ligand/osteoprotegerin axis to favor bone resorption.[14],[15] All of these factors result in local tissue damage, increased breakdown of the periodontal connective tissues and resorption of alveolar bone, thus exacerbation of periodontitis. Adiposity and pro-inflammatory adipokines (cytokines secreted by adipose tissue) further contribute to the pro-inflammatory environment.[15] It has also been shown that individuals with periodontitis and diabetes have elevated levels of circulating TNF-α, C-reactive protein and markers of oxidative stress, with reductions in the levels of these mediators following periodontal treatment.[14]

Several studies investigated the impact of periodontal treatment on glycemic control in people with diabetes. The findings of these studies (many of which were conducted as randomized controlled trials) demonstrated reduction in HbA1c following periodontal therapy. The precise mechanisms that lead to reductions in HbA1c and improved glycemic control following periodontal treatment in people with diabetes are not completely clear, but are presumed to arise from the combined effects of reduced systemic inflammation and reduced bacterial challenge systemically, leading to improvements in insulin resistance and insulin signaling.[14]

Dry mouth or xerostomia may result from hyperglycemia-associated dehydration [Figure 2]. Diabetic patients therefore might suffer from xerostomia related complications such as increased risk of dental caries, candidal infection, and angular chelitis, and abnormal taste sensation.[9] Occasionally, there is swelling of salivary glands (sialosis) due to autonomic neuropathy. Mucosal changes such as lichenoid white lesions and glossitis have been described in diabetic patients [Figure 3].[9] Burning mouth or tongue may develop in diabetic patients as a result of xerostomia, candidiasis, or diabetic neuropathy. Poorly controlled diabetics are predisposed to severe infections such as mucormycosis (deep fungal infection) of the paranasal sinuses and osteomylitis of the jaw.[9]
Figure 2: Thick and frothy saliva as a sign of salivary hypofunction in a poorly controlled diabetic patient

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Figure 3: Tongue Depapillation and candidal infection in a poorly controlled diabetic patient

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  Dental Management Considerations Top

Dental management of diabetic patients is based on an understanding of the diabetic patient's history. Important information in the patient's medical history includes details of the current diabetic regimen, adequacy of blood sugar control, status of diabetic complications, and status of comorbidities such as hypertension, obesity, lipid disorders, osteoporosis, and smoking.[16] Patients with well controlled diabetes can often be treated in a similar way to nondiabetic individuals. Poorly controlled diabetics should be referred for improved control of their blood glucose before elective surgical procedures [Figure 4].
Figure 4: Algorithm for the management of diabetic patients in dentistry

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Dental appointments should not interfere with the patient's meals schedule. Morning appointments are preferable because diabetic patients are often more stable and better able to tolerate dental procedures. In addition, multiple short appointments are more suitable than a single prolonged appointment.

Frequent assessment of the patient's periodontal health status is important because diabetic patients have an increased risk of periodontitis and poor periodontal health has been linked to insulin resistance and increased risk of diabetes-related complications.[15] Therefore, maintenance of good oral hygiene and frequent appointments for periodontal prophylaxis are recommended.

Diabetic patients, especially poorly controlled, have compromised cell-mediated immunity, phagocytosis, and bactericidal activity.[17] Therefore, odontogenic infections in diabetic patients should be treated early and aggressively to prevent rapid spread and systemic involvement. In addition, severe odontogenic infections can upset glycemic control and predispose diabetic patients to acute complications such as DKA and hyperosmolar nonketotic coma.[17] Therefore, severe odontogenic infection in poorly controlled diabetic patients may require hospital admission for observation, glycemic control, and administration of intravenous antibiotics.

The use of antibiotics to prevent postoperative infection in diabetic patients is a controversial issue. Unfortunately, limited evidence-based data are available about the risk of infection in diabetic patients following oral surgical procedures.[16],[17] However, it is generally held that poor glycemic control is associated with delayed wound healing and an increased risk of postoperative infection.[16] On the other hand, the well-controlled diabetic is probably at no greater risk of postoperative infection than is the nondiabetic.[16] Therefore, routine uncomplicated oral surgical procedures in well-controlled diabetic patients (HbA1c < 8%) do not require antibiotic prophylaxis. Prophylactic antibiotics should be considered for surgical procedures in poorly controlled diabetic patients, particularly if the procedure is prolonged, complicated, or extensive.

  Diabetic Emergencies Top


Hypoglycemia is the main issue that encounter dentists when treating diabetic patients. Hypoglycemia is more common in diabetic patients treated with insulin but it may occur also in patients controlled by oral hypoglycemic drugs. The main precipitating factors are excessive therapeutically administered insulin or oral hypoglycemic drugs, missed or inadequate meals, and unplanned exertion. Symptoms of hypoglycemia occur when blood glucose level is <3 mmol/L (60 mg/dl), although many people with DM, who are used to higher blood glucose, have symptoms at higher blood glucose levels.[18] The cardinal features of hypoglycemia are initially anxiety, poor concentration with impaired cognition, proceeding to a decrease in conscious level which may progress to coma and seizures. Sweating, tremor, and tachycardia are common physical signs observed in hypoglycemic patients.[18] Early recognition of symptoms and signs of hypoglycemia is important to prevent unwanted consequences such as cardiac arrhythmias and transient cognitive defects. Immediate treatment with glucose should be given orally if the patient is conscious. Glucagon 1 mg may be administered by intramuscular or subcutaneous injection if the patient is unable to cooperate or swallow oral glucose. Alternatively, hypoglycemia should be corrected with the administration of intravenous dextrose saline [Figure 5].[18]
Figure 5: Algorithm for the management of hypoglycemic coma in a dental setting

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Hyperglycemia: Diabetic ketoacidosis and hyperosmolar nonketotic coma

DKA and hyperosmolar nonketotic coma (HNOK) occur as a result of relative or absolute insulin deficiency; resulting in hyperglycemia. High plasma glucose levels cause osmotic diuresis with loss of sodium and water, which can lead to hypotension and shock. Infections, myocardial infarction, excessive sugary intake, and trauma/surgery are the main precipitating factors. Symptoms usually develop relatively slowly and include thirst, polyuria, dehydration, vomiting, abdominal pain, and impaired consciousness. DKA and HNOK are unlikely to occur in a dental setting, however, if suspected, prompt transfer to the emergency department is required. The management usually involves intravenous fluid replacement, intravenous insulin, and correction of metabolic acidosis.[18]

Conclusion: The current review highlights diabetes related dental emergencies and complications. On the otherhand, there is a limitation of available consistent data on incidences of diabetic dental emergencies in dental practice. Hence this review alerts and reinforces general dental practitioners and specialists' knowledge and preparedness in a situation of such a medical emergency.

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Conflicts of interest

There are no conflicts of interest.

Declaration of patient consent: The authors certify that they have obtained all appropriate patient consent forms. In the form the 1 patient(s) has/have given his/her/their consent for 2 his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

  References Top

Diabetes Canada Clinical Practice Guidelines Expert Committee, Punthakee Z, Goldenberg R, Katz P. Definition, classification and diagnosis of diabetes, prediabetes and metabolic syndrome. Can J Diabet 2018;42 Suppl 1:S10-5.  Back to cited text no. 1
King H, Aubert RE, Herman WH. Global burden of diabetes, 1995- 2025: Prevalence, numerical estimates, and projections. Diabetes Care 1998;21:1414-31.  Back to cited text no. 2
Ajlouni K, Batieha A, Jaddou H, Khader Y, Abdo N, El-Khateeb M, et al. Time trends in diabetes mellitus in Jordan between 1994 and 2017. Diabet Med 2019;36:1176-82.  Back to cited text no. 3
Petersmann A, Nauck M, Müller-Wieland D, Kerner W, Müller UA, Landgraf R, et al. Definition, classification and diagnosis of diabetes mellitus. Exp Clin Endocrinol Diabetes 2018;126:406-10.  Back to cited text no. 4
American Diabetes Association. 2. Classification and diagnosis of diabetes: Standards of medical care in diabetes-2018. Diabetes Care 2018;41 Suppl 1:S13-27.  Back to cited text no. 5
American Diabetes Association. 3. Comprehensive medical evaluation and assessment of comorbidities: Standards of medical care in diabetes-2018. Diabetes Care 2018;41 Suppl 1:S28-37.  Back to cited text no. 6
Janež A, Guja C, Mitrakou A, Lalic N, Tankova T, Czupryniak L, et al. Insulin therapy in adults with type 1 diabetes mellitus: A narrative review. Diabetes Ther 2020;11:387-409.  Back to cited text no. 7
Hong, T., Su, Q., Li, X., Shan, Z., Chen, L., Peng, Y., Chen, L., Yan, L., Bao, Y., Lyu, Z., Shi, L., Wang, W., Guo, L., Ning, G., Mu, Y. and Zhu, D. (2021), Glucose-lowering pharmacotherapies in Chinese adults with type 2 diabetes and cardiovascular disease or chronic kidney disease. An expert consensus reported by the Chinese Diabetes Society and the Chinese Society of Endocrinology. Diabetes Metab Res Rev e3416. https://doi.org/10.1002/dmrr.3416  Back to cited text no. 8
Mauri-Obradors E, Estrugo-Devesa A, Jané-Salas E, Viñas M, López-López J. Oral manifestations of Diabetes Mellitus. A systematic review. Med Oral Patol Oral Cir Bucal 2017;22:e586-94.  Back to cited text no. 9
Papachristoforou E, Lambadiari V, Maratou E, Makrilakis K. Association of Glycemic Indices (Hyperglycemia, Glucose Variability, and Hypoglycemia) with Oxidative Stress and Diabetic Complications. J Diabetes Res. 2020 Oct 12;2020:7489795. doi: 10.1155/2020/7489795. PMID: 33123598; PMCID: PMC7585656.  Back to cited text no. 10
Mealey B L, Ocampo G L. Diabetes mellitus and periodontal disease. Periodontol 2000;44:127-53.  Back to cited text no. 11
Tsai C, Hayes C, Taylor GW. Glycaemic control of type 2 diabetes and severe periodontal disease in the US adult population. Community Dent Oral Epidemiol 2002;30:182-92.  Back to cited text no. 12
Kocher T, König J, Borgnakke WS, Pink C, Meisel P. Periodontal complications of hyperglycemia/diabetes mellitus: Epidemiologic complexity and clinical challenge. Periodontol 2000;78:59-97.  Back to cited text no. 13
Polak D, Shapira L. An update on the evidence for pathogenic mechanisms that may link periodontitis and diabetes. J Clin Periodontol 2018;45:150-66.  Back to cited text no. 14
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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

  [Table 1], [Table 2]


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