The oral cavity (mouth) plays many critical roles in physiologic processes such as, digestion, respiration, and speech and this makes it an important anatomical structure in the body. It is also unique for the presence of exposed hard tissue (teeth) surrounded by mucosa. However, a wide array of systemic diseases, encountered in internal medicine has manifestations in the oral cavity. It is important to state that most of these oral manifestations should alert us as individuals and also the dental practitioners to the possibility of concurrent systemic disease or latent systemic disease that may develop subsequently.
Many systemic diseases are reflected in the oral mucosa and the jaw bones. Some of the effects of these systemic diseases that can be seen in the oral cavity include;
Mucosal changes which may include ulceration or mucosal bleeding.
Immunodeficiency can lead to opportunistic diseases such as infection and neoplastic changes.
Bone disease can affect the maxilla and mandible.
Systemic disease can cause dental and periodontal changes.
Drugs prescribed for a systemic disease can affect oral tissue.
Systemic diseases may predispose the mucosa more easily to injury and mild irritation and chronic inflammation may cause lesions that otherwise would not occur.
The various systemic conditions that can have effect in the mouth are;
Endocrine disorders
GIT diseases
Immunological disorders
Drug induced conditions
Haematological disorders
Nutritional disorders
Cardiovascular disorders
Cutaneous diseases
Let’s start with Endocrine disorders and our focus today will be on diabetes mellitus (DM) and the associated effects it has in the oral cavity. However, before I go into the nitty-gritty of oral changes that occur in diabetes mellitus, let me acquit you with what diabetes mellitus is.
DIABETES MELLITUS
It is a chronic disorder of carbohydrate metabolism that is characterized by, abnormally high blood glucose levels. This can result from a lack of insulin, defective insulin that does not work to lower blood glucose levels, or increased insulin resistance due to obesity.
In an healthy individuals, the blood sugar levels of 72 to 108 mg/dL (4.0-6.0 mMol/L) is considered normal when fasting and up to 140 mg/dL (7.8mMol/L) 2 hours after eating.
Glucose normally signals the pancreatic beta cells to produce insulin. The hormone is then secreted into the bloodstream to facilitate the uptake of glucose into fat and skeletal muscle. In the presence of insulin, fat and skeletal muscle cells can use glucose as an energy source.
Without insulin, tissue is broken down to provide energy and weight loss occurs. A severe hyperglycemia can lead to diabetic coma. Ketone can be produced by the breakdown of fatty acids resulting in ketoacidosis in which the pH of blood is lowered. When this occurs, the phagocytic activity of macrophages is reduced and neutrophil chemotaxis is delayed. There will also be abnormal collagen production.
There are three types of diabetes mellitus;
Insulin-dependent diabetes mellitus---------Type 1
Non–insulin-dependent diabetes mellitus-----Type 2
Gestational diabetes mellitus which occur during pregnacy.
Insulin dependent diabetes (Type 1)
This is thought to be an autoimmune disease in which the Insulin-producing cells of the pancreas are destroyed. About 3 to 5% of all diabetic patients have this type. It can occur at any age; however the peak is at 20years. Acute onset of type 1 diabetes usually present with polydipsia (excessive thirst and intake of fluid), polyuria (excessive urination), and polyphagia (excessive appetite).These patients will require insulin their entire lives.
The current approach to management of these patients involves multiple insulin injections and proper diet, exercise, and frequent determination of blood glucose levels. But multiple injections of insulin can more readily lead to low blood sugar (hypoglycemia) and insulin shock (severe hypoglycemia).New methods of treatment include use of Nasal spray rather than injection and Insulin pump.
Non- Insulin dependent diabetes mellitus (Type 2)
It is characterized by insulin resistance. It is the most common type of DM. About 95% of all diabetic patients have this type. It usually occurs in patients aged 35 to 40 years or older. Many of these individuals are obese. Obesity probably decreases the number of receptors for insulin binding in sensitive tissues like fat or muscle. Diet and weight reduction and lifestyle modifications may control it in some individuals; others may require oral hypoglycemic agents.
Oral manifestations in Diabetes Mellitus include;
Taste disturbances
More than one-third of adults with diabetes has hypogeusia or diminished taste perception, which could result in hyperphagia and obesity. This sensory dysfunction can inhibit the ability to maintain a proper diet and can lead to poor glycemic regulation.
Also, glossodynia and/or stomatopyrosis or Burning mouth syndrome has been associated with diabetes mellitus. Patients may experience long-lasting oral dysesthesias, which could adversely affect oral hygiene maintenance.
Periodontal diseases
Persistent poor glycemic control is associated with the incidence and progression of diabetes-related complications, including gingivitis, periodontitis and alveolar bone loss.
Several mechanisms of periodontal diseases in DM including alterations in host response, subgingival microflora, collagen metabolism, vascularity, gingival crevicular fluid and heredity patterns have been proposed. Multiple pathophysiological mechanisms (compromised neutrophil function, decreased phagocytosis and leukotaxis) have also been implicated in the increased alveolar bone loss found in patients with diabetes.
Evidence supports the observation that periodontal infections contribute to problems with glycemic control. Periodontitis-induced bacteremia will cause elevations in serum pro -inflammatory cytokines, leading to hyperlipidemia, and ultimately causing an insulin-resistance syndrome and contributing to destruction of pancreatic beta cells.
Therefore, an essential aspect of managing diabetes is by treating chronic periodontal infections.
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Salivary dysfunction
People with diabetes have been reported to complain of dry mouth, or xerostomia, and experience salivary gland dysfunction. This may be related to polyuria or to alterations in the basement membranes of salivary glands.
Xerostomic complaints may be due to thirst, a common manifestation of diabetes. Saliva may be useful to diagnose and/or monitor systemic diseases, and it may be possible in the future to evaluate glucose levels or diabetes-specific autoimmune markers from oral fluids, thus eliminating the need for serum blood evaluation for diagnosis and monitoring.
Oral mucosal diseases
Greater prevalence of oral lichen planus and recurrent aphthous stomatitis as well as oral infections are seen in patients with DM. This may be due to chronic immunosuppression and require continued follow-up by health care practitioners. In patients with type 1 diabetes, chronic immunosuppression most likely is a sequel of the disease, whereas in patients with type 2 diabetes, acute hyperglycemia causes alterations in immune responsiveness.
Oral infections
Fungal infections of oral mucosal surfaces and removable prostheses are more commonly found in adults with diabetes. Candida pseudohyphae, a cardinal sign of oral Candida infection, have been associated significantly with cigarette smoking, use of dentures and poor glycemic control in adults with diabetes.
Salivary hypofunction may also increase the oral candidal carriage state in adults with diabetes.
In conclusion, the global goal of oral health is to minimize the impact of oral manifestations of systemic diseases on individual and society at large and to use these manifestations for early diagnosis, prevention and effective management of patients.
Thank you all for reading through.
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