These findings are intriguing but should be interpreted cautiously, because cause and effect could not be established. Nevertheless, these data clearly support the idea that a healthy mouth is essential for people living with diabetes.
Gum disease is not the only oral problem associated with diabetes. Dental cavities (also called caries) are the result of certain bacteria that accumulate on the tooth surface as part of the plaque. These bacteria (Streptococcus mutans, Lactobacillus species) metabolize sugar and other fermentable carbohydrates, producing lactic acid as a by-product. This acid can dissolve the mineral component of teeth (hydroxapatite). The dissolution results in a cavity, which can be sensitive to changes in temperature when the demineralization extends into the deep layers of the tooth.
The outer covering of the part of the tooth that is visible (the crown) is enamel; cavities become painful when the underlying dentin is affected. If the cavity progresses into the pulp, the inner chamber at the center of each tooth that contains nerves and blood vessels, the pain can become very intense. This “toothache” is often accompanied by facial swelling, as the infection spreads into the bone and soft tissue surrounding the tooth. In addition, when receding gums are present, a root cavity can develop. This is decay that develops mostly in older individuals if the root of the tooth is exposed. The root is covered with a softer mineralized tissue known as cementum. The cementum layer is not as dense as enamel and therefore very susceptible to the effects of acid.
The association between diabetes and tooth decay is not clear, and both higher and lower rates of cavities have been reported in people with diabetes compared with the general population. The reasons for these conflicting findings may relate to diet: a high carbohydrate intake can contribute to the development of dental cavities. Conversely, a low carbohydrate intake, which describes the dietary habits of many people with diabetes, results in a lower risk of cavities.
Recent studies involving older adults may help clarify this situation. Saliva not only helps begin the digestive process when food is in the mouth, but is also very important in buffering the acid produced by bacteria that metabolize fermentable carbohydrates. Some people with poorly controlled diabetes have reduced salivary flow (called xerostomia). Furthermore, a side effect of many medicines is a reduction in saliva. This change in the flow of saliva tends to occur in older individuals and appears to be more pronounced in people with diabetes.
People with reduced salivary flow are particularly susceptible to root cavities. Root cavities can be prevented or minimized by practicing good oral hygiene. This means removing plaque from the exposed root surfaces through brushing, as well as getting regular professional cleanings. Using a fluoride-containing toothpaste or receiving professional fluoride treatments may also help. Some severe cases may require dental restorations to cover the exposed and susceptible root surfaces.
Other oral problems
Another recognized oral complication of diabetes is burning mouth syndrome (BMS). BMS is not unique to diabetes and can have a variety of other causes, including the use of a number of medicines as well as certain hormonal abnormalities that occur predominately in women. In diabetes, BMS is often associated with a reduction in the production of saliva and a secondary yeast (Candida) infection. In BMS, the lining of the mouth is irritated, and the mucosal surfaces appear red. If saliva production is reduced, the mouth will also feel dry, and chewing food or even talking may become difficult.
Yeast infection can take a variety of forms and may contribute to the redness of the mucosa, or it may appear as white patches. It may be possible to scrape these yeast accumulations off the mucosal surfaces of the mouth. A visit to the dentist, and a comprehensive evaluation that includes an assessment of blood glucose control, are needed in any case of BMS.