Cavities, gum disease, abscessed teeth -- everyone knows a dentist is looking for these at your checkup. What most people don't know is that the dentist is also looking for the connections these things may have to your overall health. From diabetes to osteoporosis, and from heart disease to acid reflux, dentists help patients discover what ails their bodies, by seeing what's in their mouths.

Take diabetes, for example. Dr. Tim McGaw, professor of oral medicine and pathology at the University of Alberta, says, "We know that people with poorly controlled diabetes are more likely to have oral health problems."

Research confirms diabetics have a harder time fighting infections such as gum disease and that they are less able to repair the bone loss caused by such infections. A dentists may be the first health-care provider to suspect diabetes when gum disease is found at a routine checkup.

The dentist's observations of a patient who already knows that they have diabetes can also be useful. If a patient's diabetes is not properly managed, the dentist may notice that their medication has caused the patient to have dry mouth (xerostomia). Saliva acts to help keep the teeth and gums clean, and also acts as a buffer to neutralize the harmful acids produced by cavity-causing bacteria. Sometimes patients don't even notice they have a dry mouth, but the dentist may notice the sudden appearance of cavities, or irritated or infected gums.

However, there's good news from dentists for diabetic patients. "The relationship between periodontal disease and diabetes appears to be a two-way street," says McGaw. "Preliminary studies have documented that when the periodontal disease is cleaned up or managed through improved personal oral care, professional cleaning and scaling, and/or antibiotics, there has also been improvement in the medical control of the diabetes."

As studies illustrate this link, oral health care will be as important to controlling diabetes as diet and exercise.

Menopausal women are also especially prone to periodontal disease, due to changes in calcium levels in the body making bone loss difficult to repair, as in diabetics. Interestingly, observation of a patient's full-jaw X-ray could give the dentist reason to believe the patient is suffering from osteoporosis and to refer them to their physician for assessment.

Pregnant women should not skip dental checkups. With rapidly changing hormone levels, many pregnant women find that their gums swell and bleed during pregnancy. This is important to manage, given findings that periodontal disease may be linked with not only low birth weight, but pre-term labour.

Oral bacteria are also implicated in respiratory diseases. Those with periodontal disease and untreated decay are more prone to respiratory infection. There is a correlation between oral diseases and chronic obstructive pulmonary disease and, of particular concern to the ill, of pneumonia being caused by the inhalation of oral bacteria. Regular dental care is as essential to the ill or hospitalized patient as it is to a healthy one.

Digestive disorders are also often discovered by the dentist. Bulimia or acid reflux (or gastroesophageal reflux disease) can lead to a very specific erosion of the teeth. Other signs dentists watch for include cobblestone fissures in the mouth, which can denote gastro-intestinal diseases such as Crohn's. Swollen lips can also indicate Crohn's, ulcerative colitis or similar gastro-intestinal diseases. Chronic liver disease or hepatitis can result in thin, yellowish gum tissue, and candidiasis (thrush) will cause white patches to appear.

"Candidiasis is often a sign of an underlying disease that is compromising the immune system," says Dr. Randall Croutze, a dentist in Edmonton and past-president of the Alberta Dental Association and College.

While dentists look for connections to overall health, it's crucial that patients keep their dentists informed of changes to their health.

People with prostheses such as artificial joints, pacemakers or heart valves, or on chemotherapy, are prone to infections, and oral bacteria can get into the bloodstream to cause severe infection, so antibiotics may be prescribed before or after dental treatment for prevention.