Sherry Lee DeMone suffered from allergies, depression and intestinal issues for more than seven years before she was diagnosed with celiac disease. Many of her symptoms improved after she eliminated gluten from her diet, but her mouth shows permanent damage. At age 46, DeMone already wears dentures and is missing many of her teeth.

As her damaged teeth were extracted one by one, "dentists didn't give any reasons for why my teeth were in terrible shape," said DeMone, who lives outside Lunenburg, N.S.

Nevertheless, dental problems are common in people with celiac disease, studies have shown. But "if you talk to most dentists, they would not know this connection," said Dr. Mohsin Rashid, a gastroenterologist at the IWK Health Centre in Halifax.

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Awareness of the link is crucial, since in some patients, tooth enamel defects and recurrent canker sores are the only manifestations of celiac disease, Rashid said. If a dentist notices abnormalities in tooth enamel in a routine check-up, "this is a relatively easy way of suspecting or identifying this condition," he explained.

Celiac disease is a severe form of gluten intolerance. In patients with the disease, the surface of the small intestine is damaged by gluten protein found in such grains as wheat, rye and barley. The disease interferes with the body's ability to absorb essential nutrients, including vitamins and minerals. Symptoms can include anemia, diarrhea, weight loss and depression. Left untreated, the disease can lead to osteoporosis, serious vitamin and mineral deficiencies and an increased risk for lymphoma and other cancers.

Celiac disease affects about 1 in 100 Canadians, but according to Rashid, up to 90 per cent are undiagnosed. Screening for celiac disease involves a blood test – which is covered by medicare in every province except Ontario – and an intestinal biopsy to confirm results.

Although celiac disease affects the small intestine, more than half of celiac patients have no gastrointestinal symptoms, Rashid said. Dental enamel defects, however, are found in the majority of celiac patients, according to a study published in April in the European Journal of Internal Medicine. Researchers from the University of Pavia, Italy, detected enamel defects in 46 out of 54 patients with celiac disease – or 85 per cent.

The prevalence of enamel defects in the study is consistent with findings from previous studies, said Anthony Iacopino, a spokesman for the Canadian Dental Association and dean of dentistry at the University of Manitoba. "Anywhere between 70 and 80 per cent of celiac patients do have some type of tooth abnormality."

In patients with celiac disease, dental enamel may be rough and discoloured, with spots of yellow or brown. There may be structural defects, include deep horizontal grooves and large pits, or the entire tooth may be irregular in shape.

Researchers have presented two possible explanations for the defects. Autoimmune responses triggered by celiac disease may affect tooth development. Another theory is that malabsorption of nutrients such as calcium and vitamin D may prevent patients from building healthy tooth enamel.

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Iacopino noted that patients may have dental enamel defects for other reasons, including a genetic predisposition or exposure to tetracycline antibiotics. "Just because you see [enamel defects] doesn't mean it's celiac disease," he said. But if the patient has tooth abnormalities as well as frequent canker sores, celiac disease is a likely culprit, he added.

In patients with no other symptoms, dentists and dental hygienists can play an important role in recommending screening for celiac disease, noted a 2011 report in the Journal of the Canadian Dental Association.

Early diagnosis is especially important for children. Although celiac disease can strike at any age, dental-enamel defects "can only occur when teeth are forming," Iacopino said. Children diagnosed with celiac disease before their adult teeth are fully formed, at about age 7, have a good chance of developing healthy tooth enamel if the disease is treated with a gluten-free diet, he said.

A diagnosis in adulthood is too late to reverse the damage to a patient's teeth, however. Treatment options for dental enamel defects include sanding the teeth into more regular shapes and adding veneers and crowns, Iacopino said.

In DeMone's case, her teeth were so weak that one dentist recommended extracting them all. DeMone refused, opting instead to wear upper dentures and live with gaps in the bottom row. The teeth that were lost, she said, "weren't even worth fixing."