A searing 98.6 degrees... Without any water.
by Aileen SalinasIt’s like trying to eat with a mouth full of sand.
That is how some people describe living with the complications of salivary dysfunction. A low saliva flow rate can make a person’s life unbearable and those with salivary dysfunction face serious health risks.
The average person produces just over two cups of saliva every day. Although many people assume saliva merely aids in food digestion, its main role is protection against disease and decay of the mouth’s tissue.
Chih-Ko Yeh, Ph.D., B.D.S., associate professor of dental diagnostic science, is one of the Health Science Center’s experts unlocking the secrets of saliva to find relief for patients with salivary dysfunction. Their knowledge will be the basis for developing better care for patients like Keiko Fabacher. Fabacher, age 65, recently was diagnosed with Sjögren’s syndrome, an autoimmune disease that causes the body’s immune system to attack salivary glands. It affects more than 2 million Americans, predominantly postmenopausal women.
During a routine dental visit, Fabacher’s dentist noticed a calcification in her salivary glands. "I noticed my eyes were dry and I sometimes had to drink more water with my meals, but I didn’t think anything of it," Fabacher said. Her dry eyes and dry mouth were symptoms of Sjögren’s syndrome. "Now my tongue is dry and cracked and I always need to drink something to help me eat."
Howard Dang, Ph.D., associate professor of community dentistry, is exploring the source of Sjögren’s syndrome. "In Sjögren’s, salivary glands are attacked. We believe the lymphocytes may induce cell death," Dr. Dang said. "We’re pursuing research that investigates that process. By understanding how these cells die, we could develop better therapies for Sjögren’s and potentially other diseases linked with low salivary flow rate."
While current medications and treatments offer some relief, they do not compare to the comfort and protection of natural saliva. "Before I go to bed I have to put something under my tongue to help lubricate my mouth," Fabacher said. "Nights are the most painful. Sometimes I develop sores on the sides of my tongue because my mouth is so dry. And my symptoms have worsened as I have aged."
Eventually, Health Science Center researchers hope to treat salivary dysfunction by regenerating the salivary gland. "Gene therapy would be an ideal way to treat this disorder. We could inject the gene therapy directly into the glands themselves," Dr. Yeh said. "That’s our dream. We’re working on it."
Besides discomfort, low saliva flow rate compromises a person’s overall health. "A low saliva flow rate can pose severe quality of life issues to people," said Dorthea Johnson, M.S., who has studied saliva for more than 30 years. Johnson is an adjunct associate professor of community dentistry. Without saliva, people can have difficulty talking. And because saliva coats the food as a person chews, swallowing without much saliva can be a chore. "Saliva also has all these products in it that are protective of the oral surfaces," Johnson said. "It has a high concentration of calcium so that the teeth don’t dissolve. It coats the mouth to maintain hydration. And saliva has anti-microbial proteins that protect against infection." Those proteins are known to prevent tooth decay and protect the body against bacteria and viruses trying to invade through the mouth.
"Decreased salivary flow rate really impacts tooth health," Dr. Yeh said. "A patient producing less saliva has an increase in rampant caries, or decay. In certain situations, it could pose life-threatening risks, especially if the decay affects the jawbone."
Johnson and Drs. Yeh and Dang have been investigating salivary dysfunction in several areas. Their major interests are to understand how salivary glands and saliva are compromised with Sjögren’s syndrome, HIV infection and age. "The dogma has been that aging does not affect saliva,"Johnson said. "But our work is showing that it does."
Johnson and Dr. Yeh were part of a comprehensive study called Oral Health:
San Antonio Longitudinal Study on Aging (OH: SALSA). Thanks to the research, they now have a source to study any questions that arise from their research data. "We’ve probably analyzed more than 5,000 saliva samples in the past five years," Dr. Yeh said. "We’re finding a link between salivary dysfunction and major diseases like diabetes, hypertension and HIV. And we also see a correlation between salivary dysfunction and certain drugs." Drugs that decrease salivary flow are a problem for about 7 percent of people age 65 or older.
"The opportunity for us to investigate those links is exciting for us," Dr. Yeh said. "The big picture is that we are enriching the knowledge of the role of diseases in salivary dysfunction. But our research is not just limited to diseases of the salivary glands. It will provide insight on other diseases that affect the whole human body."
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