MIX Disease: Diagnosis and Treatment
By Dr. Richard Bullock, D.D.S

Medication-induced xerostomia (MIX disease) is becoming a more common problem for Americans. There are now about 3,000 prescription medications that list xerostomia (dry mouth) as a possible side effect, but drug companies by and large, have not included specific labeling to alert the consumer about xerostomia and its increased risk for dental caries.

MIX disease affects people of all ages. With xerostomia, a patient has insufficient saliva to maintain oral health. Symptoms may range from irritation, inflammation, and/or recession of the soft tissues to rapid caries, destruction of the hard tissues. Other signs and symptoms can include candidiasis (fungal infection) and burning mouth syndrome. This is a condition becoming more problematic as people are living longer and frequently taking multiple medications. Healthy people don’t usually decrease saliva production when they age. Mouth burning, particularly when saliva flow decreases during sleep, also will lead to dry mouth symptoms for some patients. Patients with sleep apnea using a continuous positive airway pressure (CPAP) device may experience xerostomia. Other causes of xerostomia are radiation therapy that affects the major salivary glands and Sjogren’s syndrome, which is an autoimmune disease affecting saliva flow. However, the most common cause of xerostomia is medication.

Many drugs list xerostomia as a potential side effect. The most common classes of xerostomia medications include antihistamines and antihypertensives, but many drugs commonly contribute to dry mouth, and the multiple potential drug combinations compound the problem. This condition is prevalent in many senior patients but also is being seen in children taking antihistamines for asthma; antidepressants; and behavioral-modification drugs for attention deficit disorder. It is also common for patients experiencing dry mouth to suck on hard candy to stimulate saliva flow. The continuous exposure to sugar, resulting in continuous periods of acid pH in the mouth, can have disastrous effects for a person with inadequate saliva.

A frequent and serious side effect of MIX disease is dental caries (tooth decay).
Saliva is the best adaptation for controlling pH (acidity), because it contains a buffering system that helps maintain a healthy pH range in the mouth (about 7.0 to 9). For patients with xerostomia or MIX disease, the lack of saliva reduces the body's ability to buffer the acidic conditions, which results in dental caries.

Treatments include good oral hygiene, effective dietary counseling, and strategies to neutralize pH. For MIX disease patients, saliva-stimulating drugs, use of saliva substitutes, staying hydrated and plaque control are important. The daily use of oral care products that keep the pH within healthy ranges includes fluoride toothpastes, fluoride rinses and xylitol-containing candies. The use of xylitol-containing candies and gums, up to 15 grams per day, drastically reduces tooth decay. Xylitol-containing candies and gums are readily available in drug stores. Enjoy them daily because they actually prevent tooth decay.

Drug manufacturers should clearly label drugs with any potential for xerostomia, and warn the consumer of the likelihood of severe tooth decay if the product is used chronically (for more than two to three months). Ask your physician and dentist if any of the medications you take can cause dry mouth.

Dr. Richard Bullock, D.D.S., F.A.C.P. is an American Dental Association-recognized specialist in restoring and replacing teeth. He can be found at University Park Dentistry in Palm Desert: (706) 340-5107.