Inadequate saliva and fluoride can contribute to tooth decay

Tooth enamel is tough, harder even than skeletal bone. But even with good dental hygiene, the enamel protecting teeth may show signs of decay in older adults. The January issue of Mayo Clinic Health Letter covers what to look out for and what to do to promote an enamel-friendly setting in the mouth. According to the newsletter, two significant contributors to tooth decay are too little saliva and inadequate fluoride.

Too little saliva: Saliva helps repair the earliest stages of tooth decay. It supplies high levels of calcium and phosphate particles that enhance protection of the tooth's enamel surface. In addition, saliva protects the mouth by washing away food and the sticky film of acid-producing plaque that can cling to teeth.

Because of saliva's importance, dry mouth symptoms should be evaluated by a care provider. Dry mouth can be caused by medical conditions or their treatments. Examples include Sjogren's syndrome, an autoimmune disorder, diabetes and HIV or AIDS. Dry mouth is a common side effect of many prescription and nonprescription medications, including some antidepressants and anti-anxiety medications, antihistamines, medications for high blood pressure, anti-diarrheals, muscle relaxants and medications for urinary incontinence and Parkinson's disease.

For some people, medications or doses can be changed to minimize this side effect. When that's not possible, chewing sugar-free gum sweetened by a naturally occurring sugar substitute called xylitol can help. Studies have shown that the frequent use of gum with high levels of xylitol can prevent cavities and even harden a tooth's surface where a cavity has begun. Chewing gums that contain Recaldent also can help. This ingredient is a form of calcium phosphate that penetrates and binds to the tooth enamel. It's found in Trident Xtra Care gum.

Inadequate fluoride: This mineral is an important enamel ally that can make teeth stronger and can enhance saliva's remineralizing, anti-decay properties. Most people get adequate fluoride exposure through drinking fluoridated water and brushing twice daily with fluoride toothpastes.

But people who drink primarily bottled or filtered water may not be getting adequate fluoride. Even with adequate fluoride, dry mouth can throw off the normal balance teeth need to stay healthy.

A dentist may recommend fluoride treatment to protect and strengthen tooth enamel. Fluoride can be applied two to four times a year. Another option is nonprescription fluoride rinses available in drugstores.

Also helpful is limiting tooth enamel contact with acids that come from many foods and beverages. Examples include citrus fruits, tart candies, diet and regular sodas or sports drinks, fruit juices and wine.