Nutrition plays two quite different roles in oral health - protective and preventive. The protective role is in promoting healthy development and maintenance of the mouth's tissues and their natural protective mechanisms. The role of nutrition is also to prevent oral disease through the influence of the food's properties on plaque development and saliva flow. As in dietary guidance for general health, consuming a variety of foods is important for oral health.

Diet and nutrition may affect the development and progression of diseases of the oral cavity and oral infectious diseases can affect diet and nutrition.

For many years, oral health care focused on prevention of dental caries (tooth decay) in children by emphasizing dietary influences on caries formation. Now, the emphasis has shifted to other preventive factors such as fluoride, use of sealants, frequency of eating, the length of time that foods and beverages are retained in the mouth, and, of course, good oral hygiene. With evolving science, specific foods no longer are being singled out as major risk factors for dental caries.

In a major review of fluoridation facts, the American Dental Association credited fluoride with being the major factor for the dramatic reduction in dental caries over the past two decades. Since the first two-city experiment in1945, the practice of fluoridating drinking water has been expanding steadily. The use of fluorides in other ways has also been rising rapidly.

Virtually all toothpaste used in the U.S. contains fluoride. Fluoride mouthwashes and tablets are used in schools and homes and topical fluorides are applied in dental offices. Around the world, dental caries reduction is also being seen with the use of fluoride-containing toothpaste alone. In some underdeveloped countries, fluoridation of the water supply may not be realistic.

Poor dental care, eating patterns and food choices can be important factors in tooth decay. Everything eaten passes through the mouth where it can be used by the bacteria in plaque. Plaque, in turn, produces acids that can destroy tooth enamel. Plaque is an almost invisible deposit of bacteria that constantly forms on teeth. Plaque holds the acids on the teeth. Over time, the acids cause tooth enamel to break down, forming a cavity.

Frequency of eating. Each time carbohydrate-containing foods are consumed, acids are released to work on teeth. The more frequently carbohydrates are consumed, the more opportunity there is for acids to damage teeth.

Food characteristics: Some foods tend to cling or stick to the teeth. Not necessarily foods one would consider sticky, "cooked starches" such as chips and crackers rank high on the list of sticky foods as compared to candy bars and toffee.

Time that food remains in the mouth: Foods that are slow to dissolve, such as cookies and granola bars, provides more time for the acids that destroy enamel to work than those that dissolve quickly, such as caramels and jelly beans.

Whether or not the food is eaten as part of a meal: High carbohydrate-containing foods produce less acid when eaten with a meal than when eaten alone because saliva production is increased during a meal to help neutralize acid production and clear food from the mouth. Also, when consumed with beverages, sticky foods may be washed from the teeth more quickly, lessening the opportunity for acid production.

Regular dental care is important from as early as six months after birth throughout the life cycle.

For children, preventing decay of primary teeth, including baby bottle tooth decay, is critical. This condition can occur when an infant is allowed to nurse continuously from a bottle of milk, formula, sugar water or fruit juice during naps or at night. Preschool years are an important time to establish good eating habits and good oral hygiene.

For adults, the regular dental exam provides important information on your overall health, and, indeed, on general health. The dentist will check for gum disease as well as pre-cancerous or cancerous lesions; oral sores or irritations; fit of dentures or bridges and proper bite.

Check-ups are important because some diseases or medical conditions have signs that appear in the mouth. Diabetes, nutrient and vitamin deficiencies and hormonal irregularities may be detected by oral examination.

Dietitians working with clients can include assessment of oral health in nutrition assessment protocols (i.e., chewing ability, salivary output, dental status) and, if indicated, request a dental consultation.

Those working in community settings can develop nutrition education messages that encourage and promote oral health in school and community nutrition programs.

In research settings, dietitians can identify and support oral health issues in appropriate clinical nutrition research.