SALIVA

Adequate saliva flow is essential for oral health and maintenance of soft tissues in oral cavity, including the taste buds. Saliva, secreted by the salivary glands, is essential in taste sensations, functioning to:

  1. lubricate oral tissues to assist in chewing, swallowing, and digestion
  2. remove debris from teeth
  3. provide antibacterial action
  4. neutralize, dilute, and buffer bacterial acids
  5. aid in remineralization (the restoration or return of calcium, phosphates, and other minerals into areas that have been damaged, as by incipient caries, abrasion, or erosion)
  6. affect the rate of plaque accumulation
  7. influence taste
  8. allow for ease in talking

   This complex fluid helps maintain the integrity of the teeth against physical, chemical, and microbial insults. Saliva is supersaturated with calcium phosphates that allow demineralized areas of the hydroxyapatite in enamel to be remineralized. Demineralization occurs as a result of the removal or loss of calcium, phosphate, and other minerals from tooth enamel, causing tooth enamel to dissolve.
   Acidic, sour, or bitter tastes stimulate saliva flow. Saliva production is also increased with consumption of tasty foods and gum chewing. An increase in oral clearance rate decreases risk of caries formation. Saliva blended with food particles moistens foods so that they are more easily manipulated and prepared for swallowing. 
Some chemical action or hydrolysis of nutrients begins in the mouth.

  •  Mucin (glycoprotein) lubricates food for easier passage and protects lining of the gastrointestinal tract
     
  •  Ptyalin – amylase (enzyme) initiates hydrolysis of complex carbohydrates to simple sugars
      
  • Lysozyme – antibody (enzyme) breaks down cell walls of some ingested bacteria

Because food is normally in the mouth briefly, ptyalin, or salivary amylase, initiates starch digestion. If a carbohydrate food, such as a cracker, is chewed and held in the mouth for a few seconds, it will begin to taste sweet, denoting the fact that some starch is being hydrolyzed to dextrin and maltose.
   Dry mouth from inadequate salivary secretion, also called xerostomia, leads to diminished gustatory function. Xerostomia may result in frequent oral ulcerations, increased sensitivity of the tongue to spices and flavors, and increased risk of dental caries. Many drugs, including diuretics, cause xerostomia. Diuretics, prescribed to help the body eliminate fluids, also cause a decrease in salivary flow. Increasing fluid intake to 8 to 10 cups daily is important to compensate for these losses.