Читать книгу Basic Guide to Oral Health Education and Promotion - Alison Chapman - Страница 58

Saliva is made up of 99.5% water and 0.5% dissolved substances, although the composition varies between individuals [7].

Dissolved substances include:

 Mucins – these are glycoproteins that give saliva its viscosity (stickiness), lubricate the oral tissues, and are the origin of the salivary pellicle (the sticky film which forms on teeth within minutes of cleaning).

 Enzymes – there are many, but the OHE needs only to remember the main ones:Salivary amylase (ptyalin), which converts starch into maltose.Lysozyme, which attacks the cell walls of bacteria, thus protecting the oral cavity from invading pathogens.

 Serum proteins – albumin and globulin (saliva is formed from serum; the watery basis of blood).

 Waste products – urea and uric acid.

 Gases – oxygen, nitrogen, and carbon dioxide in solution. The latter vaporises when it enters the mouth and is given off as a gas.

 Inorganic ions – including sodium, sulphate, potassium, calcium, phosphate, and chloride. The important ones to remember are calcium and phosphate ions, which are concerned with remineralisation of the teeth after an acid attack (see Chapter 5) and the development of calculus (see Chapter 2).

 Saliva also contains large numbers of microorganisms and remnants of food substances.