BIOLOGICAL ROLE OF SALIVA:
Dr. Bibi Halima Shamaz
Wilson garden, Bengaluru Jan 27, 2017
Saliva is also called as ‘liquid enamel’ as it is a rich source
of various minerals.
pH of saliva – 6.9 – 7.2
The buffering effect of saliva is based mainly on bicarbonate –carbonic acid and phosphate buffer systems.
Lysozyme, a hydrolytic enzyme, lactoperoxidase, hemoprotein enzyme are present in saliva which play a role in the prevention of bacterial colonization on tooth surface.
The most prominent antibody found in the saliva is the sIgA,which reflects the lifetime caries experience of the individual and may not have a protective function.
Rapid flow of highly buffered, mobile saliva would reduce the fall in plaque pH. Thus less caries is associated with the rapid flow of saliva.
Low viscosity is also associated with low caries activity due to the rapid clearance of the sugar from the oral cavity.
BUFFERING POWER OF SALIVA:
Diffusion of inorganic buffers from the saliva into the dental plaque plays an important part in reducing the effect of acids produced by the bacteria. Bicarbonates are the most important buffers of saliva. Phosphates also play some part.
Buffers work by converting any highly ionized acids or alkalis which tends to alter the pH of the solution into more weakly ionized substance. Bicarbonates release the weak carbonic acid when an acid is added and since this acid is rapidly decomposed into water and carbon dioxide, which leave the solution.