OCB02-2022 Functions of Saliva Flashcards
When is saliva secretion at its lowest?
During no tasting/chewing
Which salivary glands produce the most saliva in resting conditions?
Submandibular/ sublingual glands
Which salivary glands produce the most saliva when stimulated?
Parotid glands
When do salivary flow rates decrease?
Reduced by a wide range of medications
higher in males than females
correlate with the size of the glands
What area are saliva films the thickest?
Along the dorsum of the tongue
What area are saliva films the thinnest?
The hard palate and tooth surfaces
What do xerostomia sufferers experience?
A dry mouth during the day Night waking due to dryness Difficulty speaking/swallowing/eating Burning sore mouth and tongue Candidiasis Bad taste Discomfort wearing denture
What are the 3 overarching functions of saliva?
Tooth protection
Protection and maintenance of the oral mucosa
Regulate oral microbiota
Why do low salivary flow rates favour the diseased states?
Reduces clearance of sugar and bacteria and increases risk of dental caries as there is longer for bacteria to metabolise sugar
What do high salivary flow rates favour?
clearance
What state do low salivary flow rates favour?
diseased state
What ion in saliva is responsible for buffering?
bicarbonate
What is the purpose of buffering pH?
Bicarbonate ions react with protons from acid in biofilm which shifts the equation left
Which prevents acid build up and demineralisation
What is the equation for buffering in saliva?
CO2 + H2O <=> H2CO3 <=> HCO3- + H+
What enzyme is responsible for buffering in saliva?
Carbonic Anhydrase 6
What is the salivary bicarbonate concentration when stimulated?
30mM
What is the salivary bicarbonate concentration when rested?
1mM
How does saliva contribute to the acquired enamel pellicle formation?
The early pellicle is formed mainly by calcium binding salivary proteins in saliva (including statherin, histamines and acidic proline-rich proteins)
What is the purpose of the acquired enamel pellicle?
Formation of this protein prevents surface demineralisation and enhances sub-surface remineralisation
It also lubricates the tooth
What is remineralisation in teeth dependent on?
Supersaturation of saliva with calcium and phosphate
What is the concentration of Ca2+ in resting saliva?
2mM
What protein is responsible for salivary supersaturation with calcium phosphate? why?
Statherin
It has calcium binding properties so calcium concentration increases
When will demineralisation occur?
If the saliva pH decreases to 5.5 due to dietary or plaque acid as saliva is no longer saturated with Ca2+ PO4 3-
How does saliva protect and maintain oral mucosa?
Wound healing due to the presence of growth factors which proliferates epithelial ells
Lubrication
Moisture
Mucins form a hydrated barrier over the mucosal surfaces of the oral cavity to prevent bacterial penetration
How is saliva essential in regulating oral microbiota?
Flow of saliva clears microorganisms from the mouth
Acquired enamel pellicle modifies adherence of microorganisms to teeth, as salivary proteins become binding sites for commensal bacteria
Salivary agglutinin, mucins and other proteins in saliva aggregate microorganisms and facilitate clearance
Contain many anti-microbial, growth-limiting factors
