Saliva Function and Production

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Questions and Answers

What is the total saliva flow rate in milliliters for 24 hours?

400 ml

800 ml

600 ml (correct)

700 ml

What is the percentage of contribution to whole mouth saliva by the parotid glands when stimulated?

60%

46% (correct)

40%

52%

What is the unstimulated whole mouth salivary flow rate in milliliters per minute?

0.30 ml/min

0.25 ml/min

0.35 ml/min (correct)

0.40 ml/min

During which time period does the unstimulated whole mouth salivary flow rate increase by 70%?

9am - 5pm Signup and view all the answers

What is the contribution of the submandibular and sublingual glands to whole mouth saliva when stimulated?

45% Signup and view all the answers

What is a possible consequence of having a decreased saliva flow rate?

Bad taste Signup and view all the answers

What is the primary function of salivary proteins in the acquired enamel pellicle?

To inhibit microbial growth Signup and view all the answers

Which of the following salivary glands makes the greatest contribution to resting flow rate?

Submandibular and sublingual glands Signup and view all the answers

What is the role of salivary bicarbonate?

To buffer acid pH and prevent demineralization Signup and view all the answers

What is the primary function of histatins and defensins in saliva?

To inhibit microbial growth Signup and view all the answers

What is the role of calcium and phosphate in saliva?

To enable tooth remineralization Signup and view all the answers

What is the primary function of mucins in saliva?

To determine the microbial flora Signup and view all the answers

What is the main component of salivary fluid produced by the acinus?

Water and electrolyte Signup and view all the answers

What is the role of salivary proteins in the enamel pellicle?

To provide binding sites for commensal bacteria Signup and view all the answers

What is the importance of salivary bicarbonate concentration in maintaining teeth?

To prevent acid build up and tooth apatite solubility Signup and view all the answers

What happens to the pH of saliva when it decreases to approximately pH 5.5 due to dietary or plaque acid?

Demineralization occurs Signup and view all the answers

What is the role of saliva in regulating oral microbiota?

To maintain normal numbers and composition of oral microorganisms Signup and view all the answers

What is the effect of very low salivary flow on oral health?

Increases the risk of dental caries Signup and view all the answers

What is the role of the acquired enamel pellicle in tooth mineralization?

It prevents surface mineralization but enhances sub-surface remineralization Signup and view all the answers

What is the role of salivary agglutinin in oral health?

It aggregates microorganisms and facilitates clearance from the mouth Signup and view all the answers

What is the composition of whole mouth saliva?

GCF, shed epithelial cells, and transudate Signup and view all the answers

What is the role of carbonic anhydrase in saliva?

It converts CO2 to H2CO3 Signup and view all the answers

Study Notes

Composition of Saliva

Whole mouth saliva consists of biofilm, enamel/dentine, GCF (Gingival Crevicular Fluid), shed epithelial cells, and transudate
Acinus produces salivary fluid containing water, electrolytes, blood proteins, and salivary proteins
Ducts produce Na+, Cl-, and glandular salivas

Cells, Microorganisms, and Microparticles in Saliva

Cells in saliva include epithelial cells and neutrophils
Microorganisms in saliva include bacteria (10^8/ml), viruses, candida, and protozoa
Microparticles in saliva include exosomes (increased flow and oral clearance)

Functions of Saliva

Buffers pH and maintains enamel pellicle
Protects and maintains oral mucosa through wound healing, lubrication, and barrier formation
Regulates oral microbiota through clearance, killing, and agglutination of pathogens, and colonization, adhesion, and feeding of commensals
Aids in taste and processing of food/nutrients

Flow Rate and Oral Clearance

Very low salivary flow rate increases the risk of dental caries
Buffering in saliva by bicarbonate involves the reaction: CO2 + H2O → H2CO3 → HCO3- + H+

Acquired Enamel Pellicle

A thin layer (<1 μm) formed by calcium-binding salivary proteins (statherin, histatins, and acidic proline-rich proteins)
Prevents surface mineralization and enhances sub-surface remineralization
Lubrication reduces friction by 20-fold

Saliva and Tooth Mineralization

Tooth apatite (Ca10(PO4)6OH2) is dependent on supersaturation of saliva with calcium and phosphate
Concentration of Ca2+ in resting saliva is approximately 2mM
Supersaturation of saliva with calcium and phosphate is due to salivary protein statherin

Saliva and Oral Mucosa

Saliva forms a hydrated, barrier film on the oral mucosa
Lubrication, barrier function, and interaction with the mucosal surface are essential
Saliva regulates oral microorganisms by clearing microorganisms, modifying the adherence of microorganisms to teeth, and modulating microbial growth

Anti-Microbial Factors in Saliva

Saliva contains anti-bacterial proteins (cystatins, histatins, defensins, cathelicidins, lysozyme, lactoferrin, lactoperoxidase, SLPI, chromogranin A, PLUNCs, immunoglobulins, mucins)
Saliva also contains anti-fungal and anti-viral proteins

Summary

Saliva enables oral tissues to cope with a range of problems associated with oral functions
Resting (unstimulated) flow of saliva is crucial for oral health
Submandibular and sublingual glands contribute the most to resting flow rate, while parotid glands contribute more to stimulated flow rate
Saliva forms films and pellicles on hard and soft tissues in the mouth

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Description

This quiz covers the basics of saliva, including its production rates, circadian rhythm, and contribution of different salivary glands to saliva in the mouth.