Role of Saliva in Caries Process (Amaechi 3) Flashcards
Salivary glands
- Submandibular
- Parotid
- Sublingual
- Minor mucous
Types of saliva
- Ductal saliva
- Whole (mixed) saliva
Salivary composition
- Inorganic components
- Organic components
List the inorganic components
Na+, Cl-, HCO3, K+, Ca2+, Mg, PO4—, F-
Inorganic components are factors that affect the ________ of both the cations and anions in saliva.
Concentrations
Salivary ______ determines the concentration of ions in saliva.
Flow rate
As the saliva flow rate increases, the pH and concentrations of proteins, Na+, Cl- & HCO3 ____ while the concentration of Mg & phosphate ____. The F concentration in saliva (≈ 0.019 ppm) is relatively _______ of flow rate
- rise
- fall
- independent
_____ is the most potent stimulus for salivary secretion.
Acid
Other factors that affect salivary secretion
- Chewing gum
- Duration of stimulus
- Circadian rhythms
- Medications
___% of prescribed drugs cause xerostomia
80%
What affect does the buffering action of bicarbonate have?
Raises pH of saliva and plaque
______ in saliva will bind and buffer hydrogen ions, neutralizing the acid produced by the bacteria in the plaque. This buffering action will reduce the dissolution rate up to the point when pH is at 5. At pH 5, all _______ has been protonated and the ______ has no further capacity to bind hydrogen ions.
Phosphate
At high salivary flow rate with its associated increase in salivary pH:
- The ______ conc. increases
- The fraction of total phosphate present as _____ increases markedly
- The ______ conc. in saliva also incresases
- Calcium ion
- PO4—
- Hydroxyl ion
Saliva promotes remineralization by overall _____ in Ip of saliva. When Ip > Ksp, the saliva is supersaturated with respect to HA.
Increase
Proteins in saliva function to maintain tooth integrity (protect against _____) and control cariogenic microflora (______ function).
- Demineralization
- Antimicrobial
Saliva maintains tooth integrity by binding _____ and releasing it as necessary.
Calcium
Saliva maintains tooth integrity by maintaining high concentrations of ____ at or near the tooth surface, thereby preventing loss of mineral from the tooth tissue.
Calcium
Saliva maintains tooth integrity by preventing the precipitation of ______ from saliva.
Hydroxyapatite
Saliva maintains tooth integrity by forming a semi-permeable membrane called a ______ which covers the tooth.
Pellicle
The pellicle prevents _____ of the tooth from rapidly dissipating into saliva and blocks the sits of ______ deposition at the tooth surface.
- Calcium
- Hydroxyapatite
Salivary proteins and derivatives involved in the maintenance of the integrity of the tooth
- Statherin
- Acidic proline-rich proteins
- Acquired salivary pellicle
Statherin allows saliva to be super-saturated with _______ by adsorbing to the crystal growth sites and thus preventing the formation of crystals.
calcium phosphate salts
Statherin creates an environment, at the surface of the tooth, that is supersaturated with respect to ______ and ______, thus preventing diffusion of these ions out of tooth tissue.
calcium and phosphate
Statherin adsorbs to the tooth surface and blocks the site of
mineral deposition, thereby inhibits additional deposition
of _______ at the tooth surface.
hydroxyapatite
Acidic proline-rich proteins bind calcium in such a manner that:
- at low calcium ionic strength, calcium can be ______.
- at high calcium concentrations, calcium is ______.
- at low pH, calcium binding is _____.
- released
- bound
- reduced
Acidic proline-rich proteins inhibits hydroxyapatite deposition at the tooth surface as it selectively adsorbs on tooth surface and blocks the sites of _________ growth, and thus prevents unwanted mineral accumulation on the tooth surface.
hydroxyapatite crystal
Composition of acquired salivary pellicle
Acidic proline-rich proteins Statherin Immunoglobulins Amylase Lysozyme Salivary peroxidase Glycoproteins Serum proteins Mucins
The acquired salivary pellicle is semipermeable to charged ions, thus it reduces the mobility of ___ and ____ to and from the tooth surface into the saliva and reduces the diffusion of ____ to the tooth surface during demineralization either by caries or erosion process.
- Ca and PO4
- acid
Proteins involved in control of cariogenic microflora
LACTOFERRIN LYSOZYME SALIVARY PEROXIDASE (lactoperoxidase) GLYCOPROTEINS SALIVARY AGGLUTININS HISTIDINE-RICH PROTEINS ACIDIC PROLINE-RICH PROTEINS
Control of Oral Microflora occurs by causing direct lysis of the cell membrane of the microorganism (i.e., ______).
lysozyme
Control of Oral Microflora occurs by interferring with growth (i.e., _________).
histidine-rich proteins
Control of Oral Microflora occurs by removing nutrients from the environment (i.e., ______)
lactoferrin
Control of Oral Microflora occurs by Causing aggregation of bacteria so they can be cleared by swallowing (i.e., ____, ______)
agglutinins, basic proline-rich glycoprotein
Control of Oral Microflora occurs by Making products which interfere with bacterial systems (i.e., _______)
salivary peroxidase
Control of Oral Microflora occurs by providing sites of attachment for micro-organisms which are organism/strain specific (i.e., ______)
acidic PRP
Lactoferrin binds____, an essential bacterial nutrient, thereby making it unavailable for microbial survival
and growth.
iron
_____ causes lysis of the bacteria cells by enzymatic hydrolysis of the N-glycosidic linkages in microbial cell membrane.
Lysozyme
Mechanism of salivary peroxidase
H2O2 + Thiocyanate ion –salivary peroxidase–> Hypothionate –> Inactivation of glycolytic and carbohydrate transport enzyme in bacteria (Efficacy against S. mutans is pH-dependent and is more efficient below pH 6)
______ are proteins having a polypeptide core and
linked side chains of carbohydrate.
Glycoproteins
Glycoproteins are classified into…
- Serous (immunoglobulins and proline-rich glycoproteins)
- Mucinous
Immunoglobulins (secretory IgA) functions include:
- block _____ determinants of bacteria
- induce _______ of bacteria
- interfere with _________
- adherence
- aggregation
- colonization-associated enzymes
Proline-rich glycoproteins, unlike acidic proline-rich proteins, are ______ and ______. They function to Bind to _____ and _____, a property that may interfere with attachment to the tooth surface, or may inhibit growth.
- glycosylated and basic
- S. mitis and S. sanguis
Mucinous glycoproteins are very viscous and hydrophilic and function to:
- Interact with specific ______.
- cause _______, and hence enhance the clearance of micro-organisms since they can then be removed by swallowing
- micro-organisms
- bacterial aggregation
Salivary agglutinins exhibit selective agglutinating characteristics. It specifically agglutinates ____, but not other species of Streps.
S. mutans
Salivary agglutinins, if free in saliva, may cause ______ of the micro-organisms so that they can be cleared by swallowing.
aggregation
Salivary agglutinins, if adsorbed to the tooth surface, may allow ______ of that organism by providing a site for attachment.
colonization
Histidine-rich proteins are growth inhibitory and bactericidal for ______.
S. mutans
Saliva increases clearing effect, such as clearance of:
- ______
- _______
- Acid from plaque
2. Fermentable carbohydrate from oral cavity
Saliva is a risk indicator for dental caries. Unstimulated flow rate ____ ml/min and Stimulated flow rate ____ ml/min places the individual at high caries risk.
- <0.2 ml/min
- <0.7 ml/min
