1. SALIVA
Seminar
Stomatology

2. MAJOR FUNCTIONS OF SALIVA
Solvent
Buffering
Lubrication
Remineralization
Digestion
Anti-bacterial
Anti-fungal
Temperature regulation
Production of growth factors and other regulatory peptides

3. A CONSIDERABLE VOLUME OF SALIVA IS PRODUCED OVER A DAY
0.5 to 1.5 liter of fluid is secreted in a day
This represents about 1/5 of the total plasma volume
This fluid is not lost as most of it is swallowed and reabsorbed by the gut
Parotis, submandibularis, sublingualis

4. THE SECRETORY UNIT The basic building block of all salivary glands
Saliva formed in acini flows down DUCTS to empty into the oral cavity.
ACINI - water and ions derived from plasma

5. Hypotonic final saliva into mouth
TWO STAGE HYPOTHESIS OF SALIVA FORMATION
Most proteins
Na+ Cl- resorbed
Hypotonic final saliva into mouth
Water & electrolytes
Some proteins electrolytes
K+ secreted
Isotonic
primary saliva

6. Inorganic components
Saliva compositon

7. Calcium and phosphate Help to prevent dissolution of dental enamel
1,4 mmol/l (1,7 mmol/l in stimulated saliva)
only cca 50% in ionic form
sublingual > submandibular > parotis
Phosphate
6 mmol/l (4 mmol/l in stimulated saliva)
90% in ionic form
pH around 6 - hydroxyapatite is unlikely to dissolve
Increase of pH - precipitation of calcium salts => dental calculus

8. Hydrogen carbonate Buffer
Low in unstimulated saliva, increases with flow rate
Pushes pH of stimulated saliva up to 8
pH 5,6 critical for dissolution of enamel
Defence against acids produced by cariogenic bacteria
Derived actively from CO2 by carbonic anhydrase

9. Other ions Fluoride Thiocyanate Sodium, potassium, chloride
Low concentration, similar to plasma
Thiocyanate
Antibacterial (oxidated to hypothiocyanite OSCN- by active oxygen produced from bacterial peroxides by lactoperoxidase)
Higher conc. => lower incidence of caries
Smokers - increased conc.
Sodium, potassium, chloride
Lead, cadmium, copper
May reflect systemic concentrations - diagnostics

10. Concentration (mM)
FLOW RATE ml/min

11. Organic components
Saliva composition

12. Organic components of saliva
Mucins
Proline-rich proteins
Amylase
Lipase
Peroxidase
Lysozyme
Lactoferrin
sIgA
Histatins
Statherin
Blood group substances, sugars, steroid hormones, amino acids, ammonia, urea

13. Multifunctionality Amylases, Cystatins, Carbonic anhydrases,
Histatins, Mucins,
Peroxidases
Carbonic anhydrases,
Histatins
Anti-
Bacterial
Buffering
Amylases,
Mucins, Lipase
Cystatins,
Mucins
Anti-
Viral
Digestion
Salivary
Functions
Mineral-
ization
Anti-
Fungal
Cystatins,
Histatins, Proline-
rich proteins,
Statherins
Histatins
Lubricat-
ion &Visco-
elasticity
Tissue
Coating
Amylases,
Cystatins, Mucins,
Proline-rich proteins, Statherins
Mucins, Statherins
adapted from M.J. Levine, 1993

14. Mucins
Lubrication
Glycoproteins - protein core with many oligosaccharide side chains attached by O-glycosidic bond
More than 40% of carbohydrates
Hydrophillic, entraining water (resists dehydration)
Unique rheological properties (e.g., high elasticity, adhesiveness, and low solubility)
Two major mucins (MG1 and MG2)

15. Amylases Calcium metalloenzyme
Hydrolyzes (1-4) bonds of starches such as amylose and amylopectin
Several salivary isoenzymes
Maltose is the major end-product (20% is glucose)
Parotis; 30% of total protein in parotid saliva
“Appears” to have digestive function - inactivated in stomach, provides disaccharides for acid-producing bacteria
Why is it also present in tears, serum, bronchial, and male and female urogenital secretions?
A role in modulating bacterial adherence?

16. Lingual Lipase Secreted by lingual glands and parotis
Involved in first phase of fat digestion
Hydrolyzes medium- to long-chain triglycerides
Important in digestion of milk fat in new-born
Unlike other mammalian lipases, it is highly hydrophobic and readily enters fat globules

17. Statherins
Calcium phosphate salts of dental enamel are soluble under typical conditions of pH and ionic strength
Supersaturation of calcium phosphates maintain enamel integrity
Statherins prevent precipitation or crystallization of supersaturated calcium phosphate in ductal saliva and oral fluid
Produced by acinar cells in salivary glands
Also an effective lubricant

18. Proline-rich Proteins (PRPs)
40% of AAs is proline
Inhibitors of calcium phosphate crystal growth
Part of pellicula dentis
Subdivided into three groups
Acidic 45%
Basic 30%
Glycosylated 25%

19. Lactoferrin Iron-binding protein
„Nutritional“ immunity (iron starvation)
Some microorganisms (e.g., E. coli) have adapted to this mechanism by producing enterochelins.
bind iron more effectively than lactoferrin
iron-rich enterochelins are then reabsorbed by bacteria
Lactoferrin, with or without iron, can be degraded by some bacterial proteases.

20. Lysozyme Present in numerous organs and most body fluids
Also called muramidase
hydrolysis of (1-4) bond between N-acetylmuramic acid and N-acetylglucosamine in the peptidoglycan layer of bacteria.
Gram negative bacteria generally more resistant than gram positive because of outer LPS layer

21. Histatins A group of small histidine-rich proteins
Potent inhibitors of Candida albicans growth

22. Cystatins Are inhibitors of cysteine-proteases
Are ubiquitous in many body fluids
Considered to be protective against unwanted proteolysis
bacterial proteases
lysed leukocytes
May play inhibit proteases in periodontal tissues
Also have an effect on calcium phosphate precipitation

23. Salivary peroxidase systems
Sialoperoxidase (SP, salivary peroxidase)
Produced in acinar cells of parotid glands
Also present in submandibular saliva
Readily adsorbed to various surfaces of mouth
enamel, salivary sediment, bacteria, dental plaque
Myeloperoxidase (MP)
From leukocytes entering via gingival crevice
15-20% of total peroxidase in whole saliva

24. CIRCAIDIAN RHYTHM OF SALIVA FLOW
No sleep
sleep
12 am
6 am
12 pm
6 pm 30 20 10
Time of day

25. Effect of feeding on salivary secretion
Meal
during
this
period
10 min collection periods

26. Variations in salivary composition
Unstimulated flow
Submandibular g. 70%
Parotid g. 20%
Accesory g. 7%
Sublingual 2%
Acid stimulation
Submandibular g. 45%
Parotid g. 45%
Chewing
Submandibular g. 30%
Parotid g. 60%

27. Variations in salivary composition
Parotid secretion increased amylase content
Submandibular secretion increased calcium concentrations

28. Gingival cervicular fluid
Seminar
Stomatology

29. Gingival cervicular fluid
Synonyms:
Gingival fluid
Cervicular fluid
Sulcular fluid
Similar composition as interstitial fluid
Flow rate related to degree of gingival inflamation, circa 0,5-2,4 ml/day

30. Composition Cells Inorganic ions Organic components
Desquamated epithelial cells
Neutrophils
Small amount of lymphocytes and monocytes
Bacteria
Inorganic ions
Similar to plasma
Potassium 2 x higher than in plasma (cell break-up)
Calcium higher than in oral fluid
Organic components
Similar to plasma - serum albumin, globulins, complement, protease inhibitors
Small organic molecules - lactate, urea, hydroxyproline
Enzymes

31. Function
Protective flow towards oral cavity - washes out potentially harmful cells and molecules
Antibacterial - immunoglobulins
Calcium assists pellicle and plaque fromation but may contribute to calculus formation
Rather response to inflamation

32. THANK YOU