Saliva nitika jain


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Saliva nitika jain

  1. 1. SALIVADr. Nitika Jain
  2. 2. contents• Introduction• Salivary gland anatomy• Secretion of saliva• Composition of saliva – Organic components – Inorganic components• Functions of saliva8/12/2012 SALIVA 2
  3. 3. What is saliva• Saliva serves multiple and important functions. Three major, paired salivary glands produce the majority of saliva: the parotid, the submandibular, and the sublingual glands. In addition, 600-1,000 minor salivary glands line the oral cavity and oropharynx, contributing a small portion of total salivary production.8/12/2012 SALIVA 3
  4. 4. Major salivary glands• Parotid• Sub – mandibular• Sub - lingual8/12/2012 SALIVA 4
  5. 5. Salivary gland - secretion• Serous: very thin and watery o parotid gland o lingual glands of von Ebner (serous glands of von Ebner) Serous acini8/12/2012 SALIVA 5
  6. 6. • Mucous: very thick and viscous o palatine glands o posterior lingual glands o labial buccal glands Mucous acini8/12/2012 SALIVA 6
  7. 7. • Mixed secretions: mix of the two o Sublingual glands – Mostly mucous with some serous o Submandibular glands – Mostly serous with some mucous o Anterior lingual glands – Mixed secretion Mixed: mostly serous acini (dark), partially mucous acini8/12/2012 SALIVA (light cells) 7
  8. 8. Parotid gland8/12/2012 SALIVA 8
  9. 9. Parotid gland• Largest of all the salivary glands• Purely serous gland which produces thin, watery, amylase rich saliva• Superficial portion lies in front of the external ear and deeper portion lies behind the ramus of the mandible• Stensons duct – Open out adjacent to maxillary second molar8/12/2012 SALIVA 9
  10. 10. • It is 5.8 cm in the craniocaudal dimension, and 3.4 cm in the ventral-dorsal dimension.• Weight is 14.28 g. It is irregular, wedge shaped, and unilobular.8/12/2012 SALIVA 10
  11. 11. • Superior border – Zygoma• Posterior border – External Auditory Canal• Inferior border – Styloid Process, Styloid Process musculature, Internal Carotid Artery, Jugular Veins• Anterior border – a diagonal line drawn from the Zygomatic to external auditory canal.8/12/2012 SALIVA 11
  12. 12. • Stensen’s duct arises from the anterior border of the Parotid and parallels the Zygomatic arch, 1.5 cm inferior to the inferior margin of the arch. Stensen’s duct runs superficial to the masseter muscle, then turns medially 90 degrees to pierce the Buccinator muscle at the level of the second maxillary molar where it opens onto the oral cavity.8/12/2012 SALIVA 12
  13. 13. Sub – mandibular gland8/12/2012 SALIVA 13
  14. 14. Sub – mandibular gland• Second largest salivary gland• Produces 65-70% of total saliva output• The duct is called Wharton’s duct• Wharton’s duct exits on the floor of the mouth opposing the lingual surface of the tongue8/12/2012 SALIVA 14
  15. 15. • Located in a depression on the lingual side of the mandibular body• Innervated by parasympathetic nerve endings and possesses NO sympathetic receptors• The parasympathetic fibers arrive through the facial and glossopharyngeal nerves• Mixed secretion – mostly serous8/12/2012 SALIVA 15
  16. 16. Sub – lingual gland8/12/2012 SALIVA 16
  17. 17. Sub – lingual gland – Smallest of the major glands – Produce less than 5% of total saliva output • Saliva delivered via the ducts of Bartholin • The Bartholin ducts exit on the base of the lingual surface of the tongue – Innervated by parasympathetic fibers – Little or no sympathetic influence – Mixed secretion – mostly mucous8/12/2012 SALIVA 17
  18. 18. Minor salivary glands• Minor salivary glands are found throughout the mouth: –Lips –Buccal mucosa (cheeks) –Alveolar mucosa (palate) –Tongue dorsum and ventrum –Floor of the mouth• Together, they play a large role in salivary production.8/12/2012 SALIVA 18
  19. 19. Histology of salivary gland• The acini are the primary secretory organs but the saliva is modified as it passes through the intercalated, striated, and excretory ducts before being discharged into the mouth and oropharynx.8/12/2012 SALIVA 19
  20. 20. • The serous cells contain numerous proteinaceous secretory (zymogen) granules. These granules contain high levels of amylase. In addition, the secretory cells produce kallikrein,lactoferrin, and lysozyme.8/12/2012 SALIVA 20
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  23. 23. Saliva• General characterstics:Consistency - slightly cloudy due to presence of mucins and cells Reaction - usually slightly acidic (pH 6.02- 7.05).On standing or boiling, it loses Co2 and becomes alkaline. Specific gravity - 1.002-1.012 Freezing point - 0.07-0.34° Celsius8/12/2012 SALIVA 23
  24. 24. • Percentage contribution of different salivary glands during unstimulated saliva:8/12/2012 SALIVA 24
  25. 25. Unstimulated flow• resting salivary flow―no external stimulus oTypically 0.2 mL – 0.3 mL per minute oLess than 0.1 mL per minute means the person has hyposalivation Hyposalivation – not producing enough saliva8/12/2012 SALIVA 25
  26. 26. Stimulated Flow• response to a stimulus, usually taste, chewing, or medication eg, at mealtime oTypically 1.5 mL – 2 mL per minute oLess than 0.7 mL per minute is considered hyposalivation8/12/2012 SALIVA 26
  27. 27. The average person produces approximately 0.5 L – 1.5 L per day•Salivary flow peaks in the afternoon•Salivary flow decreases at night.•There is a difference in the quality between stimulated and unstimulated saliva8/12/2012 SALIVA 27
  28. 28. Ions and salivary flowAs saliva passesthrough the salivaryducts, cations(sodium and chloride)are reabsorbed intothe adjacentblood vessels.8/12/2012 SALIVA 28
  29. 29. As saliva passes through the salivary ducts, cations(sodium and chloride) are reabsorbed into theadjacent blood vessels. In exchange, bicarbonatesand potassium are transferred from the blood 29
  30. 30. Stimulated Salivary Flow • Saliva passes through the salivary duct very rapidly o It impedes the exchange of sodium and chloride for potassium and bicarbonateUnstimulated Salivary Flow • Has a high content of potassium and bicarbonate o The quality of unstimulated saliva will change when flow increases because of a stimulus (chewing gum, thinking about lemons, looking at a food you crave)8/12/2012 SALIVA 30
  31. 31. composition• Water content - 99.5%• Solids - 0.5%  Inorganic content - 0.2%  Organic content - 0.3%  Gases - 1ml oxygen/100ml - 2.5ml nitrogen/100ml - 50ml carbondioxide/100ml  Cellular elements8/12/2012 SALIVA 31
  32. 32. Organic Components of SalivaEnzymes:• Amylase – converting starch into glucose and fructose• Lysozymes – prevents bacterial infections in the mouth• Histatins – prevents fungal infections• Secretory IgA – immunity mediator8/12/2012 SALIVA 32
  33. 33. • Lactoperoxidases – stimulation of minor salivary glands• RNase and Dnase – cellular maintenance• Lipase – initiates digestion of fat• Kallikrein – vasoreactive substances8/12/2012 SALIVA 33
  34. 34. Cellular Composition• The cellular composition consists of: • Epithelial cells • Neutrophils • Lymphocytes • Bacterial flora8/12/2012 SALIVA 34
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  36. 36. -Amylase• Present in parotid saliva at conc. of 60-120 mg/ 100ml in submandibular saliva at approx. 25 mg/100 ml.• Very little amylase activity in the sublingual and minor glandular secretions.• 6 isoenzyme forms exist; alpha-amylase (ptyalin) is Ca++ dependent and readily inactivated by a pH of 4 or less.• The enzyme hydrolyses the alpha 1:4 glycosidic bond between glucose units in the polysaccharide chain of starch.8/12/2012 SALIVA 36
  37. 37. Lysozyme• An antibacterial enzyme.• The mean concentration in whole saliva – resting: 22 mg/100ml. – Stimulated: 11 mg/100 ml.• Lysozyme acts on the B (1-4) bond between N-acetyl-muramic acid and N-acetyl glucosamine in the Gram positive bacterial cell wall component.• Lysozyme may also be bactericidal,• Inhibits mucosal colonization by microbial aggregation.8/12/2012 SALIVA 37
  38. 38. Kallikrein •Splits serum beta-globulin into bradykinin •Functional vasodilatation to supply an actively secreting gland. Dextranases Increased whole saliva dextranase levels may be associated with impaired oral hygiene and over consumption of sucrose and related fermentable carbohydrates which support the growth of organisms producing dextranases. Invertases •High invertase activity is based on the involvement of several enzymes chiefly derived from dental plaque S.Mitis and S.Salivarius. • High invertase activity ---- consume high sucrose and it usually parallels with high lactobacillus and streptococcus counts of plaque.8/12/2012 SALIVA 38
  39. 39. Glycoprotein (Mucins)• Lubricant• Types—MG1 & MG2• Polypeptide chain that stick together• Low solubility, High viscosity, Strong adhesiveness• Aids in mastication, speech, swallowing by lubrication8/12/2012 SALIVA 39
  40. 40. Glycoprotein (Mucins)• Preserve mucosal integrity• Protective barrier against excessive wear• Antibacterial action by selective adhesion of microbes to oral tissue surface• Barrier against acid penetration8/12/2012 SALIVA 40
  41. 41. MG1 • High molecular-wt • Adsorbs tightly to tooth surface--enamel pellicle formation--Protection from acid challenges • High in caries susceptible patients8/12/2012 SALIVA 41
  42. 42. MG2• Low molecular wt• Binds to enamel but get displaces easily• Promotes the aggregation and clearance of oral bacteria (S.mutans)• High in caries resistant cases8/12/2012 SALIVA 42
  43. 43. Secretory leucocyte proteinase inhibitor (SLPI) Proteinase inhibitory property Antimicrobial and antiviral Imp. Role in wound healing8/12/2012 SALIVA 43
  44. 44. Tissue inhibitors of metalloproteinase Remodeling of extracellular matrix in inflammation Growth promoting activity Stimulation of osteoclastic bone resorption8/12/2012 SALIVA 44
  45. 45. Immunoglobulins• Secretory IgA is the predominant immunoglobulin - 20mg/100ml• 90% of the total parotid lgA• 85% of whole saliva lgA• 30-35% of which is derived from minor glands, IgG (1.5 mg/100ml) & IgM (0.2 mg/100ml)• Secretory IgA is synthesized by plasma cells within the glands in addition to the mucosal epithelial cells.• Secretory IgA --- non-lymphoid-derived glycoprotein designated as the secretory component.8/12/2012 SALIVA 45
  46. 46. Immunoglobulins• This IgA exhibits 3 possible functions: -Inhibition of bacterial colonization, probably by agglutination. - Binding to specific bacterial antigens involved with adherence. -Affecting8/12/2012 specific enzymes essential for bacterial metabolism. SALIVA 46
  47. 47. Structural features of salivary proteins• Proline – rich proteins• Statherins• Cystatins• Histatins8/12/2012 SALIVA 47
  48. 48. Proline-rich protein (Glycoprotein) 70% of total secretory proteins Acidic (Large), Basic (Small) Present in enamel pellicle Larger PRP promote bacterial attachment Smaller reduces the initial bacterial attachment A.Viscosus, S.mutans, S.Gordoni8/12/2012 SALIVA 48
  49. 49. Statherin (Phosphoprotein)• Is a small phosphoprotien (12000 daltons) relatively rich in tyrosine and proline which has the property of inhibiting Hydroxyapatite crystal growth.• Potential precursor of enamel pellicle• Inhibit spontaneous precipitation of cal. phosphate in saturated solution8/12/2012 SALIVA 49
  50. 50. Cystatins• Several cystatins are phosphorylated and bind to HA• Inhibit crystal growth of Cal. Phosphate salts8/12/2012 SALIVA 50
  51. 51. Histatin• Parotid and Submandibular saliva• Bind to HA, precursor of acquired pellicle• kills C.Albican in yeast form and mycelia form• Bacteriostatic• Inhibit hem agglutination and thereby colonization8/12/2012 SALIVA 51
  52. 52. Other organic compounds Free Amino acids- (Below 0.1 mg/100 ml) o Too low to provide nutrient source for bacterial growth Urea (12-20 mg /100 ml) o Hydrolyzed by bacteria with the release of Ammonia---Rise in pH Glucose (0.5- 1 mg/ 100ml) o Too low for bacterial growth o Increase in DM8/12/2012 SALIVA 52
  53. 53.  Lipids  Cholesterol, fatty acid glycerides, phospholipids  Corticosteroids  Cortisol and cortisine  1-2 mg/100ml  Vitamins  Water soluble vitamins8/12/2012 SALIVA 53
  54. 54. Function of salivaProtective properties: – Lubrication – Maintenance of mucous membrane integrity – Soft tissue repair – Dilution and clearance – Aggregation – Action of lactoferrin – Salivary peroxidase system – Antifungal activitySALIVA8/12/2012 54
  55. 55. Function of saliva – Antiviral activity – Buffering capacity of saliva – Maintenance of tooth integrity• Digestion• Taste• Saturation8/12/2012 SALIVA 55
  56. 56. Lubrication• Coat the food, the oral soft and hard tissues.• Allows food to travel through the digestive system surfaces with minimal friction.• Without appropriate lubrication, food is retained and impacted around the teeth,• Both mg1 and mg2 can provide fluid layers with high- film strength8/12/2012 SALIVA 56
  57. 57. Maintenance of mucous membrane integrity Salivary mucins possess rheological properties that include low solubility, high viscosity, elasticity, and adhesiveness. Provide an effective barrier against desiccation and environmental factors Protect the underlying cells from sudden changes in osmotic pressure. Second line of defense against protease activity-cysteine containing phosphoprotien8/12/2012 SALIVA 57
  58. 58. Soft tissue repair• EGF involved in oral wound healing• Hormone like properties in stimulating epithelial cells• Parotid gland is the major source• VEGF also known as vasculotropin---- an angiogenic cytokine• PAF ---- a potent phospholipid mediator8/12/2012 SALIVA 58
  59. 59. Dilution and clearance Saliva dilutes and eliminates dietary sugars and acids This process is dependent on flow rate and swallowing frequency Oral sugar clearance extensively prolonged when unstimulated whole saliva flow rate is below .2ml/min8/12/2012 SALIVA 59
  60. 60. Aggregation  Inhibit bacterial attachment  Inhibits the adherence of these cariogenic organisms to teeth and protection against caries. Expectorated or swallowed Hinder effective adherence Clumping of bacteria Histidine-rich peptide has growth-inhibitory and bactericidal effects on oral bacteria.8/12/2012 SALIVA 60
  61. 61. Action of lactoferrin• Lactoferrin, the exocrine gland secretion• The bacteriostatic properties are attributed to the ability of the unsaturated protein to bind two iron atoms per molecule• Lactoferrin is capable of both a bacteriostatic and a bactericidal effect on S mutans that is distinct from simple iron deprivation.8/12/2012 SALIVA 61
  62. 62. Action of salivary peroxidase• The antimicrobial effect of salivary peroxidase against S mutans is significantly enhanced by interaction with secretory lgA.• Interaction with each other and with high molecular weight mucin. This mucin serve to concentrate a defense force on the mucosa against the external environment, entrapping and incapacitating microorganisms.8/12/2012 SALIVA 62
  63. 63. Antifungal activity• Parotid fluid has an antifungal capacity, reflecting properties of both the neutral and the basic histidine rich peptides.• Pollock and others showed that the basic peptides could cause 99% loss of viability of Candida albicans at levels of 25 mg/ml,• Oppenheim and others found that the neutral histidine rich peptide was a potent inhibitor of C. albicans germination at levels as low as 2 mg/ml.8/12/2012 SALIVA 63
  64. 64. Antiviral activity• Antibodies (secretory lgA) can directly neutralize viruses.• Mucins are also effective antiviral molecules.• A major function of saliva is to prevent the establishment of unwanted species in the first place8/12/2012 SALIVA 64
  65. 65. Buffering at an arbitrary point. Resistance to pH changes capacity   3 buffer systems : pH o Carbonic acid / bicarbonate o Phosphate Buffer capacity Secretion rate o Protein CA CA o CO2 + H2O H2CO3 H+ + HCO3- o Concentration of bicarbonates is highest in parotid saliva8/12/2012 SALIVA 65
  66. 66. Maintenance of tooth integrity• Physical flow of saliva (the hydrokinetic property) coupled with muscular activity,• Small decrease in the resting salivary flow rate can greatly prolong sugar clearance time.• Interaction with saliva provides a post eruptive maturation through the diffusion of ions8/12/2012 SALIVA 66
  67. 67. • This enrichment of the crystal structure increases hardness, decreases permeability, increases resistance to caries.• The original pellicle is replaced by a constantly replenished salivary film selectively absorbed proteins with a high affinity for hydroxyapatite provides a protective barrier8/12/2012 SALIVA 67
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  70. 70. Mechanism of saliva formationSaliva is formed in 2 stages :• A primary secretion occurs in the acini• Then modified as it passes through the ducts8/12/2012 SALIVA 70
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  72. 72. METHOD OF COLLECTING SALIVA Passive drool Oral swab Infant swab Spitting method Suction method8/12/2012 SALIVA 72
  73. 73. • • Avoid alcohol for 12 hours before sample collection.• • Avoid eating major meal within 60 minutes of sample collection.• • Avoid dairy products for 20 minutes before sample collection.8/12/2012 SALIVA 73
  74. 74. • Avoid foods with high sugar or acidity, or high caffeine content, immediately before sample collection, since they may compromise the assay by lowering saliva pH and increasing bacterial growth.• • Rinse mouth with water to remove food residue before sample collection. Wait at least 10 minutes after rinsing before collecting saliva toSALIVA sample dilution. 748/12/2012 avoid
  75. 75. Prior to saliva collection• Participants should rinse with water 10 minutes prior to collection.• Cut plastic drinking straws into 2-inch (5 cm) pieces.8/12/2012 SALIVA 75
  76. 76. PASSIVE DROOL• Passive drool is highly recommended because it is cost effective and approved for use with almost all analytes. To avoid problems with analyte retention or the introduction of contaminants, use only high quality polypropylene vials for collection, such as our 2 ml cryovials. The vials used must seal tightly and be able to withstand temperatures as low as -80ºC.8/12/2012 SALIVA 76
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  78. 78. Instructions to the patient• Allow saliva to pool in the mouth.• With head tilted forward, participants should drool down the straw and collect saliva in the cryovial. (It is normal for saliva to foam, advise using a vial with twice the capacity of the desired sample volume.)8/12/2012 SALIVA 78
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  80. 80. • Repeat as often as necessary until sufficient sample is collected. One mL (excluding foam) is adequate for most tests. Collection of samples to be analyzed for multiple analytes may require larger vials.8/12/2012 SALIVA 80
  81. 81. Salimetrics Oral Swab (SOS)• Participants who are not willing or able to drool saliva into a vial. If the saliva samples are to be analyzed for cortisol, testosterone, α-amylase, chromogranin A, cotinine, C-reactive protein, or SIgA, the Oral Swab is an excellent alternative to passive drool because of its ease of use. The SOS also helps filter mucus from the sample, help improve immunoassay results.8/12/2012 SALIVA 81
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  85. 85. Children and infant swab8/12/2012 SALIVA 85
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  88. 88. To be continued…• Saliva as a diagnostic marker• Diseases• Xerostomia• Conclusion8/12/2012 SALIVA 88