Saliva hitesh


Published on

Published in: Education, Technology
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Saliva hitesh

  3. 3. INTRODUCTION Saliva, commonly known as spittle, spit, slobber, slaver, sputum or dribble, is the watery liquid that is secreted into the mouth by the salivary glands and bathes the oral mucosa and the teeth. There are three major pairs & many minor salivary glands. Major are - i) Parotid gland ii) Submandibular gland & iii) Sublingual gland Minor glands are located in the submucosa. 3
  4. 4. The parotid glands normally contribute about 25% of the total volume of unstimulated whole saliva, while the submandibular glands contribute 60%, the sublingual 7–8%, and the minor mucous glands 7–8%. At very high stimulated flow rates, the parotid becomes the dominant gland, contributing about 50% of the whole saliva. Saliva is sterile until it enters the oral cavity when it becomes mixed with micro-organisms in the mouth- bacteria and often viruses and yeats leucocytes and dietary substances from recently consumed food and drink. 4
  5. 5. DEVELOPMENT  All salivary glands show a similar pattern of development.  They originate from oral epithelial buds invading the underlying mesenchyme.  The origin of epithelial bud is believed to be ectodermal in parotid and minor salivary gland and endodermal in submandibular and sublingual glands. 5
  6. 6.  The Primordia of the glands of humans appear during sixth week whereas the primordium of sublingual glands appear after 7 to 8 weeks of fetal life.  The minor salivary glands begin their development during the third month. The epithelial bud grows into an extensively branched system of cords of cell that are first solid but gradually develop a lumen and become ducts.  The secretory portions develop later than the duct system and forms by repeated branching and budding of the finer cell cords and ducts. 6
  7. 7. Epithelium protrudes into underlying ectomesenchyme & as the epithelium invaginates , it forms a small bud connected to the surface by trailing cord of epithelium - Initial bud stage. At the same time , ectomesenchyme cells condense around this bud. The bud undergoes branching to produce a cluster of branches & buds, -known as Pseudoglandular Stage . 7
  8. 8. Since salivary glands are formed from an initially solid core of epithelial cells –for the proper functioning of the gland the duct needs to undergo cavitation -to allow free access between the saliva producing acini and oral cavity.- known as Canilicular Stage. 8
  9. 9. 9
  10. 10. ANATOMY OF GLANDS Secretory units are composed of serous, mucous and myoepithelial cells arranged into secretory tubules called-acini. Serous cell specialised for the synthesis, storage and secretion produce protein & glycoprotein ( typically N linked ) Mucous cell produce mucin , glycoprotein ( typically O linked ) & function mainly to lubricate & form barrier against micro- organism. 10
  11. 11. SEROUS CELLS Typically spherical in shape . 8-12 cells . Cells are pyramidal in shape, with its broad base resting on a thin basal lamina and its narrow apex bordering on the lumen of end piece. The spherical nucleus is located in the basal region of the cell. 11
  12. 12. The secretory proteins are synthesized by membrane bound ribosome, transferred to the cisternal space of RER, and migrate to Golgi apparatus , where carbohydrate addition and other post transitional modification are completed and they are packaged into secretory granules. 12
  13. 13. 13
  14. 14. MUCOUS CELLS Polyhedral & Contain mucinogen granules. (1) they have little or on enzymatic activity and serve for lubrication and protection of the oral tissues (2) the ratio of carbohydrate to protein is greater, and larger amounts of sialic acid and sulphated sugar residues are present. 14
  15. 15. Secretion of mucus droplet is some what other mechanism then exocytosis when a single droplet is discharged it fuses with the apical plasma membrane, resulting in single membrane separating droplets from the lumen. This separating membrane then fragment and being lost and with the discharge of mucus or the droplet maybe discharged with the membrane intact surrounding it. 15
  16. 16. 16
  17. 17. Intercalated ducts The small ducts are intercalated ducts; they are thin branching tubes of variable length that connect to the terminal secretory units to the next larger ducts. Primary saliva produced by secretory end piece passes first thorough intercalated ducts. Diameter of these ducts are smaller. 17
  18. 18. The intercalated ducts cells often contain secretory granules in their apical cytoplasm, and two of the antibacterial proteins in saliva, lysozyme and lactoferrin, have been localized to these ducts. 18
  19. 19. STRIATED DUCTS Constitute largest portion of ductal system located within lobules of Salivary glands . The striated duct cells contain kallikrein, an enzyme found in saliva, and synthesize secretory glycoproteins, which are stored in the apical granules. 19
  20. 20. EXCREATORY DUCTS Located in connective tissue septa between lobules of gland Larger in diameter then striated duct . 20
  21. 21. 21
  22. 22. PAROTID GLAND Largest of all glands Average Wt - 25gm Located in the preauricular region and along the posterior surface of the mandible. 22
  23. 23.  Each parotid gland is divided by the facial nerve into a superficial lobe and a deep lobe.  The superficial lobe, overlying the lateral surface of the masseter, is defined as the part of the gland lateral to the facial nerve.  The deep lobe is medial to the facial nerve and located between the mastoid process of the temporal bone and the ramus of the mandible 23
  24. 24. PAROTID DUCT Ductus parotideus; Stensen’s duct 5 cm in length Appears in the anterior border of the gland Runs anteriorly and downwards on the masseter b/w the upper and lower buccal branches of facial N. At the anterior border of masseter it pierces Buccal pad of fat Buccopharyngeal fascia Buccinator Muscle 24
  25. 25.  Because of oblique course of duct through buccinator inflation of duct is prevented during blowing.  It opens into the vestibule of mouth opposite to the 2nd upper molar. 25
  26. 26. SUBMANDIBULAR GLANDS  Large superficial and small deeper part continuous with each other around the posterior border of mylohyoid.  Superficial Part Situated in the digastric triangle  Wedged b/w body of mandible and mylohyoid. 26
  27. 27. Submandibular duct  Also called as Wharton's duct  5 cm long  Emerges at the anterior end of deep part of the gland.  Runs forwards on Hyoglossus b/w lingual and hypoglossal Nerve.  At the ant. Border of Hyoglossus it is crossed by lingual nerve  Opens in the floor of mouth at the side of frenulum of tongue. 27
  28. 28. SUBLINGUAL SALIVARY GLAND  Smallest of the three glands  3-4 gm  Lies beneath the oral mucosa in contact with the sublingual fossa on lingual aspect of mandible. 28
  29. 29. Duct of Rivinus 8-20 ducts Most of them open directly into the floor of mouth Few of them join the submandibular duct. 29
  30. 30. Minor salivary glands are located beneath the epithelium in almost all parts of the oral cavity. These are  Labial and buccal glands,  Glossopalatine glands,  Palatine glands  Lingual glands. These cells consist of small groups of secretory units opening via short ducts directly into the mouth . They lack connective tissue capsule , instead mixing with the connective tissue of submucosa or muscle fibers of the tongue and cheek. 30
  31. 31. 31
  32. 32. CONNECTIVE TISSUE (Histology ) Cells : fibroblasts, macrophages, mast cells, occasional leukocytes, fat cells and plasma cells. Fibers: collagen and reticular fibers, are embedded in a ground substance composed of proteoglycans and glycoproteins. The vascular supply to the glands is also embedded within the connective tissue, entering the glands along the excretory ducts and branching to follow them into the individual lobules. 32
  33. 33. FORMATION AND SECREATION OF SALIVA Fluid and electrolyte secretion is two step procedure.  1st step : Occures In acinar cells  2nd step : Occurs In salivary ducts. 33
  34. 34. The acinus is known as secretory end piece and produce plasma like primary saliva.This process is driven by trans epithelial Cl movement. The acinar tight junctions provide cationic selective pathway for Na. Flux down its electrical gradient into the acinar lumen and resultant osmotic gradient for NaCl causes water movement via water channel.Acinar cell secrete a NaCl-rich fluid called primary saliva. 34
  35. 35. The primary saliva is subsequently modified through its passage along the ductal tree mostly by reabsorbing NaCl and secreting K & HCO3. Because the ductal epithelium is poorly permeable to H2O, the final saliva is hypotonic. 35
  36. 36. COMPOSTION OF SALIVA  Saliva is 99.5% Water and 0.5% solid.  Serum proteins, including IgA, IgM & IgG.  Secretory IgA – synthesized by Plasma cells & mucosal epithelial cells.  Salivary Enzymes – Amylase , Lysozyme , Lipase Peroxidase , Kallikrein 36
  37. 37. Mucoproteins & Glycoproteins- Proline , Glycine & Glutamic acid. Blood Group substances- Hormones , Carbohydrates, Lipids, Nitrogen containing compounds, Lactoferrin. Inorganic substances - Sodium, Potassium , chloride, Bicarbonate, Hydrogen ion, Iodine, Fluoride, Thiocyanate, Phosphate 37
  38. 38. Factors Affecting the Salivary Composition  Gland source  Flow rate  Duration & Nature of stimulation  Plasma composition( diet)  Hormones & Pregnancy 38
  39. 39. DAILY OUTPUT OF SALIVA Salivary flow rate follows a circadian rhythm and peaks in the late afternoon, while there is a trough during sleep when saliva flow almost ceases. There is a wide range of ‘normal’ salivary flow rates from 0.3–0.4 ml/min when unstimulated and 1.5–2.0 ml/min when stimulated. The average daily amount produced by adults is 0.5–0.6 litres.Women have a lower salivary flow rate than men. 39
  40. 40. Saliva is unique in a way that it is controlled exclusively by nerves. No hormone has been discovered which controls specifically its rate of flow although hormones may alter its composition and the hormones of the thyroid gland and suprarenal cortex influence the general activity of gland. Saliva flow is reduced during stress,inhibited during muscular exercise,during application of sensory stimuli to skin. 40
  41. 41. The acts of swallowing and yawning are followed by a transient increase in rates of flow from the parotid and then usually a compensatory pause. These changes arise as a result of mechanical pressure altering the dead space of gland rather than the true secretion rate. 41
  42. 42. RESTING FLOW Salivary glands are always secreting under walking conditions, even in the absence of obvious stimuli. The resting flow may be detected by means of a lashley cannula. A simpler method is to allow saliva to drain directly into a beaker from the open mouth with the head bent forward to a horizontal position. The methods used affects the results draining giving a lower and spitting a higher quantity. 42
  43. 43. PSYCHIC FLOW The experiments of pavlov proved the exixtence of conditioned reflex in the control of salivary flow.Lashley in 1916 found that mention of food even to a hungry individual had no effect on parotid flow but the sight of food gave a positive response. Kerr found out that conditioned stimuli cause unconscious movements in the mouth which may squeeze out secretions in the ducts. 43
  44. 44. VISCOSITYAND SPINNBARKEIT Saliva is a viscous fluid and also shows the property of spinnbarkeit i.e. the ability to be drawn out into long elastic threads. THE REDUCING POWER OF SALIVA In any complex biological system like saliva with its teeming flora some chemical reactions in progress will be oxidation and others reductions.Overall mixed saliva has reducing properties. 44
  45. 45. PROTECTION AND LUBRICATION Saliva keeps the mouth moist and comfortable: it acts as a lubricant by coating the oral tissues, thus facilitating mastication (chewing) and deglutition (swallowing). Mucus helps bind masticated food into a slippery bolus in preparation for swallowing. 45
  46. 46. Saliva protects hard and soft tissues against mechanical, thermal and chemical irritation and tooth wear—it protects enamel and prevents caries and gingivitis. Saliva helps smooth air flow and assists speech. It also helps to keep dentures in place. 46
  47. 47. CLEANSING ACTION Saliva clears food from the mouth and assists deglutition. A major function of saliva is the clearance of carbohydrates from recently eaten food that could cause caries. The faster the flow of saliva, the quicker substances are cleared from the mouth. Areas of slow clearance are the labial and upper anterior region; fast clearance occurs from the lingual and lower anterior region, while the buccal region is an intermediate area. 47
  48. 48. ANTIMICROBIAL ACTION Lysozyme has an antibacterial action, controlling oral microflora, and thus helps to control disease of the oral cavity. In turn, this helps to prevent halitosis.  Taste To stimulate taste buds, which is one of its functions, saliva dissolves food molecules.  Digestion Saliva initiates digestion by secreting alpha amylase (ptyalin), which breaks down starchy foods into maltose, maltotriose and dextrins. 48
  49. 49. BUFFERING ACTION Saliva neutralises acids produced by acidogenic microorganisms, thus preventing enamel demineralisation. The resting pH of the mouth is neutral at 6.7; demineralisation of enamel takes place below a critical pH of about 5.5 49
  50. 50. It also prevents the colonisation of potentially pathogenic microorganisms by denying them optimal environmental conditions. The lowest pH occurs around the upper anterior teeth on approximal surfaces, as clearance of substances is slow in these areas. This explains the higher incidence of caries interdentally on upper anterior teeth. Tests of salivary buffering capacity and of salivary mutans streptococci and lactobacilli levels in saliva can be used to assess caries risk. 50
  51. 51. WATER BALANCE When there is dehydration and the body water balance is low, saliva flow is reduced to conserve water, urine production decreases and thirst increases. 51
  52. 52. EXCREATION Substances that are secreted in the saliva are excreted as, technically, the oral cavity is outside the body. There are trace elements of urea and uric acid in saliva. 52
  53. 53. PELLICLE FORMATION Salivary and other proteins form a thin pellicle on the surface of the enamel., this acquired enamel pellicle can be considered a renewable lubricant that helps to protect the teeth from attrition and abrasion. In addition, it protects against demineralisation and facilitates remineralisation of the enamel. It is important to remember that oral bacteria can bind to the pellicle and so it may influence the formation and makeup of the bacterial biofilm. 53
  54. 54. HYPERSALIVATION If one or more of the salivary glands is overactive, hypersalivation will result. The excessive production of saliva can occur when eating spicy or very sour foods as the taste buds on the tongue react to the stimulus. Acidic foods appear to generate more saliva than sweet. 54
  55. 55. Hypersalivation can occur as a reaction to a medical condition or disease, including neurological disorders such as Parkinson’s disease, gastroesophageal reflux disease (GORD) and hyperhydration. It can lead to problems with swallowing. Chronic drooling can occur, particularly where patients have lost muscle control in their face and mouth, for example following a stroke, or if they develop bell’s palsy or parkinson’s disease. 55
  56. 56. HYPOSALIVATION Underactivity of salivary glands causes too little production of saliva. This results in dry mouth/xerostomia. A flow rate of <0.1 ml/min is considered objective evidence of hyposalivation. 56
  57. 57. Patients experiences difficulty with eating, swallowing; speech, the wearing of dentures, trauma to and ulceration of the oral mucosa, taste alteration, poor oral hygiene, a burning sensation of the mucosa, oral infections including candida and rapidly progressing dental caries. In addition, dry and cracked lips, halitosis, glossitis and difficulty with sleeping are well known to occur. 57
  58. 58. Whole saliva has long been known to contain large numbers of bacteria. Little attention has been given to the question of why bacteria are in saliva, when oral surfaces seem to provide a much more favourable environment for growth. Saliva exerts shearing forces as it flows. This might lead to passive detachment of some microbes from biofilm surfaces. However, the unstimulated velocity of the salivary film is low in most regions of the mouth. 58
  59. 59. Biofilm bacteria play an active role in their transition to the planktonic state. In several biofilm models, sessile bacteria produce enzymes that promote their release into the fluid medium. Similar mechanisms have been observed for biofilms of S. mutans, the primary etiologic agent of dental caries . . 59
  60. 60. Selection by Saliva against Bacteria Bacteria in biofilms tend to be much more resistant to antibiotics and disinfectants.. This is a particularly important issue for biofilms in medical devices, but it also extends to the mouth. Chlorhexidine is widely used as an antimicrobial rinse in the treatment of periodontitis. Experiments comparing biofilms of oral species with broth cultures have consistently shown that much higher chlorhexidine concentrations are required to achieve significant killing in biofilm. 60
  61. 61. One such mechanism may be aggregation followed by clearance. Many strains of oral species form large aggregates when they are incubated with saliva. Several salivary proteins have been associated with this process. Most are large glycoproteins such as mucin glycoprotein 2,parotid proline-rich glycoprotein , and parotid salivary agglutinin, but secretory IgA lactoferrin , and lysozyme also may be involved . 61
  62. 62. Interspecific coaggregates also might be subject to clearance in the mouth. However, coaggregation of aerobic or facultative species with anaerobes likewise might promote the survival of anaerobes during transit. The survival of planktonic anaerobes there depends on the presence of both aerobes and Fusobacterium nucleatum, which coaggregates with many different species . 62
  63. 63. Selection by Saliva in Favour of Bacteria Salivary proteins also may act in ways that facilitate biofilm formation. The most fundamental of those is to provide ligands for attachment. Oral microbes are capable of adhering to bare hydroxyapatite but this probably never occurs in the mouth. Pellicles form on oral soft tissues as well, through covalent bonding to cell-surface proteins that is mediated by the enzyme transglutaminase . 63
  64. 64. It is now being recognized that oral pellicles from different sites are not uniform in content. Instead, they reflect the composition of saliva from the glands that are closest to them. Bacterial aggregates in vitro typically precipitate out of suspension. It has been assumed that oral aggregates will be less likely to adhere to surfaces, and thus will be cleared by swallowing. 64
  65. 65. There is little direct evidence to show that this happens in the mouth. However, several investigators have shown that the adherence of labeled bacteria to saliva-coated hydroxyapatite is considerably reduced when bacteria are suspended in saliva instead of buffer . 65
  66. 66. Holistic Concept of Salivary Function Biofilm composition varies greatly among hosts. It is difficult to anticipate how any single species will behave within a mixture of cooperating species. Saliva composition is equally diverse. Many proteins belong to polymorphic multigene families . 66
  67. 67. Since the composition of products of various glands differs it is clear that the mixed saliva will depend on the relative activity of each gland. The most convenient method for separating parotid saliva from that of other glands is by means of cannula. This consists of two concentric rings of metal or plastic attached to a disc about half an inch in diameter. Tubes are inserted so that outer space between the two rings may be evacuated and from inner space which is placed over the parotid duct lead the saliva away into a receptacle placed outside the mouth . 67
  68. 68. This design has been further modified by rounding off the sharp edges which irritated the mucosa after prolonged use . For the separate collection of saliva from the submandibular and sublingual glands a device has been designed. Its is made of acrylic appliance appliance with three separate chambers a central core which is placed over the duct of the submandibular gland and two lateral ones which cover the numerous ducts of the sublingual glands. 68
  69. 69. 69
  70. 70. It is composed of secretions from parotid,submandibular, sublingual and minor mucous glands as well as from gingival crevicular fluid,desqumated epithelial cells ,micro organisms,leucocytes,food residue and blood. This type of saliva is used in the majority of diagnostic studies. 70
  71. 71. This has been obtained in repsonse to masticatory(chewing on paraffin wax,rubber glands,gum base), gustatory( use of citric acid or sour candy drops on the subjects tongue) or psychologic(imagination of meal) stimulation. Stimulated saliva flow rate is 4 ml/minute. 71
  72. 72. The most commonly used laboratory diagnostic procedures involve the analyses of the cellular and chemical constituents of blood. Other biologic fluids are utilized for the diagnosis of disease, and saliva offers some distinctive advantages. 72
  73. 73.  Whole saliva can be collected non-invasively, and by individuals with limited training. No special equipment is needed for collection of the fluid.  Diagnosis of disease via the analysis of saliva is potentially valuable for children and older adults, since collection of the fluid is associated with fewer compliance problems as compared with the collection of blood.  Further, analysis of saliva may provide a cost-effective approach for the screening of large populations. 73
  74. 74. (1) SYSTEMIC DISEASES Some systemic diseases affect salivary glands directly or indirectly, and may influence the quantity of saliva that is produced, as well as the composition of the fluid. These characteristic changes may contribute to the diagnosis and early detection of these diseases. 74
  75. 75. HEREDITARY DISEASES Cystic fibrosis (CF) is a genetically transmitted disease of children and young adults, which is considered a generalized exocrinopathy. The gene defect causing CF is present on chromosome 7 and codes for a transmembrane-regulating protein called the cystic fibrosis transmembrane conductance regulator. The abnormal secretions present in CF caused clinicians to explore the usefulness of saliva for the diagnosis of the disease. Most studies agree that saliva of CF patients contains increased calcium levels. 75
  76. 76. The submandibular saliva of CF patients was also found to contain more lipid than saliva of non-affected individuals, and the levels of neutral lipids, phospholipids, and glycolipids are elevated. These alterations in salivary lipids in CF patients may account, in part, for the altered physico-chemical properties of saliva in this disease. 76
  77. 77. Apparently, salivary alterations in CF patients are to a large extent due to alterations in submandibular saliva. Elevations in electrolytes (sodium, chloride, calcium, and phosphorus), urea and uric acid, and total protein were observed in the submandibular saliva of CF patients . 77
  78. 78. Minor salivary glands are also affected. Elevated levels of sodium and a decrease in flow rate were reported for these glands in CF patients. However, the parotid saliva of CF patients does not demonstrate qualitative changes as compared with that of healthy individuals. 78
  79. 79. AUTOIMMUNE DISEASES- Sjogren’s syndrome Sjögren's syndrome (SS) is an autoimmune exocrinopathy of unknown etiology. The accepted procedure for the diagnosis of the salivary involvement of SS is a biopsy of the minor salivary glands of the lip. SS is characterized by the presence of a lymphocytic infiltrate (predominantly CD4+ T-cells) in the salivary gland parenchyma . A low resting flow rate and abnormally low stimulated flow rate of whole saliva are also indicators of SS . 79
  80. 80. Serum chemistry can demonstrate polyclonal hypergammaglobulinemia and elevated levels of rheumatoid factor, antinuclear antibody, anti-SS-A, and anti-SS-B antibody . The immunologic mechanisms involved in the pathogenesis of the diseases appear also to involve B-cells (the majority of lymphomas associated with SS are of the B-cell type), salivary epithelial cells, an activated mononuclear cell infiltrate,cytokines, and adhesion molecules. 80
  81. 81. MALIGNANCY Salivary analysis may aid in the early detection of certain malignant tumors. p53 is a tumor suppressor protein which is produced in cells exposed to various types of DNA-damaging stress. Inactivation of this suppressor through mutations and gene deletion is considered a frequent occurrence in the development of human cancer. 81
  82. 82. Defensins are peptides which possess antimicrobial and cytotoxic properties. They are found in the azurophil granules of polymorphonuclear leukocytes. Elevated levels of salivary defensin-1 were found to be indicative of the presence of oral SCC. A high-positive correlation was observed between salivary defensin-1 levels and serum levels of SCC-related antigen. 82
  83. 83. Tumor markers that can be identified in saliva may be potentially useful for screening for malignant diseases. Salivary diagnosis may be part of a comprehensive diagnostic panel that will provide improved sensitivity and specificity in the detection of malignant diseases and will assist in monitoring the efficacy of treatment. 83
  84. 84. 2) VIRAL DISEASES The antibody response to infection is the basis for many diagnostic tests in virology. Saliva contains immunoglobulins that originate from two sources: the salivary glands and serum. The predominant immunoglobulin in saliva is secretory IgA (sIgA), which is derived from plasma cells in the salivary glands, and constitutes the main specific immune defense mechanism in saliva. 84
  85. 85. Although the minor salivary glands play an important role in sIgA-mediated immunity of the oral cavity, cells in the parotid and submandibular glands are responsible for the majority of the IgA found in saliva. In contrast, salivary IgM and IgG are primarily derived from serum via GCF, and are present in lower concentrations in saliva than is IgA. Antibodies against viruses and viral components can be detected in saliva and can aid in the diagnosis of acute viral infections, congenital infections, and reactivation of infection . 85
  86. 86. Saliva was found to be a useful alternative to serum for the diagnosis of viral hepatitis. Acute hepatitis A (HAV) and hepatitis B (HBV) were diagnosed based on the presence of IgM antibodies in saliva. The ratio of IgM to IgG anti-HAV antibody correlated with the time interval from onset of infection. Saliva may also be used for determining immunization and detecting infection with measles, mumps, and rubella. 86
  87. 87. For newborn infants, the salivary IgA response was found to be a better marker of rotavirus (RV) infection than the serum antibody response. The shedding of herpesviruses (human herpesvirus – 8,cytomegalovirus, and Epstein-Barr virus) in nasal secretions and saliva of infected patients has been reported. 87
  88. 88. Other investigators suggested that reactivation of herpes simplex virus type-1 (HSV-1) is involved in the pathogenesis of Bell's palsy and reported that PCR-based identification of virus in saliva is a useful method for the early detection of HSV-1 reactivation in patients with Bell's palsy. 88
  89. 89. HIV Studies have demonstrated that the diagnosis of infection with the human immunodeficiency virus (HIV) based on specific antibody in saliva is equivalent to serum in accuracy, and therefore applicable for both clinical use and epidemiological surveillance . Antibody to HIV in whole saliva of infected individuals, which was detected by ELISA and Westernblot assay, correlated with serum antibody levels . 89
  90. 90. As compared with serum, the sensitivity and specificity of antibody to HIV in saliva for detection of infection are between 95% and 100% . Salivary IgA levels to HIV decline as infected patients become symptomatic. It was suggested that detection of IgA antibody to HIV in saliva may, therefore, be a prognostic indicator for the progression of HIV infection. 90
  91. 91. 3) Drug Monitoring Similar to other body fluids (i.e., serum, urine, and sweat), saliva has been proposed for the monitoring of systemic levels of drugs. A fundamental prerequisite for this diagnostic application of saliva is a definable relationship between the concentration of a therapeutic drug in blood (serum) and the concentration in saliva. 91
  92. 92. For a drug to appear in saliva, drug molecules in serum must pass through the salivary glands and into the oral cavity. Therefore, the presence of a drug in saliva is influenced by the physicochemical characteristics of the drug molecule and its interaction with the cells and tissues of the salivary glands, as well as by extravascular drug metabolism. 92
  93. 93. Factors such as molecular size, lipid solubility, and the degree of ionization of the drug molecule, as well as the effect of salivary pH and the degree of protein binding of the drug, are important determinants of drug. Saliva may be used for monitoring patient compliance with psychiatric medications and monitoring levels of anti-epileptic and anti-cancer drugs. 93
  94. 94. 4) The Monitoring of Hormone Levels Due to their lipid solubility, steroid hormones can be detected in saliva. Salivary cortisol levels were found to be useful in identifying patients with Cushing's syndrome and Addison's disease , and also for monitoring the hormone response to physical exercise and the effect of acceleration stress. 94
  95. 95. Salivary aldosterone levels demonstrated a high correlation with serum aldosterone levels,and increased aldosterone levels were found in both the serum and saliva of patients with primary aldosteronism. 95
  96. 96. 5) Diagnosis of Oral Disease with Relevance for Systemic Diseases Insulin can be detected in saliva, and salivary insulin levels have been evaluated as a means of monitoring serum insulin levels. The monitoring of gland-specific secretions is important for the differential diagnosis of diseases that may have an effect on specific salivary glands, like obstruction or infection. 96
  97. 97. Quantitative alterations in saliva may be a result of medications. At least 400 drugs may induce xerostomia. Diuretics, antihypertensives, antipsychotics, antihistamines, antidepressants, anticholinergics, antineoplastics, and recreational drugs such as opiates, amphetamines, barbiturates, hallucinogens, cannabis, and alcohol have been associated with a reduction in salivary flow. 97
  98. 98.  Saliva can be used for the detection of oral candidiasis, and salivary fungal counts may reflect mucosal colonization.  Saliva may be used for the monitoring of oral bacteria. Bacteria (including anaerobic species) can survive in saliva, and can utilize salivary constituents as a growth medium.  It also can serve as a vector for bacterial transmission, and also as a reservoir for bacterial colonization  It may also be used for periodontal diagnosis, due in large part to contributions from GCF. 98
  99. 99. ANALYSIS OF SALIVA FOR PERIODONTAL DIAGNOSIS(SALIVARY BIOMARKERS) The diagnosis of active phases of periodontal disease, and the identification of patients at risk for active disease, represents a challenge for both clinical investigators and clinicians. 99
  100. 100. In general, clinical parameters including probing depth, attachment level, bleeding on probing (BOP) plaque index (PI) and radiographic loss of alveolar bone are used to assess disease severity . Occasionally, monitoring of the microbial infection and analysis of the host response in gingival crevicular fluid (GCF) are utilized in an attempt to identify individuals at risk for future breakdown. 100
  101. 101. However, as of yet, no clinical or laboratory test is routinely employed in the monitoring of patients with periodontal disease. Clinical and radiographic assessment of periodontal disease remains the basis for patient evaluation. This is true despite the fact that clinical monitoring is time consuming, subject to considerable measurement error, and is often poorly tolerated by patients. In addition, the frequency of radiographic evaluation is limited. These measures provide information primarily about disease severity, and are not useful measures of disease activity. 101
  102. 102. It has long been realized that a rapid and simple diagnostic test that can provide a reliable evaluation of periodontal disease and identify patients at risk for active disease would be of value to both clinicians and patients. Saliva is a fluid that can be easily collected, contains locally- derived and systemically- derived markers of periodontal disease, and hence may offer the basis for a patient specific diagnostic test for periodontitis. 102
  103. 103. 1) ENZYMES Enzymes present in saliva can be produced by cells in the salivary glands, oral microorganisms, polymorphonuclear leucocytes (PMNs), epithelial cells, and can be derived from GCF entering the oral cavity.  Fibronectin is a glycoprotein that promotes selective adhesion and colonization of certain bacterial species, while inhibiting others.  Therefore, the production of fibronectin-degrading enzymes by certain bacteria present in dental plaque may promote their adhesion and colonization. 103
  104. 104. 2) IMMUNOGLOBULINS The predominant immunoglobulin in saliva is secretory IgA (sIgA) which is derived from plasma cells in the salivary glands. Although the minor salivary glands play an important role in sIgA mediated immunity of the oral cavity, cells in the parotid gland are responsible for the majority of the IgA found in saliva sIgA constitutes the main specific immune defense mechanism in saliva and may be important in maintaining homeostasis in the oral cavity. 104
  105. 105. sIgA may control the oral microbiota by reducing the adherence of bacterial cells to the oral mucosa and teeth . There are two subclasses of IgA: IgA1 and IgA2. IgA1 predominates in serum while IgA2 is found in higher concentrations in external secretion. 105
  106. 106. Specific immunoglobulins in saliva directed towards periodontal pathogens have also been examined for their diagnostic potential. A number of studies have examined the correlation between non- enzymatic, non immunoglobulin proteins in saliva and periodontal disease. 106
  107. 107. 3) OTHER PROTEINS Epidermal growth factor (EGF) is involved in oral wound healing and functions with hormone-like properties to stimulate epithelial cells. In humans, the parotid gland is the major source of EGF. Vascular endothelial growth factor (VEGF), also known as vascular permeability factor or vasculotropin, is a multifunctional angiogenic cytokine important in inflammation and wound healing. This cytokine was found to be a component of whole saliva. 107
  108. 108. 4) Epithelial keratins Epithelial cells from the lining of the oral cavity are found in saliva, but the contribution of crevicular or pocket epithelial cells to the total number of salivary epithelial cells is not known . To study epithelial cell function in periodontal disease and periodontal diagnosis, specific keratin antigens in saliva may be evaluated. Furthermore, detection of keratins by monoclonal antibodies may have diagnostic value in detection of epithelial dysplasia, oral cancer, odontogenic cysts and tumors. 108
  109. 109. 5) Inflammatory cells The number of leukocytes in saliva varies from person to person, and cell counts vary for an individual during the course of the day. The majority of salivary leukocytes enter the oral cavity via the gingival crevice . 109
  110. 110. 6) Salivary ions Calcium(Ca)is the ion that has been most intensely studied as a potential marker for periodontal disease in saliva. A high concentration of salivary Ca was correlated with good dental health in young adults, but no relationship was detected with periodontal bone loss as measured from dental radiographs. 110
  111. 111.  Elevated serum cortisol levels associated with emotional stress exert a strong inhibitory effect on the inflammatory process and immune response.  Salivary volatiles have been suggested as possible diagnostic markers and contributory factors in periodontal disease. 111
  112. 112. Oral consequences of salivary dysfunction 112 1 ) Dry mouth (Xerostomia) – It is a frequent clinical complaint A loss of salivary function or a reduction in the volume of secreted saliva may lead to the sensation of oral dryness. This occurs as a side effect of mediations taken by the patient for other problems. Many drug cause central or peripheral inhibition off salivary secretion. Destruction is another common cause.
  113. 113. Loss of gland function occurs after radiation therapy for head and neck cancer because the glands are included in the radiation field, chemotherapy may also cause this condition. Temporary relief is achieved by frequent sipping of water or artificial saliva . 2 )Age Changes – With age a generalized loss of gland parenchymal tissue occurs.The lost salivary cells often are replaced by adipose tissue. 113
  114. 114. 3) Caries: a major problem of a reduced salivary flow is the increased risk of caries as saliva normally washes away acids. There may be an increase in recurrent decay on coronal as well as root surfaces. Incisal edges of interior teeth may also develop carious lesions as well as recurrent lesions on the margins of restorations. 114
  115. 115. 4) Dental erosion: salivary gland hypofunction can cause deficient remineralisation. ‘Low buffering capacity and flow rate indicate a greater erosion risk and advice should be given to the patient to minimise this. This should include following acidic intake with a glass of water to aid clearance and finishing each meal with a neutral salivary stimulant, such as cheese, to promote salivary flow. Chewing sugar-free gum also stimulates production of saliva. 115
  116. 116. 5) Gingivitis: lack of saliva leads to retention of food particles in the mouth, particularly interdentally and under dentures. This may result in gingivitis and, in the long term, periodontitis. 6) Oral ulceration: reduced saliva flow may result in recurrent aphthous ulceration, pain, lichen planus, delayed wound healing and secondary infection, such as candidiasis. 116
  117. 117. 7) Mucositis: this is a painful condition where the mucous membrane of the oral cavity becomes ulcerated and inflamed. It increases susceptibility to fungal infections such as candidiasis. Mucositis can lead to dysphagia, dehydration and impaired nutrition. 8) Swallowing: there are problems with too much saliva or too little often accompanied by complaints of dysphagia. 117
  118. 118. 9) Dysgeusia: distortion of taste may occur due to lack of saliva as it ‘plays a critical role in taste function as a solvent for food, a carrier of taste. eliciting molecules, and through its composition. This reduces enjoyment of eating. In addition, irradiation of the head and neck area may damage or destroy taste buds or salivary glands. 10) Glossitis: with salivary hypofunction,the tongue can appear red, dry and raw, particularly on the dorsum, while the filiform papillae may be lost. 118
  119. 119. 11) Dentures: patients with hyposalivation often complain their dentures lose retention and stability. This can cause problems with speech, chewing, swallowing and nutritional intake. It also increases the risk of candidal infections, ulceration, gingivitis, aspiration pneumonia, bacteraemia, viral infections and caries in the remaining teeth. Denture fixatives may be required to retain the removable prosthesis. 119
  120. 120. 12) Halitosis- Saliva gives rise to bad odours especially during mouth breathing prolonged talking or hunger. Eating reduces halitosis partly because it increases saliva flow and friction in the mouth. 120
  121. 121. Saliva has an important role in patient’s quality of life. Dental professionals need to be aware of the problems that arise when there is an overproduction or underproduction of saliva, and also a change in its quality. It may be advantageous for dentists to measure the salivary flow of patients on a regular basis to see if any changes occur over time. This knowledge enables early diagnosis, treatment and, if possible, prevention of problems. Checking the patient’s medical history regularly can identify conditions or medications that can adversely influence saliva production. 121
  122. 122. Saliva offers an alternative to serum as a biologic fluid that can be analysed for diagnostic purposes. Whole saliva contains locally produced as well as serum-derived markers that have been found to be useful in the diagnosis of a variety of systemic disorders. Despite some limitations, the use of saliva for diagnostic purposes is increasing in popularity. Several diagnostic tests are commercially available and are currently used by patients, researchers, and clinicians 122
  123. 123. Due to its many potential advantages, salivary diagnosis provides an attractive alternative to more invasive, time- consuming, complicated, and expensive diagnostic approaches. However, before a salivary diagnostic test can replace a more conventional one, the diagnostic value of a new salivary test has to be compared with accepted diagnostic methods. 123
  124. 124. 1.Orban’s oral histology 2.Tencate’s oral histology- 6TH Edition 3.Carranza’s clinical periodontology- 10 th edition 4.Eliaz Kaufman,Ira B.Lamster The diagmostic applications of saliva – A review.Crit Rev Oral Biol Med 2009 5.Kaufman E,Lamster ib.Analysis of saliva for periodontal diagnosis.A review J Clini Periodontol 2000 6.J.D.Rudney Saliva and dental plaque Adv Dent Res December 2000 7.Patricia Machperson The role of saliva in oral health and disease.Dental nursing october 2013 124
  125. 125. 125