SALIVA 1

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SALIVA By Dr. J eswin M. Thomas

CONTENTS:

CONTENTS INTRODUCTION ANATOMY AND STRUCTURE CLASSIFICATION COMPOSITION pH FUNCTION SECRETION DIAGNOSTIC TOOL

INTRODUCTION:

INTRODUCTION 3 Saliva is complex fluid produced by salivary glands Maintain the well being of mouth. Saliva is a clear, slightly acidic mucoserous exocrine secretion.

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Average daily flow = 500 to 1500 ml Un-stimulated flow 20% Parotid 65% Submandibular 7–8% Sublingual 10% Minor glands Stimulated flow 50% Parotid

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Whole saliva is a complex mix of fluids from major and minor salivary glands and from GCF, which contains oral bacteria and food debris. Duct saliva is saliva flowing from individual gland. 5

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Saliva is critical to the preservation and maintenance of oral health. Saliva also has become useful as a noninvasive systemic sampling measure for medical diagnosis and research . 6

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W hole saliva contains contributions from non-glandular sources such as gingival crevicular fluid in an amount that depends on the periodontal status of the patient Whole saliva, in contrast to glandular saliva, also contains vast amounts of epithelial cells from the oral mucosa and millions of bacteria. These components give whole saliva its cloudy appearance, which is different from glandular saliva, which is transparent like water.

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Parotid gland Largest Serous gland Duct – Stenson’s duct opens into the oral cavity opposite the buccal surface of the maxillary second molar Blood supply – external carotid artery Nerve supply – Parasympathetic – glossopharyngeal nerve Sympathetic – superior salivary ganglion

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Submandibular gland Mixed gland – serous Duct – Wharton’s duct opens at the summit of the sublingual papilla just lateral to the frenum of the tongue . Ducts – less in number Blood supply – facial & lingual artery Nerve supply – Parasympathetic – lingual nerve

Anatomy:

Anatomy Sublingual gland Smallest Mixed gland – mucous Ducts – Bartholin’s duct , duct of ravinus opens close to the duct of the submandibular gland. Ducts – poorly developed

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11 Stenson’s duct Duct of Rivinus Bartholin’s duct Wharton’s duct

Anatomy:

Anatomy

Anatomy:

Anatomy Labial and buccal glands Labial:-situated beneath mucous membrane around the orifice of mouth. mainly mucous secretion. Buccal:- between the mucous membrane and buccinator muscle. mainly– mucous Glossopalatine glands Isthmus of palatoglossal fold Mucous glands

Anatomy:

Anatomy Palatine glands Mucous glands Found beneath the mucus membrane of the soft palate.

Anatomy:

Anatomy Lingual glands Posterior lingual glands – mucous-post 1/3 of tongue Posterior serous glands – glands of von Ebnor – ducts open in trough of vallate and foliate papilla.

Structure:

Structure

Secretory cells:

Secretory cells Serous cells 8-12 pyramidal cells Luminal end – intercellular canaliculi Cytoplasm Spherical nucleus Cell organelles Secretory granules Secretion – saliva rich in enzymatic and antibacterial activity.

Serous cells:

Serous cells

Secretory cells:

Secretory cells Mucous cells Tubular cells Secretions – mucins (glycoprotein), lubricate surfaces and bind & aggregate microorganisms.

Mucous cells:

Mucous cells

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Mucous secretion differs from serous secretion They have little or no enzymatic activity and probably serve mainly for lubrication and protection of the oral tissues. The ratio of carbohydrate to protein is greater and larger amounts of sialic acid and occassionally sulfated sugars are present.

Secretory cells:

Secretory cells Serous Demilune Crescent shaped serous cells covering mucous cells – crescent of Giannuzzi Mixed glands

Myoepithelial cells:

Myoepithelial cells Contractile cells Location.-on the surface of the acini Stellate shape and branching processes Basket cells Processes – actin and myosin filaments Functions – Contraction – secretion Maintain structure and polarity Accelerate initial outflow of saliva from the acini .

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Support the underlying parenchyma and reduce the back permeation of fluid. Help salivary flow to overcome increase in peripheral resistance of the ducts.

Myoepithelial cells:

Myoepithelial cells

Structure :

Structure

Ducts:

Ducts Intercalated ducts Simple cuboidal epithelium Small ducts – large ducts – striated ducts Functions lysozyme and lactoferrin. Undifferentiated cells

Ducts:

Ducts Striated ducts Lined by columnar epithelium Function – modification of primary saliva

Ducts:

Ducts Excretory ducts Lined by – pseudostratified columnar epithelium Located between lobules of gland Cells Mucous or goblet cells Tuft or brush cells Dendritic cells

Classification:

Classification Based on presence of ducts Exocrine Endocrine Based damage of secretory cells at discharge Merocrine – no damage – salivary glands Apocrine – contribute part of protoplasm to secretions – sweat glands Holocrine – extreme damage of cells – sebaceous glands.

Classification :

Classification Based on size Major salivary glands Parotid Submandibular Sublingual Minor salivary glands Based on histology of secretory structures Serous Mucous Mixed

Classification:

Classification Based on location Glands with ducts open in vestibule Lip – labial glands Cheek – buccal and parotid gland Glands with ducts open in oral cavity proper Floor of mouth – submandibular, sublingual glands Tongue – anterior and posterior lingual glands Palate – palatine glands

COMPOSITION :

COMPOSITION Saliva contains inorganic ions and organic molecules of varying proportions dissolved in water. More than 99% of saliva is water . 34

Organic components :

Organic components PROTEIN – 200mg/100ml approx. Alpha amylase :- Parotid- 60 -120mg/ml Submandibular- 25mg/ml Immunoglobulin:- IgA- 20 mg/ml IgG - 1.5 mg/ml IgM - 0.2 mg/ml 35

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Antibacterial enzyme Lysozyme Lactoferrin Sialoperoxidase Glycoprotein Mucous glycoprotein (MG1 & MG2) Prolin rich glycoprotein 36

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Other polypeptides Statherin Sialin Other Organic Compound Free amino acids Urea Glucose Blood group substances Kallikrein 37

Other enzymes-:

Other enzymes- Proteases Amino peptidases Carboxypeptidase Lipases Urease Glucoronidase Hyaluronidase Esterase Choline esterase Phosphatases Sulphatases Alkaline and acid ribonucleases Glycolytic pathway enzymes 38

Inorganic components:

Inorganic components 39 Calcium Phosphorus Magnesium Potassium Thiocyanate B icarbonate Chloride S odium

FACTORS INFLUENCING COMPOSITION:

FACTORS INFLUENCING COMPOSITION Flow Rate Protein, Sodium, Chloride & Bicarbonate increase Phosphate & Mg decrease Differential gland contribution Duration of stimulus Nature of stimulus Salt – High protein content Sweet – High amylase content Diet 40

pH:

pH Mainly determined by the bicarbonate concentration. pH increases with the flow rate. It may be slightly acidic as it is secreted at unstimulated flow rates but it may reach a pH of 7.8 at high flow rates. As it is exposed to the atmosphere, carbon dioxide will diffuse out and pH will rise often to 9 or more in saliva present as a thin film. Sialin is an arginine peptide which is found to increase the pH rise factor, present in saliva which rapidly clears glucose from plaque.

Functions of saliva:

Functions of saliva Protection Buffering Pellicle formation Maintain oral homeostasis Maintain tooth integrity Antimicrobial action Antifungal action Antiviral activity Tissue repair Digestion Taste

Functions of saliva:

Functions of saliva Protection Flushes bacteria and debris Clearance of sugars Mucins - Lubrication Barrier against noxious stimuli

LUBRICATION & PROTECTION:

LUBRICATION & PROTECTION Mucins:- Mastication Swallowing Speech Antibacterial function 44

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MG1 adsorbs tightly to the tooth Enamel pellicle Protects the tooth from acid challenges . 45

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MG1 complexes with amylase, proline -rich proteins, statherin & histatins attracting the attachment of bacteria providing a short term nutrient source for bacteria. MG2:- Promotes the aggregation and clearance of oral bacteria 46

Functions of saliva:

Functions of saliva Buffering Bicarbonate and phosphate ions Saliva provides a buffer that protects the oral cavity in two ways: Many bacteria require a specific pH for maximal growth; Buffering capacity of saliva prevents potential pathogens from colonizing the mouth by denying them optimal environmental conditions.

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2. Plaque microorganism can produce acid from sugars, which, if not rapidly buffered and cleared by saliva , can demineralize enamel Sialin plays a imp role in raising the pH of dental plaque after exposure to fermentable carbohydrate.

Functions of saliva:

Functions of saliva Pellicle formation Salivary pellicle Phosphoproteins , albumin, mucin complex with glycolipids and phospholipids Functions Lubricating film Diffusion barrier against acid

Functions of saliva:

Functions of saliva Maintain tooth integrity Saliva saturated with calcium and phosphate ions The high concentration of these ions ensures that ionic exchange with the tooth surface is directed to the tooth. This exchange begins as soon as the tooth erupts. Interaction with saliva results in posteruptive maturation through diffusion of such ions as calcium, phosphorus, magnesium, and chloride into the surface apatite crystals.

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This maturation increases surface hardness, decreases permeability, and heightens the resistance of enamel to caries. Remineralization of initial caries before cavitation is achieved largely through the availability of phosphate and calcium ions in the saliva.

Functions of saliva:

Functions of saliva Antimicrobial action Barrier effect by histatin Secretory IgA – agglutination of microorganisms (McNabb, 1981) Lysozyme Lactoferrin Peroxidase

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Lysozymes Basal cells of striated ducts in parotid Catalyses the degradation of the negatively charged peptidoglycan matrix of the microbial cell walls Split bacterial cell walls

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Peroxidase (sialoperoxidase) Secreted by acinar cells , It convert the thiocyanate in saliva into highly reactive chemical compounds. This highly reactive chemical compounds bind and inactive several intracellular microbial enzyme systems as well as microbial surface components . Protects mucosa from the strong oxidizing effects of hydrogen peroxide produced by oral bacteria

IgA :

IgA Predominant immunoglobulin present in saliva. It inhibits adherence and thereby prevents colonization of mucosal surfaces and teeth by organisms, facilitating their disposal by swallowing

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Cystatins :- inhibit cysteine-proteinase involved in the pathogenesis of periodontal disease Proteins such as glycoproteins, statherins , agglutinins, histadine -rich proteins, and proline -rich proteins work to aggregate bacteria

Antimicrobial action:

Antimicrobial action Lysozyme + salivary anions (thiocyanates) Activate autolysins Destabilise cell membrane Inhibit growth Reduce glucose utilisation and lactic acid production

Antimicrobial action:

Antimicrobial action Lactoferrin Bind 2 iron atoms per molecule Bacteria requiring ferric ions - affected Nutritional immunity

Functions of saliva:

Functions of saliva Antifungal action Basic and neutral histidines – antifungal activity Oppenheim, 1986 – histidines – inhibit C.albicans - 2 µm/ml.

Functions of saliva:

Functions of saliva Antiviral activity Arachibald, 1986 – IgA – polio, rhino virus and inhibit transmission – HIV. Heineman, 1980 – mucins protect – herpes simplex virus.

Functions of saliva:

Functions of saliva Tissue repair When saliva is experimentally mixed with blood, the clotting time increases. Experimental studies in mice have shown that the rate of wound contraction is increased in the presence of saliva due to the presence of epidermal growth factor in the saliva produced by the submandibular glands.(Hutson in 1979)

Functions of saliva:

Functions of saliva Digestion Saliva participates in digestion by providing a fluid environment for solubilization of food through the action of the digestive enzymes principally, Amylase. The action of amylase on ingested carbohydrates to produce glucose and maltose begins in the mouth and continues for upto 30min in the stomach before the amylase is inactivated by the acid pH and proteolysis. Lipase :- converts triglycerides into fatty acids

SALIVA & TASTE:

SALIVA & TASTE The hypotonicity of saliva enhances the tasting capacity of salty foods and nutrient sources. It permits the recognition of noxious substances. Dissolve the substance to be tasted and carry them to the taste buds. Dissolved substances stimulate the taste buds Saliva also contains a protein, called gustin that is thought to be necessary for growth and maturation of the taste buds.

Secretion:

Secretion There are two varieties of salivary secretion: (1) spontaneous and (2) stimulated. Spontaneous secretion occurs all the time, without any known stimulus and it is this secretion which keeps our mouth moist all the time

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Stimulated secretion of saliva occurs after a known stimulus. The known stimulus may be, visual ( eg: seeing delicious food), taste ( eg: tasting good food) and others ( eg: during vomiting)

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Unconditioned reflexes are reflexes which are present since birth, that is, they are inborn and their presence requires no experience or training. Example : place lemon juice on the tongue of a new born baby there is salivation

Salivary Gland dysfunction:

Salivary Gland dysfunction It includes- Increase in salivary output( hyperfunction ) Sialorrhoea:- result of underlying neurological disorder cerebral palsy, parkinson’s disease

:

Decrease in salivary output( hypofunction ) Iatrogenic:-medications (antideppressents, diurectics, antihistamines). Autoimmune diseases:-rheumatoid arthritis, sjogren’s syndrome. Neurological disorders:-mental depression, bell’s palsy. Infections:-HIV infection Metabolic disturbances:-vitamin deficiency Local salivary gland diseases:-sialolithiasis, sialadenitis

Artificial Saliva:

Artificial Saliva Artificial saliva is a product that is used by people who have too little of their own naturally occurring saliva (a condition known as dry mouth). Products are available in an aerosol or a liquid that is squirted into the mouth saliva substitutes namely xialine and saliveze

How is artificial saliva different from real saliva?:

How is artificial saliva different from real saliva? Although more than 99 percent of saliva is water, saliva also contains buffering agents, enzymes and minerals that keep teeth strong and play a crucial role in maintaining a healthy environment in the mouth. Artificial saliva normally contain a mixture of buffering agents, cellulose derivatives (to increase stickiness and moistening ability) and flavoring agents (such as sorbitol). However, they do not contain the digestive and antibacterial enzymes and other proteins or minerals present in real saliva. Research is underway to try and develop artificial saliva that more closely mimic natural saliva.

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Some commercially available saliva substitutes include: • Carboxymethyl, or hydroxyethylcellulose solutions: • Entertainer's Secret® (KLI Corp) , spray • Glandosane® (Kenwood/Bradley) spray • Moi-Stir® (Kingswood Labs) spray • Moi-Stir® Oral Swabsticks (Kingswood Labs) swabs • Optimoist® (Colgate-Palmolive) spray • Saliva Substitute® (Roxane Labs) liquid • MouthKote® (Parnell) , spray

Dentifrices::

Dentifrices: These are antixerostomia dentifrices that contain three salivary enzymes, lactoperoxidase, glucose oxidase and lysozyme, specifically formulated to activate intra-oral bacterial systems . Currently available formulations include: • Biotene® Dry Mouth Toothpaste • Biotene® Gentle Mouthwash • Biotene® Dry Mouth Gum • Oralbalance® Long-lasting Moisturizing Gel • Biotene® Dry Mouth Kit

DIAGNOSTIC ASPECTS:

DIAGNOSTIC ASPECTS The analysis of saliva, like blood-based analyses, has two purposes: To identify individuals with disease To follow the progress of the affected individual under treatment

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Sreebny and Zhu (1996) proposed a panel of salivary determinants that could be used clinically for the diagnosis of Sjogren's syndrome. Flow rate pH Buffer capacity Lactobacillus, and yeast concentration

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Salivary IL-2 and IL-6 concentrations are significantly elevated among individuals suffering from Sjogren's syndrome. Levels of these cytokines appear to be lowered with the systemic administration of pilocarpine or with mucosally administered interferon

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Currently, the following steroids can be accurately assessed in saliva: Cortisol Estradiol Estriol Progesterone Testosterone. Useful in evaluations of Mood and cognitive emotional behavior To predict sexual activity in adolescent males To study child health and development In considerations of premenstrual depression

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Saliva can be used to measure beta2 microglobulin and/or soluble tumor necrosis factor α -receptor levels, and thus assess the disease activity in patients with HIV infection or other chronic inflammatory disease states. PCR assay is available to detect H. pylori DNA in saliva and confirm the presence of H. pylori infection in patients. A relatively new immunologic assay that reportedly can detect H. pylori antibodies in saliva may be valuable for predicting risk for gastric adenocarcinoma .

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Dental caries Streptococcus mutans Lactobacillus acidophilus Periodontal disease. Porphyromonas gingivalis reduced anti oxidant level

Conclusion:

Conclusion Saliva is critical for preserving and maintaining the health of oral tissues. However, it receives little attention until its quantity diminishes or its quality becomes altered.

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Thankyou

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