2 Contents: Introduction Salivary gland anatomy Functions of saliva Secretion of salivaComposition of salivaOrganic componentsInorganic componentsHypofunction of salivary glandsXerostomiaPtyalismBurning mouth syndromeSaliva:A diagnostic fluidDiagnostic imaging of salivary glands
3 Saliva lacks the drama of blood,the emotion of tears and toil of sweat but it still remains one of the most important fluids in the human body.Its status in the oral cavity is at par with that of blood i.e. to remove waste,supply nutrients and protect the cells
4 What is saliva?Saliva is composed of more than 99% water and less than 1% solids,mostly electrolytes and proteins,the latter giving saliva its characteristic viscosityThe term saliva refers to the mixed fluid in the mouth in contact with the teeth and oral mucosa,which is often called ‘whole saliva’Normally the daily production of whole saliva ranges from 0.5 to 1.0 litres
5 90% of the whole saliva is produced by three paired major salivary glands Parotid GlandSubmandibular glandSublingual gland
6 Secretions from many minor salivary glands in the oral mucosa (labial,lingual,palatal,buccal,glossopalatine and retromolar glands) also contribute (less than 10%) to the saliva secretionIn addition,whole saliva contains contributions from non-glandular sources such as gingival crevicular fluid in an amount that depends on the periodontal status of the patient
7 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.
8 Salivary gland anatomy Parotid gland:Largest of all the salivary glandsPurely serous gland that produce thin,watery amylase rich salivaSuperficial portion lies in front of external ear & deeper portion lies behind the ramus of mandibleStensen's Duct (Parotid Papilla)Opens out adjacent to maxillary second molar
9 Submandibular gland Second largest salivary gland Mixed gland Located in the posterior part of floor of mouth,adjacent to medial aspect of mandible & wrapping around the posterior border of mylohyoid muscleWharton's DuctOpens beneath the tongue at sub-lingual caruncle lateral to the lingual frenum
10 Sublingual gland:Smallest salivary glandMixed gland but mucous secretory cells predominateLocated in anterior part of floor of mouth between the mucosa and mylohyoid muscleOpens through series of small ducts (ducts of rivinus) opening along the sub-lingual fold & often through a larger duct(bartholin’s duct) that opens with the wharton’s duct at the sub-lingual caruncle
12 MAJOR FUNCTIONS OF SALIVA Fluid or LubricantSaliva coats the mucosa & helps to protect against mechanical,chemical and thermal irritation.It also assists smooth airflow,speech & swallowing.BufferingSaliva helps to neutralise plaque pH after eating thus reducing time for demineralization caused by bacterial acids produced during sugar metabolismRemineralizationSaliva is supersaturated with ions,which facilitate remineralization of teeth
13 DigestionBreakdown of starch-amylaseFat-lingual lipaseMoistening and lubricative properties of saliva:allow the formation & swallowing of food bolusAnti-microbial actionLysozyme,lactoferrin,sialoperoxidase help against pathogenic microorganisms specificallyImmunoglobulins and secretory IgA also act against microorganisms.
14 CleansingClears food and aids swallowing.Agglutinationimmunoglobulins and secretory IgA cause agglutination of specific microorganisms, preventing their adherence to oral tissues. Mucins as well as specific agglutinins also aggregate microorganisms.
15 Pellicle formationDerived from salivary proteins,it forms a protective diffusion barrier to acids from plaque.TasteSaliva has a low threshold concentration of sodium chloride,sugar,urea etc allowing perception of taste to occur. It acts as a solvent allowing mixing and interaction of food with taste buds
16 Water balanceOsmoreceptors act as per state of hydration of the body to transmit information to the hypothalamusTissue repairA variety of growth factors & other biologically active peptides and proteins are present in small quantities in saliva.under experimental conditions,many of these promote tissue growth & differentiation,wound healing and other beneficial effects.
17 Regulation of saliva secretion Afferent signals from sensory receptors in mouthTrigeminal,facial,glossopharyngealnervesSalivary nuclei in the medulla oblongata of brainParasympathetic nerve bundle sympathetic nerve bundlesalivary glands
18 Innervation Parasympathetic innervation to major salivary glands Otic ganglion fibers supply Parotid GlandSubmandibular ganglion supplies other major glandsSympathetic innervation promotes saliva flowStimulates muscle contractions at salivary ducts
19 Saliva secretion is also controlled by the conditioned reflexes. Besides receiving impulses from the afferents,the salivary nuclei also receives impulses from higher centers of brain which leads to release of variety of neurotransmitters resulting in facilatory or inhibitory effectsAs a result of such control,unstimulated salivation is inhibited during sleep,fear & mental depressionStress may increase or decrease salivary flow
20 THE SECRETORY UNIT The basic building block of all salivary glands ACINI - water and ions derived from plasmaSaliva formed in acini flows down DUCTS to empty into the oral cavity.
21 Salivary secretion:two step model Formation of primary saliva:Initiated by binding of neurotransmitters in the acinar cell membranesAcinar cell loses K⁺ to the interstitium & Cl⁻ to the lumenGain of Cl⁻ creates negative potential in the lumen,driving interstitial Na⁺ into lumen thereby restoring electroneutralityWater flux follws the movement of salt into the lumen for osmotic reasons,resulting in acinar cell shrinkageOutcome is the formation of isotonic primary saliva
22 Ductal modification of primary saliva: Occurs principally through reabsorption & secretion of electrolytesThe luminal & basolateral membrane have abundant transporters that function to produce a net reabsorption of Na⁺ & Cl⁻ resulting in formation of hypotonic final salivaThe final electrolyte composition of saliva varies depending on the salivary flow rate
23 At high flow rates,saliva is in contact with the ductal epithelium for shorter time & Na⁺ & Cl⁻ concentration increase & K⁺ concentration decreaseAt low flow rates,the electrolyte concentration change in the opposite directionThe HCO₃⁻ concentration increases with increased flow rates,reflecting the increased secretion of HCO₃⁻ by the acinar cells to drive fluid secretion
24 Hypotonic final saliva into mouth TWO STAGE HYPOTHESIS OF SALIVA FORMATIONMost proteinsNa+ Cl- resorbedHypotonic final saliva into mouthWater & electrolytesSome proteins electrolytesK+ secretedIsotonicprimary saliva
25 Saliva production Differential saliva production by glands Unstimulated salivation (Salivary gland at rest)1.5 Liters produced per day (basal rate)Major salivary glands: 90% of saliva producedSubmandibular and sublingual glands: 70% of salivaStimulated salivationSaliva production increases 5 foldParotid gland produces majority of saliva
28 Testing of saliva production Unstimulated production – collection of saliva into container during 15 minStimulated production – collection of saliva during 5 min of chewing 1g paraffinUnstimulated whole saliva flow rates of <0.1 ml/min. and stimulated whole saliva flow rate’s of <1.0 ml/min. are considered abnormally low& indicative of marked salivary hypofunction.
29 Recent work in Sjogren syndrome is beginning to identify changes in salivary cytokine & other protein levels that may have diagnostic significance .Saliva may play a greater diagnostic rolein monitoring for the presence and concentrations of drugs of abuse and therapeutic agents.
32 Calcium and phosphate Help to prevent dissolution of dental enamel 1.4 mmol/lt. (1.7 mmol/lt. in stimulated saliva)50% in ionic formsublingual > submandibular > parotidPhosphate6 mmol/lt. (4 mmol/lt. in stimulated saliva)90% in ionic formpH around 6 - hydroxyapatite is unlikely to dissolveIncrease of pH - precipitation of calcium salts => dental calculus
33 Hydrogen Bicarbonate Buffer Low in unstimulated saliva, increases with flow ratePushes pH of stimulated saliva up to 8pH 5.6 critical for dissolution of enamelDefence against acids produced by cariogenic bacteriaDerived actively from CO2 by carbonic anhydrase
34 Other ions Fluoride Thiocyanate Sodium, potassium, chloride Low concentration, similar to plasmaThiocyanateAntibacterial (oxidated to hypothiocyanite OSCN- by active oxygen produced from bacterial peroxides by lactoperoxidase)Higher conc. => lower incidence of cariesSmokers - increased conc.Sodium, potassium, chlorideLead, cadmium, copperMay reflect systemic concentrations - diagnostics
36 Organic components of saliva MucinsProline-rich proteinsAmylaseLipasePeroxidaseLysozymeLactoferrinSecretory IgAHistatinsStatherinBlood group substances, sugars, steroid hormones, amino acids, ammonia, urea
37 MucinsProducts of acinar cells from submandibular,sublingual and some minor salivary glands.Asymmetrical molecule with open, randomly organized structureGlycoproteins - protein core with many oligosaccharide side chains attached by glycosidic bondHydrophillicUnique rheological properties (e.g., high elasticity, adhesiveness, and low solubility)
38 Major salivary mucins are: MG1-adsorbs tightly to the tooth surface contributing to the enamel pellicle formation, thereby protecting the tooth surface from chemical & physical attack including acidic challengesMG2-also binds to the tooth surface but is easily displaced, however it promotes clearance of oral bacteria by aggregation
39 Mucin Functions Tissue Coating Lubrication Protective coating about hard and soft tissuesPrimary role in formation of acquired pellicleConcentrates anti-microbial molecules at mucosal interfaceLubricationAlign themselves with direction of flow (characteristic of asymmetric molecules)Increases lubricating qualities (film strength)Film strength determines how effectively opposed moving surfaces are kept apart
40 Aggregation of bacterial cells Bacteria adhere to mucins-result in surface attachment, orMucin-coated bacteria may be unable to attach to surfaceBacterial adhesionMucin oligosaccharides mimic those on mucosal cell surfaceReact with bacterial adhesins, thereby blocking them
41 Amylases Produced by acinar cells of major salivary glands Metabolizes starch and other polysaccharides into glucose & maltoseCalcium metalloenzymeParotid; 30% of total protein in parotid saliva“Appears” to have digestive function - inactivated in stomach, provides disaccharides for acid- producing bacteriaIt is also present in tears, serum, bronchial, and male and female urogenital secretionsA role in modulating bacterial adherence
42 Lingual Lipase Secreted by sublingual gland and parotid gland Involved in first phase of fat digestionHydrolyzes medium to long chain triglyceridesImportant in digestion of milk fat in newbornUnlike other mammalian lipases, it is highly hydrophobic and readily enters fat globules
43 Statherins Produced by acinar cells in salivary glands Acidic peptide containing relatively high levels of proline,tyrosine and phosphoserineInhibits spontaneous precipitation of calcium phosphate salts from supersaturated saliva & favours remineralizationCalcium phosphate salts of dental enamel are soluble under typical conditions of pH and ionic strength
44 Supersaturation of calcium phosphates maintain enamel integrity Also an effective lubricant for the tooth surface thus protecting it from physical forces
45 Proline-rich Proteins (PRPs) Like statherin, PRPs are also highly asymmetricalPresent in the initially formed enamel pellicle and in “mature” pellicles2 types:BasicAcidicBoth are secretory products of major salivary glandsAcidic proline-rich protein binds tightly to hydroxyapatite and prevents precipitation of calcium phosphate and thereby protecting the enamel surface & preventing demineralizationAlso bind to oral bacteria including mutans streptococcci
46 Role of PRPs in enamel pellicle formation Acquired enamel pellicle is µm thick layer of macromolecular material on the dental mineral surfacePellicle is formed by selective adsorption of hydroxyapatite-reactive salivary proteins, serum proteins and microbial products such as glucans and glucosyl-transferasePellicle acts as a diffusion barrier, slowing both attacks by bacterial acids and loss of dissolved calcium and phosphate ions
47 Remineralization of enamel and calcium phosphate inhibitors Early caries are repaired despite presence of mineralization inhibitors in salivaSound surface layer of early carious lesion forms impermeable barrier to diffusion of high mol.wt. inhibitors.Still permeable to calcium and phosphate ionsInhibitors may encourage mineralization by preventing crystal growth on the surface of lesion by keeping pores open
48 Calculus formation and calcium phosphate inhibitors Calculus forms in plaque despite inhibitory action of statherin and PRPs in salivaMay be due to failure to diffuse into calcifying plaqueProteolytic enzymes of oral bacteria or lysed leukocytes may destroy inhibitory proteinsPlaque bacteria may produce their own inhibitors
49 Interaction of oral bacteria with PRPs and other pellicle proteins Several salivary proteins appear to be involved in preventing or promoting bacterial adhesion to oral soft and hard tissuesPRPs are strong promoters of bacterial adhesionAmino terminal: control calcium phosphate chemistryCarboxy terminal: interaction with oral bacteriaInteractions are highly specific
50 Lactoferrin Iron-binding protein Prevents iron from being used by microorganism that require it for metabolismNutritional immunity (iron starvation)Some microorganisms (e.g., E. coli) have adapted to this mechanism by producing enterochelins.bind iron more effectively than lactoferriniron-rich enterochelins are then reabsorbed by bacteriaLactoferrin, with or without iron, can be degraded by some bacterial proteases.
51 LysozymePositively charged enzymatic protein which binds to salivary anions of various types (bicarbonate,fluoride,iodide,nitrate) and forms a complex which binds to cell wall of bacteria & destabilizes the cell wallPresent in numerous organs and most body fluidsAlso called muramidaseAlters glucose metabolism in sensitive bacteriaCauses aggregation,contributing to clearance of bacteria from the oral cavity
52 Histatins A group of histidine-rich proteins The major form in the oral cavity are histatin 1,histatin 3 and histatin 5Binds to hydroxyapatite and prevent calcium phosphate precipitation from a supersaturated saliva and favour remineralizationPotent inhibitors of Candida albicans growth
53 Cystatins Are inhibitors of cysteine-proteases Are present in many body fluidsPrevent the action of potentially harmful proteases on the soft tissue of oral cavityConsidered to be protective against unwanted proteolysisbacterial proteaseslysed leukocytesAlso inhibits calcium phosphate precipitationPromotes supersaturation of saliva with calcium and phosphate,thus protecting the tooth surface
54 Salivary peroxidase systems Sialoperoxidase (SP, salivary peroxidase)Produced in acinar cells of parotid glandsAlso present in submandibular salivaReadily adsorbed to various surfaces of mouthMyeloperoxidase (MP)From leukocytes entering via gingival crevice15-20% of total peroxidase in whole saliva
56 Clinical evaluation Patient’s complaints: Oral dryness and soreness Burning sensation of oral mucosa and tongueDifficulties in speechDifficulty in chewing dry foodTaste impairment and disturbancesDifficulties in wearing removable denturesDry lipsAcid reflux,nausea,heart burnSensation of thirstThe oral symptoms are often associated with other symptoms such as dry skin,dry nose,dry eyes,dry vaginal mucosa,dry throat,dry cough and constipation
57 Signs:Mucosal dryness:dry glazed and red oral mucosaLobulation and fissuring of the dorsal part of tongueAtrophy of filiform papillaeDry lips,angular cheilitisIncreased caries experienceOral candidiasis
58 XerostomiaIt is a clinical manifestation of salivary gland dysfunction and it does not represent a disease entity .Dry mouth varies from minimal viscous appearance of saliva to complete absence of any salivary flow.More prevalent in women.Can cause significant morbidity and a reduction in a patient’s perception of quality of life.When unstimulated salivary flow is less than to 0.16 ml/minute, a diagnosis of hypofunction is established.
60 Etiology Sjogren’s syndrome Other salivary gland diseases Radiotherapy Acini atrophy fibrosis or replaced by fatty tissueSerous acini: more sensitive to R/TSaliva: thickened, altered electrolytes, pH↓,secretion of immunoglobulins↓>1000rad (2-3wk): felt oral dryness>4000rad: irreversible changeSjogren’s syndromeOther salivary gland diseases
61 Symptoms & Signs Symptoms: Oral dryness (most common) Halitosis Burning sensationLoss of sense of taste or bizarre tasteDifficulty in swallowingTongue tends to stick to the palateDecreased retention of denture
62 Signs: Saliva pool disappear Mucosa: dry or glossy Duct orifices: viscous and opaque salivaTongue:glossitis fissured red with papilla atrophyAngular cheilitisRampant caries: cervical or cusp tipPeriodontitisCandidiasis
63 Clinical Appearance: Oral mucosa appears dry, pale, or atrophic. Tongue may be devoid of papillae with fissured and inflamed appearance.New and recurrent dental caries.Difficulty with chewing, swallowing, and tasting may occur.Fungal infections are common.
69 Dietary & Environmental Considerations Avoid drugs that may produce xerostomiaAvoid dry & bulky foodsHigh fluid intake & rinsing with waterAvoid alcohol, smoking and sugarTake protein and vitamin supplementsEnvironment:Maintain optimal air humidity in the homeUse Vaseline to protect the lips
70 Preventive Dental Care Measures Smooth sharp cusps, occlusal grooves or fissures, irregular fillings.Check and adjust the denture.Fluoride rinses & chlorhexidine rinses.Antifungal medications:Denture: Miconazole gel,amphotericin or nystatin ointmentTopical: Nystatin, amphotercin suspension or fluconazole..
74 Saliva Stimulants:The use of sugar free gum, lemon drops or mints are conservative methods to temporarily stimulate salivary flow in patients with medication xerostomia or with salivary gland dysfunction.Biotine chewing gumPilocarpine HClMay need 2-3 months to determine effectiveness.Side effects include sweating and diarrhea.Avoid in patients with narrow angle glaucoma, severe asthma, pulmonary diseases.
75 Ptyalism Pathophysiology Normal Submandibular Saliva production ml/minPtyalism may result in 1-2 L/day of Saliva lossMechanisms of excessive SalivaDecreased Saliva swallowing and clearanceExcessive Saliva productionNeuromuscular diseaseAnatomic abnormalities
76 Causes Saliva Overproduction Pregnancy (Ptyalism Gravidarum) Excessive starch intakeGastrointestinal causesGastric distention or irritationGastroesophageal RefluxAcute Gastritis or Gastric UlcerPancreatitisLiver disease
77 Medications and toxins Clozapine(Clozaril)Potassium ChloratePilocarpineMercury PoisoningCopperArsenic poisoningAntimony (used to treat parasitic infections)IodideBromideAconite (derived from Aconitum napellus root)Cantharides
78 Stomatitis and localized oral lesions Aphthous UlcersOral chemical burnsOral suppurative lesionsAlveolar abscessEpulisOral infectious LesionsDental CariesDiphtheriaSyphilisTuberculosisSmall Pox
79 Difficulty Swallowing Saliva InfectionsTonsillitisRetropharyngeal AbscessPeritonsillar AbscessEpiglottitisMumpsChancreActinomycosisBone LesionsJaw fracture or dislocationAnkylosis of the temporomandibular jointSarcoma of the jaw
81 Management Non-specific Treat specific causes as below General measures to reduce SalivaTooth brushing and mouthwash has drying effectReduce starch intake from dietOrthodontic appliances that aid swallowingUpper plate to cover palate with movable beadsAids lip closureDirects Saliva toward pharynxAnticholinergic MedicationsGlycopyrrolate
82 Advanced procedures in severe and refractory cases Botulinum toxin A Salivary Gland injectionPerformed under ultrasound guidanceRadiation therapySurgerySubmandibular Gland excision or duct relocationParotid duct relocation or ligationSalivary denervation (transtympanic neurectomy)
83 Specific measuresTreat Nausea with AntiemeticsTreat Gastroesophageal RefluxNeuromuscular causesSpeech pathology (e.g. swallowing mechanism)Neurology consultationOral diseases including dental malocclusionDentist or orthodontist
84 Burning Mouth Syndrome Painful,frustating condition often described as a scalding sensation in tongue,lips,palate or throughout the mouthCan affect anyone but occurs most commonly in middle-aged or older womenoccurs with a range of medical and dental conditions, from nutritional deficiencies and menopause to dry mouth and allergiesthe exact cause of burning mouth syndrome cannot always be identified with certainty.
85 SIGNS AND SYMPTOMSModerate to severe burning in the mouth is the main symptom of BMS and can persist for months or yearsthe burning sensation begins in late morning, builds to a peak by evening, and often subsides at nightSome feel constant pain; for others, pain comes and goesAnxiety and depression are common in people with burning mouth syndrome and may result from their chronic pain.
86 Other symptoms of BMS include: tingling or numbness on the tip of the tongue or in the mouthbitter or metallic changes in tastedry or sore mouth
87 Causes: damage to nerves that control pain and taste hormonal changes dry mouth, which can be caused by many medicines and disorders such as Sjögren’s syndrome or diabetesnutritional deficienciesoral candidiasis, a fungal infection in the mouthacid refluxpoorly-fitting dentures or allergies to denture materialsanxiety and depression.In some people, burning mouth syndrome may have more than one cause. But for many, the exact cause of their symptoms cannot be found
88 Diagnosis:A review of medical history, a thorough oral examination, and a general medical examination may help identify the source of burning mouth. Tests may include:• blood work to look for infection, nutritional deficiencies, and disorders associated with BMS such as diabetes or thyroid problems• oral swab to check for oral candidiasis• allergy testing for denture materials, certain foods, or other substances that may be causing symptoms.
89 Treatment:Treatment should be tailored to individual needs. Depending on the cause of BMS symptoms, possible treatments may include:adjusting or replacing irritating denturestreating existing disorders such as diabetes, Sjögren’s syndrome, or a thyroid problem to improve burning mouth symptomsrecommending supplements for nutritional deficiencies
90 switching medicine, where possible, if a drug is causing burning mouth • prescribing medications to— relieve dry mouth— treat oral candidiasis— help control pain from nerve damage— relieve anxiety and depression.When no underlying cause can be found, treatment is aimed at the symptoms to try to reduce the pain associated with burning mouth syndrome.
91 Helpful tips: Sip water frequently. Suck on ice chips. Avoid irritating substances like hot, spicy foods; mouthwashes that contain alcohol; and products high in acid, like citrus fruits and juices.Chew sugarless gum.Brush teeth/dentures with baking soda and water.Avoid alcohol and tobacco products.
92 Clinical implications: Difficulties in chewingtastingswallowingspeakingIncreased chances of developing dental decay & other infections in mouthMouth soresDifficult for operator to work when saliva pools in mouth (in case of sialorrhea)uncoordinated swallowingpoorly synchronized lip closureabnormal increase in tone of the muscles that open the mouth
93 Inflammatory diseases of the salivary glands: Acute bacterial sialadenitisChronic sialadenitisRecurrent sialadenitisMumpsPost operative usually parotidAutoimmune diseases
94 SALIVARY GLAND TUMORS: Tumors of the salivary glands are commonest in the parotid much less common in the submandibular gland and very rare in the sublingual and minor salivary glands.
95 Classification: I. Benign: II. Malignant: a) Mixed salivary tumor or pleomorphic adenomab) Adenolymphoma or warthin’s tumorc) Oncocytomad) Monomorphic adenomaII. Malignant:a) Primary carcinomab) Secondary carcinoma – direct invasion from skin or from secondarily involved lymph nodes
96 Typical Features of Benign & Malignant Salivary Gland Tumours Slow growingSoft or Rubbery ConsistencyUsually EncapsulatedDoes not ulcerateNo associated nerve palsiesMainly affects the parotid gland.MALIGNANTAt times Fast growingMay be Hard ConsistencyIs not encapsulated.May ulcerate; invades boneMay cause cranial nerve palsies depending on the site of involvement.Usually affects minor salivary glands.
97 Dental considerations: Present as swellingunilateral or bilateralpainless or painfulSlow growing or fast growingAssociated symptoms:TrismusPyrexiaTachycardiaPurulent discharge from ductDifficulty in masticationFacial muscle weaknessNerve palsies-malignat tumourslymphadenopathy
98 Saliva and dental caries: THE CARIOGENIC CHALLENGEAlthough the etiology of dental caries is reasonably well established,the chemical- physical process that results in the demineralization of enamel and dentin often is less appreciated.The stage is set for the oral flora to metabolize the ingested carbohydrates leading to the production of acids that are capable of demineralizing enamel and dentin
99 The production of acids by microorganisms within the dental plaque continues until the carbohydrate substrate is metabolizedThe plaque’s pH goes from acidic to normal (or the resting level) within a few minutesThis is due to the carbonate and phosphate pH buffering agents in salivaSaliva also serves as the host’s defense mechanism by repairing the demineralization that occurs when the plaque pH is below 5.5 to 6.0
100 CHEMICAL BENEFITS OF SALIVA STIMULATION Stimulating the flow of saliva alters its composition. Increases the concentration of protein, sodium, chloride and bicarbonate and decreases the concentration of magnesium and phosphorus.Perhaps of greatest importance is the increase in the concentration of bicarbonate, which increases progressively with the duration of stimulation. The increased concentration of bicarbonate diffuses into the plaque, neutralizes plaque acids, increases the pH of the plaque and favors the remineralization of damaged enamel and dentin
101 Studies have shown that chewing sugar-free gum after meals results in a significant decrease in the incidence of dental caries and that the benefit is due to stimulating salivary flow rather than any chewing gum ingredient.Stimulating salivary flow after meals reduces the incidence of dental cariesso,its practical measures should be considered in caries prevention programs
102 Saliva & Age:With age, a generalized loss of salivary gland parenchymal tissue occurs. The lost salivary cells often are replaced by adipose tissue. Although decreased production of saliva often is produced in older persons,whether this is related directly to the decrease in parenchymal tissue is not clear. Some studies of healthy older individuals,in which the use of medication were carefully controlled,revealed little or no loss of salivary function. Other studies suggest that although resting salivary secretion is in the normal range,the volume of saliva produced during stimulated secretion is less than normal.
103 Saliva:A Diagnostic Fluid ADVANTAGES:non-invasivelimited trainingno special equipmentpotentially valuable for children and older adultscost-effectiveeliminates the risk of infectionscreening of large populations
104 SALIVA COLLECTION:with or without stimulationStimulated saliva-collected by masticatory action (i.e., from a subject chewing on paraffin) or by gustatory stimulation (i.e., application of citric acid on the subject's tongue)Unstimulated saliva is collected without exogenous gustatory, masticatory, or mechanical stimulationUnstimulated salivary flow rate is most affected by the degree of hydration,but also by olfactory stimulation, exposure to light, body positioning, and seasonal and diurnal factorsTwo ways:Draining method, in which saliva is allowed to drip off the lower lipSpitting method, in which the subject expectorates saliva into a test tube
105 Serum components may also reach the saliva through the crevicular fluid. This raises the prospect of using saliva in the diagnosis of certain pathologiesThe use of saliva in diagnosing caries risk is well-known, particularly in monitoring chemical treatments to control the disease,owing to the possibility of detecting the presence of S. mutans and Lactobacillus spp, as well as lactic acid which causes the sub-surface demineralisation that causes the onset of the caries lesion
106 Candidiasis-through the presence of Candida spp in the saliva The presence of periodontal pathogenic bacteria can also be diagnosed by this method-increasing the risk of cardiovascular and cerebrovascular diseasesCystic fibrosis-raised sodium chloride, calcium, phosphate, lipid and protein contents in the submaxillary saliva.An epidermal growth factor with low biological activity compared to that of healthy persons and raised prostaglandin E2 levels are also found in the saliva of these patientsIn 21-hydroxylase deficiency, a strong correlation has been found between 17- hydroxyprogesterone levels in saliva and in serum.
107 In Sjögren’s syndrome, minor salivary gland biopsy is an accepted diagnostic procedure. A predominant inflammatory infiltrate composed of CD4 lymphocytes is found, together with lowered at rest and stimulated salivary flow rates.Quantitatively, there are raised concentrations of sodium, chloride, IgA, IgG, lactoferrin, albumin, microglobulin, cystatin C and S, lipids and inflammation mediators such as prostaglandin E2, thromboxane B2 and interleukin-6In some malignant diseases, markers can be detected in the saliva, such as the presence of protein p53 antibodies in patients with oral squamous cell carcinoma
108 The presence of the c-erbB-2 tumour marker in the saliva and blood serum of breast cancer patients and its absence in healthy women is a promising tool for the early detection of this diseaseIn ovarian cancer too, the CA 125 marker can be detected in the saliva with greater specificity and less sensitivity than in serum
109 PCR detection of Helicobacter pylori in the saliva shows high sensitivity The presence of antibodies to other infectious organisms such as Borrelia burdogferi, Shigella or Tenia Solium can also be detected through the salivadetection of hepatitis A antigen and hepatitis B surface antigen in the saliva has been used in epidemiological studiessaliva has also been used to detect antibodies to the rubella, parotitis and rubeola virusesIn neonates, the presence of IgA is an excellent marker of rotavirus infection
110 HIV antibody detection is as precise in saliva as in serum and is applicable in both clinical and epidemiological studiesSalivary 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 infectionSeveral salivary and oral fluid tests have been developed for HIV diagnosisOrasure® is a testing system that is commercially available in the United States and can be used for the diagnosis of HIVThe test relies on the collection of an oral mucosal transudate (and therefore IgG antibody). IgG antibody to the virus is the predominant type of anti-HIV immunoglobulin
111 Certain drugs lithium,carbamazepine, barbiturates, benzo- diazepines, phenytoin, theophylline and cyclosporineHigh correlation between ethanol concentrations in saliva and in serum. The presence of thiocyanate in the saliva is an excellent indicator of active or passive smokingOther drugs such as cocaine or opiates can also be detected in saliva
112 Consequently, the use of saliva as an alternative method of diagnosis or as a means to monitor the evolution of certain illnesses or the dosage of certain medicines is a promising pathThe earlier the diagnosis, the better the prognosis
113 DIAGNOSTIC IMAGING FOR SALIVARY GLANDS This procedure is done to differentiate inflammatory from neoplastic disease; diffuse from focal suppurative disease, identify and localize sialoliths, & demonstrate ductal morphology.
114 The methods employed are: - Plain Film Radiography- IntraOral Radiography- ExtraOral Radiography- Conventional Sialography- Computed Tomography (CT)- Magnetic Resonance Imaging- Scintigraphy- UltraSonography
115 CONVENTIONAL SIALOGRAPHY It is a radiographic technique wherein a radiopaque contrast agent is infused into the ductal system of a salivary gland before imaging.Imaging is done with plain films, flouoroscopy, panoramic radiography, CT.This technique is mainly used to study Parotid and SubMandibular glands.In this technique, a lacrimal or periodontal probe is used to dilate the sphincter at the ductal orifice before the passage of a cannula; blunt needle or catheter; which is connected to a syringe containing contrast agent.
116 SIALOGRAPHY INDICATIONS:- Detection of calculi or foreign bodies Determination of extent of destruction of salivary gland tissueDetection of fistulae, diverticuli & stricturesDetection & diagnosis of recurrent swelling & inflammatory processesDemonstration of tumour, its size, location & origin
117 Selection of the site for biopsy Outline the plane of facial nerve as a guide in planning a biopsy or a dissectionDetection of residual stones, residual tumour or a retention cyst
118 CONTRAINDICATIONS:-Patients with a known allergy or hypersenstivity to iodine compoundsDuring the period of acute inflammation of salivary glands because:-1. contrast media cause irritation2. there is increased chance of rupture of duct & extravasation of contrast media into already inflamed gland
119 Patient scheduled for thyroid function tests in near future Patient scheduled for thyroid function tests in near future. absorption of iodine present in the contrast material, across the glandular mucosa may interfere with these studies.
120 PHASES OF SIALOGRAPHY Sialography can be divided into 3 phases:- Ductal phaseAcinar phasePost-evacuation phase
121 DUCTAL PHASEDuctal phase of both parotid and submandibular sialogram starts with the reterograde injection of contrast medium & ends when glandular parenchyma starts to become “hazy” reflecting onset of acinar opacificationVisualization of ducts draining accesory parotid gland often occur during this phase`
122 ACINAR PHASEIt begins after the ductal system has become fully opacified with contrast and the gland parenchyma becomes filled subsequently
123 POST-EVACUATION PHASE It assesses normal secretory clearance function of the gland to determine whether any evidence of retention of contrast remains in the gland or ductal system after the sialogram
124 CONTRAST SIALOGRAPHYContrast sialography can be performed either by :-A) lipid –soluble agentsB) water –soluble agents
125 LIPID-SOLUBLE AGENTS These agents contain 37% iodine, e.g. ethiadol ADVANTAGES:-It is not diluted by salivaIt is not absorbed across glandular mucosaDISADVANTAGES:-These are more viscous , hence higher injection pressure is requiredMore pain & discomfort
126 Any calculus encounterd in the duct may be displaced backward Extravasated agents can cause foreign body reaction, & can induce inflammatory reactions and granuloma formation
127 WATER –BASED AGENTSThese agents contain 28 to 38% iodine, e.g. hypaque50%, hypaque M 75%, renografin 60, isopaque, triosol & dionosilADVANTAGES:-Low viscosityLow surface tension and more miscible with salivary secretionsResidual contrast medium is absorbed and excreted through kidney
128 DISADVANTAGES:-Opacification is generally not as good as oil –based media as it is rapidly absorbed across glandular mucosaIt is diluted by salivaThe injection is accompanied by little pain & discomfort
129 TECHNIQUE EQUIPMENT:- Polythene tubing with a special blunt metallic tip with side holes for parotid gland injectionA 5-10ml syringeLacrimal dilatorContrast mediumLemon slices or artificial lemon extract
130 PROCEDURE:-1) Identification of the location of duct orificesThe parotid duct is located at the base of the papilla in the buccal mucosa opposite maxillary 1st and 2nd molar teethThe area of the mucosa in the vicinity of the orifice is dried with a small spongeThe application of gentle pressure over the area would lead to expression of salivaThe submandibular duct orifice is situated on the summit of papilla by side of lingual frenum
131 2)EXPLORATION OF THE DUCT WITH A LACRIMAL PROBE- In view of torturous course of the parotid duct, patient”s cheek must be turned outward prior to insertion of the probe into the duct.This eversion of cheek reduces the chances of penetration of duct at the sharp angles in its course.
132 In case of the submandibular duct, the probe should pass through the considerable length of the floor of the mouth to the level of posterior border of mylohyoid muscle, apx 5cmIn both the ducts, the probe should slide easily back & forth and also rotate freely without dragging.
133 3) CANNULATION OF THE DUCTS:- The duct orifice is slightly enlarged, & the salivary cannula is inserted into the duct.The cannula is held in place by taping the tubing wrapped in sponge.INTRODUCTION OF THE RADIOGRAPHIC DYE:-The dye is slowly introduced into the duct
134 The amount used is best determined by flouroscopic observation. The patient is instructed to inform the operator when the gland area feels tight or full.The apx. Values of the dye required vary from 0.76ml to 1.0ml for parotid gland, & 0.5 to 0.75ml for submandibular gland
135 RADIOGRAPHIC PROJECTIONS 1)LATERAL OBLIQUE PROJECTION:-This projection is best to delineate the submandibular gland, as the image is projected below the ramus of the mandible2)LATERAL PROJECTION:-This projection also shows ductal projection3)OCCLUSAL PROJECTION:-This view is useful for sialolith located in the anterior part of the wharton’s duct
136 4)ANTERIOR-POSTERIOR PROJECTION:- This projection demonstrates medial and lateral gland structures5)PANORAMIC PROJECTION:-This projection is made during the filling phase.It has following advantages:-Easier to exposeRadiation dose is relatively lowSatisfactory bony details
137 COMPUTED TOMOGRAPHY Less invasive than sialography Does not require the use of contrast materialUsed for assessment of mass lesions of the salivary glandsCan demonstrate salivary gland calculi. Especially submandibular stones that are located posteriorly in the duct, at the hilum of the gland or in the substance of gland itself.
138 MAGNETIC RESONANCE IMAGING MRI is superior to CT scanning in delineating the soft tissue detail of the salivary gland lesions, esp. tumoursWith no radiation exposure to the patient or the neccesity of contrast enhancement
139 ULTRASONOGRAPHYIt is a relatively simple, non-invasive imaging modality, with poor detail resolution.Useful in assessment of superficial structures to determine whether a mass lesion that is being evaluated is solid or cystic in nature.
140 SIALOENDOSCOPYIt is a specialised procedure that uses a small video camera with a light at the end of a flexible cannula , which is introduced into the ductal orificeCan be used diagnostically and therapeuticallyCan demonstrate strictures and kinks in the ductal system , as well as mucous plugs and calcificationsMay be used to dilate small stictures and flush clear small mucous plugs
141 SIALOCHEMISTRYAn examination of electrolyte composition of saliva of each gland may indicate a variety of salivary gland disorders.Principally, the concentrations of sodium and potassium, which normally change with salivary flow rate, are measured
142 REFERENCES: Textbook of medical physiology by guyton & hall Dental caries by Ole Fejerskov & Edwina KiddTen Cate’s Oral HistologyTextbook of Pediatric Dentistry by Shobha TandonTextbook of Oral Pathology by ShaferPreventive community dentistry by Soben Peter
143 Microbial composition of whole saliva:The Dental Clinics of North America Saliva:the precious body fluid:The Journal of the American Dental AssociationBurning mouth syndrome:NIDCRThe diagnostic applications of saliva a review: published by SAGEDry mouth:NIDCRThe effect of saliva on dental caries:The Journal of the American Dental AssociationThe role of saliva in maintaining oral health and as an aid to diagnosis:clinical dentistry