DEPARTMENT OF PUBLIC HEALTH DENTISTRY

SEMINAR

SALIVA

PRESENTED BY:-Dr.AMRITA RASTOGI

M.D.S 1st YEAR

CONTENTS

INTRODUCTIONSALIVARY GLANDSDevelopmentStructure of terminal secretory units.Classification Of Salivary GlandsMajor Salivary glandsMinor Salivary glandsNerve supply to salivary glands

• FORMATION OF SALIVA• PROPERTIES OF SALIVA• COMPOSTION OF SALIVA

• FUNCTIONS OF SALIVA• REGULATION OF SALIVA• CO-REALATION BETWEEN SALIVA AND DENTAL

CARIES• SALIVA AS DIAGNOSITIC AID• COLLECTION OF SALIVA• SALIVA AND DENTAL PLAQUECLINICAL CONSIDERATION OF SALIVAEFFECT OF DRUGS & CHEMICAL ON SALIVARY

SECRETIONCONCLUSIONREFERENCES

INTRODUCTION

The oral cavity is a moist environment; a film of fluid called saliva constantly coats its inner surfaces and occupies the space between the lining oral mucosa and teeth. Saliva is a complex fluid, produced by the salivary glands, whose important role is maintaining the wellbeing of mouth. Human saliva consist of organic and inorganic components and plays an essential role in mastication, in bolus formation, acts as a lubricant in swallowing, helps in speech production and protecting the mucosal surfaces of the oral cavity from desiccation.

The enzymes found in saliva are essential in beginning the process of digestion of dietary starches and fat. 

Saliva circulating in mouth at any given time is termed “whole saliva”.

Saliva reflects the physiological state of body including emotional endocrinal nutrional and metabolic variations also known as “THE BODY’S MIRROR”

According to Stedmen’s Dictionary Saliva is a clear, tasteless, odourless slightly acidic

(pH6.8), viscid fluid, consisting of secretions from the parotid, sublingual and submandibular salivary gland and the mucous glands of the oral cavity.

• According to Webster Medical Dictionary The watery tasteless liquid mixture of salivary &

oral mucous glands secretion that lubricates the chewing food , wets the oral wall & contains the enzyme ptyalin which function in the pre-digestion of starch.

SALIVARY GLANDS

DEVELOPMENT

All salivary glands show a similar pattern of development.

MESENCHYME

ORAL EPITHELIAL

BUDS

ECTODERMAL

ENDODERMAL

PAROTID GLAND AND MINOR SALIVORY GLANDS

SUBMANDIBULAR AND SUBLINGUAL GLAND

The Primordia of the glands of humans appear during sixth week . 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.

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 cavitations -to allow free access between the saliva producing acini and oral cavity.- known as Canilicular Stage.

STRUCTURE OF TERMINAL SECRETORY UNITS

Salivary glands are made up of cells which are arranged in small groups around a central globular cavity called acinus & alveolus.

The central cavity is continous with the lumen of the duct.

The fine duct draining each acinus is called the intercalated ducts.

Many intercalated ducts join together to form intralobular ducts.

Two or more intralobular ducts join to form interlobular ducts , which unite to form the main duct of the gland.

The gland with this type of structure & duct system is called racemose type. Racemose means the bunch of grapes

CLASSIFICATION OF SALIVARY GLANDS

MAJOR SALIVARY GLANDS

Parotid Gland

Submandibular Gland

Sublingual Gland

(a)According to size and location

MAJOR SALIVARY GLANDS

PAROTID GLAND Parotid gland is the largest salivary gland. It is irregular, wedged

shape and unilobular.

Parotid is 14-28 grams in weight and provides 60-65% of total salivary volume.

Size averaging 5.8 cm ( cranio-caudal dimension),

3.4 cm (ventral-dorsal dimension).

Parotid gland

These glands are situated at the side of the face just below and in front of the ear .

The main parotid duct – Stensens duct leaves mesial angle of gland traverses over the massetter, pierces buccinator and enters oral cavity buccal to maxillary 1st molar. Duct is about 35 to 40 mm long . Mainly Serous in secretion.

Submandibular Gland Also called as Submaxillary

gland. Its irregular andWalnut shaped.

It is 10-15gm in weight produce 20-30% of total salivary volume.

Located in the submandibular

triangle of the neck, inferior &

lateral to mylohyoid muscle.

The posterior-superior portion of the gland curves up around the posterior border of the mylohyoid and gives rise to Wharton’s duct .Wharton’s duct passes forward along the superior surface of the mylohyoid adjacent to the lingual nerve. It is 2-4mm in diameter & about 5cm in length.

Wharton’s duct, opens at the side of frenulum of tongue by the means of small opening on the papilla called Caruncula Sublingualis

SUBLINGUAL GLAND

The sublingual glands are the

smallest of the major salivary

glands, produces 2-5% of the total

salivary volume.

Each is of the size and shape of an

almond .Weighs 3-4 gms.

Glands lie beneath mucosa of floor

of mouth, above mylohyoid muscle ,

medial to mandible and lateral to

genioglossus, series of small ducts

The ducts of the sublingual glands are called Bartholin’s ducts. In most cases, Bartholin’s ducts consists of 8-20 smaller ducts of

Rivinus. These ducts are short and small in diameter. Open into oral cavity at the sublingual fold on either side of the

tongue

Minor Salivary Gland

The minor salivary glands are located beneath the epithelium in almost all parts of the oral cavity. These glands usually consist of several small groups of secretory units opening via short ducts directly into mouth.

There are 600 to 1000 minor salivary glands lying in the oral cavity and the oropharynx.

The minor salivary glands are classified according to their anatomic location.

1. Labial and Buccal GlandsLabial glands -- situated beneath the mucous membrane around

the orifices of mouth.They are circular in form, and about the size of small peas; their ducts open by minute orifices upon the mucous membrane.

Buccal glands– present between the mucous membrane and buccinator muscle.

2. Glossopalatine Glands The glossopalatine glands are pure mucous glands, they are

principally localized to the region of the isthmus in the glossopalatine fold.

3. Palatine Glands They consist of several hundred glandular aggregates in the

lamina propria of the posterior region of the hard palate and in the submucosa of the soft palate.The opening of the ducts on the palatal mucosa are often large and easily recognized

4. Lingual Glands

The glands of the tongue are divided into several groups:

(a)The anterior lingual glands ( glands of BLANDIN AND NUHN )

Location – near the apex of tongue.

The anterior region of this glands are chiefly mucous in character, whereas the posterior region is mixed.

.

(b) The posterior lingual mucous gland.

Location -- lateral and posterior to the vallate papillae and in association with the lingual tonsil.

(c) The posterior lingual serous gland ( von Ebner’s glands)

Location -- between the muscle fibers of the tongue below the vallate papillae.

(b) According to the histochemical nature of secretory products.

•This type of gland is made up of serous cells predominantly. •These glands secrete thin & watery saliva . •Parotid glands and lingual glands are serous glands.

SEROUS GLANDS

•This type of glands are made up of mucous cells mainly . •These glands secrete thick & viscous saliva with more mucin .•Lingual mucous, buccal glands & palatal glands belongs to this type.

MUCOUS GLANDS

•Mixed glands are made up of both serous and mucous cells .•Submandibular , sublingual & lacrimal glands are mixed glands

MIXED GLANDS

Nerve supply to salivary glands

Salivary glands are under the control of autonomic nervous system and receive efferent nerve fibres from both parasympathetic and sympathetic divisions of autonomic nervous system.

Parasympathetic fibers The parasympathetic nerve fibers supplying the salivary glands

arise from the superior and the inferior salivatory nuclei,which are situated in pons and medulla respectively.

Parasympathetic fibres to submandibular and sublingual glands.

The parasympathetic preganglionic fibers to submandibular & sublingual glands arise from the superior salivatory nucleus situated in pons .

After taking origin from this nucleus,the preganglionic fibers pass throgh nervous intermedius of wrisberg, geniculate ganglion,the motor fibers of facial nerve, chorda tympani branch of facial nerve & lingual branch trigeminal nerve & finally reach the submaxillary ganglion.

The postganglionic fibers arising from this ganglion supply the submaxillary & sublingual glands

Parasympathetic fibres to parotid gland. The parasympathetic preganglionic

fibres to parotid gland arises from inferior salivatory nucleus situated in the upper part of medulla oblongata.

From here , the fibres pass through the tympanic branch of glossopharyngeal nerve, tympanic plexus & lesser petrosal nerve and end in otic ganglion.

The postganglionic from otic ganglion reach the parotid gland by passing through the auriculotemporal branch in mandibular division of trigeminal nerve

Sympathetic fibersThe sympathetic preganglionic fibres to salivary glands arise from the lateral horns of first and second thoracic segments of spinal cord.

The fibres leave the cord through the anterior nerve roots and end in superior cervical ganglion of the sympathetic chain.

The postganglionic fibres from this ganglion are distributed to the salivary glands along the nerve plexus around the arteries supplying the glands

FORMATION OF SALIVA

( Mese et al., 2007, p. 711-713) The secretory acinus produces the primary saliva, which is isotonic with an ionic composition resembling that of plasma. In the duct system, the primary saliva is then modified by selective reabsorption of Na+ and Cl- (without water) and secretion of K+ and HCO3-.

Salivary secretion is a two-stage process: Initial Formation stage involves acini to secrete a primary

secretion that contains ptyalin and/or mucus in a solution of ions similar in plasma.

Modification stage is when the primary secretion flows through the ducts and the ionic composition of saliva is modified.

Initial Formation Stage:Stimulation of the parasympathetic nerve, or mainly muscarinic

cholinergic receptors, initiates intracellular second messenger events of acinar cells, the signal transduction system involves the release of Ca2+ from intracellular stores. The increase in intracellular Ca2+ levels leads to the Cl– channels at the apical membrane to open and an influx of Cl– into the lumen. Hence the change in electronegativity by Cl– influx causes Na+ to diffuse across the cation-permeable tight junction between acinar cells to preserve electroneutrality within the lumen. The net influx of NaCl creates an osmotic gradient across the acinus, which draws water from the blood supply via a tight junction. Thus, saliva secreted in the lumen (primary saliva) is an isotonic plasma-like fluid.

Modification Stage: In the next step, the composition of primary saliva is modified in the duct system. The

intralobular ducts reabsorb Na+ and Cl– excluding water, and make the final saliva hypotonic. Stimulation of the sympathetic nerve, or ß-adrenergic receptors, causes exocytosis but less fluid secretion. Activation of ß-adrenoceptors increases the intracellular cyclic adenosine monophosphate (cAMP) level, which is the primary second messenger for amylase secretion. cAMP is thought to activate protein kinase which may regulate the process by which cells release the contents of their secretory granules. This involves the fusion of the granule membrane with the luminal plasma membraneof the secretory cell followed by rupture of the fused membranes. The released contents of granules comprise a wide variety of proteins which are unique to saliva and show biological functions of particular importance to oral health. (Reference from 6: Salivary Secretion, Taste and Hyposalivation) 

PROPERTIES OF SALIVA

i) VOLUME:- 1000 to 1500 ml of saliva is secreted per day and , it is approximately about 1ml/minute . Contribution by each major salivary gland is

ii) REACTION:- mixed saliva from all the glands is slightly acidic with pH of 6.35 to 6.85.

iii) SPECIFIC GRAVITY:- it ranges between 1.002 to 1.012.

iv)TONICITY :- saliva is hypotonic to plasma.

COMPOSITIONsaliva

Water -99.5% solids 0.5%

Organic substance Inorganic substance

Gases

Enzymes Other org. substance

1.amylase 2maltase

3lingual lipase 4lysozyme

5phosphatase 6carbonic anhydrase 7kalikrein

1.Proteins- mucin & albumin

2.Blood group antigen3.Free amino acids

4.Non protein nitrogenous substances-urea,uric

acid,creatinine,xanthine hypoxanthine

1.Sodium2.Calcium

3.Potassium4.Biocarbonat

e5.Bromide6.Chlorine7.Fluoride

8.phosphate

1.Oxygen2.Carbon dioxide

3.Nitrogen

Organic Substances

Enzymes

1-AmylasesCalcium metalloenzyme.Hydrolyzes alpha (1-4)bonds of starches such as amylase and

amylopectin.Several salivary isoenzymes.Maltose is the major-end-product(20% is glucose).Appears to have digestive function.

2-LactoferinIron-binding protein.“Nutritional“ immunity (iron starvation).Some microorganisms (e.g., E. coli) have adapted to this

mechanism by producing enterochelins. bind iron more effectively than lactoferrin. iron-rich enterochelins are then reabsorbed by bacteria.

Lactoferrin, with or without iron, can be degraded by some bacterial proteases.

3-HistatinsA group of small histatine-rich proteinsPotent inhibitors of Candida albicans growth

4-CystatinsAre inhibitors of cystatine-proteasesAre ubiquitous in many body fluidsConsidered to be protective against unwanted proteolysis

bacterial proteases lysed leukocytes

May play inhibit proteases in periodontal tissuesAlso have an effect on calcium phosphate precipitation

5-Lingual lipaseSecreted by von ebners glands of tongue.Involved in first phase of fat digestion.Hydrolizes medium –to long –chain triglycerides.Important in digestion of milk fat in new-born.

it is highly hydrophobic and readily enters fat globules.

6-STATHERINSCalcium phosphate salts of dental enamel are soluble under

typical condition of ph and ionic strength.Super saturation of calcium phosphates maintain enamel

integrity.

Statherins prevent precipitation or crystallization of supersaturated calcium phosphate in ductal saliva & oral fluid.

Produced by acinar cells.Also an effective lubricant.

7-Proline Rich Proteins (PRPs)Like statherins PRPs are also highly asymmetricalInhibitors of calcium phosphate crystal growthInhibition due to first 30 residues of negatively charged amino-

terminal endPresent in the initially formed enamel pellicle & in ‘mature’

pellicle.

8-MucinsLacks precise folded structure of globular proteins Asymmetrical molecule with open , randomly organized structurePoly peptide backbone with CHO side chainsSide chains may end in negatively charged groups such as sialic

acid & bound sulphate Hydrophillic , entraining waterUnique rheological properties Two major mucins ( MG1 & MG2)

A) TISSUE CAPACITY - protective coating about hard & soft tissues

- primary role in formation of acquired pellicle

- concentrates anti – microbial molecules at mucosal interface

B) LUBRICATION - align themselves with direction of flow of saliva

- increase lubricating qualities

- film strength determines how effectively opposed moving surface are kept apart

FUNCTION OF MUCIN

C) AGGRETION OF BACTERIAL CELLS

- bacterial adhere to mucins may result in surface attachment

- mucin coated bacteria may be unable to attach to surface

D) BACTERIAL ADHESION

- mucin oligosaccharides mimics those on mucosal cell surface

- react with bacterial adhesions , thereby blocking them

Inorganic Substances

1-SODIUMContributes to osmolarity of saliva(osmolarity is ½-3/4th of

blood).Sodium concentration give diagnostic information relating

to the efficiency of ductal transport system.

2-CALCIUMsaliva is supesaturated with calcium and hence prevents

dissolution of enamel.it also facilitates enamel mineralization.

3-POTASSIUMContributes to osmolarity of saliva.Potassium reaches saliva by active processes in both acini and

ducts.Concentration falls immediately after stimulation and then

approximately constant.

4-BIOCARBONATEMost important buffer in saliva [resist change in salivary Ph

when acid or alkali added].Biocarbonates release weak carbonic acid when acid is

added;this is rapidly decomposed to H2O and CO2 which leaves the solution resulting in complete removal of acids.

5-CHLORINEContributes to osmolarity of saliva.Increased flow rate leads to increased chloride reabsorption.

6-fluoridefluoride is well known for its anti-caries property.peak concentration of fluoride in gland saliva are observed some

30-60 minutes after ingestion of fluoride dose.

7-phosphorousit is actively transported into saliva,probably mainly in the acini

but possibly also in the ducts

FUNCTIONs OF SALIVA

Saliva is very essential . Since it has many functions , its absence leads to many inconveniences.

- preparation of food for swallowing

- appreciation of taste

- digestive function

- cleansing and protective functions

- role in speech

- excretory function

- regulation of body temperature

- regulation of water balance

1)PREPARATION OF FOOD FOR SWALLOWINGWhen food enters the mouth , saliva moistens and dissolves it.The mucous membrane of mouth is also moistened and masticated food is rolled into a bolus.The mucin of saliva lubricates the bolus and facilitates the swallowing.

2)APPRECIATION OF TASTETaste is a chemical sensation. Saliva by its solvent action dissolves the solid food substance , so that the dissolved substances can stimulate the taste buds.The stimulated taste buds recognize the taste.

3)DIGESTIVE FUNCTION

Saliva has three digestive enzymes namely,salivary amylase,maltase,and lingual lipase

SALIVARY AMYLASE• salivary amylase is a carbohydrate splitting(amylolytic)enzyme.• It acts on cooked or boiled starch and converts it into maltose ,major

part of it occurs in the stomach because,the food stays only for a short time in the mouth.

• The optimum pH necessary for the activation salivary amylase is 6.• The salivary amylase cannot act on cellulose.

MALTASE• The enzyme maltase is present only in traces in human saliva.• It converts maltose into glucose.

.

LINGUAL LIPASE• The lingual lipase is secreted from serous glands situated on the

posterior aspect of tongue.• It digest milk fats(pre-emulsified).• It hydrolyses triglycerides into fatty acids.

4)CLEANSING AND PROTECTIVE FUNCTION• due to the constant secretion of saliva,the mouth and teeth are

rinsed and kept free from food debris,shed epithelial cells and foreign particles.

• In this way,saliva prevents bacterial growth by removing materials,which may serve as culture media for the bacterial growth.

• the enzyme lysozyme of saliva kills some bacteria such as staphylococcus,streptococcus,and brucella.

• mucin present in the saliva protects the mouth by lubricating the mucous membrane of the mouth.

5)ROLE IN SPEECHBy moistening and lubricating the soft parts of mouth and lips,saliva

helps in speech. If the mouth is dry,articulation and pronunciation become difficult.

6) EXCRETORY FUNCTIONMany substances,both organic and inorganic,are excreted in saliva.It excretes substances like mercury,potassium iodide,lead and

thiocyanate.Saliva also excretes some viruses such as those causing rabies and

mumpsIn some pathological conditions, saliva exretes substances like

sugar in diabetes mellitus, calcium in hyperparathyroidism.

7)REGULATION OF BODY TEMPERATUREIn dogs and cattle excessive dripping of saliva during panting

helps in loss of heat and regulation of body temperature.However,in human being sweat glands play major role in the

temperature regulation and saliva does not play any role in this function.

8)REGULATION OF WATER BALANCEWhen the body water content decreases ,salivary secretion

also decreases.This causes dryness of the mouth and induces thirst.When the water is taken,it quenches the thirst and restores

the body water content.

REGULATION OF SALIVARY SECRETION

Salivary secretion is regulated by nervous mechanism & it is a reflex phenomenon.

Salivary reflexes are of two types:- 1)Unconditioned reflex

2)Conditioned reflex

1)UNCONDITIONED REFLEXSecretion of saliva when any substance is played in the mouth is

called the unconditioned reflex.It is due to the stimulation of nerve endings in the mucuos

membrane of the oral cavity.This reflexes is present since birth & hence it is also called

inborn reflex.

2) CONDITIONED REFLEXSecretion of saliva by the sight,smell,heaving or thought of food

is called conditioned reflex.It is due to the impulses arising from the eyes,ear,etc.It is an acquired reflex & needs previous experience.

CO-REALATION BETWEEN SALIVA AND DENTAL CARIES

It is capable of regulating the pH of the oral cavity by the help of its bicarbonate content as well as its phosphate and amphoteric protein constituents.

Increase in secretion rate usually results in an increase in pH and buffering capacity.

Because of its calcium and phosphate content it helps to maintain the integrity of teeth.

Tooth dissolution is prevented or retarded and re-mineralization is enhanced by the presence of copious salivary flow.

The flow of saliva can reduce plaque accumulation on the tooth surface.

The diffusion into plaque of salivary components such as calcium, phosphate, hydroxyl and fluoride ions enhances re-mineralization of early carious lesions.

The carbonic acid-bicarbonate buffering system as well as ammonia and urea constituents of the saliva act as buffer

The total concentration of IgA in saliva may be inversely related to caries experience.

Carbonic acid-bicarbonate

system

IgA

•Lysozyme, lactoperoxidase and lactoferrin in saliva have a direct antibacterial action on plaque•Salivary proteins could increase the thickness of the acquired pellicle and so help to retard the movement of calcium and phosphate ions out of enamel.

lact

ofe

rrin

lysozyme

lactoperoxid

ase

CHEMICAL BENEFITS OF SALIVA STIMULATION Stimulating the flow of saliva alters its composition. Dawes

noted that increasing the rate of salivary flow 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 remineralisation of damaged enamel and dentin.

Increasing the rate of salivary flow increases the concentration of protein, sodium, chloride and bicarbonate and decreases the concentration of magnesium and phosphorus in saliva.

Salivary Flow Rate, Buffer Effect, and Dental Caries

Probably the most important caries-preventive functions of saliva are the flushing and neutralizing effects, commonly referred to as "salivary clearance" or "oral clearance capacity“ (Lagerlof and Oliveby, 1994). In general, the higher the flow rate, the faster the clearance (Miura et al., 1991) and the higher the buffer capacity (Birkhed and Heintze, 1989).

Reduced salivary flow rate and the concomitant reduction of oral defense systems may cause severe caries and mucosal

inflammations (Daniels et al., 1975; Van der Reijden et ah 1996). Dental caries is probably the most common consequence of hyposalivation (Brown et al, 1978; Scully, 1986).

Caries lesions develop rapidly and also on tooth surfaces that areusually not susceptible to caries. Subjects with impaired saliva flow rate often show high caries incidence (Papas et al., 1993; Spak et al, 1994) or cariessusceptibility (Heintze et al).

SALIVA - AS A DIAGNOSTIC AID

Human saliva performs a wide variety of biological functions that are critical for the maintenance of the oral health.

Saliva, a multi constituent oral fluid, has high potential for the surveillance of general health and diseases.

Why saliva?Non – invasiveLimited trainingNo special equipmentPotentially valuable for children and

older patientsCost effectiveEliminates the risk of infectionEasy, No pain, No needle prick, Fast Screening of large population

No Pain

What is a biomarker?A biomarker is an objective measure that has been evaluated and

confirmed either as an indicator of physiologic health, a pathogenic process, or a pharmacologic response to a therapeutic intervention.

Biomarkers, whether produced by normal healthy individuals or by individuals affected by specific systemic diseases, are tell - tale molecules that could be used to monitor health status, disease onset, treatment response and outcome.

Detect disease

Stage disease

Treatment efficacy

Response to treatment

Monitor progression / recurrence

BIOMARKERS

Classification of salivary biomarkers

Locally produced proteins of host and bacterial

origin (enzymes, immunoglobulins

and cytokines)

Genetic ⁄ genomic

biomarkers such as DNA and

mRNA of host origin

Bacteria and bacterial

products, ions, steroid hormones

and volatile compounds

Salivary proteomic, genomic and microbial biomarkers for periodontal diagnosis

Salivary biomarkers have been used to examine the effect of lifestyle factors, including smoking, on periodontal health.

Levels of salivary markers including prostaglandin E2, lactoferrin, albumin, aspartate aminotransferase, lactate dehydrogenase, alkaline phosphatase were significantly lower in current smokers than in non-current smokers.

Stress biomarkers in saliva.Salivary α-amylase Chromogranin ASalivary cortisol Salivary – α amylase Chromogranin A Biomarkers of acute stress and a-amylase is

better. Both salivary CgA and a-amylase are considered

biomarkers of the stress response by the sympatho–adreno–medullary system, unlike cortisol, which is considered a biomarker of stress response by the Hypothalamic pituitary adrenal system.

Salivary cortisol Its level in saliva is lower than that in blood. Advantage of salivary over serum cortisol

measurement is the minimisation of stress from fear of needles during collection, which may bias the results.

Various other diagnosisCandidiasis – Through the presence of candida spp in salivaThe presence of periodontal pathogenic bacteria can also be

diagnosed by this method - increasing the risk of cardiovascular and cerebrovascular diseases.

Cystic fibrosis Cystic fibrosis (CF) is a genetically transmitted disease of children

and young adults, which is considered a generalized exocrinopathy. CF is the most common lethal autosomal-recessive disorder.

The abnormal secretions present in CF caused clinicians to explore the usefulness of saliva for the diagnosis of the disease.

21-Hydroxylase deficiency an inherited disorder of steroidogenesis which leads to

congenital adrenal hyperplasia. In non-classic 21-hydroxylase deficiency, a partial deficiency of the enzyme is present.(Carlson et al., 1999).

In 21- hydroxylase deficiency, a strong correlation has been found between 17- hydroxyprogesterone levels in saliva and serum.

In some malignant diseases, markers can be detected in saliva, such as the presence of protein p53 in patients with oral squamous cell carcinoma.

Other biomarkers for OSCC: M2BP MRP14 CD59 Profilin Catalase

The presence of the c- erb- 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 disease.

In ovarian cancer too, the CA 125 marker can be detected in the saliva with greater specificity and less sensitivity than in serum.

PCR detection of H. pylori in the saliva show high sensitivity.The presence of antibodies to other infectious organisms such as

Borrelia burdogferi, shigella can also be detected in saliva.Detection of hepatitis A and hepatitis B surface antigen in the

saliva has been used in epidemiological studies.

In neonates the presence of Ig A is an excellent marker of rota virus infection

HIV antibody detection is as precise in saliva as in serum and is both applicable in clinical and epidemiological studies.

Salivary and oral fluid test: Orasure ( available in USA)

SALIVA COLLECTION METHODS

SUBMANDIBULR /SUBLINGUAL

Alternatively , for et al have described a simpler method for the collection of submandibular-sublingual.After blocking the parotid saliva secretion by placing a gauze pad at the orifice of the parotid ducts. Saliva can be collected from the floor of the mouth with a micropipette.

MINOR GLANDSMinor gland secretions can be collected by micropipette,absorbent filter paper or strips from the inner surface of lips,palate,or buccal mucosa and quantitated by weight differences or using a Peritron device.

SALIVA AND DENTAL PLAQUE

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.

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 .

CLINICAL CONSIDERATIONS OF SALIVA

1.HYPOSALIVATION The reduction in the secretion of saliva is called hyposalivation. It is of

two types , namely- Temporary - Permanent

1) Temporary hyposalivation occurs in

i) emotional conditions like fear

ii) fever

iii) dehydration

2) Permanent hyposalivation occurs in

- sialolithiasis – obstruction of salivaary duct

- congenital absence or hypoplasia of salivary glands

- bell’s palsy – paralysis of facial nerve

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. 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 .

SJOGREN’S SYNDROME

-Sjögren syndrome is a chronic autoimmune disorder characterized by xerostomia (dry mouth), xerophthalmia (dry eyes), and lymphocytic infiltration of the exocrine glands.

This triad is also known as the sicca complex. It is an autoimmune disorder in which the immune cells destroy exocrine glands such as lacrimal glands & sweat glands . It is named after HENRIK SJOGREN who discovered it.

In some cases it causes dryness of skin , nose.

In severe condition the organs like kidneys ,lungs, liver , pancreas , thyroid , blood vessels & brain are affected

Age Changes – With age a generalized loss of gland parenchymal tissue occurs.The lost salivary cells often are replaced by adipose tissue.

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.

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.

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.

Oral ulceration: reduced saliva flow may result in recurrent aphthous ulceration, pain, lichen planus, delayed wound healing and secondary infection, such as candidiasis.

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.

Swallowing: there are problems with too much saliva or too little often accompanied by complaints of dysphagia.

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.

Glossitis: with salivary hypofunction,the tongue can appear red, dry and raw, particularly on the dorsum, while the filiform papillae may be lost.

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.

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.

2. HYPERSALIVATION The excess secretion of saliva is known as hypersalivation . Hypersalivation in

pathological condition is known as ptyalism , sialorrhea , sialism or sialosis.

Hypersalivation occurs in the following conditions :-

1) Decay of tooth or neoplasm of mouth or tongue due to continuous irritation of nerve endings in the mouth

2) Disease of esophagus , stomach & intestine

3) Neurological disorder such as cerebral palsy & mental retardation

4) Cerebral stroke

5) Parkinsonism

6) Some psychological & psychiatric conditions

7) Nausea & vomiting

DROOLING Uncontrolled flow of saliva outside the mouth is called

drooling . It is often called ptyalism.Drooling occurs because of excess production of saliva

in association with inability to retain saliva within the mouth.

Drooling in small children is a normal part of development. 

Teeth are coming in, they put everything in their little mouths, and they haven’t developed the habit of keeping the lips together.

While child is teething ,their gums will produce excessive saliva.

The saliva which is produce during drooling is designed to moisten and lubricate babys tender gums.

Drooling serves to help make teething process more bearable for child.

CHORDA TYMPANI SYNDROME Chorda tympani syndrome is the condition

characterized by sweating while eating. During the regeneration of the nerve fibers following trauma or surgical division , which pass through chorda tympani branch of facial nerve may deviate & join with the nerve fibers supplying sweat glands.

FREY'S SYNDROMEor GUSTATORY SWEATING also known

as Baillarger’s syndrome,Dupuy’s syndrome, Auriculotemporal syndrome or Frey-Baillarger syndrome) is a food related syndrome which can be congenital or

acquired specially after parotid surgery and can persist for life.

The symptoms of Frey's syndrome are redness and sweating on the cheek area adjacent to the ear. They can appear when the affected person eats, sees, thinks about or talks about certain kinds of food which produce strong salivation.

PARALYTIC SECRETION OF SALIVA - when the parasympathetic nerve to salivary gland is cut ,

salivary secretion increases for the first 3 weeks & later diminishes; finally it stops at about 6th week. The increased secretion of saliva after cutting the parasympathetic nerve fibers is called paralytic secretion.

AUGMENTED SECRETION OF SALIVA - if the nerve supplying salivary glands are stimulated

twice , the amount of saliva secreted by the second stimulus is more than the amount secreted due to the first stimulus.

- it is because , the first stimulus increases excitability of acinar cells , so that when the second stimulus is applied , the salivary secretion is augmented.

EFFECT OF DRUGS & CHEMICAL ON SALIVARY SECRETION

1) Sympathomimetic drugs like adrenaline & ephedrine stimulates salivary secretion

2) Parasympthomimetic drugs like acetylcholine , pilocarpine , muscarine & physostigmine increase the salivary secretion

3) Histamine stimulates the secretion of saliva4) Sympathetic depressants like ergotamine .5) Parasympathetic depressants like atropine inhibit the

secretion of saliva6) Anaesthetics like chloroform & ether stimulate the

reflex secretion of saliva . However , deep anaesthesia decrease the secretion due to central inhibition.

CONCLUSION

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.

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