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