2. Saliva has been described as a complex secretion of the salivary
glands which constantly, bathes the teeth and the oral mucosa.
It plays a vital role in the integrity of the oral tissues; in the
selection, ingestion and preparation of food for digestion and in
our ability to communicate with one another.
INTRODUCTION
3. EMBRYOLOGY
CLASSIFICATION
MAJOR SALIVARY GLANDS
MINOR SALIVAR GLANDS
HISTOLOGY OF SALIVARY GLANDS AND DUCTAL SYSTEM
PHYSIOLOGY OF SALIVARY SECRETION
COMPOSITION OF SALIVA
CONTENT
4. Major salivary glands develop from the 6th-8th weeks of gestation as
outpouchings of oral ectoderm into the surrounding mesenchyme
The development of major salivary glands is thought to consist of
three main stages
4
EMBRYOLOGY
5. The first stage is marked by the presence of a primordial analge and
the formation of branched duct buds due to repeated epithelial cleft
and bud development.
Ciliated epithelial cells form the lining of the lumina, while external
surfaces are lined by ectodermal myoepithelial cells
5
FIRST STAGE
6. • The early appearance of lobules and duct canalization occur during
the second stage.
• Primitive acini and distal duct regions, both containing
myoepithelial cells, form within the seventh month of embryonic
life
6
SECOND STAGE
7. The third stage is marked by maturation of the acini and
intercalated ducts, as well as the diminishing prominence of
interstitial connective tissue.
7
THIRD STAGE
8. GLANDS ORIGIN INTRA-UTERINE LIFE
PAROTID Corners of stomatodeum 6th week
SUBMANDIBULAR Floor of mouth End of 6th week
SUBLINGUAL Lateral to submandibular
primodium
8th week
MINOR Buccal epithelium 12th week
9. The parotid gland buds are the first to appear, at the 6th week
after conception. . They appear on the inner cheek near the angle
of the mouth and then grow back towards the ear.
The submandibular gland buds appear late in the 6th week as a
grouped series, forming epithelial outgrowths on either side of
the midline in the linguogingival groove of the floor of the
mouth at the sites of future papillae
9
10. The sublingual glands arise in the 8th week post conception as a
series of about 10 epithelial just lateral to the submandibular gland
anlagen. These branch and canalize to provide a number of ducts
that open independently beneath the tongue.
A great number of small minor salivary glands arise from the oral
ectodermal and endodermal epithelium and remain as discrete acini
and ducts scattered throughout the mouth
10
12. SEROUS
• Parotid
• Glands of von
ebner
MUCOUS
• Labial
• Palatine
• Posterior
palatine
MIXED
• Submandibular
• Sublingual
• Anterior lingual
BASED ON SALIVA SECRETED
13. PAROTID SUBMANDIBULAR SUBLINGUAL
SIZE Largest Next in size Smallest
WEIGHT 20-30g each 10-15g About 2g
POSITION In front of the ear and
behind the ramus of the
mandible
In posterior part of floor of mouth
beneath the mandible
Lies immediately below the
mucosa of the floor of mouth
and superficial to the
mylohyoid muscle
DUCT Stenson’s duct Wharton’s duct Duct of Rivinus-minor ducts
Bartholin’s duct-major duct
DUCT OPENING Pierces the buccinator to
open into the vestibule
opposite 2nd maxillary
molar
Runs forward and opens at the
summit of the sublingual papilla
lateral to the lingual frenum of the
tongue
May open into the
submandibular duct or
directly into the mucosa of the
floor of the mouth
CAPSULE Dense capsule Capsule present Devoid of capsule
ANATOMY
16. Largest salivary gland.
Average weight-25gm.
Located subcutaneously in front
of external ear, deep portion lies
behind ramus of mandible.
Shape is flat, three sided
pyramid, tapering inferiorly to a
blunt apex.
16
PAROTID GLAND
17. About 5cm long; runs forward
across the masseter muscle, turns
inward at anterior border of
masseter, runs obliquely forwards
for a short distance between
buccinator and oral mucosa and
opens into oral cavity at a papilla
opposite 2nd maxillary molar
17
STENSONS DUCT
24. PREGANGLIONIC FIBERS from
lateral horns of T1 and T2 of spinal cord
superior cervical sympathetic ganglion
POSTGANGLIONIC FIBERS distributed
along the artery( ECA)
salivary gland
24
SYMPATHETIC NERVE SUPPLY
25. Irregular in shape and about
the size of a walnut.
Weight 10-15gm
Situated in the post part of
floor of mouth, adjacent to
medial aspect of mandible
and wrapping around the
posterior border of
mylohyoid muscle.
Roughly J- shaped
25
SUBMANDIBULAR GLAND
26. 5cm long;
It emerges at the anterior end of deep part of gland and runs forward
between the hyoglossus and mylohyoid. It opens into floor of the
mouth, on summit of sublingual papilla, at side of frenulum of tongue.
26
WHARTONS DUCT
30. PREGANGLIONIC FIBERS from
lateral horns of T1 and T2 of spinal cord
superior cervical sympathetic ganglion
POSTGANGLIONIC FIBERS distributed
along the artery( ECA)
salivary gland
30
SYMPATHETIC NERVE SUPPLY
31. Smallest gland.
Weight – 3-4gm
Located in anterior part
of floor of mouth,
between mucosa and
mylohyoid muscles in
contact with sublingual
fossa on lingual aspect
of mandible.
Shape – narrow, flat and
shaped like an almond
31
SUB LINGUAL GLAND
32. It has 8-20 excretory ducts.
The smaller ducts called as duct
of Rivinus opens on summit of
sublingual fold.
The larger ducts called as
Bartholins duct opens with the
submandibular duct at sublingual
caruncle.
32
37. • About 600 to 1,000 minor salivary glands, ranging in size from 1
to 5 mm, line the oral cavity and oropharynx
• The greatest number of these glands are in the lips,tongue, buccal
mucosa, and palate, although they can also be found along the
tonsils, supraglottis, and paranasal sinuses.
• Each gland has a single duct which secretes, directly into the oral
cavity, saliva which can be either serous, mucous, or mixed.
37
38. • Postganglionic parasympathetic innervation arises mainly from the
lingual nerve.
• The palatine nerves, however, exit the sphenopalatine ganglion to
innervate the superior palatal glands.
• The oral cavity region itself determines the blood supply and
venous and lymphatic drainage of the glands
38
41. Round acini
SEROUS CELLS
Pyramidal in shape,
round nucleus situated at
basal third
basal cytoplasm stains
basophilic due to rough
endoplasmic reticulum
apical cytoplasm
contains secretory
granules which stain with
acidophilic stains.
41
SEROUS ACINI
42. Basal cytoplasm contains
numerous rough
endoplasmic reticulum .
Secretory granules has
variable appearance,
ranging from
homogenously electron
dense to combination of
electron dense and
electron lucent regions .
42
ELECTRON MICROSCOPY
43. SEROUS SECRETION
Produce proteins and
glycoproteins which
have N-linked
oligosaccharide side
chains
Watery and rich in
protein and enzymes
FUNCTION
Produce mucins
which are also
glycoproteins
Enzymatic, anti-
microbial and
calcium-binding
activities
43
44. Tubular in shape
Mucous secretory cells
filled with pale staining
secretory material and
little cytoplasm .
Nucleus is compressed
against the basal cell
membrane and contains
densely stained
chromatin.
Lumina are larger than
those of serous end
pieces.
44
MUCOUS ACINI
45. Mucous secretory
granules appear
electron lucent.
Mucous cells have a
large Golgi complex
located mainly basal
to the mass of
secretory granules.
Endoplasmic
reticulum and other
organelles are
mainly restricted to
basal cytoplasm.
45
ELECTRON MICROSCOPY
46. MUCOUS SECRETION
Produce mucins
which are also
glycoproteins
Viscous, thick and
rich in mucins
FUNCTION
Functions mainly
to lubricate and
form a barrier on
surfaces and to
bind and aggregate
microorganisms.
46
48. Contractile cells associated with
secretory end pieces and
intercalated ducts
Stellate shaped
Present between the basal
lamina and basement membrane
of acinar secretory cells and
also intercalated duct cells
Joined to cells by desmosomes.
Aid in contraction, and thus
forced secretion, of the acinus.
48
MYOEPITHELIAL CELLS
49. The ductal system of salivary glands is a varied network
of tubules that progressively increase in diameter
beginning at secretory end pieces and extending into
oral cavity.
The three classes of ducts are:
Intercalated duct
Striated duct.
Excretory duct
49
DUCT
51. Located in the connective tissue septa between lobules of
the gland and hence are known as extralobular or
interlobular duct.
Has columnar cells.
As the duct reaches near the opening, the epithelium may
become striated squamous epithelium
Function : controls flow of saliva along duct.
51
EXCRETORY DUCTS
52. It leads from the serous acini to the striated duct
The primary saliva produced by secretory end pieces
passes first through the intercalated ducts.
Lined by simple cuboidal epithelium.
Scanty cytoplasm and centrally placed nucleus.
Has secretory granules.
The apical cell surface has few short microvilli projecting
into lumen.
Functions: Contribute macromolecular components that
are stored in their secretory granules to the saliva. These
include lysozyme and lactoferrin.
52
INTERCALATED DUCT
53. The striated duct receives the primary saliva from
intercalated duct and constitutes largest portion of duct
system
They are the main ductal component located within
lobules of gland i.e. intralobular.
The cells are columnar, with centrally placed nucleus and
large amount of pale acidophilic cytoplasm.
The ductal surface has short microvilli.
Function: modification of primary saliva by reabsorption
and secretion of electrolytes
53
STRIATED DUCTS
55. 55
• STAGE 1- Formation of primary saliva
by acinar cells and intercalated ducts.
Secretion of water and electrolytes
Secretion of salivary proteins
• STAGE 2- Ductal modification
56. Water moves in to the lumen to maintain the osmotic balance
Increase in extra cellular K ion concentration, which activates a carrier
membrane protein which causes K to reenter the cell, coupled with Na & Cl
ions, which draws Na ions into the lumen
Change in permeability of K ions, which leave the acinar cell
Release of calcium from intracellular stores
Neurotransmitter binds to receptor
60. Daily secretion 0.5 – 1.5 l approximately
Flow rate 0.25-0.5 ml/min
Specific gravity 1.002-1.008
Average P.H. 6.7
P.H range 6.2-7.6
Water content 99%
Freezing point : 0.07 to 0.34 degree C
Tonicity Hypotonic with respect to plasma
60
PHYSICAL PROPERTY
64. SODIUM AND
POTASSIUM
• Osmoregulators
• Helps in membrane transport of actively
transported compounds during saliva secretion
CALCIUM
• Maintenance of tooth structure
• Remineralisation
• Activation of amylase
MAGNESIUM
• Activator of enzyme
64
65. CHLORIDE
• Osmoregulator
• Activator of amylase
• Oxidation of peroxidase (host defense)
BICARBONATE
• Buffering action
• Osmoregulator
• Formation of soluble bicarbonates and phosphate compounds
PHOSPHATES
• Maintenance of phosphate in tooth
• Remineralisation
• Buffering action
65
IODIDE
• Antioxidant and anti tumour activity prevents oral and salivary
gland diseases.
72. • Viscosity of saliva
• Parotid secretion is watery- low mol wt
glycoprotein
• Sub mand & sub lin has high mol wt
glycoprotein
• Aggregates microorganisms in oral cavity
and helps in its clearance
GLYCOPROTEINS
72
75. WHOLE SALIVA
Saliva is a complex mix of fluids which consists of:
Secretions from major & minor salivary glands.
Constituents of non-salivary origin.
Gingival crevicular fluid
Serum & blood cells.
Desquamated epithelial cells
Bacteria & bacterial products
Viruses & fungi
Food debris
Expectorated bronchial secretion.
Whole saliva can be of 2 types:
Unstimulated/basal/resting saliva
Stimulated saliva
76. Unstimulated/basal/resting saliva
This is whole saliva that is continuously secreted under resting
conditions, without any exogenous stimulation.
Characterized by a slow flow of saliva
Keeps the mouth moist and lubricates the mucous membranes
Primarily serves to maintain the integrity of oral tissues.
Stimulated saliva
This is whole saliva secreted in response to exogenous stimuli.
- Contributes as much as 80% - 90% of the average daily salivary
production
78. Salivary flow can be of two types
Resting flow ( Spontaneous secretion)
Reflex flow ( After a stimulus)
REFLEX
CONDITIONED
UNCONDITIONED
78
SALIVARY FLOW
79. It is the unstimulated flow which occurs without any exogenous
stimuli
Factors affecting Resting flow
Circadian rhythm
Light & Arousal
Hydration
Exercise & Stress
79
Resting flow-
89. 89
CRITICAL PH
The critical pH is the pH at which saliva and plaque fluid cease to
be saturated with calcium and phosphate, thereby permitting the
hydroxyapatite in dental enamel to dissolve
90. Diffuse into plaque and neutralize acids and increases plaque
pH.
The carbonic acid produces bicarbonate ions that neutralizes
acid .
90
BUFFERING SYSTEM
91. The physicochemical properties of saliva play a major role in the
development of caries compared among the caries free and caries
active children
Flow rate, pH, buffering capacity were slightly reduced in caries
active children, but total protein and total antioxidant capacity of
saliva increased significantly in caries active children and the total
calcium decreased significantly in caries active children
. 91
92. Hemadi et al 2017, research has generated abundant
information that contributes to a better understanding of
the roles of microorganisms and salivary proteins in ECC
occurrence and prevention. This review summarizes the
microorganisms that cause caries and tooth-protective
salivary proteins with their potential as functional
biomarkers for ECC risk assessment. The identification
of biomarkers for children at high risk of ECC is not only
critical for early diagnosis but also important for
preventing and treating the disease.
;
92
93. The Zn concentration in the stimulated saliva showed a significant
increase in the group of caries-free children and could be
described as a positive value for the reduction of caries.
Zinc salts have antibacterial actions due to their ability to inhibit
bacterial adhesion, metabolic activity, and growth
Zn is easily incorporated as a substitute for Ca++ ions. Its
incorporation in the enamel helps decrease its solubility.
93
94. Periodontal disease is a chronic disease of the oral cavity
comprising a group of inflammatory conditions affecting the
supporting structures of the dentition.
Saliva, as a mirror of oral and systemic health, is a valuable source
for clinically relevant information because it contains biomarkers
specific for the unique physiologic aspects of periodontal diseases
The fluid mostly collected for salivary diagnostic purpose is
expectorated whole saliva, a mix composed largely of the secretions
from the major salivary glands along with the modest contributions
from the minor salivary glands and gingival crevicular fluid.
94
SALIVA AND PERIODONTAL HEALTH
95. Two major roles
1-Plaque accumulation
2- Plaque mineralization into calculus
Decreased salivary secretion cause gingival inflammation.
95
96. Salivary diagnostic markers for periodontal diseases have included
serum and salivary molecules such as immunoglobulins, enzymes
constituents of gingival crevicular fluid, bacterial components or
products, volatile compounds, and phenotypic markers, such as
epithelial keratins .
96
97. Salivary MMP-8 levels were significantly higher in
periodontitis patients compared with healthy controls
overall
97
98. The various advantage offered by saliva to be used as an effective
diagnostic tool include.
Simplicity in obtaining samples
Painless
Non-hazardous
Readily accepted by patients
Economic
Convenient
Requires less time
Does not require any trained personnel
Storage is relatively easy as compared to blood which requires
anticoagulants.
98
SALIVA A DIAGNOSTIC TOOL
100. 100
Caries activity tests
Biomarker for periodontal disease---presence of matrix metallo proteinase in
GCF
Antibodies to HIV
Biomarker for oral cancer ( IL-8), antibody against p53 tumour supressor
antigen, salivary defensin
Forensic odontology to identify blood group antigen
101. Human saliva has attracted attention as a liquid biopsy for the
detection of oral diseases like dental caries, gingivitis, periodontitis
(chronic/aggressive), Bechet disease, oral squamous cell carcinoma,
cleft palate and lips, salivary gland diseases, oral leukoplakia,
chronic graft-versus-host disease (cGVHD), and systematic diseases
such as breast cancer, diabetes, human immune deficiency virus
(HIV).
Biomarkers are defined as a biological molecules found in blood,
saliva and other body fluids, or tissues that are a sign of a normal
or abnormal process, or of a condition or disease.
Many of these biomarkers enter saliva through blood via passive
diffusion, active transport or extracellular ultra-filtration.
Therefore, saliva can be a good reflection of the physiological
function of the body 101
102. The article by Yu et al. potential salivary biomarkers for the early
detection of oral squamous cell carcinoma (OSCC)
102
103. Collection of unstimulated whole saliva
Collection of stimulated whole saliva
Collection of saliva from individual glands
103
SALIVA SAMPLE COLLECTION
104. WHOLE
SALIVA
BLOOD AND BLOOD
PRODUCTS,GCF,SERUM
EXUDATE,INTRA ORAL
BLEEDING
FOOD
DEBRIS,MOUTH
RINSE,TOOTH PASTE
COMPONENTS
OTHER FLUIDS –
BRONCHIAL AND
NASAL
SECRETION
LINING CELLS
EPITHELIAL
KERATINS
SALIVARY GLAND
DERIVATIVES
(WATER,PROTEIN
AND
CELLS),ELECTROLY
TES,SMALL
ORGANIC
MOLECULES
MICROBIOTA
BACTERIA,FUNGI
AND VIRUSES
104
110. Dental caries
Oral mucosa become prone to traumatic
ulceration and infection
Burning sensation of mucosa
Atrophic changes in mucosa and tongue
Altered taste sensation
Difficult speech
Radiation caries.
110
CONSEQUENCES OF REDUCED SALIVARY
SECRETIONS
111. Severely restricted salivary flow in which, the oral
tissues are dry & inflamed accompanied with
soreness of oral mucosa.
True xerostomia – salivary flow is reduced
False xerostomia – sensation of dryness despite
normal salivary output.
111
XEROSTOMIA
112. CAUSES
Mouth breathing
Psychological
Head and neck radiotherapy
Absence or surgical removal of salivary gland
Inflammatory disease of salivary gland
Sjogrens syndrome, parotitis.
Local inflammation- Sialadenitis, Sialolithiasis, Sialadenosis
112
114. Drooling is an indication of an upset in the coordinated
control mechanism of orofacial musculature leading to
excessive pooling of saliva in the anterior floor of mouth &
resulting in unintentional loss of saliva
This condition is normal in infants but usually stops by
15to18 months of age.
114
HYPERSALIVATION/PTYALISM/ SIALORRHEA
115. Pathophysiology of drooling is multifactorial.
It is generally caused by conditions resulting in excess production of
saliva-due to local or systemic causes
Local causes-Oral inflammation-teething, Infection tonsillitis,
peritonsilar abscess
Systemic-
Mercury ,snake poisoning
Medication-tranquilizers, anticonvulsants, anticholinesterases ,
lithium
Neuromuscular-cerebra lpalsy, Parkinson’s disease ,motor neuron
disease, bulbar/pseudobulbar palsy, Stroke
Infection-rabies
Gastric-gastro esophageal reflux 115
116. Physical
Peri oral chapping(skin
cracking)
Foul odour
Speech disturbance
Interference with feeding
116
SYMPTOMS
118. The knowledge of normal salivary composition, flow and function
is extremely important on a daily basis when treating the patients.
Recognition should be given to saliva for the many contribution it
makes to the preservation and maintenance of oral and systemic
health.
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
Saliva as it reflects physiologic and pathologic state of human , is
now gaining popularity as biomarker for various for systemic
health , which gives a new era for diagnosis.
118
CONCLUSION
119. BD Chaurasias Human Anatomy for Dental Students.
Essentials of medical Physiology,K.Sembulingam-5th
edition
Orbans. Oral Histology & Embryology, 12th Edition
Shafers.Textbook Of Oral Pathology, 5th Edition,
Elsevier Pvt Ltd, 2006
Textbook of Pediatric Dentistry , SG Damle , 5th edition.
119
REFERENCES
Hinweis der Redaktion
Circadian rhythm:- Unstimulated flow (peaks at approximately 5pm) in most individuals, with a minimum flow during the night.
Light & Arousal: - If one is blindfolded, or kept in an unlit room, the unstimulated flow rate falls. This is because; probably visual input is required in maintaining a state of arousal
Hydration: - A loss of 8 % body water results in cessation of saliva flow. The resultant drying of oral cavity is a feature of thirst.
Exercise & Stress:- Dry mouth is a feature of ‘Fright & Flight’ response
Ring a bell & supply a piece of
meat to a dog, after few such
sessions the dog associates the
ringing of bell with supply of
meat. Now ring a bell & don’t
supply meat to the dog, the mere
ringing of bell will induce
salivation in the dog, this is because the dog is conditioned to associate the ringing of bell with supply of meat
Mastication (3 fold increase in salivation)
receptors - muscles of mastication, TMJ, PDL
Gustatory stimuli (10 fold increase in salivation)
sour stimulus is most effective, followed by sweet, salt, bitter
Stress – decreases salivation
Vomiting – increases salivation because vomiting centers are located close to salivary centers, & so when vomiting centers are stimulated the impulses spread to the neighboring salivary nucleus & it gets stimulated
Preethi BP, Reshma D, Anand P. Evaluation of flow rate, pH, buffering capacity, calcium, total protein and total antioxidant capacity levels of saliva in caries free and caries active children: An in vivo study. Indian J Clin Biochem. 2010;25:425–8
Hemadi et al , Salivary proteins and microbiota as biomarkers for early childhood caries risk assessment, International Journal of Oral Science , 10 November 2017
Sejdini et al; The Role and Impact of Salivary Zn Levels on Dental Caries
International Journal of Dentistry Volume 2018 (2018)
Patil PB, Patil BR. Saliva: A diagnostic biomarker of periodontal diseases. J Indian Soc Periodontol 2011;15:310-7
Zhang et al, Salivary matrix metalloproteinase (MMP)-8 as a biomarker for periodontitis, J.Medicine (Baltimore) 2018 Jan; 97(3): e964
Rehman et al ,Role of Salivary Biomarkers in Detection of Cardiovascular Diseases (CVD)
J . Proteomes. 2017 Sep; 5(3): 21.
Yu JS, et al. Saliva protein biomarkers to detect oral squamous cell carcinoma in a high-risk population in Taiwan. Proc Natl Acad Sci USA. 2016;113(41):11549–11554
