Salivary glands and saliva / oral surgery courses

SALIVARY GLANDS
AND SALIVA
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

CONTENTS:
 INTRODUCTION
 DEVELOPMENT OF SALIVARY GLANDS
 CLASSIFICATION OF SALIVARY GLANDS
 ANATOMY OF SALIVARY GLANDS
 MICROANATOMY
 HISTOLOGY OF SALIVARY GLANDS
 CLINICAL CONSIDERATIONS
 SALIVA
 SECRETION OF SALIVA
 XEROSTOMIA
 PROSTHODONTIC CONSIDERATIONS.

INTRODUCTION:
 Important organs of the
oral cavity.
 Produce saliva.
 Helps in
mastication
swallowing
digestion.

DEVELOPMENT OF SALIVARY
GLANDS
 Interaction of epithelium with underlying
mesenchyme.
Salivary gland
Functional glandular
tissue)(parenchyma)
Capsule,septa and
Blood vessels
(connective tissue
stroma)
Epithelial outgrowths
Mesenchyme
(ectomesenchyme)

ORIGIN OF THE SALIVARY
GLANDS
PAROTID BUD-CORNER OF
STOMODAEUM -6TH
WEEK
SUBMANDIBULAR BUD –FLOOR OF THE
MOUTH –END OF THE 6TH
WEEK.
SUBLINGUAL
LATERAL TO
THE SUB
MANDIBULAR
PRIMORDIUM-
8TH
WEEK
MINOR
SALIVARY
GLANDS FROM
BUCCAL
EPITHELIUM-
12TH
PRENATAL
WEEK.

STAGES OF DEVELOPMENT
 STAGE 1:bud formation :
induction of oral
epithelium by
underlying mesenchyme.

 Stage 2:formation and
growth of epithelial
cord
mesenchyme
Epithelial cells
Basal lamina

 Stage 3:initiation of
in terminal parts of
epithelial cord and
continuation of
glandular
epithelium

 Stage 4:dichotomous
branching of epithelial
Cord and lobule
formation

 Stage 5:canalization
of presumptive ducts
6th
month

 Stage 6:cytodifferentiation
 Cells of bulb region differntiate
In to terminal tubule cell
Histodifferentiation of the functional
acini and intercalated ducts
Proacinar
cells
Acinar cells
Intercalated duct
cells
serous mucous
Myoepithelial cells –epithelial stem cell and
develop with acinar cytodifferentiation.

Classification of salivary glands
 Exocrine glands
 Merocrine glands.
 Compound tubuloacinar

 Major salivary glands
parotid
submandibular
sublingual
 Minor salivary glands
buccal
labial
lingual
palatine
glossopalatine

Based on histochemical nature of
secretory products
 Mucous
Serous
mixed
Labial,
Buccal
Palatine
glossopalatine
Parotid
Vonebner glands
Submandibular(predominantl
y serous)
Sublingual (predominantly
mucous)
Posterior lingual glands

Based on duct system:
 Simple: minor salivary glands
 Compound: submandibular
parotid
sublingual

Anatomy of the salivary glands
MAJOR SALIVARY GLANDS

THE PAROTID GLAND
 Largest
sternocleidomastoid
Ramus of the mandible
masseter
External auditory
meatus
Accesory parotid between
zygomatic arch and parotid
duct.

Parotid capsule:
Investing layer of the deep
cervical fascia.
Superficial fascia
Zygomatic bone
Deep lamina
Stylomandibular ligament

External features:
 3 sided pyramid: 4 surfaces
 Three borders:
Superior
Superficial
Anteromedial
posteromedial
Anterior
Posterior
medial

Relations:
 Apex:
Posterior belly of digastric
Divisions of retromandibular vein
Cervical branch of facial nerve

The superior surface (concave)
External acoustic meatus
Posterior surface of
temperomandibular joint
Superficial
temporal
vessels
Auriculotemporal
nerve

Superficial surface: (largest)
Greater auricular nerve
Preauricular
lymphnodes
Posterior fibres of platysma
Skin
Superficial fascia
Parotid fascia
Deep parotid lymphnodes

Anteromedial surface
Grooved by posterior border of
ramus
masseter
Medial pterygoid
Emerging branches of facial nerve.

Posteromedial surface:
Mastoid process
Styloid process
sternomastoid
Posterior belly of
digastric
External carotid
artery

The anterior border:
Parotid duct
Terminal branches of
facial nerve
Transverse facial vessels

The posterior border:
Posterior border
overlapping
sternocleidomastoid
muscle

Stuctures within the parotid gland:
Arteries veins nerves

Parotid duct:(5cm)

Opening of
parotid(stenson’s)duct

Nerve supply:

Lymphatic drianage:
Parotid lymphnodes
Superficial deep cervical
lymphnodes

Applied anatomy:
 Parotid swellings
 Mumps
 A parotid abcess
 Parotidectomy

The sub mandibular salivary gland:
 J –shaped.
Indented by posterior border of
Mylohyoid muscle
Small part lying deep to the
muscles
Larger part superficial to
the muscle

Superficial part(digastric triangle)
 Three surfaces
medial
lateral
inferior
Deep cervical fascia
Deep layer of
cervical fascia
attached to
mylohyoid line
Superficial layer of deep cervical fascia covering inferior surface

Relations:
 Inferior surface and lateral surface

 Medial surface:

Deep part:

SUBMANDIBULAR DUCT(WHARTON’S
DUCT)

Blood supply
Facial artery Facial vein

Lymphatic drianage:
Submandibular lymphnodes

NERVE SUPPLY
 PARASYMPATHETIC
(SUBMANDIBULAR GANGLION)
(SECRETOMOTOR)
PREGANGLIONIC FIBRES FROM
SUPERIOR SALIVATORY NUCLEUS)
CHORDATYMPANI,LINGUAL
NERVE
SUBMANDIBULAR GANGLION
POST GANGLIONIC FIBRES TO
GLANDS
SYMPATHETIC: PLEXUS AROUND FACIAL
ARTERY.
SENSORY:LINGUAL NERVE

Sub lingual salivary gland:
 Smallest.lacks the connective tissue capsule.

MINOR SALIVARY GLANDS

labial glands:(mucous or mixed)
Buccal glands –
continues the labial
glands posteriorly
Labial glands-numerous in mid
line
Scattered in the vestibule,lie internal to facial muscles in the submucosa
Nerve supply:
Buccal and mental branch of
mandibular nerve.

Buccal glands:mucous or mixed
 Anteriorly:sparse and irregularly spaced
 Posteriorly:numerous
and larger.
Molar or retromolar glands

Lingual gland: (mixed or mucous)
Anterior parts-close to the
inferior surface.
Glands of nuhn’s,glands of
blandin
Close to apex and
midline,covered by thin
mucous membrane.

 Dorsal group:  Incisive glands:
vonebner’s
(serous)
Posterior lingual glands
(mucous)
Open in to the crypts of
lymphoid follicles
Floor of the mouth.
Near the insertion of
lingual frenum,behind
lower incisors.

Palatal glands: (purely mucous)
Hard palate
Soft palate
uvula
Submucous layer of hard and
soft palate.

Microanatomy of salivary glands:

Intercell
ular
canalicul
li

Secretory cells:
 Serous cells mucous cells
(Serous secretion) Mucous secretion
mucin
Lubricant,digestion,deglutition
,form a barrier on surface ,to
bind and aggregate
microorganisms.
Contains
water,enzymes-primary
salivary
amylase(ptyalin),salts.

Serous cells:
nucleus
Secretory
granules
Intercellular
canalliculi
RER
Golgi complex

Junctional complex : seperates the luminal
surface from the basolateral surface of cells
Regulate the passage of material from the
lumen to the intercellular spaces and vice
versa.
holds the adjacent cells
together.
Secretory granules attached to basal lamina and connective
tissue-hemidesmosomes

Mucous cells:
Tubular shaped
Intercellular canaliculli absent

Myoepithelial cells:contractile cells.
Stellate process
Provide support for endpiece
During active secretion of
saliva.
Help expulsion of saliva from
the end piece in to duct
system.
Contraction of myoepithelial
cells of intercalated ducts
may shorten and widen the
ducts helping to maintain
their patency.

Duct system:
 Intercalated
 Striated
 excretory

Intercalated ducts:
Length of the intercalated duct is
variable in different major and
minor salivary glands.
Simple cuboidal epithelium.

Striated ducts:largest percent
Columnar cells

Excretory ducts:
Pseudostratified epithelium.

Connective tissue:

Histology of salivary glands:
Parotid gland:
Blood vessels
Intercalated duct
Interlobular
septum
intercalated
Serous acini

Sub mandibular salivary gland:
Serous
demilune
Adipose
cells
Intercalated cells
Mucous
cells
Serous cells
Interlobular excretory ductInterlobular
septum

Sub lingual salivary gland:
Serous demilune
Serous acini
Mucous acini
Blood vessels
Interlobular excretory duct
Intralobular excretory
duct

Minor salivary glands:
Hard palate
Labial salivary gland

Clinical considerations:
 Age changes
 Diseases:viral and bacterial infections
 Sialoliths
 Tumours
 Auto immune disease-sjogren’s syndrome
 AIDS
 Cystic fibrosis
 Diabetes
 Drymouth(xerostomia)
 Mucoceles
 Caries and periodontal diseases
 irradiation

saliva
 Stedman’s medical dictionary 26th edition
states that,
Saliva is a clean, tasteless, odorless slightly
acidic viscous fluid, consisting of secretions
from the parotid, sublingual, submandibular
salivary glands and the mucous glands of
oral cavity.

Functions of saliva:
 Preparation of food for swallowing
 Appreciation of taste
 Maintainance of tooth integrity
 Digestive function
 Role in speech
 Excretory
 Regulation of waterbalance.
 Protective function Lysozyme
IgA
Peroxidases
Leucocytes,buffering action

Mechanism of salivary secretion:
 Salivary gland innervation
 Reflex mechanism of salivary secretion
 Salivary control
 Formation of saliva
 Disturbances in salivary secretion

Salivary gland innervation

Reflex mechanism of salivary action:
 Unconditioned or inborn:

Conditioned reflex:

Salivary control:
 Afferent pathway:
 Central control:
 Efferent path way:parasympathetic
Local factors-acid stimuli
olfactory irritants
irritation
unilateral proprioceptive stimulatio
Emotional(psychic)stimuli
Stimulation from other organs
Nucleus salivatorius superior
Nucleus salivatorius inferior

 Parasympathetic –neurotransmitter-
acetylcholine.
 Sympathetic-norepinephrine.
 Neuronal control-complex

Formation oF saliva
Parasympathetic Sympathetic
Fluid secretion Macromolecule secretion &
electrolyte transport
in ducts.
Capillaries formation of interstitial fluid
Acinar cells taken up & modified , polypeptides &
proteins are synthesized & released by
exocytosis

 2 stages:1.primary salliva
2.modified in
ducts.

Lumen of acini ISOTONIC SECRETION
Intercalated duct
Striated duct Active reuptake of Na+
ions
Passive movement of Cl-
ions
Reabsorption of bicarbonate ions
HYPOTONIC SECRETION

EXCRETORY DUCT Further reabsorption of sodium ions &
secretion of potassium ions
HYPOTONIC SECRETION
Final electrolyte composition of saliva varies,depending on flow
rate.

Composition of saliva:
Water 99.5% Solids.5%
Organic
Proteins
Enzymes
Kallikrein
Blood group
components
Non protein
nitrogenous
substances
Inorganic
Calcium
Sodium
Potassium
Flouride
Bicarbonate
phosphates

Salivary secretion
Saliva is clear, slightly acidic mucoserous exocrine secretion. It is
very dilute fluid composed of more than 99% water.
Properties
 Hypotonic to plasma
 pH : 6.2 – 7.6
average – 6.7
 Average daily flow : 1 – 1.5 Lt.
A large proportion is secreted at mealtime when the
secretory rate is highest.
 Consistency: slightly cloudy because of the presence of cells
and mucin.

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 secretions

Whole saliva can be of 2 types:
Unstimulated / basal / resting
saliva
Stimulated saliva

Disturbances in salivary secretion:
 Hyposalivation
 Temporary
emotional conditions
fever
dehydration
 Permanent
sialolithiasis
xerostomia
bell’s palsy
 Hypersalivation
/sialorrhea
 Pregnancy
 Continuous irritation of
nerve endings in mouth
 Nausea and vomiting

Xerostomia
Definition:
Xerostomia, more commonly called “dry mouth”, is a common
subjective complaint of medical & dental patients that usually, but
not always, is associated with salivary gland hypofunction
(objective evidence of reduced salivary output)

CAUSES OF XEROSTOMIA
 Drugs / medication
 Irradiation
 Psychogenic disease
 Decreased mastication
 Aging
 Organic diseases
 Autoimmune – SLE, RA
 AIDS
 Diabetes mellitus, hypertension
 Neurologic
 Bell’s palsy
 Cerebral palsy
 Trauma

Clinical signs associated with xerostomia
 Loss of moist glistening oral mucosa
 Dry, thin pale oral mucosa
 Fissured, lobulated tongue dorsum
 Angular cheilitis
 Gingivitis
 Inflammation
 Candidiasis
 Increased dental caries, esp cervical
 Thicker, stringier whole saliva
 Difficulty milking saliva from major gland duct.
 Mirror test

EVALUATION OF XEROSTOMIA & SALIVARY GLAND
HYPOFUNCTION
It is four step approach:
 Chief complaint
 Medical history & review of systems
 Clinical evaluation
 Further diagnostic workup

PRESENTING COMPLAINT / SYMPTOM
 Sticky, Dry mouth
 Often thirsty
 Difficulty with swallowing (dysphagia)
 Difficulty with speaking (dysphonia)
 Difficulty with eating dry foods
 Need to sip water while eating
 Difficulty with wearing dentures
 Frequent use of means to keep the mouth moist eg. Chewing
gums, consumption of sour candies.
 Unpleasant taste, or loss of sense of taste
 A burning feeling in the mouth
 Cracked lips
 Mouth sores
 An infection in the mouth

MANAGEMENT OF XEROSTOMIA
 Patient education
 Identification and elimination of cause
 Palliative / symptomatic treatment
 Treatment of xerostomia related complications

IDENTIFICATION & ELIMINATION OF THE CAUSE
It involves:
 Treatment of systemic disease
o Autoimmune diseases
o Irreversible damage by therapeutic irradiation of head & neck
region
o Xerostomia related to emesis, diarrhoea or fever
o Drug induced xerostomia

SYMPTOMATIC TREATMENT
The degree of patient’s gland impairment decides the choice of
treatment.
For this, patient may be grouped as:
 Responders ( some amount of glandular function remains,
possible to stimulate salivary flow)
 Non – responders ( do not have sufficient salivary function,
salivary flow stimulation is not possible)

Treatment of responders
(SIALOGOGUES)
Includes:
 Local stimulation
 Systemic stimulation
Local stimulation:
masticatory stimulation
chemical stimulation
electronic devices
Systemic stimulation:
drugs like bromhexine, anethole
trithione, pilocarpine

Treatment of non-responders
Many methods have been employed to moisten the oral tissues:
 Frequent intake of water
 Avoid alcoholic/ caffeinated beverages, fluids containing
sugar & alcoholic mouth rinses.
 Use of room humidifiers, esp at night aids in relieving
dryness of throat & tongue.

• Artifical saliva/ saliva substitutes can be used like:

Prosthodontic considerations:
 Lack of saliva adversely affects the retention
of dentures ,increases the possibility of oral
infection,and because of loss of lubrication
causes,can result in generalised soreness
and burning sensation.
 With age change saliva decreases in quantity
and quality.
 Excessive salivation-difficulty for
impressions.

Role in retention of dentures:
adhesion
cohesion

Interfacial force:
Interfacial surface
tension
Viscous tension
Thin layer of fluid
Ability to wet the
surrounding
material.(low surface
tension)
Capillary attraction
Concave meniscus because
of cohesive forces

Viscous tension:force holding two parallel plates together,due
to the viscosity of the interposed fluid.
Stefan’s law:
F=(3/2)kr4
V
h3

 Excessive secretions of mucous from the
palatal glands
 An excessive flow of saliva after insertion of
dentures
 Thick saliva can create hydrostatic pressure
In the area anterior to posterior palatal seal
resulting in downward dislodging forces.

 Extended flange of the denture obstruct the
flow of secretion from the salivary gland.
 Saliva and oral galvanism
 Saliva is an inexpensive, non invasive & easy
to use diagnostic aid for oral & systemic
diseases
 Isolation of saliva in dental operatory.

 Denturesurfaceshould besmooth so asto incerasethe
salivaflow
 In patientswith xerostomia,thedenturebasesticksto the
mucosa,thisdoesnot help in retention and isirritating to the
patients.
 Excessivesalivation isproblematic during impression
making –atropinesulphatecan beorally administered

Review of literature:
 Mira edgerton etal;(1987) saliva :a significant
factor in removable prosthodontic treatment.
reviewed the relationship of saliva to various aspects of
prosthodontic treatment and denture related disease.
 salivary constituents that show a high affinity for binding with the
denture surface may be responsible for many surface properties of the
denture base,which includes microbial adherence and plaque
formation.salivary igA and mucins play an important role.
 yeast antigens and toxins of denture plaque as significant factors in
the initiation and maintainance of denture induced stomatitis.
 The quantitity and quality of palatine secretions may be an significant
factor for evaluation in patients with poor denture retention.
 Taste changes are due to some change in the salivary characteristics.

B.W.Darvell and R.K.F.Clark(2000)the physical
mechanism of complete denture retention stated-
 Denture retention is a dynamic issue dependent on the control of
the interposed fluid and thus its viscosity and film thickness.the most
important concerns being goodbase adaptation and borderseal.
Sue P.Humphrey etal (2001) a review of saliva:normal
composition ,flow and function.

Ana M.diaz-arnold and CindyA.marek(2002)The impact of
saliva on patient care:
discussed about the various causes of salivary gland
dysfunction and it’s management.management included
patient education,consultation with physician for substitution
of offending medication and other symptomatic relief
treatment procedures.
 Krisztina Marton etal (2004)evaluation of unstimulated flow
rates of whole and palatal saliva in healthy patient’s wearing
complete dentures and in patients with sjogren’s syndrome
conducted a study on 24 healthy individuals and ii patients with
sjogren’s syndrome to determine whether palatal saliva flow
rates and unstimulated flow rates differed in the two groups
and its influence on new complete dentures .they concluded
palatal saliva flow is not significantly decreased in complete
denture patients with sjogren’s syndrome and their was no
effect on the dentures.

Conclusion:
 Saliva is a most valuable oral fluid that often
is critical in preservation and maintainance of
oral health. it is necessary for a clinician to
have a good knowledge base concerning the
norm of salivary flow and function for the
proper functioning of the prosthesis and the
protection of the tissues.

References:
 REFERENCES:
 C.C. Chattergee Human Physiology 11th edition :
 D.B. Chaurasia:Human Anatomy 10th edition :
 Heartwell:Syllabus of complete dentures,4th edition,
 Tencate : Oral Histology, 3rd Edition, Jaypee Brothers. 1989
 Zarb,bolender:Boucher’s :prosthodontic treatment for
edentulous patients,9th edition 1993,CBS
 ORAL DEVELOPMENT AND HISTOLOGY:james k.avery
 Di Fiore’s aatlas of histology 8th edition.
 Applied oral physiology:Christopher L.B.Lavelle 2nd
edition

 Mira Edgerton etal.saliva: a significant factor in removable prosthodontic
treatment . the journal of prosthetic dentistry,volume57,issue1,1987.
 B.W.Darvell and R.K.F.Clark:The physical mechanism of complete denture
retention. British dental journal,volume 189,no.5,September 2000.
 Sue P.Humphrey etal : a review of saliva:normal composition ,flow and
function .The Journal of prosthetic dentistry volume 85,issue2,febraury
2001,pg162-169
 Ana M.diaz-arnold and CindyA.marek:The impact of saliva on patient care:The
Journal of prosthetic dentistry volume 88,issue 3,September 2002,pages 337-
343
 Krisztina Marton etal :evaluation of unstimulated flow rates of whole and palatal
saliva in healthy patient’s wearing complete dentures and in patients with
sjogren’s syndrome:the journal of prosthetic dentistry,volume91,issue6,june
2004,pg 577-581..

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