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www.petesmif.org.uk
Pete Smith
Senior Lecturer in
Oral Biology / Physiology
1st BDS Teaching Lead
School of Dentistry
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Ingestion of a meal
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•
•
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Mastication
Salivary glands and salivation
Deglutition
Salivary gland pathology
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Muscles of Mastication
Temporalis: arises from
the temporal fossa and
inserts onto the coronoid
process of the mandible
temporal
maxilla
mandible
temporalis
hyoid
Masseter: arises from the
zygomatic process of the
maxilla and inserts into the
angle and ramus of the
mandible
Muscles for closing the mouth
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Muscles of Mastication
Lateral pterygoid: arises
from the sphenoid and
inserts onto the condyloid
process of the mandible
temporal
maxilla
mandible
hyoid
temporalis
lateral
pterygoid
Muscles for opening the mouth
All of the muscles of
mastication are innervated by
the mandibular branch of the
trigeminal nerve
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Digastric: posterior: arises
from the mastoid notch;
anterior arises from lower
border of the mandible.
Insert onto the hyoid
Infrahyoid: (4 pairs if
muscles) arise from hyoid
insert onto clavicle (ish).
Control of Mastication
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•
•
•
Voluntary
Reflexes: Jaw opening reflex; Jaw-jerk reflex
Brain stem pattern generator
Fine tuning via sensory feedback through
periodontal ligaments and proprioceptors
• A change in occlusion (e.g. following dentistry) will
alter the chewing pattern.
• There are 3 main movements of mastication
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Movements of Mastication
The temperomandibular joint (TMJ) allows three
movements of mastication:
open/close; protrusion/retraction; lateral
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Salivation
mastication
taste
smell
anticipation
Superior (pons)
+
-
vomiting
fear
Salivary
Nuclei
Inferior (medulla)
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VII
submandibular
sublingual
IX
Salivary
glands
parotid
Functions of Saliva
• Tooth maintenance
rampant caries
• Lubrication: allows speech, mastication and deglutition
• Antibacterial/antifungal
candida infection
• Digestive: salivary amylase; lingual lipase
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Functions of Saliva
• Tooth maintenance: dilution, clearance and buffering
Stephan Curve
7
rampant caries
Plaque pH
6.5
6
Critical pH
teeth
demineralise
5.5
5
0
20
Time (seconds)
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40
Functions of Saliva
• Lubrication: salivary glycoproteins are sticky
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Functions of Saliva
• Antibacterial/antifungal: protective barrier; IgA; lysozyme etc.
Much more detail available in:
Many copies available in the library
Saliva and Oral Health
3rd Edition
Saliva and Oral Health
4th Edition
ISBN: 9780956566836
Paperback: £25.00
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Salivary Secretion
mucous
minor glands
serous
Parotid
mucous
sublingual
mixed
submandibular
All salivary glands secrete
both protein and fluid.
The constituency of saliva
is determined by the
nature of the secreted
protein
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Serous acinus
Mucous acinus
myoepithelia cell
Serous demilune
Intercalated duct
Striated duct
Excretory duct
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basolateral or blood side
endoplasmic reticulum
nucleus
secretory vesicles
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apical or lumenal side
parasympathetic nervous system
sympathetic nervous system
acetylcholine
noradrenalin
cyclic
adenosine
StimulusSecretion
Coupling
monophosphate
cAMP
Ca2+
protein fluid
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CHOH.CH2.NH2
b adrenergic receptor
OH
OH
noradrenaline
G-protein
NH2
adenylate cyclase
cyclic AMP C
PO4
OH
Protein
Secretion
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cAMP stimulates
gene transcription,
glycosylation and
formation of
secretory vesicles
and exocytosis
IgA
R
Transcellular translocation of serum IgA
Polymeric immunoglobulin receptor
PIgR
R
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M3 muscarinic receptor
CH3
CH3 N.CH2.CH2.O.CO.CH3
CH3
acetylcholine
G-protein
inositol 1,4,5 trisphosphate
IP3
Fluid
Secretion
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phospholipase C
NaCl
Ca2+ release
receptor
activation
IP3
increased
[Ca2+]i
Na+ ClSCHOOL
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ion channel
activation
CH3
CH3 N.CH2.CH2.O.CO.CH3
CH3
osmotic gradient
K+
fluid & electrolyte
secretion
Deglutition
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•
•
Oral/buccal: voluntary: the bolus is
pushed to the back of the mouth
by the tongue. The teeth are
brought together. The soft palate
elevates to close the nasal cavity.
The larynx rises to close the
airways (inspiration is inhibited)
Pharyngeal: involuntary (reflex):
cricopharyngeal sphincter relaxes
to open the oesophagus. The
epiglottis steers the bolus over the
trachea and the peristalsis starts
Oesophageal: peristalsis; all of the
above reverse….
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Salivary gland pathology
•
•
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What causes xerostomia?
Drugs
Disease
•
Sjogren’s syndrome : an autoimmune
condition that causes
salivary gland dysfunction
and atrophy
Much more detail available via:
www.petesmif.org.uk
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rampant caries