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1
SURGICAL ANATOMY OF PERIODONTAL STRUCTURES
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CONTENTS1) Introduction2) Anatomy of mandible3) Attachments and relations of mandible4) Age changes in mandible5) Anatomy of maxilla6) Age changes in maxilla7) Anatomic spaces8) Applied aspects of maxilla and mandible
3
•INTRODUCTION
SURGICAL ANATOMY may be defined as
the presentation of anatomical facts
which have a local significance in relation
to injury, to particular diseases, or to the
surgical intervention which these may
entail. (Cunningham's Textbook)
4
ANATOMY OF MANDIBLELargest and strongest bone of faceHorseshoe shaped bodyContains a pair of rami
Parts of mandible• Body• Ramus of mandible• Angle of mandible
5
6
Right half of mandible seen from the lateral side
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Right half of the mandible seen from the medial side
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NERVE SUPPLY OF MANDIBLE
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MUSCLES OF MANDIBLE – POSTERIOR GROUP
1) Masseter
Origin: Inferior 2/3 zygomatic
bone & medial surface of
zygomatic arch
Insertion :Lateral ramus and
angle of mandible
Innervation: Masseteric branch
of anterior division of mandibular
nerve (V)
Action: Elevate and protrude
mandible
11
2) TEMPORALIS MUSCLE
Origin: Limits of temporal fossa
Insertion: Medial surface coronoid
process, anterior surface of ramus down
to occlusal plane
Innervation:Two deep temporal
branches of mandibular nerve (V),
sometimes reinforced by middle temporal
nerve
Action: Elevates mandible, posterior
fibres are the only muscle fibres to retract
the mandible
12
3) MEDIAL PTERYGOID
Origin: Pterygoid fossa, mainly
medial surface of lateral pterygoid
process
Insertion :Medial surface of
ramus and angle of mandible
Innervation :Branch from main
trunk of mandibular nerve
Action: Pulls angle of mandible
superiorly, anteriorly and medially
13
4) LATERAL PTERYGOID
MUSCLE
Origin: Upper head from
infratemporal surface of skull,
lower head from lateral
pterygoid plate
Insertion Upper head inserts
into TMJ capsule, lower head
into anterior surface of condylar
neck
Innervation Branch of anterior
division of mandibular nerve
Action Lateral movement,
protrusion, important in active
opening of the mouth
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MUSCLES OF MASTICATION
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Muscles of the mandible – Anterior group
Origin Insertion Innervation Action
Genioglossus
Upper genial tubercles
Dorsum of tongue Hypoglossal nerve (XII)
Depresses tongue, protrudes tongue
Geniohyoid Lower genial tubercles
Body of hyoid bone C1 through hypoglossal nerve (XII)
Pulls hyoid bone anterosuperiorly, shortens floor of mouth and widens pharynx
Mylohyoid Mylohyoid line of mandible
Raphe and body of hyoid bone
Mylohyoid nerve, a branch of inferior alveolar nerve (V3)
Elevates hyoid bone, floor of mouth and tongue during swallowing and speaking
Digastric Anterior: Digastric fossa of mandiblePosterior: Mastoid notch of temporal bone
Intermediate tendon to body and superior (greater) horn of hyoid bone
Anterior: Mylohyoid nerve (V3)Posterior: Facial nerve (VII)
Depresses mandible, raises hyoid bone and steadies it during swallowing and speaking
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ACTIONS OF MUSCLES
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OTHER MUSCLES1) Mentalis2) Platysma3) Depressor anguli oris4) Depressor labii
inferioris5) Buccinator
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AGE CHANGES IN MANDIBLEANATOMICAL LANDMARKS
AT BIRTH ADULT OLD AGE
Formation of mandible
Two halves of mandible fuse during first year of life
Alveolar ridge Alveolar and sub dental region of body are equal
Alveolar bone gets resorbed
Mental foramen
Opens below the two deciduous molars near the lower border
Opens mid way between upper and lower border
Close to alveolar border
Ramus Vertical in direction
Oblique in direction
Angle 140 degree More than 110 degree
More than 140 degree
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ANATOMY OF MAXILLA2nd largest bone of face2 maxillae forms whole of upper jawEach maxilla contributes in formation of –
1. Face2. Nose3. Mouth 4. Orbit5. Infra temporal fossa6. Pterygopalatine fossa
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Each maxilla has –1. A body2. 4 processes – frontal zygomatic alveolar palatine
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1) BODY OF MAXILLA:•Shape – pyramidal• It has –
1. Base – directed medially at nasal surface2. Apex - directed laterally at zygomatic process3. Four surfaces
a) anterior / facialb) posterior / infratemporalc) medial / nasald) superior / orbital
Encloses a cavity – maxillary sinus
23A) ANTERIOR / FACIAL SURFACE
• Directs laterally• Incisive fossa – origin of depressor septi• Incisivus – arises from alveolar margin• Nasalis – superiolateral to the fossa, along nasal
notch
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•Canine fossa – levator anguli oris• Infraorbital foramen• levator labii superioris•Medially – the nasal notch - anterior nasal spine
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B) POSTERIOR / INFRATEMPORAL SURFACE• Concave• Directed – backward & laterally• Forms – anterior wall of infratemporal fossa• Separated from anterior surface by zygomatic process• Posteroinferiorly – maxillary tuberosity &gives origin laterally to
superficial head of medial pterygoid muscle• Above maxillary tuberosity -anterior wall of pterygopalatine fossa
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D) SUPERIOR / ORBITAL SURFACEi. Smooth, triangular & slightly concaveii. Forms – Greater Part Of Floor Of Orbitiii. Anterior border forms – part of inferior orbital margin
continues with lacrymal crest of frontal process
27m
iv) Posterior border –
smooth & rounded
inferior orbital fissure
In middle – infraorbital groove
v) Medial border –
• Anteriorly lacrymal notch, converted into nasolacrymal canal
• Behind the notch, articulation with lacrymal crest
vi) The superior surface presents –
• Infraorbital groove & canal
• Inferior oblique muscles
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PROCESSES OF MAXILLA
1.FRONTAL
2.ZYGOMATIC
3.ALVEOLAR
4.PALATINE
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FRONTAL PROCESS• Projects upward & backwards to articulate above – nasal margin of frontal bone infront – nasal bone behind – lacrymal bone• Lateral surface – divided by anterior lacrymal crest into
anterior smooth & posterior grooved• anterior lacrymal crest gives attachment to lacrymal fascia & medial palpebral ligament
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•Medial surface – forms lateral wall of nose from above downwards –
1. Uppermost roughened area for articulation with ethmoid
2. Ethmoidal crest – a horizontal ridge, articulates with middle nasal concha
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•ZYGOMATIC PROCESS•Pyramidal lateral projection•Anterior, posterior & superior surfaces converge here•Superiorly – rough, to articulate with zygomatic bone
32ALVEOLAR PROCESS•Forms half of alveolar arch•Bears socket for maxillary teeth• In adults = 8 sockets•Maxillay torus (occasionally)
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4)PALATINE PROCESSMedial border –• Thicker anteriorly• Groove between nasal crest of two maxilla receives lower border vomer
Anterior part of ridge – incisal crest & anterior nasal spine, Incisive canal
Posterior border articulates with horizontal plate of palatine bone
Lateral border is continuous with alvolar process• .
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•Superior surface –
concave from
side to side & forms floor of nasal cavity
•Various foramina & pits
•Posterolaterally –
greater palatine foremen
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AGE CHANGES IN MAXILLA
1) AT BIRTH –
• Transverse & anterioposterior diameter > vertical
diameter
• Well marked frontal process
• Tooth sockets – close to orbit
• Maxillary sinus is a mere furrow on the lateral wall
of nose
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2) IN ADULTS –
• Vertical Diameter Is more due to –developed alveolar
process and increased size of maxillary sinus
3) IN OLD –
• Infantile condition
• Resorption of alveolar bone
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ARTERIAL SUPPLY TO THE ORAL CAVITY
38
NERVE SUPPLY TO ORAL CAVITY
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CONTENTS1) Introduction2) Anatomy of mandible3) Attachments and relations of mandible4) Age changes in mandible5) Anatomy of maxilla6) Age changes in maxilla7) Anatomic spaces8) Applied aspects of maxilla and mandible
41
ANATOMICAL SPACES
• Anatomical spaces or compartments are
generally "potential spaces" that become
opened or expanded by invading infection
that intervenes between the structures
surrounding the space. Such spaces are of
particular significance in the head and
neck as they may serve as pathways for the
spread of infection from one region to
another.
42
TYPES OF SPACESPrimary maxillary- canine, buccal.
• Primary mandibular- submental, sublingual, buccal,
submandibular.
• Secondary spaces- masseteric, pterygomandibular,
superficial & deep temporal, lateral pharyngeal,
retropharyngeal, parotid, prevertebral
43
1) CANINE SPACEIt is the region between anterior surface of maxilla and
overlying levator muscles of upper lip.Contains angular artery & vein, infraorbital nerve. Etiology-Maxillary canine & 1st premolar infection &
sometimes mesiobuccal root of first molars.
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Boundaries-
•Superiorly: levator superioris
alaque nasi and levator labii
superioris
•Inferiorly: caninus muscle
•Medially: anterolateral surface of
maxilla
•Posteriorly: buccinator mucsle.
•Anteriorly: orbicularis oris
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Clinical Features-
• Swelling of cheek, lower eyelid & upper lip.
• Drooping of angle of mouth.
• Nasolabial fold obliterated.
• Odema of lower eyelid
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2) BUCCAL SPACEBoundaries-
• Superiorly: zygomatic arch.
• Inferior: inferior border of mandible.
• Laterally: skin & subcutaneous tissue.
• Medially: buccinator muscle ,buccopharyngeal fascia.
• Posteriorly: anterior edge of masseter muscle.
• Anteriorly: posterior border of zygomaticus major &
depressor anguli oris.
47
Contents-
Buccal fat pad.
Stenson’s duct.
Facial artery
Etiology-
Infected mandibular & maxillary premolars & molars.
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Clinical Features-• Obliteration of nasolabial fold.• Angle of mouth shifted to opposite side.• Swelling in cheek extending to corner of mouth to
zygomatic arch.
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4) SUBMENTAL SPACEBoundaries-• Roof: mylohyoid muscle.• Inferior: deep cervical fascia, platysma, superficial
fascia & skin.• Laterally: anterior belly of digastric.• Posteriorly: submandibular space.Contents-Lymph nodes, anterior jugular vein.
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Etiology-• Infected mandibular incisors.• Anterior extension of submandibular space.Clinical Features-• Chin appears glossy & swollen.• Pain & discomfort on swallowing.
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5) SUB LINGUAL SPACEBoundaries-• Superiorly: mucosa of floor of mouth.• Inferior: mylohyoid muscle. • Posteriorly: body of hyoid bone.• Anteriorly & laterally: inner aspect of mandibular
body.• Medially: geniohyoid,styloglossus,genioglossus
muscle..
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Contents-• Deep part of Submandibular gland.• Wharton’s duct.• Sublingual gland.• Lingual & hypoglossal nerves.• Terminal branches of lingual artery
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Etiology-Infected mandibular premolar & 1st molar.Clinical Features-• Swelling of floor of mouth.• Elevated tongue.• Pain & discomfort on swallowing
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6) SUB MANDIBULAR SPACEBoundaries-• Superiorly: mylohyoid muscle• Inferior: anterior & posterior belly of digastric.• Laterally: deep cervical fascia, platysma, superficial
fascia & skin.• Medially: hyoglossus,styloglossus,• mylohyoid muscle.• Posteriorly: to hyoid bone.• Anteriorly:: submental space.
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Contents-• Submandibular salivary gland.• Proximal portion of Wharton’s duct.• Lingual & hypoglossal nerves.• Branches of facial artery-
palatine,tonsillar,glandular,submental
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•Etiology-• Infected mandibular 2nd & 3rd molars.• From submental,sublingual spaces.
Clinical Features-• Indurated swelling in submandibular region.• Usually bulges over lower border of mandible.
Spread of Infection-• Across midline to contralateral space.• To contiguous pharyngeal spaces.
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7) PTERYGOMANDIBULAR SPACEBoundaries-• Superiorly: lower head of lateral pterygoid muscle.• Laterally: medial surface of ramus.• Medially: medial pterygoid muscle.• Posteriorly: deep part of parotid.• Anteriorly: pterygomandibular raphe.
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Contents-
• Inferior alveolar neurovascular bundle.
• Lingual & auriculotemporal nerves.
• Mylohyoid nerve & vessels
Etiology-
• Infected mandibular 3rd
molars(mesioangular/horizontal)
• Pericoronitis.
• Infected needles or contaminated LA solution
.
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.Clinical Features-• Absence of extra-oral swelling.• Severe trismus.• Difficulty in swallowing.• Anterior bulging of half of soft palate & tonsillar
pillars with deviation of uvula to unaffected side.Spread of Infection-• Superiorly to infratemporal space.• Medially to lateral pharyngeal space.• To submandibular space
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8) MASSETERIC SPACEBoundaries-• Superiorly: zygomatic arch.• Inferiorly: inferior border of mandible.• Laterally: masseter muscle.• Medially: ramus of mandible.• Posteriorly: parotid gland & its fascia.• Anteriorly: buccal space & buccopharyngeal fascia.
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Contents-
Masseteric artery & vein.
Etiology-
Mandibular 3rd molars(pericoronitis).
Clinical Features-
1) Swelling limited to masseter muscle.
2) Severe trismus & throbbing pain.
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SURGICAL ANATOMYMANDIBLE1) Anterior facial region2) Anterior lingual region3) Posterior facial region4) Posterior lingual region
MAXILLA5) Anterior facial region6) Posterior facial region7) PalateRETROMOLAR REGIONS AND MAXILLARY
TUBEROSITY
63
MANDIBLE 1) Anterior F a c i a l Region:The main concerns are•the location of the muscle attachments
and •the thinness or absence of radicular bone
64
MENTALIS MUSCLES
65
•The plate of bone overlying the facial and
lingual root surfaces of the anterior teeth
is usually quite thin.
•A prominent mental tuberosity may also
limit the depth of the vestibule by forming
a flat projection in the midline of the
mandible
66
2) An terior Lingual Region:
•presence of an unusually large or high
genial tubercle upon which several
muscles attach.
•The tubercles could approximate deep
osseous defects in the area and prevent
lingual osseous recontouring during
periodontal surgery.
67
3)Posterior Facial Region.
• the presence of a
prominent external
oblique ridge.
• If the periodontal osseous
defects extend below the
level of the ridge, osseous
recontouring in an
attempt to eliminate
these defects would
require extensive and
unwanted removal of
large amounts of bone.
68
• Anterior border of the ramus
of the mandible often sharply
approximate the last
mandibular molar
• In such situations loose
aerolar mucosa is often found
attached by a narrow ring of
gingiva to the distal surface of
the last molar.
• Surgical correction of distal
defects in these areas which
attempt to widen the band of
attached tissue are hampered
by the vertical bony
prominence of the ramus.
69
• The thin attachment of the
buccinator muscle to the
mandible along the molar
teeth may also limit any
necessary extension of the
vestibule.
• The buccinator muscle forms
a portion of the medial wall of
the buccal space. If the
buccinator muscle were
perforated while elevating a
buccal flap, the buccal space
would be entered, producing
the possibility of an infection
in the space.
70
Inferior alveolar artery
normally continues its
course deep within the
cheek and is not disturbed
while elevating mucosal
flaps from the mandible.
• Danger exists when
surgeon's knife could
accidentally penetrate to
the depth of the inferior
border of the mandible
and possibly sever the
artery.
71
MENTALFORAMEN
Traumatizing or severing the
mental nerve could result in
temporary to permanent
paresthesia of the lip and
gingiva.
• Severing the mental artery is
less significant as adequate
collateral circulation exists
for the area supplied by the
vessel; the immediate
problem of hemorrhage
control should be achieved.
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4) POSTERIOR LINGUAL REGION
• Avoid incising the
superficial structures
which lie just under the
thin mucosa which forms
the floor of the mouth.
• The lingual nerve is most
easily damaged as it lies
very close to the mucosal
surface in the region of
the second and third
molars
73
• Whenever the attached
gingiva is elevated from the
lingual aspect of a
mandible, or when the
mucosal lining of the floor
of the mouth is perforated,
the sublingual space may be
entered.
• Infection within the space
may spread to the opposite
side and into the body of
the tongue resulting in an
elevation of the tongue and
respiratory difficulty.
74
MAXILLA1) ANTERIOR FACIAL REGION
• Severe bone loss in this
region could result in the
base of the periodontal
pocket approximating both
zygomatic process of the
maxilla and the attachment of
the buccinator muscle.
• Each could complicate and
surgical attempt to deepen
the vestibule or increase the
zone of attached gingiva.
75
• Perforation of the buccinator muscle would
establish entry into the buccal space and
possible postoperative infection.
• As in the anterior facial region of the maxilla, a
surgical technique may be employed which
prevents exposure of the bone and possible
postoperative recession.
• The maxillary sinus closely approximates the
roots of the maxillary first and second molars
and may extend as far forward and posteriorly
as the canine and third molar respectively
76
• Deep infrabony pockets
approach the floor of the
sinus and when the
thickness of supporting
bone becomes very thin or
nonexistent
• In these situations,
ostectomy to gain more
desirabl postoperative
contours must be limited
in order to prevent sinus
perforation.
77
•The sinus may also be a factor to consider
when performing osseous ramping of
edentulous ridges.
•Osseous ridge thinning performed to gain
more favorable contours in preparation
for prosthetic replacement may often be
contraindicated by the expansion of the
sinus in an edentulous area.
78
Greater palatine foramen and its contents:
• Severance of the greater
palatine artery must be
avoided as it is very difficult
to stop the hemorrhage by
local clamping or by
tamponade. In certain
instances stoppage has only
been accomplished by ligation
of external carotid artery.
• Vertical incisions in the
posterior portion of the palate
are hazardous since the
possibility of severing a large
vessel or nerve is likely.
79
NASOPALATINE NERVES
The nasopalatine nerve
emanates from the incisive
foramen to supply the sensory
innervation for the palatal
mucosa from canine to canine.
• Surgery to eliminate
periodontal pockets in this
region of requires removing or
undermining the incisive
papilla, which could result in
servering the nasopalatine
nerve and a temporary
paresthesia of the area
supplied.
80
OSSEOUS CONSIDERATIONS
IN THE PALATE
• Prominent exostoses or a flat,
shallow palatal roof make
osseous interproximal ramping
either impossible or difficult to
accomplish.
• In Gingivectomy procedures on
the palate, if the alveolar
process is very short due to a
shallow palatal vault, it would
be very difficult to achieve a
properly beveled result without
making an extremely wide
incision with its probable
postoperative discomfort.
81
RETROMOLAR REGIONS
• If a mucosal incision were
carried through and distal
to the retromolar pad and
medial to the anterior
border of the ramus, the
buccinator of superior
pharyngeal constrictor
muscles could be
perforated or the
pterygomandibular raphe
divided.
82
• Such an overextended incision
would create entry to the
pterygomandibular space
housing the lingual and
inferior alveolar nerves and
the inferior alveolar vessels.
the free communication of the
pterygomandibular space with
the retromandibular space
(containing the parotid gland)
and the parapharyngeal space.
• An infection of the
pterymandibular space could
potentially spread into deeper
structures
83
• The mucosa behind the
maxillary tuberosity also
covers a mass of areolar-
glandular tissue.
• An incision carried through
and behind this mass would
perforate the superior
pharyngeal constrictor muscle
and establish entry into the
parapharyngeal space (if
perforation is medial to the
internal pterygoid muscle) or
into the pterygomandibular
space (if perforation is lateral
to the muscle)
84
SUMMARY
Eloquent advice to the periodontal surgeon
(a) constantly revise your knowledge of
anatomy;
(b) constantly think of the local anatomy in
relation to injury and disease;
(c) never take a knife in your hand without
picturing in your mind's eye the structures in
and adjacent to your operative field,
however small that field may be."
85
REFERENCES
• B.D. Chaurasia- human anatomy• Anatomical considerations in periodontal surgery
by michael a . clarke, d.d.s., m.s. j.p 1977Oral anatomy- sicher
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