Osteology of maxilla and mandible / oral surgery courses

OSTEOLOGY OF MAXILLA
AND MANDIBLE
-
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

CONTENTS:
 BASIC SCIENCE ABOUT BONE:
 OSTEOLOGY OF MAXILLA
DEVELOPMENT AND OSSIFICATION
STRUCTURE OF MAXILLA
AGE CHANGES
PROSTHODONTIC CONSIDERATION
 OSTEOLOGY OF MANDIBLE
STRUCTURE OF MANDIBLE
AGE CHANGES
PROSTHODONTIC CONSIDERATIONS

OSTEOLOGY
It is the study of bones and cartilages,
which together constitute the skeletal
system.

BONE
Bone is a living, hardest structure of the human
body which forms the skeletal framework. It is a
specialized mineralized connective tissue.
COLLAGEN is a protein that provides a soft
framework, and makes it tough and resilient.
CALCIUM PHOSPHATE is a mineral that adds
strength and hardens the framework and offers
resistance to compressive forces.www.indiandentalacademy.com

COMPOSITION:
BONE
ORGANIC
MATRIX(33%)
INORGANIC(67%)
HYDROXY APATITE
CRYSTALS.
28% TYPE 1
COLLAGEN
5% NON
COLLAGENOUS
PROTEIN(OSTEONEC
TIN,OSTEO CALCIN,
BONE MORPHOGENIC
PROTEIN.

FUNDAMENTAL STRUCTURE OF
BONE
LAMELLA
LACUNAE
OSTEOCYTES
CANALICULI
OSTEOBLASTS
OSTEOCLASTS

MACROSCOPICALLY
SPONGY BONE COMPACT BONE
It is more dense tissue usually
found on the surface of bones.
It is organized in cylindrical
shaped elements called
osteons composed of
concentric lamellae
Lamellae stacked
one over another
to form plates of
bone called
trabeculae with
numerous cavities
filled with bone
marrow.

The skeleton arises from fibrous
membranes
and hyaline cartilage during the first
month of embryonic development.
These tissues are replaced with bone by two
different bone-building, or ossification
processes during the development called
osteogenesis.
DEVELOPMENT OF BONE:

OSSIFICATION
Intramembranous ossification bone-
formation of bone from mesenchyme
Endochondral ossification -formation of
bone from cartilage

According to development
Membrane or dermal bone -bones of the
vault of skull and facial bones.
Cartilaginous bones -limbs vertebrae,
thoracic cage.
Membrano-cartilaginous bones-
mandible,clavicle,occipital,temporal,sphen
oid.

OSTEOLOGY OF MAXILLA

-Maxilla, is second largest of facial bones
It is a paired bone enters into formation of the
face
nose
mouth
orbit
Part of the infratemporal
Part of pterygopalatine fossa

DEVELOPMENT AND OSSIFICATION:
It is formed from the
mesoderm of the first
branchial arch.
It is formed by the
intramembranous
ossification of the
mesenchyme of the
maxillary process.

Ossification is from three centres.
one for maxilla proper –above the canine
fossa during 6th
week of intrauterine life.
Two for premaxilla-1.above the incisive
fossa during 7th
2.ventral margin of nasal septum during
10th

SIDE DETERMINATION

STRCUTRE OF MAXILLA
BODY
4 PROCESSES
ZYGOMATIC
FRONTAL
ALVEOLAR
PALATINE

It is roughly pyramidal
and encloses maxillary
sinus. The base of the
pyramid is formed by
the nasal surface and
the apex is directed
towards the zygomatic
process

It has 4 surfaces:
• Anterior/facial surface :
• Posterior/infra temporal:
• Superior/orbital surface :
• Medial/nasal surface :
It encloses a large cavity:THE MAXILLARY SINUS

ANTERIOR (FACIAL)SURFACE:
INCISIVE FOSSA
CANINE FOSSA
INFRAORBITAL
FORAMEN
NASAL NOTCH

Medially the anterior
surface ends at a deeply
concave nasal notch,
which ends in a pointed
bony projection called
anterior nasal spine.
NASAL NOTCH

Infra-orbital Foramen:
Lies above the canine
fossa.
It transmits the infra
orbital vessels and
nerve.

POSTERIOR (INFRATEMPORAL
SURFACE)
Maxillary
tuberosityOpenings for
alveolar
canals(posterior
superior alveolar n
Maxillary tuberosity
articulating with
palatine bone
Groove
for
maxillary
nerve(gre
ater
palatine)

SUPERIOR(ORBITAL SURFACE)
Smooth, roughly triangular and
slightly concave forming greater part
of floor of orbit.
Anterior border – forms inferior
margin of orbital opening.
Posterior border – forms greater
part of anterior margin of inferior
orbital fissure.
Medial border – separates it from
nasal (medial) surface.
It presents lacrimal notch anteriorly.

Infra orbital groove
Infraorbital canal
canalis sinosus
Infraorbital foramen
Infraorbital nerves and vessels
Anterior superior alveolar nerves and
vessels

MEDIAL(NASAL)SURFACE

PROCESSES OF MAXILLA

FRONTAL PROCESS
It projects postero-superiorly
between the nasal and lacrimal
bones.
•The frontal process apically joins
with the nasal notch of frontal bone
at fronto -maxillary suture.
•Anterior border articulates with
lateral border of nasal bone and the
posterior with lacrimal bone.

ZYGOMATIC PROCESS
It is a pyramidal projection
where anterior, infra
temporal and orbital
surfaces converge.
• It articulates with the
maxillary process of
zygomatic bone.

ALVEOLAR PROCESS
It is thick and arched
and projecting
downward and socketed
for tooth roots.
•With its fellow of
opposite side forms
alveolar arch. www.indiandentalacademy.com

PALATINE PROCESS
Greater palatine foramen
(greater palatine nerves and
vessels)
Intermaxillary suture
Incisive foramen
(terminal parts of
nasopalatine nerves and
Greater palatine vessels)
Posterior nasal spine
Alveolar process
Palatomaxillary suture
Palatine torus seen
sometimes

MAXILLARY SINUS
Pyramidal
Roof:floor of the orbit
traversed by the
infraorbital canal.
Floor:by the alveolar process of
maxilla.
Lies about half inch below the
level of the floor of the nose.www.indiandentalacademy.com

Sinus opens in to middle meatus of nose
usually by two openings.
In the lower part of the haitus semilunaris.
The second opening at posterior end of
haitus.
First paranasal sinus to develop.

ARTICULATIONS OF MAXILLA
1. Frontal
2. Lacrimal
3. Nasal
4. ethmoid
5. Opposite maxilla
6. Inferior Nasal Choncha
7. Palatine
8. Vomer
9. zygomatic
superiorly
medially
laterally

MUSCLE ATTACHMENT

AGE CHANGES

1) AT BIRTH :
-The transverse and antereo-posterior(sagital)
diameter are more than the vertical diameter.
-Frontal process is more prominent
-Body portion a little more than alveolar process,
-The tooth sockets reaching almost to the floor of
the orbit.
- Maxillary sinus is mere furrow on the lateral
wall of the nose.

2) IN THE ADULT:
Vertical diameter is greatest due to
development of the alveolar process and
increase in the size of the sinus.
3)IN THE OLD:
Height reduced due to absorption of alveolar
process.

PROSTHODONTIC CONSIDERATIONS:
THE ZYGOMATICO ALVEOLAR CREST-if not
relieved in denture causes poor denture
retention.
MAXILLARY TUBEROSITY- medial and lateral
walls resists horizontal movement of denture
base and the posterior wall resists anterior
movement,so to take an advantage of this
denture base should cover the tubercles .

MID PALATAL SUTURE:If prominent
becomes fulcrum point around which
denture rotates which causes discomfort
to patient and damage to the soft tissue.
PALATAL TORUS:
INCISAL FORAMEN:
FLAT OR A LOW PALATE: amount of
spongy bone greater than in high palate.

OSTEOLOGYOSTEOLOGY
OFOF
MANDIBLEMANDIBLE

Neural crest cells
I branchial arch
Mandibular process
Mandibular bone
CT tissue
Ectomesenchymal condensation
Lateral to Meckels cartilage
Osteogenic membrane
mandible

Second bone to ossify in the body.
Greater part ossifies in membrane
Parts ossifying in cartilage-part below
incisor teeth,coronoid,condyloid process
and upper half of ramus above the level of
mandibular foramen.
At birth -2 halves connected at symphysis
menti by fibrous tissue.

Each half of mandible ossifies from only
one centre of ossification at 6th
week of
intrauterine life, in the mesenchymal
sheath of meckel’s cartilage near the
future mental foramen.

The ventral end of meckel’s cartilage
ossifies from parent centre during 10th
week and forms the incisive part.
Secondary cartilages.
Condyloid cartilage
Coro
noid
cartil
age
Symphyseal cartilage.

The largest and
strongest bone of
the face
It has horse shoe
shaped body which
lodges teeth and a
pair of rami which
projects from the
posterior ends.

The cortical bone is thicker anteriorly and at the
lower border of the mandible, while posteriorly
the lower border is relatively thin.
The cancellous bone of the body forms, a loose
network with large bone-free spaces.
Thus mandible is strongest anteriorly in midline
with progressively less strength towards condyle.

BODY OF THE MANDIBLE
U-shaped BODY
Has two surfacesEXTERNAL and
INTERNAL surfaces
Two borders UPPER and LOWER borders.

EXTERNAL SURFACE
1. Symphysis menti
2. Mental protuberance
3. Mental foramen
4. External oblique line
5. Incisive fossa 1
4

INTERNAL SURFACE
1. Mylohyoid line
2. Submandibular fossa
3. Sublingual fossa
4. Genial tubercles
5. Mylohyoid groove
6. Upper alveolar
border
7. Lower border /base
8. Mandibular tori
maybe present www.indiandentalacademy.com

SUPERIOR
BORDER
(ALVEOLAR BORDER)
It is hollowed into
cavities for the
reception of the
teeth. these cavities
are sixteen in
number, and vary
in depth and size
according to the
teeth which they
contain. www.indiandentalacademy.com

INFERIOR BORDER
Is rounded, longer
than the superior,
and thicker
anteriorly.
Digastric fossa an
oval depression is an
near the midline.

 Is quadrilateral
 2 surfaces2 surfaces
1. Lateral
2. Medial
 4 borders4 borders
1. Upper
2. Lower
3. Anterior
4. Posterior
 2 processes2 processes
1. Coronoid 2.condylar
RAMUS OF MANDIBLE

 Lateral surfaceLateral surface – flat with oblique
ridges
 Medial surfaceMedial surface –
Features-
1. Lingula
2. Mandibular foramen
3. Mylohyoid groove
4. Upper border-forms
mandibular notch

The upper border is thin,
and is surmounted by two
processes, the coronoid in
front and the condyloid
behind, separated by a
deep concavity, the
mandibular notch.
LOWER BORDER-
continuation of the base of the
mandible. www.indiandentalacademy.com

AnteriorAnterior border-
continuous with
coronoid process
PosteriorPosterior border-
extends from condyle
to angle
AB

Coronoid process
Flat ,triangular
Upward and forward
projection from
anterosuperior part of
ramus
Anterior border
continuous with
anterior border of
ramus
Posterior border
bounds the mandibular
notch.

Condyloid process
Upward projection from
postero superior part of
ramus
Apically enlarged as head of
condyle.
Articulates with temporal
bone’s mandibular fossa to
form temperomandibular
joint
Pterygoid fovea anterior to
neck www.indiandentalacademy.com

ATTACHMENTS AND RELATIONS
EXTERNAL SURFACE:
BUCCINATOR
MENTALIS
DEPRESSOR LABI INFERIORISDEPRESSOR ANGULI ORIS
PLATYSMA
MASSETER

INTERNAL SURFACE
TEMPORALIS
SUPERIOR CONSTRICTOR
DIGASTRIC
MYLOHYOID
MEDIAL PTERYGOID
LATERAL PTERYGOID

GENIOGLOSSUS
GENIOHYOID
DIGASTRIC

1. Mental foramina - mental nerve and vessels
2. Mandibular notch - massetric nerve and vessels
3. Medial side of neck - auriculo temporal nerve
4. Mylohyoid groove - mylohyoid nerve and
vessels
5. Medial surface of ramus in front of mylohyoid
groove- lingual nerve
6.Mandibular canal and foramina - inferior
alveolar nerve and vessels
FORAMINA AND OTHER RELATIONS

AGE CHANES IN MANDIBLE

The body of the bone is a mere shell,
containing the sockets of the two incisor, the canine, and the two
deciduous molar teeth, imperfectly partitioned.
The mandibular canal is of large size,
and runs near the lower border of the
bone;
The mental foramen opens beneath
the socket of the first deciduous molar
tooth.
The angle is obtuse (175°),
condyloid portion is nearly in line with the body.
The coronoid process is of comparatively large size, and projects
above the level of the condyle.
AT BIRTH

Two segments of the bone become joined at the symphysis.
The body becomes elongated in its whole length, but more
especially behind the mental foramen, to provide space for the three
additional teeth
Increased growth of the alveolar part,
to afford room for the roots of the teeth,
Thickening of the sub dental portion which
enables the jaw to withstand the powerful
action of the masticatory muscles;
The mandibular canal, is situated just above the level of the
mylohyoid line; and the mental foramen occupies the position usual
to it in the adult.
AFTER BIRTH
After birth

The alveolar and sub dental
portions of the body are usually of
equal depth.
The mental foramen opens
midway between the upper and
lower borders of the bone,
Mandibular canal runs nearly
parallel with the mylohyoid line.
The ramus is almost vertical in
direction, the angle measuring
from 110° to 120°.
In the adult
In adult

Bone becomes greatly reduced in size, with the loss of
the teeth the alveolar process is absorbed,
The chief part of the bone is below the
oblique line. In old
age
The mandibular canal, with the
mental foramen opening
from it, is close to the alveolar border.
The ramus is oblique in direction, the angle measures
about 140°,
Neck of the condyle is more or less bent backward.

A – Mandible at birth
B – At 6 years Lateral View
C – In an Adult

Occulsal View
A- At birth
B- At 6 yrs
C- Adult

PROSTHODONTIC CONSIDERATIONS
THE CORONOID PROCESS: discomfort
when mandible is protruded ,if distobuccal
flange of maxillary denture overfills the
vestibule.
EXTERNAL OBLIQUE RIDGE:
Termination of buccal flange of mandibular
denture.
MYLOHYOID RIDGE :

ALVEOLOPLASTY:
RIDGE AUGUMENTATION:
GENIAL TUBERCLES: often prominent
following advanced alveolar resorption are
covered by thin tissues and cannot bear
the pressure of the denture flange.
PRESSURE ON MENTAL FORAMEN:

The mandible on resorption becomes
wider and inclines outward which makes
the patient appear prognathic.
Residual Ridge Resorption is chronic,
progressive, irreversible, cumulative,
multifactorial, biomechanical disease that
results from a combination of anatomic,
metabolic and mechanical determinants

After teeth loss, alveolar bone undergoes rapid remodeling. Which results in
bone loss.
According to Atwood D.A.
Class – I – Pre extraction
Class – II – Post extraction. Immediately following exfoliaition of tooth with, the
labial and lingual alveolar process remaining
Class – III – High well rounded. The sharp edges will be rounded off by
the external osteoclastic activities leaving a high well rounded residual ridge.
Class – IV – Knife edge. As resorption continues form both labial and
lingual aspects the crest of ridge becomes increasingly narrow finally results in
knife edge.
Class – V – Low well rounded. The knife edge shortens and finally leaving
low well rounded
Class -VI-depressed.

CONCLUSION:
In order to construct a prosthesis a dentist
requires an understanding of the
foundation,it’s components,its properties
and qualities must be analysed to assure
proper support for the proposed
prosthesis.

REFERENCES:
1.INDERBERSINGH :TEXT BOOK OF HUMAN
OSTEOLOGY.
2.B.D.CHAURASIA: HUMAN OSTEOLOGY.
3. INDERBERSINGH : HUMAN EMBRYOLOGY.
4.ZARB-BOLENDER:PROSTHODONTIC TREATMENT
FOR EDENTULOUS PATIENTS
 5.SHELDON WINKLER:ESSENTIALS OF COMPLETE
DENTURE PROSTHODONTICS.
6.CHARLES M. HEARTWELL:SYLLABUS OF
COMPLETE DENTURES.
7.WARREN .H.LEWIS.-GRAY’S ANATOMY OF THE
HUMAN BODY.2000:20TH EDITION

Osteology of maxilla and mandible / oral surgery courses

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