3. BONE TISSUE
Bone tissue 2 Types of bone tissue:
is a specialized form of 1. Compact (Cortical) bone
connective tissue and is
the main element of the 2. Spongy (Cancellous) bone
skeletal tissues.
is composed of cells and
an extracellular matrix in
which fibers are
embedded.
is unlike other
connective tissues in that
the extracellular matrix
becomes calcified.
http://en.wikipedia.org/wiki/Bone_tissue
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4. http://en.wikipedia.org/wiki/Haematopoiesis
FUNCTIONS OF BONE
1. Support: provides framework that supports and anchors
all soft organs.
2. Protection: skull and vertebrae surround soft tissue of the
nervous system, and the rib cage protects vital thoracic
organs.
3. Movement: skeletal muscles use the bones as levers to
move the body.
4. Storage: fat stored in the interior of the bones. Bone
matrix serves as a storehouse for various minerals.
5. Blood Cell Formation: hematopoiesis occurs within the
marrow cavities of the bones.
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5. CLASSIFICATION OF BONE
Bone may be classified in several ways:
Developmentally Histologically By shape
Endochondral bone Compact (Cortical) Long bones
Bone
Intramembranous bone Spongy (Cancellous) Short bones
Bone
Flat bones
Irregular bones
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6. A. endochondral bone
• Where bone is preceded by a cartilagenous model that
is eventually replaced by bone In a process termed
endochondral ossification.
B. intramembranous bone
• Where bone forms directly w/in a vascular, fibrous
membrane.
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7. “Oral Anatomy, Histology, and Embryology”
CHEMICAL PROPERTIES OF BONE
60 % Inorganic
material Composition of bones
is formed from
carbonated
hydroxyapatite.
Inorganic
Substances
25 % Organic Organic
material Substances
mainly composed of Water
Type I collagen.
The organic part is
also composed of
various growth
factors: 15% Water
glycosaminoglycans,
osteocalcin,
osteonectin, bone
sialo protein,
osteopontin and Cell 7
8. ORGANIC MATRIX OF THE BONE
Bone is formed by the Organic Components of the
hardening of the Bone Matrix
matrix, entrapping the
cells. When these cells Collagen
become entrapped from
osteoblasts they become Non-
osteocytes. collagenous
proteins
The organic matrix of bone
is about:
90% collagen
10% non-collagenous
proteins.
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9. Non-collagenous Proteins of Bone
are a heterogeneous group which vary from
entrapped serum protein to glycoproteins
play a role in mineralization.
The main non-collagenous proteins comprise
the:
Proteoglycans
Glycoproteins
Bone Gla-containing proteins
Serum proteins
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10. collagen.
Contributes towards the important biomechanical
properties of tissue in terms of resisting loads
and providing necessary resilience that prevents
fractures.
The dominant collagen in bone is Type I.
Intrinsic collagen
collagen as secreted by osteoblasts.
Extrinsic collagen
Collagen formed by adjacent fibroblasts.
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11. SHARPEY’S FIBERS
Sharpey's fibers are the
terminal ends of principal
fibers (of the periodontal
ligament) that insert into the
cementum and into the
periosteum of the alveolar
bone.
A study on rats suggests that
the three-dimensional
structure of Sharpey's fibers
intensifies the continuity
between the periodontal
ligament fiber and the alveolar
bone (tooth socket), and acts
as a buffer medium against
stress.
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12. CELL TYPES IN BONE
Osteoblasts
are mononucleate cells that are responsible for bone formation
Osteocytes
When osteoblasts become trapped in the matrix they secrete, they
become osteocytes.
Bone-lining cells
Are inactive osteoblasts that cover all of the available bone surface
and function as a barrier for certain ions
Osteoprogenitor cells
relatively undifferentiated cells found on or near all of the free
surfaces of bone, which, under certain circumstances, undergo
division and transform into osteoblasts or coalesce to give rise to
osteoclasts.
Osteoclasts
is a type of bone cell that removes bone tissue by removing its
mineralized matrix and breaking up the organic bone
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13. RESORPTION AND FORMATION OF BONE DURING
REMODELLING
Resorption
Reversal
Formation
Resting
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14. http://en.wikipedia.org/wiki/Ossification
OSSIFICATION
Also called Osteogenesis
is the natural process of bone formation
There are two processes resulting in the
formation of normal, healthy bone tissue:
Endochondral (Intracartilaginous) Bone
Ossification
The formation of bone in which a cartilage template is
gradually replaced by a bone matrix, as in the formation of
long bones or in osteoarthritic ossification of synovial
cartilage.
Intramembranous Bone Ossification
thedevelopment of bone from tissue or membrane, as in
the formation of the skull.
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15. Sutural Bone Growth
variable
and irregularly shaped bones in the
sutures between the bones of the skull.
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17. http://www.answers.com/topic/alveolar-bone#ixzz12ko9kyTQ
ALVEOLAR BONE
Also called as alveolar
process
The specialized bone
structure that contains the
alveoli or sockets of the
teeth and supports the
teeth.
If the teeth are lost the
alveolar process disappears
It is composed mainly of two
parts:
alveolar bone proper
Supporting bone
20. DEVELOPMENT OF ALVEOLAR BONE
Alveolar bone develops
from the dental follicle
The ectomesenchymal
cells of the dental follicle
differentiate into
osteoblasts and lay down
the matrix called osteoid
Some osteoblasts become
embedded in the matrix
and are called osteocytes
21. Near the end of the 2nd
month of fetal life, mandible
and maxilla form a groove
that is opened toward the
surface of the oral cavity
As tooth germs start to
develop, bony septa form
gradually. The alveolar
process starts developing
strictly during tooth eruption.
22. GROSS MORPHOLOGY OF BONE
Morphology -is a branch of bioscience dealing with the study of the form
and structure of organisms and their specific structural
23.
24. Alveolar Socket
Also called Dental
alveolus
are sockets in the
jaws in which the
roots of teeth are
held in the alveolar
process with the
periodontal Alveolar socket of the second
premolar tooth in a bovine
ligament. maxillary bone.
25. Interdental Septa
“Septa” – in Latin, it
means “fence” or “wall”
Are plates of bone that
separate each
individual sockets from
one another.
Interradicular Septa
Are thin plates of bone
that separate the roots
of multi-rooted teeth
26. Cribriform Plate
also called as bundle
bone
Is the compact layer of
bone lining the tooth
socket (alveolar socket)
Reflects the sieve-like
appearance produced by
numerous Volkmann’s
canals passing from the
alveolar bone to the PDL
(periodontal ligament).
Numerous Sharpey’s
Fiber pass through it.
27. ALVEOLAR PROCESS
is the thickened ridge of
bone that contains the
tooth sockets on bones
that bear teeth.
The alveolar process
contains a region of
compact bone adjacent
to the periodontal
ligament called Lamina
dura.
Maxilla and Mandible
Are the tooth-bearing
bones
28. Lamina Dura
this part which is
attached to the
cementum of the roots
by the periodontal
ligament.
Is the bone lining the
alveolus
In clinical
radiographs, it Lamina Dura
commonly appears as Radiographic appearance of
alveolar bone proper as ‘Lamina
a dense white line. Dura’
30. FUNCTIONS OF ALVEOLAR BONE
Protection
Alveolar bone forms and protects the sockets for the teeth.
Attachment
It gives the attachment to the periodontal ligament fibers, which are
the principle fibers. These fibers which enter the bone are regarded
as Sharpey’s fibers.
Support
It supports the tooth roots on the facial and on the palatal/lingual
sides.
Shock-absorber
It helps absorb the forces placed upon the tooth by disseminating the
force to underlying tissues.
32. a) outer cortical plates
b) a central spongiosa
c) bone lining the alveolus (bundle
bone)
33. CORTICAL PLATE
Outer bony plate of varying
thickness, which is the outside
wall of the maxilla and
mandible, covered with
periosteum
Continuous with the lamina
cribriformis at the orifice of the
alveoli – alveolar crest
Consists of haversian systems
(osteons) and interstitial
lamellae
Thicker in the mandible than
maxilla
Generally greater on the
lingual than on the
buccal/facial
34. ALVEOLAR BONE PROPER OR LAMINA
An inner, heavily
perforated bony
lamellae, forming the
alveolar wall
In radiograph, appears
as radioopaque line
distinct from the adjacent
spongiosa – Lamina
Dura
Contains osteons like
other cortical bone, but
is distinguished by the
presence of Bundle
Bone
35. SPONGIOSA
Are spongy (or
cancellous/trabecullar)
bone between the 2 bony
plates and between the
lamina cribriformis of
adjacent teeth or roots
Consists of delicate
trabeculae, between which
are marrow spaces, filled
mostly with fatty marrow
Regions of maxillary
tuberosity and the angle of
mandible, erythropoietic …
37. VASCULAR SUPPLY OF ALVEOLAR PROCESS
Alveolar process of the maxilla
Anteriorand posterior alveolar arteries (branch
from the maxilla and infraorbital arteries)
Alveolar process of the mandible
Inferioralveolar arteries (internal)
Periosteal branches of submental and buccal
arteries (external)
39. http://en.wikipedia.org/wiki/Periodontal_disease
PERIODONTAL DISEASE
Periodontal disease is a
type of disease that affects
one or more of the
periodontal tissues:
Alveolar bone
Periodontal ligament
Cementum
Gingiva
While many different
diseases affect the tooth-
supporting
structures, plaque-induced
inflammatory lesions make
up the vast majority of
periodontal diseases and
have traditionally been
divided into two categories:
gingivitis or
periodontitis
40. HISTOLOGICAL ARRANGEMENT OF MATURE
BONE
Mature bone is composed of:
Compact bone
Spongy Bone
http://www.physioweb.org/skeletal/bone_tissue.html
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42. http://en.wikipedia.org/wiki/Bone_tissue
COMPACT BONE
Also called as Cortical bone
As its name implies. . .
“cortical” bone forms the cortex or outer shell of most bones.
“compact” bone is much denser than cancellous bone.
Furthermore, it is harder, stronger and stiffer than cancellous bone.
The primary anatomical and functional unit of cortical bone is the
osteon.
3 Distinct Layering of Compact Bone:
Circumferential lamella
Concentric lamella
Interstitial lamella
Functions:
facilitates to support the whole body
protect organs
provide levers for movement
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store and release chemical elements, mainly calcium.
43. 3 DISTINCT LAYERING OF COMPACT BONE:
Circumferential Lamellae
enclose the entire adult bone, forming its
outer perimeter
Concentric Lamellae
make up the bulk of compact bone and form
the basic metabolic unit of bone, the osteon
Interstitial Lamellae
interspersed between adjacent concentric
lamellae and fill the spaces between them
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45. SPONGY BONE
Also called Cancellous bone or Trabecular bone
Compared to compact bone, cancellous bone has a
higher surface area but is less
dense, softer, weaker, and less stiff.
Cancellous bone is highly vascular and frequently
contains red red bone marrow where hematopoeisis
occurs.
The primary anatomical and functional unit of
cancellous bone is the trabecula.
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