report alveolar bone_idraft
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ALVEOLAR BONE
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BONEPart I
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Bone TissueBone tissue
◦is a specialized form of connective tissue and is the main element of the 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.
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Functions of BoneSkeletal function of support,
protection, locomotion and attachment of muscles
Bone constitutes an important reservoir of minerals
Bone is for hemopoiesis
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Composition of Bone65% Inorganic
(Hydroxyapatite)◦ Mostly Calcium and
inorganic orthophosphate deposited between collagen
35% Organic◦ 28% collagen◦ 5%
Osteocalcin Sialoprotein Phosphoprotein Osteonectin Bone specific protein
Composition of bonesInorganic Sub-stances
Organic Sub-stances
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Structural Elements of Bone
Bone Cells◦ Odontoblasts – forms bone◦ Osteocytes – maintains bone◦ Osteoclasts – resorbs bone
Bone Matrix◦ is the intercelluar substance of bone consisting of
collagenous fibers ground substances & inorganic salts
Sharpey’s Fibers◦ Are a matrix of connective tissue consisting of bundles of
collagenous fibers connecting periosteum to bone
Blood vessels, nerves, lymph vessels
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Histological Arrangement of Mature BoneCompact Bone
Spongy Bone
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Compact Boneare dense outer sheet that are
closely packed3 Distinct Layering:
◦Circumferential lamella◦Concentric lamella◦Interstitial lamella
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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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Spongy BoneAlso called Cancellous boneflattened spicules surrounding
the spaces known as marrow spaces containing the bone marrow
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Osteon - basic metabolic unit of bone generally oriented in the long axis of bone
Haversian Canal - canal lined by a single layer of bone cells at the outer of an osteon; each cana; houses a capillary
Volkman’s Canal - channels that connect adjacent haversian canal; contains blood vessels
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Periosteum – osteogenic connective tissue membrane that surrounds every compact bone; consists of 2 layers
Inner layer – consists of bone cells; their precursors and a rich microvascular supply
Outer layer – more fibrous, gives rise to…
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Bone Formation (Ossification)Endochondral (Intracartilaginous)
Bone Ossification◦Has a precatilaginous stage
Intramembranous Bone Ossification◦Mandible and maxilla
Sutural Bone Growth
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ALVEOLAR SOCKETPart II:
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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 ligament.
http://en.wikipedia.org/wiki/Dental_alveolus
Alveolar socket of the second premolar tooth in a bovine maxillary bone.
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ALVEOLAR PROCESSPart II:
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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
http://en.wikipedia.org/wiki/Alveolar_process_of_maxilla
http://en.wikipedia.org/wiki/Lamina_dura
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Lamina Durais this part which is attached to
the cementum of the roots by the periodontal ligament.
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Functions of Alveolar bone
Acts as the anchoring of teeth within the alveoli
Absorption and distribution of occlusal pressures produced by intermittent tooth contacts during chewing, swallowing, speech and parafunctional activities such as grinding and chewing
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Structure of the Alveolar BoneCortical Plate – outermost part
◦Alveolar bone proper or laminaSpongiosa – spongy bone
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Cortical PlateOuter 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 maxillaGenerally greater on the lingual than on
the buccal/facial
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Alveolar Bone Proper or LaminaAn 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
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Bundle BoneMultiple layers of bone parallel to
surface of alveolar wall which are penetrated by bundles of Sharpey’s Fibers embedded nearly right angle…
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SpongiosaAre 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 …
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VASCULAR SUPPLY OF ALVEOLAR PROCESSAlveolar process of the maxilla
◦Anterior and posterior alveolar arteries (branch from the maxilla and infraorbital arteries)
Alveolar process of the mandible◦Inferior alveolar arteries (internal)◦Periosteal branches of submental
and buccal arteries (external)