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ALVEOLAR BONE CAN BE DEFINED AS THAT PART OF THE MAXILLA AND MANDIBLE THAT FORMS AND SUPPORTS THE SOCKETS OF THE TEETH. COMPARABLE TO OTHER BONE TISSUES IN THE BODY, ALVEOLAR BONE IS SUBJECTED TO CONTINOUS AND RAPID REMODELING ASSOCIATED WITH TOOTH ERUPTION AND THE FUCNTIONAL DEMANDS OF MASTICATION.
WHAT IS ALVEOLAR BONE…

FUNCTIONS..

HOLDS THE TOOTH FIRMLY IN POSITION TO MASTICATE. HELPS TO ABSORB AND DISTRIBUTE OCCLUSAL FORCES ADAPTS THE STRENGTH AND ORIENTATION OF ATTACHMENT TO VARYING LOAD. HELPS TO MOVE THE TEETH FOR BETTER OCCLUSION. SUPPLIES VESSELS FOR THE PDL & CEMENTUM. PROTECTS DEVELOPING PERMANENT TEETH WHILE SUPPORTING PRIMARY TEETH. ORGANIZES SUCCESSIVE ERUPTIONS OF PRI & SEC TEETH

COMPOSITION OF ALVEOLAR BONE..

INORGANIC
ORGANIC
ALVEOLAR BONE
HYDROXYAPATITE, TRACE ELEMENTS.
COLLOGEN-
28%
5%
OSTEOCALCIN, SIALOPROTEIN, PHOSPHOPROTEIN, OSTEONECTIN, PROTEOGLYCONS
67%
33%


Cells and intercellular matrix

BLOOD SUPPLY: SUPERIOR AND INFERIOR ALVEOLAR ARTERIES OF MAXILLA & MANDIBLE.

LYMPHATICS DRAINAGE: SUBMANDIBULAR LYMPH NODES.


NERVE SUPPLY: BRANCHES FROM ANTERIOR, MIDDLE AND POSTERIOR SUPERIOR ALVEOLAR NERVE IN MAXILLA & BRANCHES FROM INFERIOR ALVEOLAR NERVE INNERVATE MANDIBLE.


It is composed of two parts; the alveolar bone proper and the supporting boneAlveolar bone proper is that part of alveolar bone that lines the sockets It is a thin lamella of compact bone in which periodontal fibres are embeddedIt is referred to as Bundle bone because it regularly penetrated by Sharpey’s fibres of the periodontal ligament

Radiographically alveolar bone proper is referred to as lamina dura Lamina dura appears more dense and hence radio-opaque In a radiograph the widening of lamina dura indicates periodontal pathology In physiological movement of teeth, this bone is readily resorbed in zones of compression and is formed in zones of tension

Radiographic appearance of alveolar bone proper as ‘Lamina Dura’

Supporting bone The remainder of the alveolar process below the alveolar bone proper is called the supporting bone It is attached to the alveolar bone proper Supporting bone includes the compact cortical plates on the outer surface and the spongy bone between the cortical plates and the alveolar bone proper

Cortical plates (Compact supporting bone) The compact supporting bone of the alveolar process extends from the alveolar crest to the lower border of the socket on the outside surface of the maxilla and mandible It is also called the cortical bone/plate The cortical bone has Haversian systems, radiating lamellae with lacunae and canaliculi


Spongy bone (Cancellous supporting bone)

Cancellous bone is located apically between the alveolar bone proper and the cortical bone It is also called as spongy bone It supports and strengthens the alveolar bone proper

If roots are too close together, an irregular "window" can appear in the bone between adjacent roots

INTER RADICULAR SEPTUM- IT IS THE BONE BETWEEN THE ROOTS OF MULTIROOTED TEETH.

The distance between the crest of the alveolar bone and the CEJ in young adults varies between 1-1.5 mm. This distance increases with age to an average of 2.81 mm.
The mesiodistal angulation of the crest of the interdental septum usually parallels a line drawn between the cemento-enamel junctions of the approximating teeth.

Periosteum and Endosteum

HORIZONTAL BONE LOSS- BONE MARGIN IS PERPENDICULAR TO TOOTH SURFACE.
BONE DESTRUCTION PATTERN IN PERIODONTAL DISEASES

VERTICAL BONE LOSS- ANGULAR DEFECT THAT OCCUR IN vertical or oblique DIRECTION

EXOSTOSES- IT IS THE OUTGROWTH OF BONE OF VARIABLE SIZE AND SHAPE

FURCATION INVOLVEMENT- INVASION OF BIFURCATION AND TRIFURCATION OF MULTIROOTED TEETH BY PERIODONTAL DISEASE.
Furcation Probes Nabers Probe


Class 1: The concavity—just above the furcation entrance—on the root trunk can be felt with the probe tip; however, the furcation probe cannot enter the furcation area.

Class 2The probe is able to partially enter the furcation—extending approximately one third of the width of the tooth—but it is not able to pass completely through the furcation

Class 3: In mandibular molars, the probe passes completely through the furcation between the mesial and distal roots. In maxillary molars, the probe passes between the mesiobuccal and distobuccal roots and touches the palatal root.


Class 4: Same as a class III furcation involvement except that the entrance to the furcation is visible clinically owing to tissue recession.


Isolated areas in which the root is denuded of bone and the root surface is covered only by periosteum and overlying gingiva are termed fenestrations. In these instances the marginal bone is intact. When the denuded areas extend through the marginal bone, the defect is called a dehiscence. FENESTRATION- IS AN AREA OF ROOT PENETRATING THE BONE IN THE APICAL REGION. DEHISCENCE- IS AN AREA OF ROOT PENETRATING THE BONE IN CORONAL REGION. Fenestration and dehiscence are important, because they may complicate the outcome of periodontal surgery.
Dehiscence & Fenestration

ALVEOLAR BONE PATHOLOGY… HISTIOCYTE- SEVERE HORIZONTAL BONE LOSS.

CHERUBISM- WIDENING OF ALVEOLAR RIDGE AND TOOTH DISPLACMENT
FIBROUS DYPLASIA- PAINLESS ENLARGEMENT OF THE AFFECTED BONE. WITH GROUND GLASS APPEARENCE
OSTEOSARCOMA – SWELLING WITH PAIN, LOOSENING OF TEETH, PARESTHESIA. PAGETS DISEASE- GROSSLY ENLARGED ALVEOLAR RIDGES , CAUSES SPACING OF TEETH.

HYPERPARATHYROIDISM- LOSS OF LAMINA DURA, DECREASE IN TRABECULAE DENSITY.

OSTEOGENESIS IMPERFECTA- MAXILLARY HYPOPLASIA, CLASS III MALOCCLUSIAN.
OSTEOPETROSIS- INCREASE IN BONE DENSITY . BONE MARROW IS REPLACED BY DENSE BONE.
CLEIDOCRANIAL DYSPLASIA- RETENTION OF DECIDUOUS TEETH.

HISTIOCYTE

CHERUBISM

FIBROUS DYPLASIA-

OSTEOSARCOMA



CLEIDOCRANIAL DYSPLASIA-
HYPERPARATHYROIDISM

OSTEOGENESIS IMPERFECTA-

OSTEOPETROSIS