Alveolar bone forms in conjunction with tooth development to support teeth and give attachment to muscles. It is composed mainly of hydroxyapatite and collagen and contains osteoblasts, osteocytes, and osteoclasts. The alveolar bone undergoes remodeling through the balanced actions of osteoblasts, which form new bone, and osteoclasts, which resorb old bone. This allows the alveolar bone to maintain its shape and position relative to the teeth. Interruptions in the bone like fenestrations and dehiscences can complicate dental procedures or lead to issues like gingival recession.

1. ALVEOLAR BONE -
ALVEOLAR BONE -
REVISITED
REVISITED

2. It is that portion of the maxilla & mandible
that forms & supports the teeth.
It also gives attachment to Muscles and
acts as a reservoir for the ions especially
for Calcium.
It formed during eruption & lasts as the
tooth exfoliates. This develops in
conjunction with development of the teeth.
Cells from the dental follicle & cells which
are independent of tooth development are
responsible for the formation of alveolar
bone.

3. Alveolar process begins at the arbitrary portion
where root apex locates.
Shape of the jaws & morphology of the alveolar
process vary between the individuals and the
size, shape & thickness of the cortical plates.
Interdental septum very in different parts of same
jaws.Margins of the alveolar process runs
parallels to CEJ & maintains distance of about 1-
2mm
{ it depends upon position of the tooth}

4. ALVEOLAR BONE

5. COMPOSITION
 Inorganic – 60%
 organic – 25%
 Water – 15%
 Inorganic components consists of mainly
hydroxyapatite, calcium phosphate, citrate &
traces of sodium, magnesium & fluorine.
 Organic components mainly contains type I
collagen. Proteins like
Osteopontin,Osteonectin, Osteocalcin,Bone
Sailoprotein protein & proteoglycans. It also
has Decorin & Biglycan are the two small
molecule of chondratin Sulphate , bone
morphogenitic proteins.

6. Proteins present in the bone;
I} OSTEONECTIN
 One of the major non collagenous protein
 It is an acid phosphate containing
glycoprotien
 Secreted by osteoblasts
 High affinity to calcium ions
 It is also present in cementum PDL &
basement membrane
2} OSTEOCALCIN
 It is also called as bone gla protein becoz it
contains Y corboxyglutamic acid { gla}
residue.
 Small protein, secreted by osteoblasts

7.  It gets incorporated in mineral matrix of bone
and plays important role in mineralization.
3} BONE SIALOPROTEIN PROTEIN {BSP II}
 Expression of BSP II reflects late stage of
osteoblast maturation
 It is phophoglycoprotein containing about 20%
of
sialic acid
4} OSTEOPONTIN
 Also termed as BSP I, due to sialic acid
presence.
 It is a glycophosphoprotein
 Exact function not known but it helps in
attachment & movement of osteblasts &

8. Alveolar Bone consists of
 External cortical plates
 Alveolar bone proper / cribriform plate / bundle
bone
 Interdental septum
Alveolar bone acts as one functional unit so, it
can separated into
Compact bone
Cancellous bone

9. Diagrammatic cross-section through a tooth in the alveolar process of the jaw
bone. internal and external cortical plate of compact bone (C) cancellous or
spongy bone (S) , the alveolar bone proper (AB).

10. SECTION OF THE MANDIBLE SHOWING THE
PARTS OF THE ALVEOLAR BONE

11. CELLS & INTERCELLULAR MATRIX
 OSTEOBLASTS produces organic matrix of bone. These
cells gets entrapped in the matrix become OSTOCYTES.
 They are present in spaces called “lacunae”. These
cells are interconnected by canaliculi. These
interconnection helps in supply of oxygen, nutrition & to
remove the metabolic waste products.
 Cortical plates have Haversian system for internal
blood supply since it can solely depends on vessels
present in the periosteum.
 Other cells are – OSTEOCLASTS – responsible for bone
resorption
 OSTEOPROGINATOR CELLS – long thin cells .situated
next to the blood vessels. They are stem cells to
generate Osteoblasts.

12. OSTEOBLASTS
OSTEOCYTES

13. BONE REMODELING
 Bone is a rigid but elastic tissue
 The shape, position, size & density of the bone
maintains by constant resorption & formation of the
bone
 Formation is by osteoblasts. These cells lay down
osteoid material. Hydroxyapatite crystal deposition in
osteoid material makes it mineralized.
 Osteoclasts to cause resorption of the bone,
Osteoblasts should present.
 Remodeling influenced by local & systemic factors;
 Local factors – PGE2, Leukotrines (Il-2,IL-3, IL-6 )&
cytokines ( TNF alpha& beta,TGF beta & PDGF)
 Systemic factors – Parathyroid hormones, Vit D3 &
Calcitonin.

14. Remodeling in three area;
1-Adjacent to PDL
2- Periosteum of the facial & lingual plates
3- Endosteal surfaces.
Bone contains 99% of calcium ions of the body. This will be
released into the blood stream when blood calcium
decreases. This will be controlled by the hormone PTH.
Dec blood cal incr PTH production stimulates IL-6
production
Monocytes migrates to bone area Osteoblasts
produces
Leukemic inhibition factor makes monocytes coalesces
Osteoclasts
Resorption of the bone. Cal released into blood normal
blood cal

15. During the process of resorption ,collagen breaks
down & releases osteogenic substrate which are
bound to collagen are in turn stimulates
osteoblasts to deposit bone.this interdependency
of osteoblasts & osteoclasts in remodeling called
as coupling
Bone matrix formation by osteoblasts called as
osteoid.
Bone resorption is a complex process involves
mainly by osteoclasts.

16. Osteoclasts are originates from haemopoitic
cells,they are formed by the fusion of two
mononuclear cells to form multinucleated giant
cells.
They create ruffled border by the hydrolytic
enzymes. These enzymes digest organic portion
of the bone.
Osteoclasts are regulated by the PTH &
Calcitonin hormones since they have receptors
for these hormones.
Another mechanism is by creating acidic
environment dissolute the mineral contents

17. SEQUENCE OF EVENTS
1 – Attachments of Osteoclasts
2- Creation of sealed acidic environment. Through
the proton pump which demineralizes the bone
& exposes organic matrix
3 – Degradation of organic matrix by acid
Phosphatase & cathepsin
4 – Sequestering of mineral ions & amino acid
within the osteoclasts.

18. SOCKET WALL
Consists of lamellated bone which has Haversian
system
Referred as - BUNDLE BONE – more sharpey’s
fibers are inserted.
CRIBRIFORM PLATE
LAMINA DURA – radiographically.
This bone has perforations for vascular
communication.

19. LAMINA DURA
SOCKET WALL

20. CANCELLOUS BONE
Predominant in interdental & inter radicular area
It has irregularly shaped marrow & trabeculae
Trabeculae are lined by endosteal layer.
Marrow spaces are filled with red bone marrow
in embryo & new born. Later it will be replaced
by yellow fatty tissue,but it may persists
commonly in maxillary tuberosity region.

21. CANCELLOUS BONE

22. PERIOSTEUM & ENDOSTEUM
 Tissue covering outer surface of the bone – Periosteum
 Tissue lining the internal cavity - Endosteum
 Periosteum consists of inner layer of osteoblasts,
osteproginator cells & outer layer consists of rich blood
vessels, nerves,collagen fibers & fibroblasts
 Endosteum composed of single layer of osteoblasts
with small amount of connective tissue layer.

23. INTERDENTAL SEPTUM
 Consists of cancellous bone bordered by cribriform
plate facial & lingual cortical plates
 If the ID spaces narrow –only cribriform plates present
 If the root are closely approximated then there may be
window formation
 Shape & size of this depends on the crown, convexity,
root position & shape, degree of tooth eruption.

24. OSSEOUS TOPOGRAPHY
 Normally bone shows concavity between the prominent
roots with thin bony margin.
 It is mostly depends on angulation of the root & occlusal
forces.
 Labially placed tooth – bone margin will be apically
placed
 Lingualy placed tooth – Bone margin will be thick

25. OSSEUS TOPOGRAPHY

26. FENESTRATION & DEHISCENCE.
 Isolated “window like” defect which is denuded of bone
& covered by periosteum is referred as fenestration.
 If the marginal bone is involved then referred as
dehiscence
 More commonly seen in anterior than posterior
 Usually it will be bilateral
 Exact cause is not known
 Prominent root contour, malposition of the teeth are
some predisposing factor
 These defects complicates periodontal surgery.

27. FENESTRATION
DEHISCENCE

28. CLINICAL CONSIDERATIONS
1. Through remodeling, the alveolar bone may
become displaced in relation to the remaining alveolar
process, thereby allowing tooth movement to take
place.
 2. Interruptions in the continuity of the lamina dura in
the apical region of an alveolus are of diagnostic
significance in the radiographic identification of

29.  3. Proximity of the alveolar bone to sinus
cavities or major nerves (mandibular nerve)
may create problems during tooth extraction or
surgical interventions.
 4.Following tooth extraction, the alveolar
process tends to resorb, a development that
may compromise the placement of
endosseous dental implants and affect the
construction of removable prostheses.

30.  5. Placement of dental implants in the alveolar
process, prior to its becoming resorbed, following tooth
extractions, will markedly decrease the rate of ridge
resorption
 6.Fenestrations may convert to dehiscences which, in
turn, may lead to gingival recession. Surgical
interventions may promote the conversion of
fenestrations into dehiscences, as well as the creation