Presentation(chapter 2)

The Edentulous
Alveolar Ridge
*Clinical Considerations
*Topography of the alveolar
process
*Topography of the
edentulous ridge

Clinical Considerations
The alveolar process forms in harmony
with the development and eruption of the
teeth and its gradually regresses when the
teeth are lost.

The morphologic characteristics of
the alveolar process are related to:
1-The size and shape of the teeth
2-Events occurring during tooth
eruption as well as the inclination of
the erupted teeth.

The tooth and its
surrounding attachment
tissues (the root
cementum, the
periodontal ligament and
bundle bone) established
a functional unit which
will distribute the forces
in different direction.
*Science direct. com


 
*Science direct. com

Tooth Average amount of
resorption (mm)
Average amount of
resorption (mm)
Difference
Maxillary teeth Buccal Lingual
Central incisor
Lateral incisor
Canine
3.03
3.47
3.33
1.46
0.86
1.91
1.57
2.61
1.42
First premolar
Second premolar
3.33
2.58
2.04
1.62
1.29
0.96
First molar 5.25 3.12 2.13
Mandibular teeth
Central incisor
Lateral incisor
Canine
2.08
3.54
3.25
0.91
1.41
1.59
1.17
2.13
1.66
First premolar
Second premolar
3.45
3.28
1.40
0.75
2.05
2.53
First molar
Second molar
4.69
4.30
2.79
3.00
1.90
1.30
Average amount of resorption
Pietrokovski &Masster (1967)

Schropp et al. (2003)
3months 6months 12 months

Classification of remaining bone
Lekhom &Zarb(1985)

Classification based on the volume of
remaining mineralized bone

Classification based on the “quality “
in edentulous site

Topography of the alveolar process

Spongy bone (anatomical)
Trabecular bone (radiographic)
Cancellous bone(histological)
bundle bone (histological term)
Ciriberiform plate(anatomical term)
Lamina dura(radiographic term)
Crest of the interdental septum
Cortical plate
Topography of the alveolar process

Cortical plate : Lamellar bone
Spongy bone: Trabeculae of lamellar bone
surrounded by marrow

What happens after extraction ????

A- Intra-alveolar processes
Amler (1969)

24h (Blood clot)
48-72h (2-3days)
*Beginning of granulation
tissue formation 96h (4-5days)
Epithelial proliferation

7days
*Young connective
tissue
*Epithelia proliferation
3 weeks
*Connective tissue will fill the socket
*Osteoid start mineralization
6w,The soft tissue
wound is closed
Woven bone

Amler’s study was a short duration study,
and the tissue composition of the fully
healed socket was not documented in depth
!!

1-Blood
clotting
2-Wound
cleansing
3-Tissue
formation
4-Tissue
modeling and
remodeling
Long -term experiment
(Cardaropoli et al.2003)

1-Blood clotting
1- Immediate after tooth extraction
2-Proteins derived from vessels lead to
formation of fibrin network
3- Platelets will interact with fibrin
network to produce blood clot ( a
coagulum)

1-Blood clotting
1- Blood clot will plugs the vessels and stop
bleeding.
4- Blood clot contains substances that will
influence the mesnchymal cells and enhance the
activity of inflammatory cells

2-Wound cleansing
1-The blood clot will start to break down by Fibrinolysis.
2-Neutrophils and macrophages migrate into the wound
and clean the site (sterilizing the wound ) by engulf bacteria
and damaged tissue.
2-Macrophages will also release growth factor and
cytokines that further promote the migration and
differentiation of mesnchymal cells

3-Tissue formation
1-Granulation tissue will gradually replace blood clot.
2- Mesenchymal cells will form a matrix by a a
process called fibroplasia.
3-Provisional connective tissue will be established by
a combination of fibroplasia and angiogenesis .
4-Osteoprogenitor cells will differentiate into
osteoblast.
5-The osteoblasts continue to lay down osteoid and
occasionally such cells are trapped in the matrix and
become osteocytes …This newly formed bone is called
WOVEN BONE

WOVEN BONE
Poorly organized
collagen matrix with large
number of osteoblasts
that are traped in its
mineralized matrix

4-Tissue modeling and
remodeling
Woven bone with primary osteons is
substituted by lamellar bone in a process that involves the
presence of bone multicellular units. The BMU contains
osteoclasts, as well as vascular structures and osteoblasts. Thus,
the osteoblasts in the BMU produce bone tissue
in a concentric fashion around the vessel, and lamellar bone with
secondary osteons is formed.

B-Extra-alveolar processes
Araujo& Lindhe(2005)
1st Week :
Blood clot and osteoclast (resorbtion of bundle bone).
2nd Week :
Formation of immature bone (woven bone).
4th weeks:
The entire socket is occupied with woven bone ,oseoclasts are
mainly presents in lateral and central aspects of the socket.
8th week:
Corticaliztion has occurred.

8th week: The marginal level of the lingual wall was
maintained during
the process of healing (solid line), while the crest of the
buccal wall was replaced >2 mm in the apical direction
(dotted line).

Topography of edentulous ridge
1-The ridge of the edentulous site in the
maxilla contains comparatively more cancellous bone
than a site in the mandible.
3- Depending on factors such as, the jaw (maxilla or
mandible), the location (anterior, posterior)
in the jaw, location of the muco-gingival junction,
depth of the buccal and lingual vestibule, and
the amount of hard tissue resorption, the edentulous
site may be lined with either masticatory, keratinized
mucosa or lining, non-keratinized mucosa.

Main points in this
chapter
Overall pattern
of socket
healing
Classification
of the bone
*Woven bone
*Lamellar bone

Presentation(chapter 2)

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Presentation(chapter 2)