For my dental students

1. Dr/ Hesham Dameer

2. The students have to know
1- Definition of alveolar bone
2- Alveolar bone components
3- Alveolar bone development
4- Alveolar bone structure & its clinical applications
5- Alveolar bone appearance in x-ray
6- Physiologic & orthodontic movements related to the alveolar bone

3. • Alveolar bone is that part of
the maxilla and mandible that
contains the alveoli or
sockets of the teeth and
supports the teeth.
• The alveolar socket is the cavity within the alveolar bone in
which the root of the tooth is held by the periodontal ligament.
If the teeth are lost the alveolar process disappears

4. • The alveolar bone
between the roots of
adjacent teeth is
known as the
Interdental Septum.
• The alveolar bone
between the roots of
multi-rooted teeth is
called the Inter-
radicular Septum.

5. Interdental Septum.
Inter-radicular Septum

7. Alveolar bone & the basal bone

8. • Anatomically no boundary exists between the alveolar bone & the
basal bone (body of the mandible and maxilla). An imaginary line
at the root apices separates the alv. bone & the basal bone of the
jaws.
Alv.
Bone
Basal
Bone

9. • The alv. bone develops with the formation and the
eruption of teeth, when the teeth are congenitally
messing (anodontia), the alv. bone do not develop at all.
• The maintenance of the alv. bone is dependent on the
presence of the teeth. When the teeth are lost, it
gradually resorbs.

10. • Near the end of the 2nd month IUL. The outer and
inner plates of the body of the maxilla and mandible
grow in a vertical direction forming a groove that is
opened towards the of the oral cavity.
• The tooth germs are contained in this groove.
• Gradually bony septa develop between the adjacent
tooth germs.

11. • The actual alveolar process formation is associated
with the root formation & the eruption process.
• With the root formation the bony crypt is
transformed into socket.
• In fetal life the alveolar bone is formed, like the rest of
the skeleton, of woven bone .

12. Structure of the alveolar process
Adult alveolar process is
composed of 2 parts :
1. Alveolar bone prope
2. Supporting bone.

13. Macro-anatomy
Alveolar
bone
proper
Supporting
alveolar
bone
Inner & outer
cortical plates
Supporting
Spongy bone
ALVEOLAR PROCESS

14. •The alveolar bone proper is a thin layer
of bone that surrounds the root and gives
attachment to the principal PDL fibers.
•It is perforated by numerous minute
foramina (Volkman's Canals) that carry
the BV & nerves into the periodontal
ligament and that is why it is called the
cribriform plate.
•The term lamina dura (dura hard) is
given to this layer of bone from its dense
radiopaque appearance in X-ray
1- The alveolar bone proper

15. Cribriform Plate

17. Lamina Dura

18. The alveolar bone proper is
made up of:
A. Bundle bone adjacent to the
PDL where the principal
fibers are attached (bone of
attachment)
B. Compact bone which
consists of superficial
parallel lamellae &
deeper portions made up of
Haversian system
Histology of the alveolar bone proper

19. Bundle
bone
Compact
bone
Bundles of the principal fibers
are inserted into the bone as
Sharpey's fibers

20. The bundle bone is
the bone of
attachment.
It varies in
thickness.
According to the
functional demands
Always its thicker
distally than
mesially
Mesial
Distal
?
bundle
bone
PDL
Tooth
root

21. • The supporting bone
consists of 2 parts :
• I) Cortical plates, which are
made of compact bone
• II) The spongy (cancellous)
bone, which fills the area
between these plates and the
alveolar bone proper .
.
2- Supporting alveolar bone

22. • The cortical plates of the
alveolar processes are
continuous with the labial &
lingual cortical plates of the
maxilla and mandible.
• Generally, they are thinner in
the maxilla than in the
mandible.

23. In the region of the
anterior teeth of
both jaws the
cortical plates are
very thin and
fused directly with
the alveolar bone
proper with no
spongy bone in
between .

24. They are thickest in
the premolar and
molar regions, where
the Ling. plate is
thicker than the
buccal one.
In the region of the
mandibular third
molar, the Lingual
plate is thinner than
the buccal one
because of the
presence of the

26. • During extraction, the last extraction movement
is toward the thinner cortical plate.

27. • In the maxilla, the outer cortical plate is perforated
by Volkman's Canals and may show defects in the
posterior teeth region.
• Larger defect exposing the root portion is known
as fenestration.
• If the defect includes the coronal alveolar crest it is
called dehiscence.

28. Defect exposing
the root portion
defect
includes the
coronal
alveolar crest

30. • It is found between the alv.
bone proper and the
cortical plates and between
the alv. bone proper of the
adjacent sockets.
• Its degree of development
is related to the forces of
mastication.
• It is absent in the anterior
region of both jaws where
the outer wall of the tooth
sockets is very thin .

31. • Cancellous bone is very sensitive to variation in
functional forces. The increase in functional force
leads to formation of new dense bone. Decreased
function leads to decrease in the volume of bone.
• This can be observed in the cancellous bone of teeth
which have lost their antagonists. Here the
cancellous bone around the alveolus is reduced and
the trabeculae become less numerous and very thin.

32. Radiographic appearance of alveolar bone
Appears as a
radioopaque (white)
line adjacent to the
root and separated
from it by a
radiolucent line (dark)
representing the space
of the periodontal
ligament.
Lamina dura

33. • The alveolar process is
classified into 2 main
types:
• Type I:
The interdental and
interadicular trabeculae
are regular and horizontal
in a ladder-like
arrangement, This type is
more seen in the mandible
Radiographic appearance of alveolar bone

34. • Type II:
• The interdental and
interadicular trabeculae
are more numerous,
delicate and irregularly
arranged. This type is
more seen in the maxilla

35. Type I Type II

36. Bone remodeling
&
Bone modeling
• Bone formation occurs throughout life by a process called
bone remodeling. During remodeling bone formation is
usually preceded by bone resorption.
• Bone formation is due to the tension (pull) of the
periodontal ligament fibers.
• Bone resorption is due to the pressure of the P.D.L fibers.
• While the process by which the overall size and shape of
bone is established is referred to as bone modeling.

37. Physiologic
movement
• Mesial drift
• Occlusal movemen
( Poste eruptive movement )
Orthodontic movement
During the orth. movement, the
alv. bone is under the remodeling
process . After orth. movement,
the alv. bone undergo modeling
process .
Tooth movement

38. Mesial Drift
• It is physiologic
tendency
of all teeth to move
towards the midline
• During mesial drift
bone is apposed
on the distal
alveolar wall
bone is resorbed
on the mesial
alveolar wall.

39. Occlussal Movement
It is physiologic tendency
of all teeth to move
towards the occlussal
plane
During occlussal
drift, there is
periapical bone
appossition causing
tooth elongation

40. Self-Evaluation Review
1. Define alveolar
2. Discuss alveolar bone structure
3. True or False
a. Alv. Bone is called cribriform plate because bundles of Sharpey’s fibers are
inserted in it ( )
b. It is called lamina dura because it appears radiolucent in x-ray ( )
c. Bundles bone is more found in the distal wall of the alveolar process ( )
d. Cancellous bone of the supporting bone is very sensitive to variation in
functional forces ( )
4. Discuss the radiographic appearance of the alveolar bone
5. Discuss bone remodeling & modeling with its applications
6. In mesial drift bone…………….is found mesial alveolar bone & ……….. is
found distal alveolar bone

41. • Antonio Nanci: Ten cat`s Oral Histology: Development, Structure, and
Function, 8th ed. Elsevier Health Sciences, Mosby, 20`3
• Bhasker, S.N.: Orban’s Oral Histology and Embryology, Edition By G.S.
Kumar, Mosby 13th ed. 2011
• Avery, J.K. : Oral development and Histology, 3rd ed New York Thieme
2002
• Avery, J.K., Daniel, J & Chiego, Jr: Essential of Oral Histology and
Embryology. A clinical Approach 4th ed 2013
• Berkovitz, B.K.B., Holland, G.R. & Moxham, B.J.: Oral Anatomy, histology
and Embryology, 4th ed Mosby 2009