1.
Presented by:
Dr.Ayesha Taha
JR I
Department of Pedodontics
and Preventive Dentistry
SPPGIDMS, Lucknow

2.
CONTENT
•Introduction
•Bone-
•Classification
•Bone Histology
•Composition
•Definition of Alveolar bone
•Development of Alveolar bone
•Parts of Alveolar bone
•Interdental Septa
•Alveolar crest

3.
•Thickness of Alveolar bone
•Periosteum
•Endosteum
•Functions of Alveolar bone
•Remodeling and Repair
•Blood supply
•Nerve supply
•Age Changes
•Clinical Considerations
•Conclusion
•References

4.
INTRODUCTION
BONE is a specialized connective tissue that is mainly
characterized by its mineralized organic matrix.
The alveolar process is the portion of maxilla and
mandible that forms and support the tooth socket.
It forms when tooth erupts to provide the osseous
attachment to the forming periodontal ligament; it
disappears gradually after the tooth is lost.

5.
These are tooth dependent bony structures therefore
the size, shape, location and function of the teeth
determines their morphology.

6.
CLASSIFICATION
OF BONE
BASED ON DEVELOPMENT
•Endochondral bone
•Intramembranous bone
•Sutural bone
BASED ON THEIR MICROSCOPIC STRUCTURE
IMMATURE BONE OR WOVEN BONE
&
MATURE BONE
•Compact (cortical) bone
•Cancellous (spongy) bone

7.
 Bone formation is preceded by
formation of cartilage which is
later replaced by bone
(Horton,1990).
Occurs in extremities of all
long bones, in vertebrae, in ribs,
in articular extremities of the
mandible and the base of skull.
Endochondral bone

8.
•Bone develops directly within
the soft connective tissue.
•Occurs in Maxilla and Body of
mandible, cranial vault and
midshaft of long bones.
INTRA MEMBRANOUS /
DIRECT BONE FORMATION

9.
•Bone forms along suture margins
•Not seen in relation to alveolar
bone.
•Occurs in skull, fibrous joints.
•Helps skull and face to
accommodate growing organs like
brain.
SUTURAL BONE
GROWTH

10.
Immature bone /Fibrous bone :
• These have more cells & fibers in them.
• These are first formed bone.
• In humans they are found only in fetus or in sockets
of alveolar bone, during fracture repair and sutures
of the skull.
• Also Known as Woven Bones.
Mature bone /Lamellar bone: The type of bone which
are composed of thin plates (lamellae) of bony
tissue.
•Compact (cortical) bone
•Cancellous (spongy) bone

11.
COMPACT (CORTICAL) BONE
• Composed of dense and concentrically arranged bony
trabeculae or lamella.
• More solid with fewer cavities.
• Found external to spongy bone
• Presence of haversian system.

12.
CANCELLOUS (SPONGY) BONE
•Composed of bone trabeculae or spicules.
•Has a simple and less organized architecture.
•Has a lattice-work pattern with numerous small cavities.
•Found internal to compact bone.
•Has no haversian system.

13.
Bone
Outer compact bone Central medullary cavity
(Trabacular / Spongy /
Cancellous bone)
BONE HISTOLOGY

14.
• Bone whether Compact or Trabecular are
deposited in layers, or lamellae, each lamella
being about 5µm thick.
Three distinct types of layering are recognised :
Circumferential lamellae encloses the entire
adult bone, forming its outer and inner perimeters.
Concentric lamellae forms the bulk of compact
bone & forms the basic metabolic unit of bone – The
Osteon.
Interstitial lamellae interspersed between adj.
concentric lamellae and fills the spaces between
them.

15.
COMPOSITION OF
BONE
BONE
Inorganic (67%)
(Hydroxyapatite )
Organic (33%)
Collagen (28%)
Non collagenous
Proteins (5%)
Cells
1.Ostoblasts
2.Osteoclasts
3.Osteocytes
4.Bone lining cells

16.
•Collagen -Type I collagen
•Noncollgenous proteins- sialoproteins,osteocalcin,
osteonectin, osteopontin,proteoglycans, growth
factors & serum proteins.

17.
Alveolar process is that portion of the maxilla and
mandible that forms and supports the tooth sockets
(alveoli).
DEFINITION
Joseph P Fiorellini, David M Kim, Satashi O Ishikawa. The
Tooth Supporting Structures. In: Fermin A. Carranza, editor.
Clinical Periodontology, 10th edition, Noida: Elsevier; 2009.
p.68–92.

18.
DEVELOPMENT OF
ALVEOLAR BONE
Near the end of 2nd month of fetal life, mandible
and maxilla form a groove that is opened toward the
surface of the oral cavity.
As tooth germ starts to develop, bony septa form
gradually.
The alveolar process starts developing strictly during
tooth eruption.

19.
PARTS OF
ALVEOLAR BONE

20.
Inner socket
wall of thin
compact bone
called alveolar
bone proper.
Cancellous
trabaculae between
these two compact
layers.
An external
plate of
cortical bone
Alveolar process
consists of :

21.
The parts of the alveolar bone
1. Alveolar bone proper
2. Supporting alveolar bone
o Cortical plates
o Spongy bone

22.
ALVEOLAR BONE
PROPER
•Cribriform plate (anatomic term)
•Lamina dura (radiographic term)
•Bundle bone (histologic term, coined by Stein and
Weinmann, 1925)
•It is that bone in which the principal fibers of the
periodontal ligament are anchored. (Sharpey’s fibers).
•This type of bone contains several layers of bone
deposited in orientation parallel to the tooth socket
wall.

23.
It is characterized by the scarcity of the fibrils in
the intercellular substance.
It contains fewer fibrils than lamellated bone.
Since bundle bone contains more calcium salts per unit
area than other type of bone tissues, they appear as
dense radioopacities in roentgenograms.

24.
SUPPORTING ALVEOLAR
BONE
 Surrounds the alveolar bone proper and gives
additional support.
 It consists of
o Cortical plates
o Spongiosa/ Cancellous

25.
•It consists of compact bone and forms the outer and
inner plates of alveolar processes.
•It is found in mandible & maxilla although cortical bone
is more prominent in mandible.
•It makes upto 80% of the body of the mandible.
CORTICAL BONE

26.
•It is formed by haversian bone and
compacted lamellae.

27.
•Spongy bone (anatomic term)
•Trabecular bone (radiographic term)
•Cancellous bone (histologic term)
Presence of trabeculae enclosing irregular marrow
spaces lined with a layer of thin, flattened endosteal
cells.
Variation in trabeculae pattern depending upon occlusal
forces and genetically.
CANCELLOUS BONE

28.
 Matrix consists of irregularly arranged lamellae
separated by incremental and resorption line.
It makes upto 20% of the body of the mandible.
Cancellous bone is metabolically more active, thus
skeletal metabolism is equal between both cortical &
cancellous bone.

29.
INTERDENTAL SEPTA
•The interdental septa are bony partitions that separate
adjacent alveoli.
•Coronally, the inner & outer cortical plates fuse 1mm apical to
the Cemento-enamel junction.
•The mesiodistal angulation of crest of the interdental septum
usually parallels a line drawn between the CEJ of the
approximating teeth.

30.
The mesiodistal and faciolingual dimensions and shape
of the interdental septum are governed by the size and
convexity of the crowns of the two approximating teeth,
as well as by the position of the teeth in the jaw and
their degree of eruption.

31.
ALVEOLAR CREST
•The alveolar crest is normally rounded or beaded.
•However on the buccal aspect of incisor & canine, the
bone margins ends in a fine sharp edge.

32.
•The contour of crestal margin varies with the shape of
root.
•When root surface is flat, the contour is straight or flat.
•When convex, the contour is scalloped.
•When concave, the bone margin arch coronally.
•Scalloping is accenuated when bone is thin & reduced when
thick.

33.
THICKNESS OF ALVEOLAR BONE-
MAXILLA
•The alveolar bone is thicker on
the palatal aspect than on the
buccal.
•The bone plate is thicker on
the posterior region than on
the anterior region.

34.
THICKNESS OF ALVEOLAR
PROCESS IN MANDIBLE
•In the incisor & premolar region, bone plate is
thinner on the buccal aspect than on the lingual.
•In the molar region, Alveolar Process is thicker on
the buccal than on the lingual.

35.
PERIOSTEUM &
ENDOSTEUM
The outer aspect of cortical bone is surrounded by a
connective tissue membrane which has two layers.
1. The outer fibrous layer – Periosteum
2. The inner cellular layer - Endosteum

36.
PERIOSTEUM
•It consists of dense irregular connective tissue.
•It serves as a reservoir of osteoblasts.
•The periosteum is important during growth,
fracture repair and healing around implants.
•Usually at the periosteal surface, bone
formation exceeds bone resorption, creating a
net increase in outer diameter of bone with age.

37.
PERIOSTEUM
Its functions are :
o Medium through which muscles, tendons and
ligaments are attached to bone.
o Nutritive function to the bone
o Osteoprogenitor cells – Important role during
development and repair after fracture
o Fibrous layer- acts as limiting membrane
(exostoses in cases of periosteal tear)
o Formation of tubercles at site of attachment of
tendons.

38.
• Rich in blood vessels,
nerves.
• Contains collagen fibres
and fibroblasts.
Outer
layer(fibrous)
• Composed of osteoblasts
and osteoprogenitor cells
• Cellular periosteum
Inner layer
(osteogenic)

39.
ENDOSTEUM
•The tissue lining the internal bone cavities is called
Endosteum.
•It is composed of a single layer of osteoblasts and a
small amount of connective tissue.
•It consists of:
An inner layer which is osteogenic layer
An outer layer which is fibrous layer.
•It consists of loose connective tissue containing
osteogenic cells, that physically seperates the bone
surface from marrow within.

40.
FUNCTIONS OF
ALVEOLAR BONE
1.Houses -root of teeth.
2. Anchors - root of teeth to Alveoli.
3. Helps to move teeth for better occlusion.
4.Helps to absorb and distribute occlusal forces
generated during tooth contact.
5. Supplies vessels to Periodontal ligament.

41.
6. Houses and protects developing permanent teeth,
while supporting primary teeth.
7. Organizes eruption of permanent and primary teeth.
8. Acts as a reservoir for ions.
9. Provide attachment to muscles.

42.
REMODELLING & REPAIR OF
ALVEOLAR BONE

43.
BONE TURNOVER
(REMODELING)
Modelling -The process by which the overall size and
shape of bones is established.
Remodeling –
•The process by which there is constant resorption of bone
occuring on a particular bony surface, followed by a phase
of bone formation.
•It is the replacement of old bone by new bone.
•Bone turnover does not stop when adulthood is reached,
although its rate slows.
•It usually takes place at the periosteal & endosteal
surfaces leading to changes in shape of growing bone.

44.
BONE REMODELLING
During remodeling, termination of bone
resorption by osteoclasts and the initiation of
bone formation by osteoblasts occurs through a
coupling mechanism.
The coupling process ensures that the amount of
bone removed is similar to the bone laid down
during the subsequent bone formation phase.
In certain diseases and with age, the resorption
exceeds formation.

45.
SEQUENCE OF EVENTS IN BONE
REMODELLING
First, the Osteoclasts tunnel into the surface of bone
which lasts for 3 weeks
In Haversian canals, closest to the surface, osteoclasts
travel along a vessel, resorb the haversian lamellae and a
part of circumferential lamellae, and form a resorption
tunnel or CUTTING CONE.

46.
After sometime the resorption ceases and osteoclasts
are replaced by osteoblasts.
These osteoblasts lay down a new set of haversian
lamellae , encircling a vessel upon a reversal line.
The entire area of osteon where active formation
occurs is termed as FILLING CONE.

47.
BLOOD SUPPLY
It receive blood supply from inferior and superior
alveolar arteries for mandible and maxilla ,
respectively and reaches Periodontal ligaments from
three sources; apical vessels, penetrating vessels from
the alveolar bone and anastomosing vessels from
gingiva.

48.
Nerve Supply
Labial aspect of maxillary incisors, canines & premolars
is innervated - superior labial branches from the
infraorbital nerve.
Buccal aspect of maxillary molar regions innervated -
branches from the posterior superior alveolar nerve.
Palatal aspect by greater palatine nerve, except for
incisor which is innervated by long sphenopalatine nerve.

49.
• Lingual aspect in mandible -
lingual nerve
• Labial aspect of mandibular
incisors & canines - mental
nerve.
• Buccal aspect of the molars -
buccal nerve.
• The nerve enters the
periodontal ligament through
Volkmann's canal of alveolar
bone.

50.
AGE CHANGES
• Similar to those occurring in remainder of skeletal system
• Osteoporosis with ageing
• Decreased vascularity
• Reduction in metabolic rate and healing capacity
• Bone resorption may increase or decrease
• More irregular periodontal surface

51.
• Thinning of cortical plates
• Rarification of bone
• Reduction in no. of trabeculae
• Lacunar resorption more prominent
• Susceptibility to fracture
• Thickening of collagen fibers
• Decrease in water content

52.
CLINICAL CONSIDERATIONS
• FENESTRATION
Isolated areas in which the root is denuded of bone and
root surface is covered only by periosteum and
overlying gingiva is termed as fenestration.
• DEHISCENCE
When denuded areas extend through the marginal
bone , defect is called dehiscence.

53.
FENESTRATION
DEHISCENCE

54.
MANAGEMENT OF FENESTRATION AND
DEHISCENCE
Several treatment modalities includes:
• Root planning along with chlorhexidene mouth rinsing,
• Full thickness mucogingival flap with primary closure,
• Pedicle flap surgery,
• Free gingival grafting,
• Guided tissue regeneration and
• Combination of bone grafting and free mucosal graft.

55.
Buttressing bone- adaptive mechanism against occlusal
force (thickened cervical portion of alveolar plate)
Buttressing bone
Management: Osteoplasty followed by gingivoplasty.

56.
The bone l o ss i n periodontal disease occurs at
local sites, but i t i s reg ulated by both
syst emic and local fact ors .
Bone resorpt ion is probably t he m ost crit ical
factor i n periodont al att ac hm ent lo ss leading
t o event ual t oot h loss .
Safe guarding the integrity of the periodontal
lig ament and t he alveolar bone i s one of the
most import ant challeng e f o r t he clinician .
CONCLUSION

57.
Joseph P Fiorellini, David M Kim, Satashi O Ishikawa. The Tooth
Supporting Structures. In: Fermin A. Carranza, editor. Clinical
Periodontology, 10th edition, Noida: Elsevier; 2009. p.68–92.
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edition;68–92.
R.Tencate,AntonioNanci;oralhistology,development,structure&f
unction;6thedition;111–143
Hagel-Bradway S, Dziak R: Regulation of bone cells
metabolism, J Oral Pathol Med 18:344,1989
Junqueria LC, Carneiro J, Kelley RO: Basic Histology, ed6,
Norwalk, Conn, 1989, Appleton & Lange.
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