The document provides information about alveolar bone, including its development, functions, composition, classification, gross morphology, histology, bone formation, bone resorption, and bone remodeling. It defines alveolar bone as the portion of maxilla and mandible that forms and supports the tooth socket. It develops from the dental follicle during tooth eruption. The size and shape of alveolar bone is dependent on the teeth. It has important functions like housing tooth roots and providing attachment for the periodontal ligament and muscles.

1. ALVEOLAR BONE
Dr. Sangeetha
GUIDED BY
Dr NEETA BHAVSAR
HEAD OF DEPARTMENT
DEPARTMENTOF PERIODONTIA

2. CONTENTS
• INTRODUCTION
• DEVELOPMENT OF ALVEOLAR BONE
• FUNCTIONS
• COMPOSITION OF BONE
• CLASSIFICATION OF BONE
• GROSS MORPHOLOGY
• HISTOLOGY
• BONE FORMATION
• BONE RESORPTION
• BONE REMODELLING
• BONE LOSS IN VARIOUS CONDITIONS
• CONCLUSION
• REFERENCES

3. INTRODUCTION
DEFINITION - Alveolar bone is the portion of maxilla and mandible that forms
and support the tooth socket.
• Together with root cementum and periodontal ligament the alveolar bone
constitutes the attachment apparatus of the tooth
• Since alveolar processes develop and undergo remodeling with tooth
formation and eruption, they are tooth dependent bony structures.
• Therefore the size , shape , location, function of teeth determine their
morphology
• Alveolar bone also called the FUNCTIONAL BONE because it is susceptible to
functional changes(it is lost after tooth extraction)

4. DEVELOPMENT OF ALVEOLAR BONE
• Alveolar process consists of bone which is formed both by cells from
the dental follicle (alveolar bone proper) & cells which are
independent of tooth development
• Maxilla & mandible develop from the 1st branchial arch or
mandibular arch.
• The maxilla forms within the maxillary process & mandible forms
within the fused mandibular processes of mandibular arch
• Both jaw bones start as small centres of intramembraneous
ossification around stomodeum

6. Both maxilla and
mandible develop
intramembraneously
8th week in utero
Alveolar process
develops from the
dental follicle during
eruption of tooth
Bell stage--
developing bone
becomes closely
related
The size of the
alveolus is
dependent upon the
size of the growing
tooth germ.
Resorption - inner
wall of the alveolus
Deposition -outer
wall
The developing
teeth lie in a trough
of bone -Tooth
Crypt
Teeth separated
from each other by
the development of
interdental septa.
With the onset of
root formation
intratrabecular bone
develops in
multirooted teeth
When deciduous
teeth shed, its
alveolar bon e
resorb
Alveolar process
gradually
incorporated into
maxillary or
mandibular body
Permanent tooth
move into place,
developing its own
alveolar bone from
its own follicle

7. • Hydroxyapatitecrystals formed
from minerals calcium and
phosphate along with hydroxy
carbonate, citrate
• Mg, Na, K, F – smaller quantity
2/3 inorganic
matter
• 90% collagen primarily type1
• 11-12%Non collagenous protein
• Osteocalcin
• Osteonectin
• BMP and proteoglycans
• Sialoproteins and phosphoproteins
1/3 organic
matter
COMPOSITION OF BONE

8. FUNCTIONS
To house
the roots of
teeth, which
is achieved
by the
insertion of
Sharpey’s
fibers into
the alveolar
bone proper
Provides
attachment
to the
forming
periodontal
ligament
Absorb and
distribute
occlusal
pressures
generated
during tooth
contact
Also gives
attachment
to muscles
Provides a
framework
for the
marrow
Reservoir of
ions,
especially
Ca

9. CLASSIFICATION OF ALVEOLAR BONE

16. STRUCTURE OF ALVEOLAR
BONE
The alveolar bone composed of two parts
1) Alveolar bone proper
2) Supporting alveolar bone

17. ALVEOLAR BONE PROPER
• The alveolar bone proper is a thin layer of compact bone
• Continuation of cortical plate forms the tooth socket
• It surrounds the roots of the teeth and gives attachment to the
principal fibers of periodontal ligament.
• It is perforated by many openings that carry the nerve and blood
vessels in to the periodontal ligament called cribriform plate
• Consists of lamellated bone and bundle bone

18. • Cribriform plate ( anatomical term),
• lamina dura (radiographic term) ,
• bundle bone( histologic term)
• Thickness – 0.1 to 0.5 mm

19. Bundle bone
The term bundle bone was chosen because the bundles of the principal fiber
continueinto bone as sharpey’s fibers
it appears as a dense white line in radiographs – lamina dura

20. Supporting alveolar bone
• It is the part of alveolar bone
which surrounds the alveolar
bone proper and gives support
to the socket
• It consists of two parts
1) cortical plates
2) spongy bone

21. CORTICAL PLATES
• Cortical plates 1.5 – 3mm thick in posterior region and thickness
various in anterior region
• It is continuous with the bony maxilla and mandible and is much
thicker in mandible than maxilla .
• They are thickest in mandibular premolar and molar area especially
buccal side
• It consists of compact bone and form outer and inner plates.

23. CANCELLOUS BONE
• Spongy bone (anatomical term), trabecular bone ( radiographic
term), cancellous bone ( histological term)
• It is fills the area between cortical plates and alveolar bone proper
• In the region of the anterior of the both jaws the supporting bone
usually thin, so no spongy bone is found.
• The presence of trabeculae enclosing irregular marrow spaces lined
with the layer of thin, flattened endosteal cells
• Matrix consists of irregularly arranged lamellae separated by
incremental and resorption lines

24. INTERDENTAL SEPTUM
• Bony partition that separate the adjacent alveoli
• Coronally septa is thin and fused consists of only inner cortical plate
• Apical septa is thicker and contain intervening cancellous bone
• Mesiodistal angulation of interdental septum is parallel to line drawn
CEJ of approximating the teeth ( Ritchey et al,1935)
• If interdental septum is narrow , septum may consists of only
cribriformplate
• If roots are together, an irregular window can appear in between
adjacent roots.

26. • The shape of interdental bone is a function of the tooth form and
embrasure width
• The more tapered the tooth , the more pyramidal is bony form
• The wider the embrasure , the more flattened is the interdental bone
mesiodistally and buccolingually

27. INTERRADICULARSEPTA
• The bone between roots of multirooted teeth
• It contain perforating canals of Zukerkandl and Hirschfeld nutrient
canal

28. BASAL BONE
• It is osseous structure of maxilla and mandible except the alveolar
process
• Anatomically there is no distinct boundary exists between the body of
the maxilla / mandible and their alveolar process

29. OSSEOUS TOPOGRAPHY
Normally: prominence on the labial version: on the lingual version:
Of the roots with the margins of the labial the margins of the
Intervening vertical bone is thinned to a labial bone is blunt &
Depression that taper knife edge & presents rounded& horizontal
Toward the margin an accentuated arc rather than arcuate
in the direction of apex

30. RED
HEMATOP
OIETIC
MARROW
• Embryo & newborn
• Ribs , sternum, vertebrae, skull,
humerus
• hemopoiesis
YELLOW
FATTY
MARROW
• Adult
• Red marrow foci found
sometimes in maxillary
tuberosity and angle of ramus
• Storage of energy

31. Cells
Osteoblast
Osteocyte
Bone lining cells
Osteoprogenitor
cells
Osteoclasts
Osteogenic cells
Osteoclast cells
HISTOLOGY

32. MATRIX COMPONENT
INORGANIC
CALCIUMHYDROXY
APATITE CRYSTALS
ORGANIC
COLLAGENMATRIX
NONCOLLAGEN
MATRIX
OSTEOCALCIN
OSTEONECTIN
OSTEOPONTINAND
BONESIALOPROTEIN
PROTEOGLYCAN
LYSYLOXIDASE AND
TYROSINE RICH ACIDIC
MARTRIX PROTEIN

33. OSTEOPROGENITOR CELLS
• The stem cell population that gives
osteoblast are called osteoprogenitor
cell
• They are fibroblast like cells with an
elongated nuclei and few organelles.
• Their life cycle may involve up to about
eight cell divisions before reaching
osteoblast stage
• They reside in the layer of cells beneath
osteoblast layer, in the periosteal region,
in the periodontal ligament or in the
marrow spaces

34. OSTEOBLAST
• During embryonic development,
intramembranous bone of
maxilla and mandible initially
forms from osteoblast arising
from condensing mesenchyme
in facial region
• The most active secretory cells
in the bone

35. FUNCTIONS
• Secrete the type 1 collagen and non collagens proteins like sialoprotein,
osteopontin, osteonenctin and growth factors –BMP, TGF, PLDGF and
insulin like growth factor
• Express and release alkaline phosphate, which has been closely
associated with new bone formation and bone remodeling
• Total alkaline phosphate activity has been recognized as a reliable
indicator of osteoblast function
• In addition it has controlling influence activating osteoclast it contains
receptor for the parathyroid hormone and regulates the osteoclast
response to this hormone
• Periosteum also serves the as important reservoir of osteoblast.

36. OSTEOCYTE (NERVE CELLS OF BONE)
• Osteocytes are entrapped osteoblast within the bone
• Most abundant cells and communicate with each other and other on
the surface of bone via dendritic process encapsulated in canaliculi
• Play role in calcium homeostasis
• Exchange of metabolic and biochemical messages occurs between
blood stream and canaliculi
• Decreased quantity of synthetic and
secretory organelles

37. BONELININGCELLS
• When bone surface neither in
formative not in resorptive phase,
the surface is completely lined by
a layer of flattened cells called
bone lining cells
• Regarded as post proliferative
osteoblast
• Retain gap junction with osteocyte

38. OSTEOCLAST
• Originate from hematopoietic
tissue
• Fusion of mononucleate cells to
form a multinucleated cell
• Very large and 5-10 nuclei
• Mobile and capable of
migrating, lie in howships
lacunae
• Acidophilic cytoplasm
• Active osteoclast has ruffled
border facing bone , hydrolytic
enzymes are secreted

39. • At the periphery of the ruffled
border the plasma membrane
smooth and closely apposed to
the bone surface
• The adjacent cytoplasm, devoid
of cell organelles, enriched in
actin, vinculin, and talin, protein
associated with integrin
mediated cell adhesion clear
(sealing) zone
• This zone create the
microenvironment in which
resorption can take place

41. Bone Reversal line or cementing line- -The site of change from bone
resorption to bone deposition is represented by a scalloped outline. -Rich
in sialoprotein & osteopontin.
Resting line – Rhythmic deposition of
bone with periods of relative quiescence
seen as parallel vertical lines

42. MATRIXCOMPONENTS
• COLLAGEN: Collagen comprises the major (80–90%) organic
component in mineralized bone tissues.
• Type I collagen (>95%) is the principal collagen in mineralized bone,
together with Type V (<5%) collagen.
• In addition, both type III and XII collagens are also present.
• Sharpey’s fibres contain type III collagen with type I collagen.
• The expression of type XII collagen in alveolar bone is related to
mechanical strain.
• Type I,V & XII are expressed by osteoblasts
• Type III & some type XII collagen appear to be produced by fibroblasts
during formation of periodontal ligament

43. NON-COLLAGENOUSPROTEIN
• Comprise the remaining 10% of the total organic content of
the bone matrix.
• OSTEOCALCIN ( Bone gla protein)
• First non collagenous protein to be recognized.
• Found in bone matrix and specifically localizes to developing
bone
• It is regulated by Vitamin D3 and Parathyroid hormone.
• The carboxy terminal segment of osteocalcin acts as a
chemoattractant to osteoclast precursors, suggesting a role in
bone resorption.

44. OSTEOPONTIN AND BONESIALOPROTEIN
• They were previously termed as Bone sialoproteins I and II.
• Bone sialoprotein is thought to function in the initiation of mineral
crystal formation in vivo.
• Osteopontin is a potent inhibitor of hydroxyapatite crystal growth.
• Osteopontin transcription is strongly upregulated by Vitamin D3
whereas Bone sialoprotein transcription is suppressed by Vitamin D3.
• It could play a role in the regulation of cell adhesion and proliferation.

45. SPARC(secretedproteins& acidic richin cysteins) /
Osteonectin/ BM-40
• It is predominantly bound to hydroxyapatite crystals.
• SPARC, which has also been characterized in basement membranes as
BM40, is a secreted calcium-binding glycoprotein that interacts with a
range of extracellular matrix molecules.

46. CHONDROITIN SULFATEPROTEOGLYCAN
• Two small proteoglycans, Biglycan (chondroitin sulfate proteoglycan I)
and Decorin (chondroitin sulfate proteoglycan II).
•These regulate collagen synthesis.
• Byglycan is more prominent in developing bone and has mineralised
to pericellular areas
• Its precise function is not known ,but it can bind TGF-β and
extracellular matrix macromolecules including collagen and thereby
regulate fibrillogenesis
Decorin: Binds mainly with in the gap region of collagen fibrils and
assuggested by its name, decorates fibril surface
• The primary calcification in bones as reported to follow removal of
decorin and the fusion of collagen fibrils

47. VASCULAR SUPPLY AND NERVE SUPPLY
• Derived from inferior and superior alveolar arteries of maxilla and
mandible, venous drainage accompanies the arterial supply,
• Branches from anterior, middle and posterior superior alveolar nerve
for maxilla and branches from inferior alveolar for mandible

48. BONE FORMATION
• Formation of bone, which appears to be linked with bone resorption
to maintain bone mass, involves the proliferation and differentiation of
stromal stem cells along an osteogenic pathway that leads to the
formation of osteoblasts
• Osteoblasts synthesize the collagenous precursors of bone matrix and
also regulate its mineralization

49. REGULATORSOF BONEFORMATION
• The overall integrity of bone is controlled
by hormones, proteins secreted by
hematopoietic bone marrow cells and bone
cells.
• HORMONES
• Parathormone
• Vitamin D3
• Glucocorticoids
• Thyroid Hormone
• Growth Hormone
• Insulin
• LOCAL REGULATORS
• Platelet derived growth factor
• Insulin growth factors
• Transforming growth factor-β
• Bone morphogenetic protein
• Fibroblast growth factor

50. BONERESORPTION
• It is the process of removal of mineral and
organic componentsof extracellular matrix
of bone by osteolytic cells called
osteoclasts.
• SEQUENCE OF EVENTS OF BONE
RESORPTION
• First phase - Formation of osteoclast
progenitors in the hematopoietic tissues.
• Second phase - Activation of osteoclastsat
the surface of mineralized bone.
• Third phase - Activated osteoclasts
resorbing the bone.

51. TENCATE SEQUENCE OF RESORPTION
• Attachment of osteoclast to the mineralized surface of bone.
• Creation of sealed acidic environment through action of the proton
pump, which demineralize the bone and expose the organic matrix
• Degradation of the exposed organic matrix to its constituent amino
acids by the action of released enzymes ,such as acid phosphatase
and cathepsin.
• Sequestering of mineral ions and amino acids with in the osteoclast

52. BONE REMODELLING
• The process by which overall shape and size of bones is established is
referred to as bone remodelling or turnover.
• It occurs in discrete, focal areas involving groups of cells called bone
remodelling or basic multicellular units.
• During this phase bone is formed along the periosteal surface and
destroyed along the endosteal surface
• The status of bone represents the net result of a balance between the
two processes. ‘Coupling’ of bone resorption and formation

53. BONEMULTICELLULAR UNIT
• Osteoclasts
• Osteoblasts
• Blood vessels& Pericytes
• The main functions of
remodeling are
• To prevent the accumulation of
damaged and fatigued bone by
regenerating new bone.
• To allow bone to respond to
changes in mechanical forces.
• To facilitate mineral
homeostasis.

54. Decrease in bloodca
1. Detected by
receptors on chief cells
of parathyroid gland
Release of PTH
Stimulateosteoblast to
release IL-1, IL-6
Stimulatemonocyte to
migrate to bone area
Monocyte coalesces to
form multinucleated
osteoclast in the
presence of LIF
Bone resorption
Release of ca ionsfrom
hydroxyapatitecrystals
Normal blood ca level
PTH secretion stopped
by feedback
mechanism

55. • The leading edge of resorption –
Cutting cone
• Released cytokines [ BMP & IGF]
stimulate stem cells to
differentiate into osteoblasts.
• osteoblasts secrete osteoid -
Filling cone

56. FACTORS INFLUENCING
REMODELLING
LOCAL INFLUENCE FACTORES:
1) Functional requirement
2) Age related changes
SYSTEMIC INFLUENCE FACTORS
Hormones (PTH, vit D, calcitonin)
REGULATION OF BONE
REMODELLING
Mechanical control: mechanical
stimulation of bone tissue
accelerate periosteal bone
formation in the regions of high
stress and effectively strengthens
bone
Local
systemic

57. AGE CHANGES
• Similar to those occurring in remainder of skeletal system
• Osteoporosis with ageing
• Decreased vascularity
• Reduction in metabolic rate and healing capacity(implants, extraction
sockets, bone grafts)
• Bone resorption may be increased or decreased
• More irregular periodontal surface

58. FACTORS DETERMINING BONE MORPHOLOGY
• Normal variation in alveolar bone
• Exostoses
• Tauma from occlusion
• Food impaction
• Aggressive periodontitis

59. NORMALVARIATIONSIN ALVEOLAR BONE
• Thickness, width and crestal
angulation of interdental septa
• Thickness of facial and lingual
alveolar plates
• Fenestrations and dehiscences
• Alignment of teeth
• Root and root trunk anatomy
• Root position within alveolar
process

60. FENESTRATION& DEHISCENCE
• Facial > lingual
• Arteriors > posteriors
• Frequently bilateral
• 20% of all teeth affected
• Caused due to malposition, root
prominence, labial protrusion and a
thin cortical plate
• Can complicate procedure and
outcome of periodontal surgery

61. EXOSTOSIS
1) These are outgrowths of bone of varied size and shape.
2) They can occur as small nodules, large nodules, sharp ridges, spike-
like projections or any combination of these.
3) In rare cases, found to develop after the placement of free gingival
grafts.

62. TRAUMA FROM OCCLUSION
• Trauma from occlusion may be factor in determining the dimension
and shape of bone deformities.
• It may cause thickening of cervical margin of alveolar bone or a
change in bone morphology( funnel like crestal bone and buttressing
bone

63. BUTTRESSINGBONE FORMATION( LIPPING)
• Bone formation sometimes occurs
in an attemptto buttress bony
trabeculae weakened by resorption.
• When it occurs within the jaw,
termed Central buttressing bone
formation.
• When it occurs on the external
surface, termed Peripheral buttressing
bone formation
• The latter may cause bulging of the
bone contour, termed as Lipping,
which sometimes accompanies the
production of osseous craters and
angular defects.

64. FOOD IMPACTION
• Forceful wedging of food into the periodontium by occlusal forces
• Interdental bone defects often occur where proximal contact is
abnormal or absent.
• Pressure and irritation from food impaction contribute to the
inverted bone architecture.
• Poor proximal relationship may result from a shift in tooth position
because of extensive bone destruction preceding food impaction

65. AGGRESSIVE PERIODONTITIS
• Aggressive periodontitis usually results in attachment and bone loss
around incisors and first molar
• Bone loss usually horizontal in nature around incisors , vertical or
angular pattern of alveolar the first molar
• The cause of localized destruction is unknown

66. BONE DESTRUCTION PATTERNSIN PERIODONTAL
DISEASE
• Horizontal bone loss
• Vertical or angular defect
• Osseous craters
• Bulbous bone contour
• Reversed architecture
• Ledges
• Furcation involvement

67. HORIZONTAL BONE LOSS
• Most common pattern of bone loss in periodontal disease.
• Bone is reduced in height.
• Bone margin remains approximately perpendicular to the tooth
surface.
• The interdental septa and facial and lingual plates are affected, but
not necessarily to an equal degree around the same tooth.

68. VERTICAL OR ANGULAR DEFECTS
• Occur in an oblique direction,
leaving a hollowed-out trough in
the bone along side of the root;
the base of the defect is located
apical to the surrounding bone.
• Vertical defects occurring
interdentally can generally be
seen on the radiograph,
although thick, bony plates
sometimes may obscure them.
• Angular defects can also appear
on facial and lingual or palatal
surfaces but are not seen on
radiographs.

69. APPARENT OR ACTUAL VERTICAL DEFECT
Line drawn across
adjacent CEJ’s should
parallel crestal lamina
dura (Ritchey &
Orban 1950)

70. OSSEOUS CRATERS
• Concavities in the crest of the
interdental bone confined within the
facial and the lingual walls.
• Reasons for high frequency of
interdental crater
• Interdental area collects plaque and
is difficult to clean.
• The normal flat or even concave
faciolingual shape of the interdental
septum in lower molars may favour
formation.
• Vascular patterns from the gingiva to
the centre of the crest may provide a
pathway for inflammation

71. REVERSED ARCHITECTURE
• These defects are produced by
loss of interdental bone,
including the facial and/or
lingual plates, without
concomitant loss of radicular
bone, thereby reversing the
normal architecture
• More common in the maxilla.

72. FURCATION INVOLVEMENT
• Invasion of bifurcation and trifurcation of multirooted teeth with
periodontal disease
• Classification of furcation:
class –I class II

73. FURCATION INVOLVEMENT
Class III class IV

74. CONCLUSION
• The alveolar processes develop and undergo remodelling with the tooth
formation and eruption- Tooth dependent bony structure.
• Although its constantlychanging its internal organization, it retains the same
form from childhood through adult life.
• Maintenance of alveolar bone is also compromised following trauma and
inflammatory episodes associated with periodontal disease.
• Preventing, or minimizing, alveolar bone loss is a major clinical objective in
dentistry, and restoration of alveolar bone mass after losses have been incurred is
extremely difficult to attain. The interdependenceof teeth and alveolar bone
make the restoration of alveolar bone more difficult than simply enhancing
osteogenesis
• Thus the sound knowledge of alveolar bone anatomy , histology, physiology will
help the clinician in diagnosing and treatment planning and favourable outcome
of surgical procedure performed.

75. REFERENCE
• Clinical periodontology & implant dentistry 5th edition – jan lindhe
• JAROSODEK&MARCD. MCKEE-Molecular & cellular biology of alveolar
bone, periodontology 2000.
• Contemporary Implant Dentistry, Carl E. Misch
• Carranza’s Clinical Periodontology, Newman, Takei, Klokkevold,
Carranza