This document discusses the structure, development, composition, histology, remodeling, and age-related changes of alveolar bone. It describes alveolar bone as consisting of alveolar bone proper surrounding tooth roots and supporting alveolar bone made of cortical plates and spongy bone. Development begins in the second month of fetal life. The composition includes inorganic material, organic material, and water. Histologically, alveolar bone contains lamellae, osteons, and Haversian systems. Bone is continuously remodeled through formation and resorption, and aging leads to changes like thinner trabeculae and greater marrow spaces.

2. • CLASSIFICATION AND STRUCTURE OF BONE
• ALVEOLAR BONE
• DEFINITION
• CLASSIFICATION
• STRUCTURE OF ALVEOLAR BONE
• DEVELOPMENT
• CHEMICAL COMPOSITION
• BONE HISTOLOGY
• BONE REMODELING
• CONCLUSION

3. BONE -CLASSIFICATION
• ACCORDING TO SHAPE
• Long bones
• Short bones
• Flat bones
• Irregular bones
• Sesamoid bones
ACCORDING TO DEVELOPMENT
• ENDOCHONDRAL BONES
• INTRAMEMBRANEOUS BONES

4. • According to structure
• A.Mature bone
• Compact bone (Cortical bone)
• Cancellous bone (Spongy bone)
• B. Immature bone (Woven Bone)

5. Composition of Bone
• Inorganic material: 65%
• Organic : 25%
• Water :15%
• Bone histology:
• Unmineralised bone is termed osteoid.
• Adult bones: Outer dense sheet is known as compact bone
• Inner cavity contains yellow/ red bone marrow with rich network of bony
trabecular.
• This network is called trabecular,spongy or cancellous bone

6. Histology of Bone

7. • Outer compact bone and inner spongy bone
• PERIOSTEUM AND ENDOSTEUM
• The outer surface of compact bone is covered by dense layer called
periosteum.
• Divided into two:
• Outer fibrous layer - Periosteal layer
• Inner osteogenic layer-Endosteal layer

8. LAMELLA
• Three types of lamella in
compact and trabecular bone
• 1. Circumferential lamella
• 2. Concentric lamella
• 3. Interstitial lamella

10. Circumferential Lamella
• Lamella arranged
in parallel layers
around periosteal
surfaces.
• It forms the outer
perimeter of bone

11. Concentric Lamellae
• Lamellae arranged in concentric layers around a central
neurovascular canal called Haversian Canal.
• Also called osteon - Osteon is the functional unit of Bone.
• The bulk of compact bone is made up of concentric lamella or
Osteons.

12. Interstitial Lamella
• Fills the space between adjacent concentric lamella
• They are the fragments or remnants of old concentric lamella after
bone Remodelling.

13. Haversian System / OSTEON
• The concentric lamella are arranged along a central vascular canal
termed Haversian Canal.
• The Haversian Canal contains capillaries and lined by a single layer of
bone cells.
• The Haversian canal along with the concentric lamella is known as
Haversian System or Osteon.
• 9-20 concentric lamella within each Haversian System.
• Longitudinally running Haversian canals are interconnected by
horizontal canals known as Volkmann’s Canal.

15. • Alveolar process is the part of jaw bone in which teeth are found.
• It is dependent on the presence of teeth for development and
maintanence

16. Definition :
The part of maxilla or mandible that forms and
supports the socket of the teeth in which the teeth
are anchored.

17. ALVEOLAR BONE PROPER
• BUNDLE BONE
• LAMELLATED BONE
SUPPORTING ALVEOLAR BONE
• BUCCAL CORTICAL PLATE
• LINGUAL CORTICAL PLATE
• CENTRAL SPONGY BONE

18. STRUCTURE OF ALVEOLAR BONE
ALVEOLAR
BONE
ALVEOLAR
BONE
PROPER
LAMELLATED
BONE
BUNDLE
BONE
SUPPORTING
ALVEOLAR
BONE
CORTICAL
PLATE
SPONGY
BONE

21. Development:
• It starts in the second month of fetal life
• Ò Maxilla and mandible forms a groove that is open towards the
surface of the oral cavity.
• Developing tooth buds are enclosed in these grooves.
• Ò Major portion of the alveolar process begins with root formation and
eruption of the teeth.
• Ò During rapid growth alveolar crest shows characteristics of cartilage
and bone - CHONDROID BONE

22. ALVEOLAR BONE PROPER
 It surrounds the root of the tooth and gives attachment to the periodontal
ligament fibres.
 It consists of
 Lamellated bone
 Bundle bone
Lamellated bone consists of osteons.
Concentric lamellae along with a central blood vessel form an osteon.

23. BUNDLE BONE
 Part of the alveolar bone where periodontal ligament fibres are inserted
(attached).
 Bundle – bundles of fibres
 Sharpeys fibres – principal fibres of the periodontal ligament that are
embedded in the bone or cementum.
 Sharpeys fibres are seen perpendicular to the bundle bone.
 Other fibrils are less and are arranged parallel to the bundle bone
surface
 Radiographically is more radiodense due to presence of thick bone
without trabeculations and is called as “lamina dura”
 Alveolar bone proper has many openings for blood vessels and nerves –
is perforated and is called as “cribriform plate”
 Interdental and interradicular septa have canals known as canals of
“ zukerkandl and hirschfeld”

24. canal of zuckerkandl
and
herschfeld
Lamina Dura

25. CRIBRIFORM PLATE VS LAMINA DURA

26. SUPPORTING ALVEOLAR BONE
 It consists of two parts –
 Cortical plates (Outer and inner)
 Spongy bone
Cortical plates: these are made up of
compact bone & form the outer and
inner plates of alveolar bone.
Cortical bone varies in thickness in
different areas – it is thicker in the
mandible than in the maxilla and thicker
in the premolar-molar region than in the
anteriors.

27.  Spongy bone: it fills the area between the cortical plates and the
alveolar bone proper.
 It contains trabaculae of bone and marrow spaces.
 Types of spongy bone (spongiosa) :-
 Type I: the trabaculae are regular and horizontal like a ladder.This
is seen most commonly in the mandible.
 Type II: irregularly arranged delicate and numerous trabaculae.
This is seen most commonly in the maxilla.
The spongy bone is very thin or absent in the anterior regions of both
the jaws.

28. Spongy bone
Spongy bone

29. BONE REMODELING AND RESORPTION
 Bone is a dynamic tissue and is always undergoing changes to adapt
for functional forces, mesial drift, and eruption of teeth.
 There is constant formation and resorption of bone. Periods of
resorption alternate with periods of rest and repair.
 Lines seen in bone:
 Resting line: these lines correspond to the resting period in the
process of continous bone formation.
 Reversal line: when a period of bone resorption is followed by bone
formation, a dark line is seen which seperates the new bone from old
bone, this resembles the shape of howships lacunae.

30. BONE REMODELING

31. AGE CHANGES IN ALVEOLAR BONE
 Brittleness due to decreased water content
 Sponge bone become thin trabecula , wide marrow spaces
 Red bone marrow become fatty
 Osteoporosis
 Alveolar crest slope distally due to mesial tilting of teeth
 With loss of teeth and resorption of alveolar ridge mental foramen
become very close also maxillary sinus in upper jaw
Thank you!!

32. • Structure of alveolar bone
• Development
• Physical and Chemical composition
• Bone histology
• Bone remodeling
• Age changes of alveolar bone .