Alveolar bone is the bone that forms the sockets for teeth and provides attachment for the periodontal ligament fibers. It has two parts - the alveolar bone proper which surrounds the root and the supporting alveolar bone which provides structural support. The alveolar bone proper consists of bundle bone, the cribriform plate containing Volkmann's canals, and lamellated bone. Osteoblasts form new bone on the surface while osteoclasts resorb bone, allowing for remodeling around teeth. The morphology and structure of alveolar bone is dependent on the number, size, shape and position of teeth.

1. Alveolar Bone
SDM
Dept. Of Oral and Maxillofacial Pathology

2. Structure of Bone
Medulla
Cortex

4. Cells

5. Cells

6. Parts of bone
Periosteum &Endosteum
Types of lamellae
Harvesian system
VolKman canal
Cells of bone
Matrix
Marrow tissue

7. Immature Bone Mature bone
Woven/bundle/Coarse fibred Lamellated/fine fibred
Increase osteocytes
-larger
Less osteocytes- small
Lacunae-Wider Lacunae-smaller
Randomly arranged Osteon
Fibres-thick ,bundles Thin, slender, regular
arrangement, lamellae
Ground substance is more Less

8. Parts of bone
Periosteum &Endosteum
Types of lamellae
Harvesian system
Volkman canal
Cells of bone
Matrix
Marrow tissue

9. Gross appearance
Compact
Cancellous

10. Definition
“Alveolar Bone is that part of maxilla & mandible
that forms & supports the teeth”
“Alveolar process is that bone of the jaws
containing the sockets for the teeth”

11. Function
It furnishes a media for attachment of
periodontal ligament
Undergoes continous remodelling in
adaptation to occlusal forces.

12. Tooth Dependent
For its development & maintenance
Morphology of Alv. Bone depends on
Size
Shape
position of teeth
If teeth are lost, Alv bone undergoes atrophy
If teeth congenitally missing – Alv. Bone not developed

13. Parts of alveolar bone
Sockets which hold the teeth -Alveolus
Alveolus
Rim
Floor
Alv. crest
Fundus

14. Boundaries
No distinct boundary
Certain areas Alveolar bone fused with basal bone
Anterior maxillary region
Posterior Mandibular region.

15. Alveolar Bone
Cortical Plate
Central spongiosa
Bone lining the alveolus

16. Structure
Two Parts:
Alveolar Bone proper:
Thin lamellated bone that surrounds the root of the tooth
Gives attachment to the PDL Fibres
Supporting alveolar Bone:
Surrounds the alveolar bone Proper
Gives support to the socket

17. Alveolar Bone proper
That lines the socket
Forms the inner wall
Two Parts:
That facing the PDL –
Bundle bone
Cribriform plate
Lamina Dura
Lamellated Bone

18. That facing towards PDL
Immature bone
Undergoes continous remodelling
Tooth
PL

19. Cribriform plate
Anatomical name
Resembles a fine holed sieve
Perforated by – foramina
Transmit nerves &Vessels
Holes – Volkman’s Canals

20. Cribriform plate

21. Bundle Bone
Histologic Name
Provides attachment to PDL fibres
Bundles of Principle fibres are inserted as- Sharpey’s fibres

22. Lamina dura
Radiologic name
Alv bone –appears as radiopaque line
Due to overlapping effect of X-Rays

23. Histology of Bundle bone

24. Lamellated bone
Continous with supporting alveolar bone
Mature bone

25. Supporting alveolar bone
Two Parts
Cortical Bone
Spongiosa

26. Cortical Bone
Compact bone
Forms inner &outer plates of the
alveolar process
Variations:
Maxilla –thinner
Mandible -Thicker
Premolar, Molar region –Thicker
Anterior region -Thin

27. Buccal cortical plate – Thick
Lingual Cortical plate -Thinner
Relation to Local anaesthesia
 maxilla
perforated by many openings
Infiltration is sufficient
 Mandible
 Dense cortical plate
Nerve Blocks required

28. Histology
Lamellated Bone

29. Spongiosa
Fills space betn. ABP and Cortical bone
Variations;
Maxilla –More
Mandible -Less
In ant region –both jaws :
Spongiosa is absent
Cortical plate is fused with ABP

30. Histology
Lamellated thin bone
More marrow spaces:
Yellow or fatty marrow
Red marrow seen in :
Condylar process
Angle of mandible
Maxillary tuberosity
Symphsis Menti

31. Interdental septum
found between two teeth
Large or Small –Gap between the teeth

32. Interradicular septum
Between two roots
Alveolar bone not fused –contain spongiosa

33. Alveolar Crest
Rim of the socket
Most prominent border of interdental septum
Alveolus
Rim
Floor
Alv. crest

34. Shape of Alveolar Crest
Usually follows cervical line
position of adjacent teeth
Degree of eruption
Buccolingual width of the teeth
Enamel contour

35. Relationship with CEJ
1.5-2mm apical to CEJ
Relation always maintained &Is constant
Attrition
Inclination

36. Arrangement of Trabeculae
Present in Spongiosa
More in max than in Mand
When masticatory stresses
increase –less spongiosa ,
thick CP
When masticatory stresses
decrease –
more spongiosa , thin CP

37. Two types –R/A
Type I
Trabeculae –
Regular
Horizontal
Thick
Ladderlike
Mandible
Trajectorial pattern
Along lines of stress

38. Type II
Irregular
Fine/Delicate
No specific arrangement
thin
Maxila
No trajectory pattern’,More
marrow soace

39. Nutrient Canals
Zuckerkandl &Herschfeld
Interdental &Interradicular septum
Contain –BV, lymph vessels and nerves
Appear as radioluscent linera shadows
Parallel to long axis of tooth

40. Transalveolar Fiberes
Sharpey;s fibres pass straight
through
Continous with adj.tooth

41. Histologic changes in Alv.
Bone
Development
maximum thickness –when teeth reach
occlusion
Loss of teeth – Atrophy
Residual alv. ridge
growth of jaws
Mesial drifting

42. Functions
supportive
Protective
Heamatopoietic
Calcium Homeostasis
Reserve tissue For PDL

43. Clinical Considerations
Maxillary teeth
Easy to extract
Infiltration is sufficient
Infection in alv. Bone –
R/F- loss of lamina dura
Periodontal disease –
Destruction of Alv.Bone

44. Orthodontic Treatment –
Plasticity of the bone
Cyst and tumours
Effect of hormones –Hypo /Hyperparathyroidism

45. Osteoblast
Line the bone surface
Types- active& Resting
No continous arrangement
Uneven distribution
Seperated from bone –thin rim of osteoid
Modified Endosteum

46. Osteoclast
Cells that resorb bone
Multinucleated cells (2-10) , can be mononucleated
Origin: Fusion of Circulating monocytes
Location: Howships lacunae- bay like recesses
Arrangement –usually in clusters
Content: Abundant golgi, mitochondria, lysosomes but
little RER.
Acid phosphatase
Function – resorb bone

47. Morphologic Characteristics
Ruffled/ Striated border
Clear zone

48. Electron Microscopy
Sequence of events;
 Removal of mineral/inorganic Matrix
 Degradation of org. matrix