1. ALVEOLAR BONE
Dr. Bassam ELGHARABLY

2. WHAT IS ALVEOLAR BONE…
ALVEOLAR BONE CAN BE DEFINED AS THAT PART OF THE MAXILLA AND MANDIBLE THAT FORMS AND SUPPORTS THE SOCKETS OF THE TEETH.
COMPARABLE TO OTHER BONE TISSUES IN THE BODY, ALVEOLAR BONE IS SUBJECTED TO CONTINOUS AND RAPID REMODELING ASSOCIATED WITH TOOTH ERUPTION AND THE FUCNTIONAL DEMANDS OF MASTICATION.

3. FUNCTIONS.. HOLDS THE TOOTH FIRMLY IN POSITION TO MASTICATE.
HELPS TO ABSORB AND DISTRIBUTE OCCLUSAL FORCES
ADAPTS THE STRENGTH AND ORIENTATION OF ATTACHMENT TO VARYING LOAD.
HELPS TO MOVE THE TEETH FOR BETTER OCCLUSION.
SUPPLIES VESSELS FOR THE PDL & CEMENTUM.
PROTECTS DEVELOPING PERMANENT TEETH WHILE SUPPORTING PRIMARY TEETH.
ORGANIZES SUCCESSIVE ERUPTIONS OF PRI & SEC TEETH

4. COMPOSITION OF ALVEOLAR BONE..
INORGANIC
ORGANIC
ALVEOLAR BONE
HYDROXYAPATITE,
TRACE ELEMENTS.
COLLOGEN-
28% 5%
OSTEOCALCIN,
SIALOPROTEIN,
PHOSPHOPROTEIN,
OSTEONECTIN,
PROTEOGLYCONS
67%
33%

5. Cells and intercellular matrix
† Osteoblasts,Osteocyte and Osteoclasts
† Bone consist of 65% hydoxyapatite (cementum?)
organic matrix consists mainly (90%) of collagen type 1 with small amounts of osteocalcin, osteonectin, bone morphogenetic protein, phosphoproteins, and proteoglycans

6. BLOOD SUPPLY: SUPERIOR AND INFERIOR ALVEOLAR ARTERIES OF MAXILLA & MANDIBLE.

7. LYMPHATICS DRAINAGE:
SUBMANDIBULAR LYMPH NODES.

8. NERVE SUPPLY:
BRANCHES FROM ANTERIOR, MIDDLE AND POSTERIOR SUPERIOR ALVEOLAR NERVE IN MAXILLA & BRANCHES FROM INFERIOR ALVEOLAR NERVE INNERVATE MANDIBLE.

9. COMPONENTS OF
ALVEOLAR BONE...

10. It is composed of two parts; the alveolar bone proper and the supporting bone
Alveolar bone proper is that part of alveolar bone that lines the sockets
It is a thin lamella of compact bone in which periodontal fibres are embedded
It is referred to as Bundle bone because it regularly penetrated by Sharpey’s fibres of the periodontal ligament

12. Radiographically alveolar bone proper is referred to as lamina dura
Lamina dura appears more dense and hence radio-opaque
In a radiograph the widening of lamina dura indicates periodontal pathology
In physiological movement of teeth, this bone is readily resorbed in zones of compression and is formed in zones of tension

13. Radiographic appearance of alveolar bone proper as ‘Lamina Dura’

14. Supporting bone
The remainder of the alveolar process below the alveolar bone proper is called the supporting bone
It is attached to the alveolar bone proper
Supporting bone includes the compact cortical plates on the outer surface and the spongy bone between the cortical plates and the alveolar bone proper

15. 1. Alveolar bone proper or
„„ Alveolar wall
„ Bundle bone
2. Trabecular bone
3. Compact bone

16. Cortical plates (Compact supporting bone)
The compact supporting bone of the alveolar process extends from the alveolar crest to the lower border of the socket on the outside surface of the maxilla and mandible
It is also called the cortical bone/plate
The cortical bone has Haversian
systems, radiating lamellae with
lacunae and canaliculi

17. Spongy bone (Cancellous supporting bone)
Cancellous bone is located apically
between the alveolar bone proper
and the cortical bone
It is also called as spongy bone
It supports and strengthens the
alveolar bone proper

18. INTERDENTAL SEPTUM
IT IS THE BONE BETWEEN TEETH, COMPOSED ENTIRELY OF Alveolar bone proper .
The interdental septum consists of cancellous bone and cortical plates.
If the interdental space is narrow, the septum may consist of only lamina dura (between mandibular 2nd premolars and 1st molars consists of only lamina dura in 15% cases).

19. If roots are too close together, an irregular "window" can appear in the bone between adjacent roots

20. INTER RADICULAR SEPTUM- IT IS THE BONE BETWEEN THE ROOTS OF MULTIROOTED TEETH.

21. Contours
† Normally conforms to the prominence of the roots,

22. The distance between the crest of the alveolar bone and the CEJ in young adults varies between mm. This distance increases with age to an average of 2.81 mm.
The mesiodistal angulation of the crest of the interdental septum usually parallels a line drawn between the cemento-enamel junctions of the approximating teeth.

23. Periosteum and Endosteum
All bone surfaces are covered by connective tissue. † outer surface periosteum internal endosteum.
† The periosteum consists of„ an inner layer composed of cells that have the potential to differentiate into osteoblasts
„ An outer layer that is rich in blood vessels and nerves and is composed of collagen fibers and fibroblasts.

24. BONE DESTRUCTION PATTERN IN PERIODONTAL DISEASES
HORIZONTAL BONE LOSS- BONE MARGIN IS PERPENDICULAR TO TOOTH SURFACE.

26. VERTICAL BONE LOSS- ANGULAR DEFECT THAT OCCUR IN vertical or oblique DIRECTION

27. EXOSTOSES- IT IS THE OUTGROWTH OF BONE OF VARIABLE SIZE AND SHAPE

28. FURCATION INVOLVEMENT-
INVASION OF BIFURCATION AND TRIFURCATION OF MULTIROOTED TEETH BY PERIODONTAL DISEASE.
Furcation Probes Nabers Probe

29. Furcation Classifications
Class 1: The concavity—just above the furcation entrance—on the root trunk can be felt with the probe tip; however, the furcation probe cannot enter the furcation area.

30. Furcation Classifications
The probe is able to partially enter the
furcation—extending approximately
one third of the width of the tooth—but it is not able to pass completely through the furcation

31. Furcation Classifications
In mandibular molars, the probe passes completely through the furcation between the mesial and distal roots.
In maxillary molars, the probe passes between the mesiobuccal and distobuccal roots and touches the palatal root.

32. Furcation Classifications
Class 4: Same as a class III furcation involvement except that the entrance to the furcation is visible clinically owing to tissue recession.

33. Dehiscence & Fenestration
Isolated areas in which the root is denuded of bone and the root surface is covered only by periosteum and overlying gingiva are termed fenestrations. In these instances the marginal bone is intact. When the denuded areas extend through the marginal bone, the defect is called a dehiscence.
FENESTRATION- IS AN AREA OF ROOT PENETRATING THE BONE IN THE APICAL REGION.
DEHISCENCE- IS AN AREA OF ROOT PENETRATING THE BONE IN CORONAL REGION.
Fenestration and dehiscence are important, because they may complicate the outcome of periodontal surgery.

35. ALVEOLAR BONE PATHOLOGY…
HISTIOCYTE- SEVERE HORIZONTAL BONE LOSS.
CHERUBISM- WIDENING OF ALVEOLAR RIDGE AND TOOTH DISPLACMENT
FIBROUS DYPLASIA- PAINLESS ENLARGEMENT OF THE AFFECTED BONE. WITH GROUND GLASS APPEARENCE
OSTEOSARCOMA – SWELLING WITH PAIN, LOOSENING OF TEETH, PARESTHESIA.
PAGETS DISEASE- GROSSLY ENLARGED ALVEOLAR RIDGES , CAUSES SPACING OF TEETH.

36. CLEIDOCRANIAL DYSPLASIA- RETENTION OF DECIDUOUS TEETH.
HYPERPARATHYROIDISM- LOSS OF LAMINA DURA, DECREASE IN TRABECULAE DENSITY.
OSTEOGENESIS IMPERFECTA- MAXILLARY HYPOPLASIA, CLASS III MALOCCLUSIAN.
OSTEOPETROSIS- INCREASE IN BONE DENSITY . BONE MARROW IS REPLACED BY DENSE BONE.

37. HISTIOCYTE
CHERUBISM

38. FIBROUS DYPLASIA-
OSTEOSARCOMA

39. CLEIDOCRANIAL DYSPLASIA-
HYPERPARATHYROIDISM

40. OSTEOGENESIS IMPERFECTA-
OSTEOPETROSIS