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Bone Histology


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The presentation include general definition of bone and it's functions. Also, describe the chemical composition of bone and then specifically describe alveolar process.

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Bone Histology

  1. 2. بسم الله الرحمن الرحيم
  2. 3. By Dr / Hoda Fansa Assistant professor of Oral Biology Umm Al Qura University
  3. 4. <ul><li>Bone is a specialized form of connective tissue. </li></ul><ul><li>It consists of cells and extracellular substance (matrix and fibers). </li></ul>
  4. 5. Functions <ul><li>Protects and supports vital organs. </li></ul><ul><li>Serves as a reservoir for calcium and phosphate (containing 99% of body calcium). </li></ul><ul><li>Contains bone marrow which function in hemopoiesis. </li></ul><ul><li>Provides for attachment of muscles. </li></ul><ul><li>Forms the body skeleton. </li></ul>
  5. 6. Physical Properties <ul><li>Yellow in color. </li></ul><ul><li>Softer than dentin. </li></ul><ul><li>Lined by soft C.T. containing osteoprogenitor cells. </li></ul><ul><li>Vascular tissue. </li></ul>
  6. 7. Chemical composition <ul><li>Organic materials + H 2 O 35% </li></ul><ul><li>Inorganic materials 65% </li></ul>
  7. 8. Inorganic Materials <ul><li>In the form of apatite crystals </li></ul><ul><li>Calcium </li></ul><ul><li>Phosphorus </li></ul><ul><li>Magnesium </li></ul><ul><li>Citrate </li></ul><ul><li>Potasium </li></ul><ul><li>Sodium </li></ul>
  8. 9. Organic Materials <ul><li>Type I collagen. </li></ul><ul><li>Ground substance of glycoproteins and proteoglycans with small amount of proteins and lipids. </li></ul>
  9. 10. Bone Cells <ul><li>Ostoproginator cells. </li></ul><ul><li>Osteoblasts . </li></ul><ul><li>Osteocytes . </li></ul><ul><li>Osteoclasts (bone resorbing cells ) </li></ul>
  10. 11. Bone cells
  11. 12. Types of Bone Lamellated bone Course fibered bone (woven bone) Bundle bone <ul><li>Cancellous </li></ul><ul><li>Compact </li></ul><ul><li>Found in embryo </li></ul><ul><li>Formed during Healing of bone </li></ul><ul><li>Contains Sharpey’s fibers </li></ul>
  12. 13. Cancellous Bone <ul><li>Sponge-like found in the head of a long bone. </li></ul><ul><li>Has large marrow spaces. </li></ul><ul><li>Surrounded by thin spicules or trabeculae. </li></ul>
  13. 14. <ul><li>Spicules are small and short containing one or two lamellae and few osteocytes. </li></ul><ul><li>Trabeculae are large composed of several lamellae. </li></ul>
  14. 15. Compact Bone <ul><li>Denser than cancellous bone. </li></ul><ul><li>Its spaces are much reduced in size. </li></ul>
  15. 16. Lamellae are organized in 4 systems: <ul><li>External circumferential lamellae. </li></ul><ul><li>Internal circumferential lamellae. </li></ul><ul><li>Interstitial lamellae. </li></ul><ul><li>Haversian canal systems (osteons). </li></ul>
  16. 18. <ul><li>Woven bone (non-lamellar bone , reticulated bone) </li></ul><ul><li>Bony tissue characteristic of the embryonic skeleton in which the collagen fibers of the matrix are arranged irregularly in the form of interlacing networks. </li></ul>
  17. 19. Periosteum <ul><li>An outer fibrous layer (collagen and fibroblasts). </li></ul><ul><li>An inner cellular layer (some collagen and osteogenic cells and osteoblasts). </li></ul>
  18. 21. Endosteum <ul><li>The endosteum is composed of osteoprogenitor cells and only a small amount of connective tissue, covering the surface of bone trabeculae and the medullary surface of cortical bone and haversian canals. </li></ul>
  19. 22. Incremental Lines of Bone: <ul><li>Resting lines. </li></ul><ul><li>Reversal line. </li></ul>
  20. 24. <ul><li>Collagen fibers of the periosteum become trapped in the calcified bone matrix ( Sharpey’s fibers ). </li></ul><ul><li>They are arranged at an angle to bone fibers. </li></ul>
  21. 26. <ul><li>It is a direct continuation of the maxilla and mandible. </li></ul><ul><li>Is derived from ectomesenchymal cells of the dental follicle. </li></ul>
  22. 27. <ul><li>Each alveolus contains one tooth. </li></ul><ul><li>Adjacent alveoli are separated by interdental septum consisting mostly of cancellous bone. </li></ul>
  23. 28. Alveolar Bone Alveolar Bone Proper Supporting Alveolar Bone <ul><li>Bundle bone(Sharpy’s fibers) </li></ul><ul><li>Lamellar bone(compact) </li></ul><ul><li>Cortical bone(compact) </li></ul><ul><li>Spongiosa (cancellous) </li></ul>
  24. 29. <ul><li>The part of the alveolus which immediately surrounds the root is the alveolar bone proper ( cribriform plate, lamina dura or bundle bone ).The rest of the alveolar bone is the supporting alveolar bone. </li></ul>
  25. 30. Lamina dura
  26. 31. Alveolar bone proper <ul><li>The bundle bone which is the most inner part lining the socket. </li></ul><ul><li>Lamellar bone (compact bone next to bundle bone). Some lamellae are arranged parallel to the surface and others form Haversian systems. </li></ul>
  27. 32. Supporting Alveolar Bone: <ul><li>Cotrical bone on the buccal and lingual surfaces. </li></ul><ul><li>The intervening cancellous bone (spongiosa) surrounding the alveolar bone proper. </li></ul>
  28. 33. Cortical bone <ul><li>Consisting of well organized lamellae </li></ul><ul><li>External circumferential lamellae. </li></ul><ul><li>Internal circumferential lamellae. </li></ul><ul><li>Interstitial lamellae. </li></ul><ul><li>Haversian canal system. </li></ul>
  29. 34. <ul><li>The spongiosa is adapted to support the alveolus proper, since its trabeculae are arranged in such a fashion as to resist occlusal force. </li></ul><ul><li>The spongiosa is absent in the regions of the incisors, where the alveolar bone proper is fused with the cortical plate. </li></ul><ul><li>In multirooted teeth, the bone septum intervenes between the root is called interradicular septum composed of spongy bone covered by a cribriform plate. </li></ul>
  30. 35. Radiographically; <ul><li>Type I : A sparse ladder-like arrangement (in the mandible). </li></ul><ul><li>Type II : An apparent haphazard arrangement (in the maxilla). </li></ul>
  31. 36. Type I Type II
  32. 37. <ul><li>The thickness of the cortical plate varies depending upon the location. </li></ul><ul><li>The cortical plates of the molar regions are thicker than those of the incisor regions. </li></ul>
  33. 38. Aging of alveolar bone <ul><li>A comparison of young and old alveolar bone reveals the following: </li></ul><ul><li>- The alveolar sockets appear Jagged and scalloped. </li></ul><ul><li>- The bone marrow appears to have a fatty infiltration. </li></ul><ul><li>- Osteoporosis indicates loss of some bony elements. </li></ul><ul><li>- The internal trabecular arrangement is more open, which indicates bone loss. </li></ul><ul><li>  </li></ul><ul><li>  </li></ul>
  34. 39. References <ul><li>Ten Cate oral histology ,development and structure and function. Antonio Nancy 7 th ed. 2007. </li></ul><ul><li>Berkovitz oral anatomy , histology and embryology. Berkovitz BKB, Maxham B J, Holland G R .4 th ed. 2009. </li></ul>