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Alveolar
- 2. Structure of bone • Bone is a specialized form of connective tissue. • It consists of : Bone matrix Cells Periosteum Endosteum
- 3. 1. Bone matrix Inorganic Organic Water 60% by weight In the form of apatite crystals Calcium Phosphorus Magnesium Potasium Sodium 25% by weight 90% Type I collagen. Ground substance of glycoproteins and proteoglycans with small amount of proteins and lipids. 15% by weight
- 4. Bones Cells a) Ostoprogenator cells. b) Osteoblasts . c) Osteocytes . d) Osteoclasts . e) Bone lining cells.
- 5. Osteoblast • Bone forming cells • Extensive endoplasmic reticulum • Numerous mitochondria and vesicle • Active in collagen and ground substance formation • Produce intercellular substance called osteoid tissue
- 6. Osteoclasts • Large multinucleated cells • Responsible for resorbtion of bone • Found in depressions in the bone called Howship’s lacunae
- 7. Osteocytes • An osteocyte, a star shaped cells is the most commonly found cell in mature bone • Osteocytes have an average half life of 25 years, they do not divide • Occupy a space called lacuna • Few organelles • Play role in calcium homeostasis
- 9. Osteoprogenitor cells • Mesenchymal fibroblast like cells • Form stem cell population to generate Osteoblast.
- 10. Bone lining cells • Undifferentiated flattened cells • Line the surface of bone when there is no deposition or resorbtion
- 11. Periosteum and endosteum • Layers of bone forming cells and connective tissue cover the external and internal surface • Provide nutrition to bone tissue • supply new osteoblasts
- 12. Types of bone 1. Mature (Lamellar) bone: Collagen fibers within each lamella are parallel Osteocytes are evenly distributed a) compact bone b) Spongy (Cancellous) bone 2. Immature (woven) bone 3. Bundle bone
- 13. Compact bone • Denser than cancellous bone. • Thick and solid • Lamellae are organized in the form of concentric cylinder surrounding a narrow canal • 5-20 lamellae surround each canal (circumferential lamellae). • The central vascular canal called Haversian canal • Haversian canals are connected by transversely running Volkmann’s canals
- 15. Haversian system
- 16. Spongy bone • Sponge-like found in the head of a long bone • Has large marrow spaces • Surrounded by thin trabeculae.
- 17. Bone Trabeculae Bone Marrow Spaces
- 18. Woven bone • Bony tissue characteristic of the embryonic skeleton in which the collagen fibers of the matrix are arranged irregularly in the form of interlacing networks. • Less ground substance and less calcified • Healing sockets after teeth extraction
- 19. Bundle Bone • Collagen fibers of PDL (Sharpey’s fibers) are embedded in it • More calcified • Restricted to alveolar bone proper
- 20. Alveolar bone The alveolar bone ( process ) • The part of maxilla or mandible which supports and protect teeth. • Dependent on the presence of teeth .
- 21. Functions • Forms the bony socket to hold the root of tooth and attach it through the PDL • It gives attachment to muscle • Framework for bone marrow • Reservoir for calcium
- 22. Jaw bones Basal bone Alveolar process Alveolar bone proper Supporting alveolar bone Cortical plates buccal ,lingual Spongy bone
- 23. Alveolar process
- 24. Alveolar process
- 26. Alveolar bone proper • Forms the socket inner wall • Gives attachment to periodontal ligament • Perforated by many openings that carry branches of interalveolar nerves and blood vessels into PDL • Consists of lamellated and bundle bone
- 27. Supporting alveolar bone • Compact bone • Thinner in the maxilla • Thickest in molar and premolar region Consist of cortical plate lingual plate (inner plate) labial plate (outer plate) supporting spongy bone (Cancellous bone between cortical plates and alveolar bone proper)