The Alveolar Bone Provides Support to Teeth and Other Functions: A Review

Alveolar bone provides structural supports to teeth.The outer and inner compact bone are formed by osteons, the basic structure of cortical bone, with a central vertical Haversian canal and rings forming a lamellar bone (bundle or alveolar bone).The central cancellous bone is the spongiosa (spongy bone).Bundles of collagen fibers (Sharpey's fibers) provide attachment of the root to bone.Perforating Volkmann's canals, limiting the inner bone are forming "the cribliform plate".Oriented horizontally, the plate contains blood vessels and nerves issued from the periosteum.Alveolar bone associates intramembranous and endochondral bones.Mesenchymal stem cells (osteoprogenitor cells) initiate bone mineralization including a differentiation cascade.Alveolar bone includes pre-osteoblasts, osteoblasts, osteocytes, and bone lining cells, all these cells being derived from hematopoietic stem cells.The alveolar bone extracellular matrix (ECM) includes collagens, elastins, glycosaminoglycans and proteoglycans, small leucine-rich proteoglycans, small integrin-binding ligand N-linked glycoprotein (phosphorylated SIBLINGs) (DSPP [fragmented after cleavage into dentin sialoprotein, dentin glycoprotein, and dentin phosphoprotein], phosphorylated proteins such as bone sialoprotein, matrix extracellular phosphorylated protein (MEPE), and osteopontin], noncollagenous non-phosphorylated proteins (osteonectin), serum derived proteins (α2-HSglycoprotein, and albumin), specific and non-specific alkaline phosphatase, metalloproteinases and tissue inhibitors of metalloproteinases (TIMPs -1 to -4) and enzymes that regulate components of the alveolar bone.Osteoclasts are stimulating osteoclastogenesis, and