7: Bone

7

Bone

Table 7.1 Composition of bone

Inorganic constituents (67 wt.%) Organic matrix (33 wt.%)
Ca-deficient hydroxyapatite 25% Type I collagen
5% Noncollagenous proteins:
   osteonectin
   osteocalcin
   bone morphogenic protein
   bone proteoglycan
   bone sialoprotein

Table 7.2 Inorganic constituents of bone (wt.%)

Constituent Average content (%) Range (%)
Calcium 35 33–36.5
Phosphorus 15 14.5–16
Carbonate 5 3–8
Sodium 0.45 0.26–0.59
Magnesium 0.45 0.32–0.78

Table 7.3 Average composition of bone mineral

Component Presence (wt.%)
Magnesium whitlockite, Ca9Mg(HPO4)(PO4)6 20
Sodium- and carbonate-containing apatite, Ca8.5Na1.5(PO4)4.5(CO3)1.5 15
Defective hydroxyapatite, Ca9(HPO4)(PO4)5(OH) 65

Table 7.4 Cells responsible for formation, maintenance, and resorption of bone

Cell Type Function
Osteoblasts Uninucleated cells Secrete bone matrix.
Synthesize collagenous and noncollagenous bone protein (the osteoid).
Mineralize osteoid.
Osteocytes Entrapped osteoblasts in bone matrix Osteocyte–osteo/>

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Jan 1, 2015 | Posted by in Dental Materials | Comments Off on 7: Bone
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