Beiträge zur Kenntnis der Kalk‐Phosphorsaure‐Verbindungen II

Plasma-Sprayed Osseoconductive Hydroxylapatite Coatings for Endoprosthetic Hip Implants: Phase Composition, Microstructure, Properties, and Biomedical Functions

“…However, only the application of X-rays to crystal structure analysis over one hundred years ago [11] allowed a paradigmatic shift from a descriptive to a predictive acquisition of information on the structural chemistry of biological calcium phosphates [12][13][14][15][16]. Willem F. de Jong [17] was first to identify the structure of the calcium phosphate phase in bone as being akin to geological apatite, and in turn, Hendricks et al [12] concluded (erroneously) that the inorganic constituent of bone contains carbonate apatite, Ca10[CO3(PO4)6]⋅H2O, thought to be structurally equal to fluorapatite.…”

“…Willem F. de Jong [17] was first to identify the structure of the calcium phosphate phase in bone as being akin to geological apatite, and in turn, Hendricks et al [12] concluded (erroneously) that the inorganic constituent of bone contains carbonate apatite, Ca10[CO3(PO4)6]⋅H2O, thought to be structurally equal to fluorapatite. The same authors mentioned oxyapatite, Ca10O(PO4)6 as an anhydrous product of heating HAp up to 900 ∘ C. This was disputed by Bredig and coworkers [16] who instead, proposed the existence of only partly dehydroxylated oxyhydroxylapatite (OHAp), Ca10(PO4)6X2mOn (X = OH -; m + n = 1). In their opinion, an empty X site would destabilize the structure, a contention that was much later confirmed by computer modelling applied to investigate the dehydration of HAp to oxyapatite (OAp) and the defect chemistry of calcium-deficient HAp [18].…”

Plasma-Sprayed Osseoconductive Hydroxylapatite Coatings for Endoprosthetic Hip Implants: Phase Composition, Microstructure, Properties, and Biomedical Functions

“…However, only the application of X-rays to crystal structure analysis over one hundred years ago [11] allowed a paradigmatic shift from a descriptive to a predictive acquisition of information on the structural chemistry of biological calcium phosphates [12][13][14][15][16]. Willem F. de Jong [17] identified the crystal structure of bone calcium phosphate as comparable to geological apatite.…”

“…Hendricks et al [12] concluded (erroneously) that the inorganic constituent of bone contains carbonate apatite, Ca 10 [CO 3 (PO 4 ) 6 ]•H 2 O, which they thought to be structurally akin to fluorapatite. The same authors mentioned oxyapatite, Ca 10 O(PO 4 ) 6 , as an anhydrous product of heating HAp up to 900 • C. This was disputed by Bredig and coworkers [16], who instead proposed the existence of only partly dehydroxylated oxyhydroxylapatite (OHAp), Ca 10 (PO 4 ) 6 X 2m O n (X = OH − ; m + n = 1). In their opinion, an empty X site would destabilize the structure, a contention that was confirmed much later by computer modeling applied to investigate the dehydration of HAp to oxyapatite (OAp) and the defect chemistry of calcium-deficient HAp [18].…”