Evidence of hydroxyl-ion deficiency in bone apatites: an inelastic neutron-scattering study

Early Stages of Biomineral Formation—A Solid-State NMR Investigation of the Mandibles of Minipigs

“…0 ppm was observed at all early stages in all samples, except for one 4w sample. This supports reports of a strong deficiency of hydroxide groups in mature bone and dental tissues [12,42,43]. In our previous studies on water absorbance on silica surfaces [44] and on hydroxyapatite-gelatin nanocomposites [22,28], we demonstrated the variation in the 1 H chemical shift depending on (1) the dimensionality of the water structures formed on the surface and related to the strength of hydrogen bonds, and (2) the chemical groups donating hydrogen atoms for hydrogen bond formation.…”

Nuclear Magnetic Resonance Spin-Spin Relaxation of the Crystals of Bone, Dental Enamel, and Synthetic Hydroxyapatites

“…This study, using homonuclear 31 P-31 P spin-spin relaxation, has not only provided additional information on the differences in the phosphate environments in bone and enamel crystals compared with synthetic hydroxyapatites and the changes that occur with maturation, but also strongly supports the conclusion that the more labile, protonated phosphates reside principally on the surfaces of the biological crystals, especially in the younger less mature crystals, and the unprotonated phosphates are located principally within a more stable internal lattice environment. The data also are consistent with crystal reactivity and radiolabeled 14 CO 2 studies, suggesting that the labile CO 3…”

Calcium orthophosphates (CaPO 4 ): Occurrence and properties

“…It is clear that the inorganic part of bone consists of biological apatite, i.e., CDHA with ionic substitutions but without the detectable amounts of hydroxide (Rey et al 1995a;Loong et al 2000;Seo et al 2007). However, the results of solid-state nuclear magnetic resonance on fresh-frozen and ground whole bones of several mammalian species revealed that the bone crystal OH -was readily detectable; a rough estimate yielded an OH -content of human cortical bone of about 20 % of the amount expected in stoichiometric HA (Cho et al 2003).…”