Calcium phosphate ceramics
Hydroxyapatite and tricalcium phosphate — synthetic analogues of bone's own mineral.
Bone mineral is essentially a carbonated hydroxyapatite, so synthesising calcium phosphate ceramics is an attempt to reproduce it. Hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) are the two workhorses, and they differ mainly in solubility: HA is stable and persists for years, β-TCP resorbs over months.
That difference is the design lever. A ceramic that never resorbs remains a permanent foreign body; one that vanishes before bone forms leaves a gap. Biphasic composites blend the two to tune resorption against the pace of remodeling. These materials are strongly osteoconductive — bone grows readily along them — but not osteoinductive: they will not persuade stem cells to become osteoblasts on their own, which is why they are combined with BMPs or cells.
Their limitation is brittleness. Strong in compression, weak in tension, they are frequently used as composites with polymers or as printed constructs. See Bone grafting: autograft, allograft, and substitutes for their clinical role.
Related articles
- BoneBone grafting: autograft, allograft, and substitutesThe established clinical standard for replacing missing bone, and the trade-offs that motivate engineered alternatives.
- BiomaterialsScaffold design principlesPorosity, strength, and degradation rate — the competing requirements every scaffold has to reconcile.
- BiomaterialsChitosan in tissue engineeringA polysaccharide derived from crustacean shells, structurally reminiscent of the body's own glycosaminoglycans.
- BoneBone remodelingThe continuous cycle of resorption and formation that rebuilds the skeleton throughout life.
- DentalBioactive glass and calcium silicate materialsMaterials that do not merely fill a space but chemically provoke a biological response.
- Biomaterials3D-printed bone scaffoldsAdditive manufacturing lets scaffold architecture be specified directly — and patient-specific.