HAコーティング層に結晶学的変化を認めた撤去症例

抄録

An AQB implant is an HA-coating implant and a simple one-piece column type. It is made of pure titanium on which crystalline HA is coated by a plasma spraying technique.
In this clinical case, one AQB implant was removed by bone resorption caused by an infection and inflammation, three years after installation.The HA coating surface of a new AQB and the removed AQB implants was examined crystallographically by SEM, EDS, and XRD. The HA-coating of the new AQB was 35-100μm in thickness, and 1-10μm in pore size, and contained a small amount of β-TCP. The HA-coating was composed of an aggregate of needle-like single crystals and polycrystals. The Ca/P ratio of their HA crystals was 4.5,much higher than the 1.67 of stoichiometric HA. The higher Ca/P originated in containing CaO in the HA-coating. In the removed implant,needle-like crystals dissolved by the inflammation,and the Ca/P ratio decreased to 1.9, slightly higher than 1.67. XRD revealed the dissolution of needle-like crystals and the presence of CaO.