Enhanced osseointegration of hydroxylapatite implant material.

This study was undertaken to determine whether the addition of calcium sulfate to hydroxylapatite (HA) implant material would improve its working properties without adversely affecting its osseointegration. The clinical and histologic examinations of bone response of three implant materials, hard tissue replacement (HTR), HA, and HA composite (HA plus calcium sulfate), were performed after 2-, 4-, and 6-week implantation in tibia and mandible of rabbits. No sign of extensive chronic inflammatory response was detected. The highest rate of bone ingrowth occurred with the HA composite, followed by HA, with HTR showing the least ingrowth. Bone was deposited directly on the surface of HA and HA composite implant materials. In contrast, HTR particles had a thin layer of fibrous tissue encapsulation with the normal bony investment.