whitlockite and Foreign-Body-Reaction

Plasma-sprayed ceramic coatings of fluorapatite (FA), magnesiumwhitlockite (MW), and hydroxylapatite (HA), and noncoated Ti-6Al-4V alloy (Ti) implants were evaluated histologically and histomorphometrically in a goat animal study. Cylindrical Ti-6Al-4V plugs were plasma-spray-coated with FA, MW, and HA. Noncoated, grit-blasted Ti plugs served as controls. The plugs were implanted into the right femur and left humerus of 20 adult goats. The results were evaluated using descriptive histology and histomorphometry. The histomorphometry consisted of measurements of bone apposition and coating thickness. The results demonstrated that FA showed a high amount of bone apposition without signs of degradation or dissolution. MW showed considerable reduction in thickness and at 12 weeks an adverse tissue reaction. However, at 25 weeks the amount of bone apposition was significantly increased compared with the 12-week implants. HA revealed considerable and progressive reduction in thickness and at 25 weeks a lower amount of bone apposition than FA and MW. At 12 weeks the Ti implants did reveal bone apposition, although frequently localized fibrous tissue was visible. At 25 weeks the Ti implants did not differ in bone apposition from the HA implants. Further studies are necessary on the effect of degradation or dissolution of HA on the compatibility with bone.

Topics: Alloys; Animals; Apatites; Biocompatible Materials; Calcium Phosphates; Durapatite; Female; Femur; Foreign-Body Reaction; Goats; Humerus; Hydroxyapatites; Magnesium; Osseointegration; Prostheses and Implants; Titanium

In this paper, the formation of a granuloma following subcutaneous implantation of beta-whitlockite powder is described. The implants were removed after 3, 5 and 7 wk and examined histologically. In the granuloma giant cells, macrophages, lymphocytes and plasma cells are present. The presence of plasma cells indicates that not only inflammation occurs, but that an immunoresponse also takes place. Resorption and phagocytosis of particles was observed and the particles were found in the regional lymph nodes after 7 wk. beta-Whitlockite powder induces an inflammation and both a cellular and a humoral immunological response, when implanted subcutaneously.

Topics: Animals; Biocompatible Materials; Bone and Bones; Calcium Phosphates; Connective Tissue; Foreign-Body Reaction; Granuloma; Inflammation; Male; Osteogenesis; Plasma Cells; Prostheses and Implants; Rabbits; Time Factors