A Comparative Experimental Study of bone Ingrowth and Osseointegration in Hydroxyapatite: coated vs . Porous-coated implants

The purpose of this study is to investigate the effect of plasma sprayed hydroxyapatite (HA) coated and porous coated titanium implants. The shear strength of the HA coatings on interface attachment, the degree of osseointegration of HA coated implants and bone ingrowth of porous-coated titanium implants were evaluated. The implants were placed transcortically in the femora of mature dogs and evaluated after six weeks. The pushout test of HA-coated implants showed 28.232±4.918 MPa and 22.661±6.347 MPa in porous-coated implants (p<0.05). In histologic observations, similar quantitative results in the amount of bone ingrowth and osseointegration on both systems. The HA coatings showed direct osseointegration on its surface without fibrous layer, but the porous-coatings showed thin fibrous layer between the ingrown bone and titanium surface. In conclusion, HA-coated implant provided earlier and stronger osseointegration than porous-coated implant.