EFFECT OF MACROTEXTURE PRODUCED BY LASER-BEAM MACHINING ON THE RETENTION OF CERAMICS IMPLANT IN BONE IN-VIVO

Cylindrical implants, made of a dense yttria- partially-stabilized zir conia/hydroxyapatite composite and a dense pure hydroxyapatite ceramic , were implanted in the mandibular bone of two beagles and the femurs of eight rabbits. Some of the cylindrical implant surfaces were drille d with a laser beam to create 200 x 200 mu m(2) dimples. The bone ingr owth and the effect of bone in the dimples on the retention of the imp lant in bone were studied. The histological evaluation revealed that n ew bone was formed in close apposition to the composite surface both i n the dogs and the rabbits. The dimpled spaces of the composite were f illed with the newly formed bone. The composite with dimpled surface r esulted in a higher bone-bonding strength than that of the composite w ith a smooth surface. The bone-bonding strength was even higher than t hat of pure hydroxyapatite. This study showed that the laser beam dril ling technique was a good machining method to produce an implant with defined surface macrostructure. The combination of bioactivity and mec hanical retention in the implant material resulted in a more stable im plant.