Comparison of ceramic and titanium implants in cats

The mechanical strengths of the bone-implant interfaces of titanium coated with glass ceramic and pure titanium implants were compared. The glass ceramic had a chemical composition similar to 45S5F Bioglass. Cylindrical implants were placed in feline femurs. Six weeks later the strength of the fixation was tested using pull-out tests. Energy despersive X-ray microanalysis was applied to pursue any possible relationship between mechanical strength and changes in elemental composition at the bone-implant interface. The ultimate shearing force for the pure titanium implants was higher than for the implants coated with glass ceramic. Also, the glass ceramic coating was partly degraded by the tissues. Evidently,the mechanical properties of the glass ceramic to bone interface were governed by some sort of chemical reaction that implied transfer of elements from the implant to bone. It appears that this reaction eventually will destroy the coating which makes this kind of material unsuitable for prosthesis fixation. (author)