Plasma immersion ion implantation treatment of medical implants

Using oxygen-plasma immersion ion implantation (PIII) into titanium it is p ossible to form hard, dense and thick rutile layers with excellent biocompa tibility in a temperature region down to 200 degreesC. The thickness and cr ystallite size can be independently adjusted by changing the process temper ature and the treatment time. As a first step towards the application for o steosynthesis plates used in jaw surgery, the biocompatibility of rutile su rface layers was tested using a rat model, which is well established for bi ocompatibility testing of metal surfaces. Small rods with a diameter of 0.9 mm and a length of 10 mm, prepared from titanium (grade 2) and two differe nt NiTi alloys (NiTi SE508, NiTi SM496), were implanted with oxygen at temp eratures between 200 degreesC and 600 degreesC with an incident dose of 5 X 10(17) O atoms cm(-2). Afterwards they were inserted into rat femurs, toge ther with untreated samples as a control group. The results of the animal t ests are correlated with the morphology and structure of the treated surfac es. (C) 2001 Elsevier Science B.V. All rights reserved.