AUTHORS: Štěpán Major, Michal Růžička, Pavel Cyrus

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ABSTRACT: Most of mechanical components in the engineering are frequently subjected to multi axial loading, which also applies to medical engineering. The cyclic-loading can lead to sudden fatigue failure. In present work the fatigue life of cylindrical titanium components of dental implants made from titanium alloys 6Al-4V ELI and Al 7Nb were studied. Contrary to surface tre tments used in industry, the main goal of titanium dioxide deposition is to improve implants biocompatibility. The effect of surface treatment on fatigue life of implant was tested experimentally. Two sets of experimental samples differed in surface layer thickness, so that its influence can be compared. Its fatigue behaviour was studied and predictive models were tested. Sixteen different models were applied and analysed in order to obtain the best way to predict fatigue life of implant. Two different types of implants were tested. First type of implant uses abutment screw to fix the crown. This type has four parts. Second type of dental replacement has only three components. This type utilizes abutment polygonal thorn to fix the crown. Experiments show that, the effect of titanium dioxide surfaces on implants mechanical properties is considered negligible. Therefore implants fatigue life is not dependent on dioxide layer thickness. The Gonçalves- Araujo- Mamiya criterion was found the best in implants fatigue prediction. The prediction of fatigue life of polygonal thorn is more complicated, so its prediction is gives inferior results contrary to the first type of implant.

KEYWORDS: - Fatigue testing, Bending-torsion loading, Titanium dioxide, Biocompatibile surface, Dental replacement, abutment screw.

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