Failure analysis in a dental implant

A Ti-6Al-4V dental implant failed catastrophically after 6 months of service. This kind of failures is rare in the short term, 6 months; however in this case, a fracture was presented at the inner screw used for fixation of the abutment. The failure examination included visual inspection, chemical analysis, metallography, microhardness testing, as well as macroscopic and microscopic fractographic observations using scanning electron microscope with EDS (Energy-dispersive X-ray spectroscopy) were made. Additionally finite element analysis (FEA) was undertaken in order to clarify the stress scenario of the failure. Based on the examination results, the failure was promoted by bone re-sorption leading a cantilever condition resulting an overload system with cyclic high level stresses. This condition along with the rough surface finish found in the screw and the concentration factor by geometry change, caused a crack which was propagated until the failure of the component.