Caracterização de ligas de titânio em implantes dentários

Abstract

An ideal biological alloy for dental implants must have very high biocompatibility, which means that such material should not provoke any serious adverse tissue response. Dental implants are generally marketed as commercially pure titanium (Ticp) due to their excellent mechanical and physical properties. However, sometimes other alloys are employed and consequently it is essential to study the chemical elements present in those alloys that could bring prejudice for the health. Considering the facts, although the manufacturing standards for dental implants seek to promote standardization as to the type and percentage limit for each metal added to the alloys, it is necessary to define the criteria for analyzing the validation of implants, in addition to the manufacturing standards for registration of these materials. In this sense, the present work sought to characterize the type of alloy and elaborate a proposal for a continuous quality control protocol for dental implants. Present work investigated 33 dental implants already used and without model or brand registration for evaluated the composition. For alloy characterization and identification of elements it was used EDXRF technique. This method allows to perform the qualitative and quantitative analysis of the materials using the spectra of the characteristic X-rays emitted by the elements present in the metal samples. The experimental setup was based on one X- ray tube, Mini X model with Au target and X-123SDD detector (AMPTEK) and a 0.5 mm Cu collimator, developed due to specific sample geometrical and topography characteristics. The complementary techniques of EDS and XPS served to support the results of the main technique. The neutron activation technique was used to establish the calibration standard for the quantitative analysis for EDXRF technique. Based on the characterization of the implants analyzed in this research and the crossing of the results obtained by the main technique and the complementary ones, it was possible to infer that the implants are not of Tip or Ti6Al4V, since the percentages of specific elements such as Ti, Al and V are incompatible for this classification. For Ti, the highest percentages were 98.9 ± 1.5% and 98.0 ± 1.4%. The highest percentage of Al and V in the samples was 0.004 ± 0.0005% and 1.3 ± 0.01%, respectively. The implants analyzed a Ti alloy containing Al, V, Cr, Ni, Cu and Fe. These results from non-standard alloys expected for Ticp emphasize the need to implement the proposed quality control protocol to certify the type of Ti alloy and ensure good manufacturing practices for this type of biomaterial.