Metallography, Oxygen and Nitrogen's Analysis, and Vickers Hardness Testing of Internal Fixation Materials Used in the Craniofacial Skeleton

Moreira, Roger

Miniplates and screws titanium compounds have excellent biological behavior, and have been designed with innovative microstructure. Changes in its mechanical properties were proposed to increase de mechanical resistance, such as ultra-fine grains or alloys nanocrystals increments, without any change in its chemical composition. However, it can be unfavorable, since the grain size is related to material degradation (Eliaz, 2012). Currently, there are several brands of plates and screws and, for this reason, studies concerning the quality of these devices are required in order to evaluate their behavior (Trivellatto, 2000).Thus, a microstructural characterization of these materials is necessary for a better understanding of the funcionality of these devices.This study aims to analyze 04 brands of internal fixation material, used in oral and maxillofacial surgery (Leibinger = group I; Tóride = group II; Engimplan = group III; Medartis = group IV) by metallography, analyzing the composition of gaseous oxygen (O) and nitrogen (N), and Vickers hardness testing. Initially,three specimens with three rings of the plate and three specimens with screws were made for each group. The preparation of the specimens was performed to metallographic analysis, attending the ASTM E3-95 standards. And then the samples were submitted to Vickers hardness test, according to the ASTM E92 standards. Thereafter, the composition analysis of the contents of O and N in all groups was performed with a ring of the plate and a screw for each group. Data were submitted to ANOVA and Tukey's test for result comparison. All steps of the process were recorded and photographed. According to the results, the screws had higher hardness, compared to the plates. Including, the plates of group IV showed the largest grain size. The analysis of the gas composition showed that all groups followed ASTM standards.

Referrences:

- Eliaz N. Degradation of Implant Materials. Springer Science Business Media, New York, 29p, 2012.

- Trivellato AE, Mazzonetto R, Passeri LA, Consani S. Estudo químico, macroscópico e da resistência à flexão de placas e parafusos de titânio usados na fixação interna rígida. Pesqui Odontol Bras, v. 14, n. 4, p. 392-398, out./dez. 2000.