To improve the implants biocompatibility many surface modifications were proposed. Investigations about the surface modification on Ti alloys by anodic oxidation are reported. This research presents a study on the stability of thin titanium dioxide grown by potentiodynamic method on Ti6Al4V surfaces up to 5.0 V. Its bioactive surface in phosphate buffer solution (PBS) and the oxide stability after immersion in artificial blood media were measured by Electrochemical Impedance Spectroscopy (EIS). Hydroxyapatite (HAP) presence was evaluated using simulated body fluid (SBF) with different immersion times. The oxides and HAP presence were analyzed by Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The oxide stability was confirmed with low dissolution rates where the Rp was around 106Ω.cm2. The results showed the TiO2 was compact and thin oxide that could prevent the severe corrosion processes and improve in few days the physical-chemical interaction of the Ti alloys with bone in physiological media.

OBJETIVO: Estudar as variações térmicas obtidas por meio da imagem infravermelha em ratos, e avaliar sua correlação com o tempo de isquemia intestinal e os achados histopatológicos. MÉTODOS: Trinta ratos Wistar foram operados após distribuição em cinco grupos com diferentes tempos de isquemia. Os termogramas foram obtidos utilizando-se uma câmera infravermelha. A técnica operatória foi padronizada para todos os grupos, abertura da cavidade abdominal por uma incisão na linha média de 5 cm de comprimento com secção de todos os planos da parede abdominal e exposição da cavidade e as alças intestinais exteriorizadas. No grupo I (controle) foi feito apenas laparotomia sem ligadura da artéria mesentérica superior. Após realizado o primeiro termograma, foi fechada a incisão com sutura contínua. Em cada rato dos grupos II, III, IV e V a artéria mesentérica superior foi localizada em sua origem na aorta abdominal, dissecada com e ocluída por um microclampe vascular submetendo o intestino à isquemia em tempos variáveis. RESULTADOS: Os ratos submetidos à isquemia de 30 minutos apresentaram hiperemia reativa, diferencial térmico de 1,8°C e exame anatomopatológico normal. A isquemia de 1 hora produziu hiperemia reativa com áreas de isquemia, diferencial térmico de 1,0°C e lesões na ponta das vilosidades. Já a de 90 minutos não demonstrou hiperemia reativa com grandes áreas de isquemia, diferencial térmico de -1,0°C e lesão no terço superior das vilosidades. A isquemia de 2 horas mostrou isquemia grave, diferencial térmico de -2,0°C e lesão em toda a extensão das vilosidades. CONCLUSÃO: Foi possível estudar as variações térmicas por meio da imagem infravermelha em ratos, que mostrou haver correlação entre a resposta térmica dos termogramas, o tempo de isquemia e achados histopatológicos.

PURPOSE: To study thermal variations obtained through infrared image in rats, and to evaluate the relationship between intestinal ischemic time and histopathological findings. METHODS: Thirty Wistar rats were operated after distribution in 5 groups with different times of ischemia. Thermograms were obtained by using a infrared camera. The surgical technique has been standardized for all groups: abdominal cavity opening by a 5cm length incision in the midline, abdominal wall plans section and cavity exposure, and exteriorization of the intestine. In group I (control), it was proceeded only laparotomy without superior mesenteric artery ligature. After first thermogram done, incision was closed with continuing suture. In each rat in groups II, III, IV and V, the superior mesenteric artery was located at its origin on abdominal aorta, dissected and occluded with a vascular microclamp, subjecting the intestine to ischemia in variable times. RESULTS: Rats submitted to a 30 minutes ischemia presented reactive hyperemia, thermal differential of 1.8°C and normal pathological examination. The 1 hour ischemia produced reactive hyperemia with ischemic areas, thermal differential of 1.0°C and injuries at villosities' tips. However, the 90 minutes ischemia had not shown reactive hyperemia with large ischemic areas, thermal differential of -1.0°C and injury in the upper third of the villosities. The 2 hours ischemia demonstrated a severe ischemia, thermal differential of -2.0°C and injury throughout the all villosities' extension. CONCLUSION: It has been possible studying thermal variations through infrared image in rats, showing correlation between thermal response in thermograms, ischemic time and histopathological findings.