In vivo performance of Al2O3-Ti bone implants in the rat femur.

BACKGROUND: Alumina-titanium (Al2O3-Ti) biocomposites have been recently developed with improved mechanical properties for use in heavily loaded orthopedic sites. Their biological performance, however, has not been investigated yet. METHODS: The aim of the present study was to evaluate the in vivo biological interaction of Al2O3-Ti. Spark plasma sintering (SPS) was used to fabricate Al2O3-Ti composites with 25 vol.%, 50 vol.%, and 75 vol.% Ti content. Pure alumina and titanium were also fabricated by the same procedure for comparison. The fabricated composite disks were cut into small bars and implanted into medullary canals of rat femurs. The histological analysis and scanning electron microscopy (SEM) observation were carried out to determine the bone formation ability of these materials and to evaluate the bone-implant interfaces. RESULTS: The histological observation showed the formation of osteoblast, osteocytes with lacuna, bone with lamellar structures, and blood vessels indicating that the healing and remodeling of the bone, and vasculature reconstruction occurred after 4 and 8 weeks of implantation. However, superior bone formation and maturation were obtained after 8 weeks. SEM images also showed stronger interfaces at week 8. There were differences between the composites in percentages of bone area (TB%) and the number of osteocytes. The 50Ti composite showed higher TB% at week 4, while 25Ti and 75Ti represented higher TB% at week 8. All the composites showed a higher number of osteocytes compared to 100Ti, particularly 75Ti. CONCLUSIONS: The fabricated composites have the potential to be used in load-bearing orthopedic applications.

Nasofacial Anthropometric Study Among Students of Shiraz University of Medical Sciences, Iran: A Population Based Study.

Anthropometry is a scientific study of linear dimensions and angles of living subjects. Knowing the details and anthropometric properties of nasofacial for each specific ethnic group is important for cosmetic operation as well as identifying individuals. In this study, facial and nasal anthropometric factors were studied in students of Shiraz University of Medical Sciences. In a cross-sectional study, 200 students of Shiraz University of Medical Sciences (100 male and 100 female and age range of 18-30 years) were selected. Nasal width (NW), nasal length (NL), nasal height (NH), face height (FH) and face width (FW) were measured in and the nasal (NI) and facial index (FI) were calculated for each case. Then, the data were analyzed using SPSS-22. The mean age was 21.84 ± 3.18 years. There were significant differences in the facial and nasal measurements including FH (P = 0.0001), FW (P = 0.0001), FI (P = 0.0001), NL (P = 0.002), NH (P = 0.001), NW (P = 0.0001) and NI (P = 0.0001) of sex groups. The most common types of face were mesoprosopic (36%) and hyperleptoprosopic (38%) types and and platyrrhine (63%) were mostly frequent. Based on the findings, all students of Shiraz University of Medical Sciences had mesoprosopic (36%) and hyperleptoprosopic (38%) types of face and platyrrhine type of nose. As well, a sexual dimorphism was recorded according to the nasofacial measurements in Iranian population that should be considered in the cosmetic operations. Sexual dimorphism and differences between different populations were recorded.

Corrosion of Al2O3-Ti composites under inflammatory condition in simulated physiological solution.

Alumina-titanium composites have shown good mechanical properties which makes them promising for orthopedic applications. The placement of an orthopedic implant involves an invasive procedure which stimulates a localized inflammatory response causing an acidic environment around the implant. This makes the study on corrosion more critical. Therefore, the aim of the present paper was to study the corrosion behavior of the composites with 75 vol% and 50 vol% Ti content (with alumina balance) fabricated by Spark Plasma Sintering under acidic condition representing inflammation and in two elapsed times (1 h and 1-day) using polarization and electrochemical impedance spectroscopy tests. For comparison, the experiments were also conducted in normal physiological solution after 1 h, and pure Ti (100vol%Ti) was fabricated by the same process and analyzed, similarly. Furthermore, behavior of the samples was studied after 48 days of immersion in the acidic and normal solutions using SEM, ATR-FTIR, AFM, and ICP-OES. The results of corrosion tests showed very good passivation behavior of 100vol%Ti and the composite containing 75vol.%Ti. The superiority of the 75vol.%Ti composite in corrosion characteristics in both solutions was also found. Its corrosion resistance was 20.3 MΩcm2 under the inflammatory condition after 1-day, which was 39% higher than that of 100vol.%Ti under the same condition. The results of SEM indicated both corroded and mineral deposition zones on all materials' surfaces and the ATR-FTIR results revealed additional adsorbed bands related to water adsorption, OH and carbonate groups after immersion. The AFM analysis showed rougher morphology, particularly for 75 vol% Ti where the Rq was increased about 50 nm, and the ICP-OES results indicated 65.87% and 61.94% deposition of solution calcium on 75vol.%Ti and 50vol.%Ti, respectively. The acidic/inflammatory condition influenced the corrosion processes of all materials. Lower pH caused the passivation to occur sooner and the corrosion resistance to be higher.