Mechanical properties, in vitro corrosion resistance and biocompatibility of metal injection molded Ti-12Mo alloy for dental applications.

A biocompatible Ti-12Mo alloy was fabricated by metal injection moulding (MIM) using non-spherical titanium, molybdenum powders and a purposely designed binder. The density, microstructure and tensile properties were characterized. This was followed by a detailed assessment of its in vitro corrosion and biocompatibility performances, compared with that of two commonly used titanium-based materials extra low interstitial (ELI) Ti-6Al-4V and commercially pure (CP) titanium. The MIM-fabricated Ti-12Mo alloy can achieve a wide range of mechanical properties through controlling sintering process. Specimens sintered at 1400 °C are characterized by fairly uniform near-ß microstructure and high relative density of 97.6%, leading to the highest tensile strength of 845.3 ±â€¯21 MPa and elongation of 4.15 ±â€¯0.2% while the highest elastic modulus of 73.2 ±â€¯5.1 GPa. Owing to the formation of protective TiO2-MoO3 passive film, the MIM-fabricated Ti-12Mo alloy exhibits the highest corrosion resistance including the noblest corrosion potential, the lowest corrosion current density and the highest pitting potential in four different electrolytes. The in vitro cytotoxicity test suggests that the MIM-fabricated Ti-12Mo alloy displays no adverse effect on MC3T3-E1 cells with cytotoxicity ranking of 0 grade, which is nearly close to ELI Ti-6Al-4V or CP Ti. These properties together with its easy net-shape manufacturability make Ti-12Mo an attractive new dental implant alloy.

Polymorphisms of CASR gene increase the risk of primary hyperparathyroidism.

OBJECTIVE: To evaluate correlations between polymorphisms of calcium-sensing receptor (CASR) gene [A986S (rs1081725), R990G (rs1042636) and Q1011E (rs1801726)] and the risk of primary hyperparathyroidism (PHPT) among human population. METHODS: Relevant studies were retrieved from online databases using computer-based search strategies, which were then supplemented by manual search strategies. Case-control studies related to our topic were identified based on strict inclusion and exclusion criteria. Statistical analyses were conducted using the Comprehensive Meta-analysis 2.0 (Biostat Inc., Englewood, NJ, USA). RESULTS: We retrieved 202 studies from online databases and other sources initially and eventually enrolled six studies into our meta-analysis. These six studies contained a sum of 693 PHPT patients and 1252 healthy controls. Our meta-analysis results showed that single nucleotide polymorphisms (SNPs) of CASR gene A986S (rs1081725) and R990G (rs1042636), but not Q1011E (rs1801726), may increase the risk of PHPT [A986S (rs1081725): allele model: P = 0.013; dominant model: P = 0.044; R990G (rs1042636): allele model: P = 0.023; dominant model: P = 0.026)]. Subgroup analyses based on ethnicity showed that among Asians, A986S (rs1081725) increased the PHPT risk (P = 0.04) under the allele model, but not under the dominant model. Among Caucasians, there was no association between gene frequencies and PHPT under both the allele and dominant model. In Asians, no significant association was observed between R990G (rs1042636) and PHPT risk, but in Caucasians, R990G (rs1042636) significantly increased the incidence of PHPT [R990G (rs1042636): allele model: P = 0.015; dominant model: P = 0.009)]. CONCLUSION: Our results indicate that SNPs of CASR gene A986S (rs1081725) and R990G (rs1042636) may increase the risk of PHPT, and the polymorphisms can potentially be used as important biological markers for early diagnosis of PHPT.