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Porous shape memory dental implant by reactive sintering of TiH2–Ni-Urea mixture

Akbarinia, S ; Sharif University of Technology | 2020

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  1. Type of Document: Article
  2. DOI: 10.1016/j.msec.2019.110213
  3. Publisher: Elsevier Ltd , 2020
  4. Abstract:
  5. We produced bifurcated bone-like shape memory implant (BL-SMI) with desirable tooth-root fixation capability by compact-sintering of TiH2–Ni-urea mixture. The primary constituents of the porous product were Ni and Ti. We could adjust the pores' shape, size, and interconnectivity for favorite bone ingrowth by using urea as a space holder. Without urea, we obtained an average porosity of 0.30, and a mean void size of 100 μm. With 70 vol % urea, we got 62% interconnected pores of 400 μm average size. Aging allowed us to tune the austenite-martensite transformation temperatures towards the needed body tissue arouse. Differential scanning calorimetry measured the transformation temperatures. Their austenite start, austenite peak, and austenite finish values were As = 4, Ap = 22, and Af = 34 °C, respectively. They retained functional shape recovery and superelastic effect at the body temperature. Mechanical properties, including Young's modulus of the specimens, matched well to maxilla and mandible bone tissue. The measured Young's modulus of the NiTi specimens was as low as 3.5 GPa, which decreased to ∼2.1 GPa with further porosity increase at higher space holder percentages. Superelasticity regime and low Young's modulus of the implant could potentially prevent stress-shielding from the surrounding bone tissues and give rise to secure fixation of the implant into the bone socket. Bending tests showed 0.9 mm recoverable deflection for specimens which assisted immediate self-fixation of the implant into the jaw bone cavity. © 2019 Elsevier B.V
  6. Keywords:
  7. Foamy implant ; NiTi shape memory alloy ; Superelasticity ; Tooth-root fixation ; Austenite ; Bending tests ; Binary alloys ; Biomechanics ; Bone ; Dental alloys ; Differential scanning calorimetry ; Elastic moduli ; Elasticity ; Metabolism ; Mixtures ; Porosity ; Shape optimization ; Shape-memory alloy ; Sintering ; Tissue ; Titanium alloys ; Urea ; Interconnected pores ; Martensite transformation temperature ; NiTi shape memory alloys ; Shape memory implants ; Superelastic effects ; Tooth root ; Transformation temperatures ; Metal implants ; Alloy ; Titanium nickelide ; Chemistry ; Materials testing ; Scanning electron microscopy ; Tooth implant ; Transition temperature ; Young modulus ; Alloys ; Dental Implants ; Elastic Modulus ; Materials Testing ; Microscopy, Electron, Scanning ; Nickel ; Phase Transition ; Titanium ; Transition Temperature
  8. Source: Materials Science and Engineering C ; Volume 107 , 2020
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0928493119319046#!