Dental Casting Properties of Ti-15Zr-4Nb-4Ta Alloy

Abstract

The dental casting properties of the Ti-15Zr-4Nb-4Ta alloy were compared with those of commercial pure Ti grade 2 and Ti-6Al-V alloy. Ti-15Zr-4Nb-4Ta dental castings were also surface-coated by TiN ion plating. Metal plates for complete and partial dentures, crowns and bridges were experimentally fabricated using the Ti-15Zr-4Nb-4Ta alloy. The cast surface down to a depth of about 200 µm had a highhardness layer due to the reaction with the dental investment. Also, there was no sharp increase in the current density caused by the breakdown of the passive film starting from the layer that reacted with the dental investment. The 0.2% proof strength, ultimate tensile strength, total elongation and Young's modulus of the Ti-15Zr-4Nb-4Ta castings, which were chemically polished by acid treatment after sandblasting, were 761 ± 33 MPa, 970 ± 31 MPa, 6 ± 4% and 90 ± 2 GPa, respectively. The micro-Vickers hardness of the TiN coated-surface was 740. The effect of TiN surface coating on the mechanical properties of the Ti-15Zr-4Nb-4Ta castings was negligible. The Ti-15Zr-4Nb-4Ta alloy exhibited a lower release of metal ions into the artificial saliva and 1% lactic acid solution than the Ti-6Al-4V alloy, and the quantity of metal ions released was less than 20% of that of titanium ions released from the Ti-6Al-4V alloy. The quantities of the titanium, zirconium and niobium ions released from TiN-coated Ti-15Zr-4Nb-4Ta casting into the artificial saliva were smaller than those released from the Ti-15Zr-4Nb-4Ta casting that was only chemically polished. Metal plates for complete and partial dentures, crowns and bridges were successfully fabricated using the Ti-15Zr-4Nb-4Ta alloy. A TiN-coated partial denture was also successfully fabricated using this alloy. The Ti-15Zr-4Nb-4Ta alloy with its excellent corrosion resistance and mechanical properties is expected to be used for dental prostheses in the future.

Mechanical Property, Fatigue Strength and Clinical Trial of Dental Cast Ti–15Zr–4Nb–4Ta Alloy

“…The minimum values of 0.2%PS , UTS and TE for Co-Cr-Mo castings in this JIS standard are specified as 500 MPa, 685 MPa and 3%, respectively. Commercially available pure Ti grade 2 lacks the necessary ultimate tensile strength, 19) but both the Ti alloys and Co-Cr-Mo alloy used in this study meet these specifications.…”

“…19) At a depth of approximately 200 mm from the surface of the castings, a high-hardness layer is formed due to the reaction of Ti alloy with the dental investment. This high-hardness layer is chemically polished to a thickness of approximately 50 mm with a mixture of nitric acid and hydrofluoric acid.…”

“…The concentrations of Ti, Zr, Nb and Ta ions released the Ti-15Zr-4Nb-4Ta alloy into the artificial saliva and 1% lactic acid solution are smaller than those of Ti, Al and V ions released from the Ti-6Al-4V alloy, and the concentration of Ti ions released from the Ti-15Zr-4Nb-4Ta alloy into the 1% lactic acid solution is less than 20% that of the Ti ions released from the Ti-6Al-4V alloy. 19) TiN is surface-coated on a partial denture made of Ti-15Zr-4Nb-4Ta alloy using a TiN ion plating apparatus.…”

“…17,18) The fatigue strength of the Ti-15Zr-4Ta-4Nb alloy annealed at 700 C for 2 h was approximately 600 MPa in Eagle's medium at 1 Â 10 8 cycles, and the fatigue strength of the Ti-15Zr-4Ta-4Nb alloy aged after solution treatment increased to 800 MPa in Eagle's medium. 19) Ti-15Zr-4Nb-4Ta alloy with its excellent mechanical properties, corrosion resistance and fatigue strength and cytocompatibility can be used for medical purposes.…”

Fatigue Property of Super-Elastic Ti–Ni Alloy Dental Castings

“…The thickness of the surface reacted layer for Ti and Ti alloy dental castings was reported to range from 100 to 200 mm, 61,62) which is one of the important factors of the fatigue strength on crack initiation. In this study, the specimen surface of Ti-Ni alloy castings at the parallel part was polished with emery paper to keep the surface condition smooth.…”