title: [Effects of the mold temperature on the castability of titanium zirconium alloy for dental clinical use].
abstract: OBJECTIVE
  The aims of this study were to investigate the influence of the mold temperature on the castability of Ti-Zr alloy and find out the reasonable method for casting Ti-Zr alloy in clinic.
  
  
  METHODS
  Ti-Zr alloy, pure titanium and Ti-6Al-4V alloy were casted respectively, by using a mold made of a zircon (ZrO2.SiO2) investment and a casting machine (China) designed, with a program of vacuum, pressure and centrifuge casting at three mold temperatures (room temperature, 300 degrees C, 600 degrees C). The castability value was obtained by counting the complete segment of the cast alloy grid. The wax pattern provided a grid with 112 segments. The percentage of complete cast segments was calculated by divided by 112, and multiplied by 100. The mesh castability values of Ti-Zr alloy, pure titanium and Ti-6Al-4V alloy were examined.
  
  
  RESULTS
  The castability of three titanium alloys was high when the mold temperature was high. The castability values of Ti-Zr alloy at three mold temperatures were 88.57% for the room temperature, 94.55% for 300 degrees C, and 96.67% for 600 degrees C. Ti-Zr alloy casted at the room temperature showed significantly lower castability value than that casted at 300 degrees C and 600 degrees C (P < 0.05), but no significant difference was found between the castability values of 300 degrees C and 600 degrees C (P > 0.05). The castability values of pure titanium at three mold temperatures were 95.33% for room temperature, 98.70% for 300 degrees C, and 98.90% for 600 degrees C. The castability values of Ti-6Al-4V alloy at three mold temperatures were 95.37% for room temperature, 96.00% for 300 degrees C, and 98.78% for 600 degrees C. When casted at room temperature, the castability values of Ti-Zr alloy were significantly decreased comparing with those of pure titanium and Ti-6Al-4V alloy (P < 0.05), but no significant difference was found when cast alloys were casted at 300 degrees C and 600 degrees C (P > 0.05).
  
  
  CONCLUSIONS
  The mold temperature is one of the major factors influencing cast quality. This study suggests that in order to obtain high castability of dental Ti-Zr alloy castings in clinic, the optimal mold temperature should be higher than 300 degrees C.
authors.affiliation: Stomatological College, Fourth Military Medical University.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.forename: T
authors.initials: T
authors.lastname: Guo
authors.forename: Z
authors.initials: Z
authors.lastname: Li
mesh_terms: D003722:Dental Alloys / Q000737:chemistry*; D003735:Dental Casting Technique / Q000592:standards*; D012016:Reference Values; D013696:Temperature; D014025:Titanium; D015040:Zirconium
chemical_list: D003722:Dental Alloys; D015040:Zirconium; D014025:Titanium