title: Phosphate-bonded ZrSiO4 investments added with ZrC and ZrN for casting titanium.
abstract: In this study, new investments for titanium were developed by adding ZrC or ZrN as chemical additive for thermal expansion to a phosphate-bonded zircon (ZrSiO4) investment. The following effects were then examined: setting expansion, residual thermal expansion, and compressive strength of these experimental investments; surface roughness of cast plate; and casting accuracy of titanium crown. For residual thermal expansion, it occurred even while investments were cooled to room temperature after firing in air atmosphere. This was due to the additives' oxidation to ZrO2--suggesting that residual thermal expansion increased with increased amount of these additives. As for casting accuracy of full-crown cast into molds at room temperature, it correlated with the ZrN content. Hence by adding the right amount of ZrN, cast titanium crowns with low surface roughness and good adaptability could be obtained.
authors.affiliation: Division of Biomaterials Science, Graduate School of Dentistry, Osaka University, Suita, Japan. j-takaha@dent.osaka-u.ac.jp
authors.forename: Junzo
authors.initials: J
authors.lastname: Takahashi
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Kitahara
authors.forename: Fuminobu
authors.initials: F
authors.lastname: Kubo
mesh_terms: D000704:Analysis of Variance; D002244:Carbon; D003442:Crowns; D003734:Dental Casting Investment / Q000737:chemistry*; D003735:Dental Casting Technique; D006358:Hot Temperature; D009584:Nitrogen; D017640:Silicates / Q000737:chemistry*; D014025:Titanium; D015040:Zirconium / Q000737:chemistry*
chemical_list: D003734:Dental Casting Investment; D017640:Silicates; C003784:zircon; D002244:Carbon; D015040:Zirconium; D014025:Titanium; D009584:Nitrogen