title: Porosity and accuracy of multiple-unit titanium castings.
abstract: The objective of this investigation was to determine whether titanium could be used to cast reproducible multiple-unit dental restorations. A metal analog was machined to simulate preparations for a three-unit fixed partial denture. Castings were made with four different sprue designs at three temperatures. Marginal accuracy and porosity were evaluated. A total of 70 titanium castings were made with an argon/electric arc/vacuum/pressure casting machine. Ten castings were made in the conventional manner by use of gold-palladium alloy as a control to compare the marginal gap. The results revealed that the porosity was less when a large individual sprue (6-gauge) was used. It was also noted that the lower pattern burnout temperatures of 910 degrees C and 920 degrees C exhibited significantly smaller marginal gaps than did the higher temperature of 930 degrees C.
authors.affiliation: Boston University, Goldman School of Graduate Dentistry, Boston, Mass., USA.
authors.forename: T I
authors.initials: TI
authors.lastname: Chai
authors.forename: R S
authors.initials: RS
authors.lastname: Stein
mesh_terms: D000704:Analysis of Variance; D001128:Argon; D003734:Dental Casting Investment / Q000737:chemistry*; D003735:Dental Casting Technique / Q000295:instrumentation; D003779:Denture Design; D003830:Denture, Partial, Fixed; D004560:Electricity; D006047:Gold Alloys / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D010165:Palladium / Q000737:chemistry; D016062:Porosity; D011312:Pressure; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014618:Vacuum
chemical_list: D003734:Dental Casting Investment; D006047:Gold Alloys; D010165:Palladium; D001128:Argon; D014025:Titanium