title: Marginal accuracy and geometry of cast titanium copings.
abstract: The biocompatibility of titanium with human tissue is well established; its potential as an alternate metal for crown restorations has yet to be fully investigated. This study measured the geometry and accuracy of coping margins cast in Ti, 99.5% chemically pure. Twenty castings with 45-degree facial and 90-degree palatal margins were made by indirect technique with a commercial system using recommended procedures. They were then cemented with ZnPO4 cement. The coping and die assemblies were embedded in resin, sectioned longitudinally, and measured with a microscope at x50 power. Casting shrinkage was characteristic, particularly along the horizontal axis in the plane of the shoulder. Although horizontal linear shrinkage of 45-degree margins was greater than that for the 90-degree form, the surface of marginal discrepancy was greatest with the 90-degree configuration.
authors.affiliation: Department of Restorative Dentistre, University of Texas Health Science Center, Dental School, San Antonio.
authors.forename: R
authors.initials: R
authors.lastname: Blackman
authors.forename: R
authors.initials: R
authors.lastname: Baez
authors.forename: N
authors.initials: N
authors.lastname: Barghi
mesh_terms: D000704:Analysis of Variance; D003442:Crowns; D003734:Dental Casting Investment / Q000737:chemistry; D003737:Dental Cavity Preparation; D003779:Denture Design; D008422:Materials Testing; D003765:Models, Dental; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D003734:Dental Casting Investment; D014025:Titanium