title: Effect of cement types on the tensile strength of metallic crowns submitted to thermocycling.
abstract: The relationship between metallic cast crowns and tensile strength according to cement types submitted to thermocycling was studied. Seventy-two metallic crowns were cast with Verabond II Ni-Cr alloy and cemented in standardized preparations with 10 masculine tapering. Three types of finishing line (45-degree chamfered, 20-degree bevel shoulder and right shoulder) were made with diamond burs on bovine teeth. Twenty-four metallic crowns in each group were randomly subdivided into three subgroups of 8 samples each according to the cement used: SS White zinc phosphate cement, Vitremer resin-modified glass ionomer cement, and Rely X resin cement and were submitted to thermocycling. Retention was evaluated according to tensile load required to displace the metallic cast crowns from tooth preparations with an Instron testing machine. ANOVA and Tukey's test showed a statistically significant difference among luting materials, with greater results for Rely X resin cement (24.9 kgf) followed by SS White zinc phosphate cement (13.3 kgf) and Vitremer resin-modified glass ionomer cement (10.1 kgf). The finishing line types did not influence the tensile resistance of the crowns fixed with the three cements. Increased tensile resistance of metallic crowns fixed on bovine teeth was obtained with resin cement, independent of the finishing line types.
authors.affiliation: Department of Dental Materials, Dental School of Piracicaba, UNICAMP, Piracicaba, SP, Brazil. consani@fop.unicamp.br
authors.forename: Simonides
authors.initials: S
authors.lastname: Consani
authors.forename: Julie Guzela dos
authors.initials: JG
authors.lastname: Santos
authors.forename: Lourenço
authors.initials: L
authors.lastname: Correr Sobrinho
authors.forename: Mário Alexandre Coelho
authors.initials: MA
authors.lastname: Sinhoreti
authors.forename: Manoel Damião
authors.initials: MD
authors.lastname: Sousa-Neto
mesh_terms: D000818:Animals; D002417:Cattle; D002858:Chromium Alloys / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D003799:Dental Stress Analysis / Q000295:instrumentation; D005899:Glass Ionomer Cements / Q000737:chemistry; D006813:Humidity; D008422:Materials Testing; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D019231:Tooth Preparation, Prosthodontic / Q000379:methods; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D002858:Chromium Alloys; D003188:Composite Resins; D003722:Dental Alloys; D003738:Dental Cements; D005899:Glass Ionomer Cements; C528569:Rely-X; D019279:Resin Cements; C084550:Vitremer; D015036:Zinc Phosphate Cement