title: Bond strengths and patterns of failure of a zinc polycarboxylate cement on surface-treated gold alloys.
abstract: The study investigated the shear strengths and fracture characteristics of a zinc polycarboxylate cement on three sets of type III gold alloy bars whose surfaces were modified by alumina blasting, heat treatment and tin plating respectively. Each set comprised 20 bars with similarly treated surfaces, cemented in pairs with the polycarboxylate cement and stored in water at 37 degrees C for 48 hours. The cement bond was then stressed to failure by application of forces in shear mode and the bond strength was determined. The mean bond strength for each type of treated gold alloy surface was calculated and then compared with the others by way of statistical analysis. The failed surfaces were observed and photographed with a stereophotomicroscope for subjective evaluation of the character of the failed surfaces. The strongest bonds were formed on the alumina-blasted surfaces where 70% of the bonds failed in an adhesive-cohesive fashion. The weakest bonds were formed on the tin-plated surfaces where cement failure was entirely adhesive. Bond strengths on the heat-treated surfaces were intermediate and a cohesive failure pattern was observed on 80% of the specimens. The differences in bond strengths on the three surfaces were statistically significant.
authors.affiliation: Department of Restorative Dentistry, College of Medicine, University of Ibadan, Nigeria.
authors.forename: A
authors.initials: A
authors.lastname: Ogunyinka
mesh_terms: D000268:Adhesiveness; D000537:Aluminum Oxide / Q000737:chemistry; D001840:Dental Bonding; D003799:Dental Stress Analysis / Q000295:instrumentation; D004595:Electroplating; D006047:Gold Alloys / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D010780:Photogrammetry; D011076:Polycarboxylate Cement / Q000737:chemistry*; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014001:Tin / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D006047:Gold Alloys; D011076:Polycarboxylate Cement; D014867:Water; C029881:Poly F cement; D014001:Tin; D000537:Aluminum Oxide