title: Load fatigue of five restoration modalities in structurally compromised premolars.
abstract: Twenty-five freshly extracted maxillary first premolars were divided equally among five modalities for rebuilding structurally compromised premolars. These modalities were: (A) buccal stainless steel Parapost/amalgam core, (B) palatal stainless steel parapost/amalgam core, (C) two stainless steel Paraposts/amalgam core, (D) two regular Link Plus TMS single-shear Minim pins/amalgam core, and (E) palatal cast gold post and core. Load fatigue was used as the testing protocol, using a 5.2-kg load applied at 72 cycles per minute. Each tooth was prepared with a 1.0-mm ferrule, and an upper limit of 250,000 load cycles was set for the testing. Two failures were exhibited, (1) preliminary failure which involved a crack in the luting cement layer, and (2) catastrophic failure wherein the core and crown separated from the root section. Statistical analysis using Kruskal-Wallis test showed three subsets (P < or = .05). The subset with the highest number of load cycles to failure contained the palatal stainless steel post/amalgam core, two stainless steel Paraposts/amalgam core, and palatal cast gold post and core.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle 98195, USA.
authors.forename: P
authors.initials: P
authors.lastname: Fan
authors.forename: J I
authors.initials: JI
authors.lastname: Nicholls
authors.forename: J C
authors.initials: JC
authors.lastname: Kois
mesh_terms: D001641:Bicuspid / Q000503:physiopathology; D003442:Crowns; D003723:Dental Amalgam; D003772:Dental Pins; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000379:methods*; D003799:Dental Stress Analysis; D006047:Gold Alloys; D006801:Humans; D008422:Materials Testing; D008437:Maxilla; D011176:Post and Core Technique / Q000295:instrumentation*; D013193:Stainless Steel; D018709:Statistics, Nonparametric; D015036:Zinc Phosphate Cement
chemical_list: C061504:Flecks; D006047:Gold Alloys; D013193:Stainless Steel; D015036:Zinc Phosphate Cement; D003723:Dental Amalgam