title: In vitro fracture behavior of maxillary premolars with metal crowns and several post-and-core systems.
abstract: The in vitro fracture behavior of severely damaged premolars, restored with metal crowns with limited ferrule and several post-and-core systems, was investigated. Crowns of maxillary premolars were removed and canals were prepared with Gates Glidden drills and with Parapost drills. Groups of 11 samples were each treated with cast post-and-cores (Parapost XP, Wironium Plus) (group 1), prefabricated metal posts (Parapost XH) (group 2), prefabricated glass fiber posts (Parapost FiberWhite) (group 3), and custom-made glass fiber posts (EverStick Post) (group 4). Posts and composite cores and metal crowns in groups 2, 3, and 4 were adhesively cemented. Post-and-cores and crowns in group 1 were cemented with phosphate cement. Thermocycling was performed (6,000x, 5-55 degrees C). Two static load tests (30 degrees ) were applied. During the first load test (preloading) no failures occurred. Failure modes from the second load test were categorized into favorable and unfavorable failures. Mean failure loads among the four groups (group 1, 1,845 N; group 2, 1,718 N; group 3, 1,812 N; and group 4, 1,514 N) were not significantly different. Unfavorable failures were root fractures and favorable failures were postcrown displacements. No differences in frequencies of unfavorable/favorable failures were seen among the groups. The results suggest that different post-and-core systems have no influence on the fracture behavior of severely damaged premolars restored with metal crowns with limited ferrule.
authors.affiliation: Department of Oral Function and Prosthetic Dentistry, College of Dental Science, University Medical Centre Nijmegen, Nijmegen, the Netherlands. w.fokkinga@dent.umcn.nl
authors.forename: Wietske A
authors.initials: WA
authors.lastname: Fokkinga
authors.forename: Cees M
authors.initials: CM
authors.lastname: Kreulen
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Le Bell-Rönnlöf
authors.forename: Lippo V J
authors.initials: LV
authors.lastname: Lassila
authors.forename: Pekka K
authors.initials: PK
authors.lastname: Vallittu
authors.forename: Nico H J
authors.initials: NH
authors.lastname: Creugers
mesh_terms: D001641:Bicuspid / Q000293:injuries*; D002858:Chromium Alloys / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D003722:Dental Alloys / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D005898:Glass / Q000737:chemistry; D006801:Humans; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry; D018915:Root Canal Preparation / Q000295:instrumentation; D013314:Stress, Mechanical; D014082:Tooth Fractures / Q000503:physiopathology*; D019231:Tooth Preparation, Prosthodontic / Q000379:methods; D014092:Tooth Root / Q000293:injuries; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D002858:Chromium Alloys; C076805:Clearfil Porcelain Bond; D003188:Composite Resins; D003722:Dental Alloys; D003738:Dental Cements; D003764:Dental Materials; C438843:Panavia-Fluoro; D019279:Resin Cements; C496140:everStick; C009753:fiberglass; C074669:Clearfil Photo Bond; D015036:Zinc Phosphate Cement