title: Fracture resistance of human enamel and three all-ceramic crown systems on extracted teeth.
abstract: This in vitro study measured the fracture resistance of intact extracted molars and three types of all-ceramic crowns; feldspathic porcelain, glass-ceramic, and glass-infiltrated alumina. All crowns were of a simplified three-cusp occlusal configuration, and were placed on prepared, extracted third molars. The ceramic crowns were bonded to dentin with a resin composite cement, except for 10 of the feldspathic crowns, which were luted with zinc phosphate cement. The fracture resistances was measured using a spherical steel indenter that contacted the occlusal surface at three points. A total of 40 ceramic crowns and 50 extracted maxillary third molars were tested. The Weibull distribution was used for data analysis. Intact extracted teeth were significantly stronger than all-ceramic crowns. Of the ceramic restorations, the glass-infiltrated alumina crowns exhibited the highest fracture resistance.
authors.affiliation: Department of Fixed Prosthodontics and Occlusion, School of Dentistry, University of Geneva, Switzerland.
authors.forename: S S
authors.initials: SS
authors.lastname: Scherrer
authors.forename: W G
authors.initials: WG
authors.lastname: De Rijk
authors.forename: U C
authors.initials: UC
authors.lastname: Belser
mesh_terms: D000537:Aluminum Oxide; D002484:Cementation / Q000379:methods; D003442:Crowns; D003743:Dental Enamel / Q000502:physiology; D003776:Dental Porcelain; D006801:Humans; D016018:Least-Squares Analysis; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000502:physiology; D015036:Zinc Phosphate Cement
chemical_list: C047475:Dicor ceramic; D003776:Dental Porcelain; C070870:In-Ceram; D015036:Zinc Phosphate Cement; C058233:Ceramco; D000537:Aluminum Oxide