title: Influence of water storage and thermal cycling on the fracture strength of all-porcelain, resin-bonded fixed partial dentures.
abstract: The purpose of this in vitro study was to evaluate the influence of water storage and thermal cycling on the fracture strength of two designs of all-porcelain, resin-bonded fixed partial dentures made with the glass-infiltrated alumina ceramic In-Ceram. Forty frameworks of In-Ceram ceramic veneered with Vitadur-N porcelain were made to replace an upper central incisor bonded to extracted natural teeth. In 20 of the restorations the pontic was veneered only labially with Vitadur-N porcelain and no proximal box preparations were made (design A). The other 20 restorations had additional box preparations proximal to the pontic and the In-Ceram ceramic pontic framework was shifted to the labial aspect and veneered circumferentially with Vitadur-N porcelain (design B). Subgroups of 10 restorations were stored for 7 days in thymol solution or alternatively for 150 days in artificial saliva with thermal cycling for 18,750 cycles between 5 degrees and 55 degrees C. Restorations with design B had a statistically significantly higher fracture strength than restorations with design A. Storage in artificial saliva with thermal cycling significantly reduced the fracture strength of the resin-bonded In-Ceram fixed partial dentures. Therefore, the long-term clinical behavior of resin-bonded In-Ceram fixed partial dentures must be evaluated before general clinical use can be recommended.
authors.affiliation: Department of Prosthodontics, Albert-Ludwigs University, School of Dentistry, Freiburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Kern
authors.forename: T
authors.initials: T
authors.lastname: Fechtig
authors.forename: J R
authors.initials: JR
authors.lastname: Strub
mesh_terms: D000537:Aluminum Oxide; D000704:Analysis of Variance; D003776:Dental Porcelain; D003799:Dental Stress Analysis; D003779:Denture Design; D016379:Denture, Partial, Fixed, Resin-Bonded; D006358:Hot Temperature; D006801:Humans; D007180:Incisor; D008422:Materials Testing; D011475:Prosthesis Failure; D012464:Saliva, Artificial; D013718:Tensile Strength; D014867:Water
chemical_list: D012464:Saliva, Artificial; D014867:Water; D003776:Dental Porcelain; C070870:In-Ceram; C058236:Vitadur N; D000537:Aluminum Oxide