title: Failure modes of Y-TZP abutments with external hex implant-abutment connection determined by fractographic analysis.
abstract: Yttria-stabilized tetragonal zirconia (Y-TZP) was introduced as ceramic implant abutments due to its excellent mechanical properties. However, the damage patterns for Y-TZP abutments are limited in the literature. Fractographic analyses can provide insights as to the failure origin and related mechanisms. The purpose of this study was to analyze fractured Y-TZP abutments to establish fractographic patterns and then possible reasons for failure. Thirty two prefabricated Y-TZP abutments on external hex implants were retrieved from a single-load-to failure test according to the ISO 14801. Fractographic analyses were conducted under polarized-light estereo and scanning electro microscopy. The predominant fracture pattern was abutment fracture at the connecting region. Classic fractographic features such as arrest lines, hackle, and twist hackle established that failure started where Y-TZP abutments were in contact with the retention screw edges. The abutment screw design and the loading point were the reasons for localized stress concentration and fracture patterns.
authors.affiliation: UNESP - University Estadual Paulista, Araraquara School of Dentistry, Department of Dental Materials and Prosthodontics, 1680, Araraquara 14801-903, SP, Brazil. Electronic address: mariana_basilio@yahoo.com.br.
authors.forename: Mariana de Almeida
authors.initials: MA
authors.lastname: Basílio
authors.affiliation: UNESP - University Estadual Paulista, Araraquara School of Dentistry, Department of Dental Materials and Prosthodontics, 1680, Araraquara 14801-903, SP, Brazil. Electronic address: ju.delben@hotmail.com.
authors.forename: Juliana Aparecida
authors.initials: JA
authors.lastname: Delben
authors.affiliation: USP - University of São Paulo, School of Dentistry, Department of Biomaterials and Oral Biology, 2227, São Paulo 05508-000, SP, Brazil. Electronic address: paulofc@usp.br.
authors.forename: Paulo Francisco
authors.initials: PF
authors.lastname: Cesar
authors.affiliation: Western University, Schulich School of Medicine & Dentistry, Department of Medical Biophysics, Medical Sciences Building, London, ON, Canada N6A 5C1. Electronic address: arizkalla@eng.uwo.ca.
authors.forename: Amin Sami
authors.initials: AS
authors.lastname: Rizkalla
authors.affiliation: Western University, Schulich School of Medicine & Dentistry, Department of Dentistry, Medical Sciences Building, London, ON, Canada N6A 5C1. Electronic address: gildo.santos@schulich.uwo.ca.
authors.forename: Gildo Coelho
authors.initials: GC
authors.lastname: Santos Junior
authors.affiliation: UNESP - University Estadual Paulista, Araraquara School of Dentistry, Department of Dental Materials and Prosthodontics, 1680, Araraquara 14801-903, SP, Brazil. Electronic address: arioli@foar.unesp.br.
authors.forename: João Neudenir
authors.initials: JN
authors.lastname: Arioli Filho
mesh_terms: D002516:Ceramics; D000044:Dental Abutments; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D008422:Materials Testing; D015019:Yttrium; D015040:Zirconium
chemical_list: D015019:Yttrium; D015040:Zirconium; C091417:yttria
keywords: Dental ceramic; Failure analysis; Fractography; Implant abutment; Zirconia