title: Effect of hygroscopic expansion on the push-out resistance of glass ionomer-based cements used for the luting of glass fiber posts.
abstract: This study examined the contribution of hygroscopic expansion of glass-ionomer (GIC) and resin modified glass-ionomer (RMGIC) luting cements to the push-out resistance of fiber posts. Glass fiber posts were luted to post spaces using different cements. Experimental specimens were stored in water, while control specimens were desiccated and stored in mineral oil to eliminate water from intraradicular dentinal tubules and/or the external environment that could have contributed to hygroscopic expansion of the cements. Thin slice push-out tests revealed no difference in retention strengths of resin composite cements that were stored in water or oil. Conversely, GIC and RMGIC cements exhibited increased retention strengths after water sorption. As unfavorable cavity geometry is taxing to dentin bond integrity in root canals, a strategy that relies on increasing the frictional resistance to post dislodgement via delayed hygroscopic expansion of glass-ionomer based materials may be a more pragmatic approach to fiber post retention.
authors.affiliation: Department of Restorative Dentistry and Dental Materials, University of Siena, Siena, Italy.
authors.forename: Alvaro H
authors.initials: AH
authors.lastname: Cury
authors.forename: Cecilia
authors.initials: C
authors.lastname: Goracci
authors.forename: Maria Fidela
authors.initials: MF
authors.lastname: de Lima Navarro
authors.forename: Ricardo M
authors.initials: RM
authors.lastname: Carvalho
authors.forename: Fernanda T
authors.initials: FT
authors.lastname: Sadek
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Tay
authors.forename: Marco
authors.initials: M
authors.lastname: Ferrari
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D017268:Dental Prosthesis Retention / Q000379:methods*; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D011140:Polyurethanes / Q000737:chemistry*; D011176:Post and Core Technique; D018709:Statistics, Nonparametric; D014867:Water / Q000737:chemistry*
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D005899:Glass Ionomer Cements; D011140:Polyurethanes; D014867:Water