title: Influence of composite inlay/onlay thickness on hardening of dual-cured resin cements.
abstract: This investigation evaluated the effect of resin composite inlay/onlay thickness on the hardness of a group of eight dual-cure resin-based cements. Fourteen disc specimens measuring 6 mm in diameter and 2.5 mm thick were prepared from each of eight dual-cure cements: Adherence, Choice, Duolink, Enforce, Lute-It, Nexus, Resinomer and Variolink. Two specimens from each material were directly light-cured while the remainder of the specimens were light-cured through resin composite spacers varying in thickness from 1 mm to 6 mm. Curing through the spacers always resulted in a decrease in the Knoop hardness number. For some cements, hardness values were reduced by 50% or more when the resin composite spacer thickness was 4 mm or greater even when measurements were made one week after dual-curing. Low hardness values indicate the presence of a weak chemical-curing mechanism that may compromise cement quality in areas of the cavity not readily accessible to the curing light.
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, University of Toronto, Toronto Ontario, Canada M5G 1G6.
authors.forename: O M
authors.initials: OM
authors.lastname: El-Mowafy
authors.forename: M H
authors.initials: MH
authors.lastname: Rubo
mesh_terms: D002484:Cementation; D003738:Dental Cements / Q000737:chemistry; D006244:Hardness; D007284:Inlays / Q000379:methods*
chemical_list: D003738:Dental Cements