title: Comparison of photo-activation versus chemical or dual-curing of resin-based luting cements regarding flexural strength, modulus and surface hardness.
abstract: This study investigated the efficiency of chemical activation of dual-cure resin-based luting cements as compared with light- and dual-curing. Curing was performed by (i) mixing base and catalyst without subsequent irradiation (chemical curing=CC), (ii) mixing base and catalyst with direct irradiation (dual-cure=DC) or with (iii) irradiation through 2.5 mm of leucite-reinforced glass-ceramics (IPS Empress, Ivoclar) (dual-cure through porcelain=DCtP), (iv) using only the base paste with direct irradiation (light-curing=LC) or with (v) irradiation through porcelain (light-curing through porcelain=LCtP). Specimens of four fine-hybrid DC resin composites and one self-cure hybrid resin composite (only CC) were prepared and tested after 24 h for flexural strength, modulus of elasticity (ISO 4049) and surface hardness (Vickers). For all materials and parameters, dual-curing produced higher values than LC, even when irradiation was performed through porcelain. Following self-curing without photo-activation, flexural strength was 68.9-85.9%, the modulus 59.2-94.5% and Vickers hardness 86.1-101.4% of the corresponding values obtained by dual-curing with direct irradiation. Light-curing through porcelain as compared with direct irradiation reduced the values for most parameters and materials. In contrast, dual-curing maintained flexural strength for all, the modulus for three and the hardness for one of the materials. The mechanical properties of the self-curing resin cement ranged between those of the DC materials.
authors.affiliation: Department of Operative Dentistry and Periodontology, Bavarian Julius-Maximilians-University of Würzburg, Germany. norbert.hofmann@mail.uni-wuerzburg.de
authors.forename: N
authors.initials: N
authors.lastname: Hofmann
authors.forename: G
authors.initials: G
authors.lastname: Papsthart
authors.forename: B
authors.initials: B
authors.lastname: Hugo
authors.forename: B
authors.initials: B
authors.lastname: Klaiber
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry; D004548:Elasticity; D006244:Hardness; D006801:Humans; D008027:Light; D008422:Materials Testing; D010710:Phosphates / Q000737:chemistry; D010777:Photochemistry; D018583:Pliability; D019279:Resin Cements / Q000737:chemistry* / Q000528:radiation effects; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013997:Time Factors
chemical_list: D000538:Aluminum Silicates; D003188:Composite Resins; C075815:IPS-Empress ceramic; C433206:Nexus; C093719:Panavia TPN-S; D010710:Phosphates; D019279:Resin Cements; C090888:Sono-Cem; D003776:Dental Porcelain; C078519:leucite; C072541:Duo Cement; C103502:Variolink; D017438:Bisphenol A-Glycidyl Methacrylate