title: Effect of plasma arc curing on polymerization shrinkage of orthodontic adhesive resins.
abstract: The purpose of this study was to evaluate the polymerization shrinkage of three orthodontic adhesive resins when polymerized with a high-energy plasma arc light (1340 mW cm(-2)) and a conventional halogen light (500 mW cm(-2)), and to correlate the polymerization shrinkage with the degree of conversion. To equalize the total light energy delivered to the adhesive resin, irradiation time was varied between 3 or 6 s for a plasma arc-curing unit, and 8 or 16 s for a halogen light-curing unit. The polymerization shrinkage of adhesive resins during the light-curing process was measured using a computer-controlled mercury dilatometer and the degree of conversion was measured using Fourier transform infrared spectroscopy. A plasma arccuring unit produced significantly lower polymerization shrinkage than a halogen light-curing unit when the equivalent total light energy was irradiated to the orthodontic adhesive resins (P < 0.05). The magnitude of polymerization shrinkage was significantly different depending on the kind of adhesive resins (P < 0.05), but there was no significant correlation between the filler fraction and the polymerization shrinkage (r2 = 0.039). There was strong correlation (r2 = 0.787) between the polymerization shrinkage and the degree of conversion with a halogen light-curing unit, but poor correlation (r2 = 0.377) was observed with a plasma arc-curing unit.
authors.affiliation: Department of Dental Biomaterials, College of Dentistry College and Intellectual Biointerface Engineering Research Center, Seoul National University, Seoul, South Korea.
authors.forename: H-C
authors.initials: HC
authors.lastname: Bang
authors.forename: B-S
authors.initials: BS
authors.lastname: Lim
authors.forename: T-H
authors.initials: TH
authors.lastname: Yoon
authors.forename: Y-K
authors.initials: YK
authors.lastname: Lee
authors.forename: C-W
authors.initials: CW
authors.lastname: Kim
mesh_terms: D001840:Dental Bonding; D003738:Dental Cements; D008027:Light; D009970:Orthodontics; D019279:Resin Cements
chemical_list: D003738:Dental Cements; D019279:Resin Cements