title: Degree of conversion and leached monomers of urethane dimethacrylate-hydroxypropyl methacrylate-based dental resin systems.
abstract: The degree of conversion (DC) and monomer leaching of three experimental urethane dimethacrylate (UEDMA)-hydroxypropyl methacrylate (HPMA)-based resin systems were studied. Three experimental resins (E1: 70.6 wt% UEDMA + 27.4 wt% HPMA, E2: 80.6 wt% UEDMA + 17.4 wt% HPMA, E3: 90.6 wt% UEDMA + 7.4 wt% HPMA) and one control resin [C: 70.6 wt% bis-phenol A glycidyl methacrylate (bis-GMA) + 27.4 wt% methyl methacrylate (MMA)] were prepared. For the DC test, cylindrical specimens [1.5 mm (h) × 6 mm (d)] were scanned with an ATR-FTIR instrument before and after light-curing (n = 5). For the monomer leaching test, block-shaped specimens [5.67 mm (l) × 2.00 mm (w) × 2.00 mm (h)] were light-cured (n = 6), stored in a 75% ethanol:water solution for 3 days, and then analyzed with HPLC. The UEDMA-HPMA-based experimental groups showed higher DC (62-78%) than the bis-GMA-MMA-based control group (58-66%), and the DC decreased as the UEDMA content increased (P < 0.05). Amongst the four groups, E3 exhibited the lowest leaching of both mono methacrylate (0.1% HPMA) and dimethacrylate (<0.043% UEDMA) monomers after 30 or 40 s of curing. The UEDMA-HPMA-based resins, therefore, exhibited higher DC and less monomer leaching compared to the bis-GMA-MMA-based resin. (J Oral Sci 58, 15-22, 2016).
authors.affiliation: Dental Materials Science, Faculty of Dentistry, The University of Hong Kong.
authors.forename: Meng
authors.initials: M
authors.lastname: Zhang
authors.forename: Mervi A
authors.initials: MA
authors.lastname: Puska
authors.forename: Michael G
authors.initials: MG
authors.lastname: Botelho
authors.forename: Eija S
authors.initials: ES
authors.lastname: Säilynoja
authors.forename: Jukka P
authors.initials: JP
authors.lastname: Matinlinna
mesh_terms: D002851:Chromatography, High Pressure Liquid; D003188:Composite Resins; D008689:Methacrylates / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D003188:Composite Resins; D008689:Methacrylates; D011140:Polyurethanes; C029824:urethane dimethacrylate luting resin; C032802:hydroxypropyl methacrylate