title: Optimizing the concentration of 2,4,6-trimethylbenzoyldiphenylphosphine oxide initiator in composite resins in relation to monomer conversion.
abstract: The aim of this study was to optimize the concentration of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin® TPO) in unfilled and filled composite resins in relation to the degree of conversion (DC). Increasing concentrations of Lucirin® TPO between 0.05-4.97 wt% were added to equimolar mixtures of Bis-GMA/TEGDMA. Filled resins contained 75 wt% fillers. Standardized samples were cured using a polywave LED light-curing unit (bluephase® G2, Ivoclar Vivadent). Increased initiator concentrations increased logarithmically the DC of unfilled and filled resins. The DC of unfilled resins was in the range of 73-91% at the top and 63-81% at the bottom surfaces and that of filled resins was in the range of 53-81% at the top and 47-70% at the bottom surfaces. The DC in unfilled and filled resins reached a plateau at 1.08 wt% and 1.50 wt% Lucirin® TPO, respectively. Fillers significantly reduced conversion but had no effect on the logarithmic relationship between initiator concentration and the DC.
authors.affiliation: Department of Restorative Odontology and Endodontics, University of Belgrade School of Dental Medicine, Rankeova 4, Belgrade, Serbia.
authors.forename: Vesna
authors.initials: V
authors.lastname: Miletic
authors.forename: Ario
authors.initials: A
authors.lastname: Santini
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental / Q000145:classification; D003764:Dental Materials / Q000737:chemistry*; D006801:Humans; D015591:Microspectrophotometry; D010316:Particle Size; D010720:Phosphines / Q000737:chemistry*; D058567:Photoinitiators, Dental / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D013499:Surface Properties
chemical_list: C520678:(2,4,6-trimethylbenzoyl) diphenylphosphine oxide; D003188:Composite Resins; D003764:Dental Materials; D010720:Phosphines; D058567:Photoinitiators, Dental; D011109:Polymethacrylic Acids; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate