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Effects of various light curing methods on the leachability of uncured substances and hardness of a composite resin
Author(s) -
Moon H.J.,
Lee Y.K.,
Lim B.S.,
Kim C.W.
Publication year - 2004
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1111/j.1365-2842.2004.01172.x
Subject(s) - irradiation , curing (chemistry) , materials science , monomer , polymerization , composite number , indentation hardness , composite material , halogen lamp , energy density , polymer , microstructure , optics , theoretical physics , physics , nuclear physics
summary The purpose of this study was to evaluate the effect of the various light curing units (plasma arc, halogen and light‐emitting diodes) and irradiation methods (one‐step, two‐step and pulse) using different light energy densities on the leachability of unreacted monomers (Bis‐GMA and UDMA) and the surface hardness of a composite resin (Z250, 3M). Leachability of the specimens immersed for 7 days in ethanol was analysed by HPLC. Vicker's hardness number (VHN) was measured immediately after curing (IC) and after immersion in ethanol for 7 days. Various irradiation methods with three curing units resulted in differences in the amount of leached monomers and VHN of IC when light energy density was lower than 17·0 J cm −2 ( P = 0·05). However, regardless of curing units and irradiation methods, these results were not different when the time or light energy density increased. When similar light energy density was irradiated (15·6–17·7 J cm −2 ), the efficiency of irradiation methods was different by the following order: one‐step ≥ two‐step > pulse. These results suggest that the amount of leached monomers and VHN were influenced by forming polymer structure in activation and initiation stages of polymerization process with different light source energies and curing times.