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Influence of visible‐light exposure on colour stability of current dual‐curable luting composites
Author(s) -
Koishi Y.,
Tanoue N.,
Atsuta M.,
Matsumura H.
Publication year - 2002
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 - 10.1046/j.1365-2842.2002.00823.x
Subject(s) - colorimeter , materials science , composite material , distilled water , curing (chemistry) , composite number , chemistry , optics , chromatography , physics
This study was conducted to evaluate influence of visible‐light exposure on colour stability of dual‐curable luting composite. Using six dual‐curable luting composites [Bistite II (BI), Clapearl DC (CL), Dicor Light Activated Cement (DI), G‐Cera Cosmotech II (GC), Lute‐It (LU) and Variolink II (VA), disk specimens were prepared with the following two methods: (i) dual‐cured specimens, exposure with visible‐light from a photo‐curing unit for 120 s and (ii) chemical‐cured specimens, chemically cured without exposure. Five specimens were produced for each material and curing mode. After 24 h, all specimens were immersed in distilled water at 37 °C for 24 weeks, during which colour accuracy was measured with a dental colorimeter. The colours characterized in the Commission Internationale d'Eclairage (CIE) L * a * b * colour space were first determined 24 h after preparation (baseline colour evaluation), and again after 1, 2, 3, 4, 8, 12, 16 and 24 weeks. The colour difference (Δ E *) values between 24 h and the other immersion periods were calculated, and then analysed by repeated measure analysis of variance ( ANOVA ). In addition, the Δ E * values after 24 weeks for dual‐cured specimens were compared with those for chemical‐cured specimens by one‐way ANOVA and by contrasts for each composite ( P < 0·05). The Δ E * values were influenced by the material and curing mode as well as immersion period ( P =0·0001). After 24 weeks the dual‐cured specimens showed significantly lower Δ E * values than the chemical‐cured specimens, except for the VA material. The CL material exhibited the least colour change (1·9 ± 0·2) among the dual‐cured specimens, and the VA material showed the least (4·5 ± 0·9) among the chemical‐cured specimens after 24 weeks. Dual‐curable luting composites should be polymerized with the dual modes to ensure colour stability.