title: Effects of cold light bleaching on the color stability of composite resins.
abstract: To evaluate the effects of cold light bleaching on the color stability of four restorations using a thermocycling stain challenge. 160 specimens (10 mm in diameter and 2 mm thick) were fabricated from 4 composite resins (Gradia Direct-A, Z350XT, Premisa, and Précis) and divided into 4 subgroups. Color was assessed according to the CIEL*a*b* color scale at baseline, after the first cycle of bleaching, after thermocycling stain challenges, and after the second cycle of bleaching. Mean values were compared using three-way analysis of variance, and multiple comparisons of the mean values were performed using the Tukey-Kramer test. All groups showed significant color changes after stain challenge, the color change was more significant in Gradia Direct and Z350XT than in Premisa and Précis. After the second cycle of bleaching, color mostly recovered to its original values. The color stability of Gradia Direct and Z350XT was inferior to that of Premisa and Précis. The discoloration of composite resin materials can be partly removed after cold light bleaching.
authors: Department of Conservative Dentistry, Laboratory of Oral Biomedical Science and Translation Medicine, School of Stomatology, Tongji University Shanghai 200072, P.R. China.
authors: Liqun
authors: L
authors: Cao
authors: Department of Stomatology, Huashan Hospital, Shanghai Medical College, Fudan University Shanghai 200040, P.R. China.
authors: Lijuan
authors: L
authors: Huang
authors: Department of Conservative Dentistry, Laboratory of Oral Biomedical Science and Translation Medicine, School of Stomatology, Tongji University Shanghai 200072, P.R. China.
authors: Meisheng
authors: M
authors: Wu
authors: Department of Conservative Dentistry, Laboratory of Oral Biomedical Science and Translation Medicine, School of Stomatology, Tongji University Shanghai 200072, P.R. China.
authors: Hua
authors: H
authors: Wei
authors: Department of Conservative Dentistry, Laboratory of Oral Biomedical Science and Translation Medicine, School of Stomatology, Tongji University Shanghai 200072, P.R. China ; Department of Stomatology, Huashan Hospital, Shanghai Medical College, Fudan University Shanghai 200040, P.R. China.
authors: Shouliang
authors: S
authors: Zhao
keywords: Composite resin; cold light bleaching; color assessment; color stability