OBJECTIVE The aim of this study is to determine the type and amount of monomer released over time after bleaching was applied to dental restorative materials containing dimethacrylate resin. METHODS Thirteen different restorative materials containing dimethacrylate resin were used in this study. Twenty samples were prepared from each material and the samples were randomly divided into 4 subgroups, namely, office bleaching, home bleaching, and separate control group for each of the bleaching methods. After bleaching, the samples were stored in 75% ethanol solution for 1, 14, and 28 days. Analysis of the samples collected to determine the type and amount of residual monomer released from the materials was performed using a liquid chromatography-tandem mass/mass spectrometer (LC-MS/MS). Data were analyzed using Friedman and Kruskal-Wallis tests. Statistical significance level was taken as p < 0.05. RESULTS In terms of bleaching groups, mostly no significant difference was found between the groups in each time period in restorative materials (p > 0.05). In terms of time periods, it was determined that the amount of release of all monomers was decreased over time. In terms of restorative materials, the highest monomer release was detected in composite resin groups and the least monomer release was detected in CAD/CAM blocks. CONCLUSIONS Although monomers were released from all materials, bleaching did not affect the amount of released monomer. Amounts of released monomers were generally below toxic limits. CONCLUSIONS Within the limits of this study, bleaching does not significantly affect monomer release in restorative materials containing dimethacrylate resin.