Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 23 0 2026 05 17 4643 4643 Somayeh Hekmatfar Department of Pediatric Dentistry, Dental Faculty, Ardabil University of Medical Sciences, Ardabil, Iran 2. Private practice, Ardabil, Iran Vahid Samadi Private practice, Ardabil, Iran Avissasadat meraji Private practice, Tehran, Iran Karim Jafari Department of Prosthodontics, Dental Faculty, Ardabil University of Medical Sciences, Ardabil, Iran 2022 10 27 2024 05 13 Objectives: The objective of this study was to investigate tooth discoloration caused by different calcium silicate-based cements (CSCs), and assess the efficacy of two bleaching techniques in restoring the original tooth color. Materials and Methods: In this in vitro study, 54 sound teeth were divided into three groups (n=18) of Endocem, MTA Angelus, and calcium-enriched mixture (CEM) cement. Baseline color assessments were conducted using a spectrophotometer, with subsequent color evaluation after 3 months. Each group was divided into two subgroups of internal bleaching and internal/external bleaching. The bleaching procedure was performed over a 2-week period. Two-way ANOVA was applied to investigate the interaction effect of bleaching technique and time on color change (∆E). The Tukey’s test was used as post-hoc for pairwise comparisons. P≤0.05 was considered significant. Results: The results indicated noticeable color change in all test groups, surpassing the perceptibility threshold (ΔE>3.3). Endocem exhibited the maximum discoloration, while CEM cement displayed the minimum. Significant differences were observed between Endocem and other groups (P<0.05). Regarding the L*, a*, and b* parameters, no significant differences were found between the two subgroups except in Endocem group, where internal/external bleaching caused a significantly greater increase in color parameters compared to internal bleaching (P=0.001). Conclusion: Endocem induced more discoloration than MTA Angelus and CEM cement. However, there was no difference in efficacy between the internal and internal/external bleaching techniques (except in Endocem), both proving effective in restoring the original color of discolored teeth. https://fid.tums.ac.ir/index.php/fid/article/view/4643 https://fid.tums.ac.ir/index.php/fid/article/download/4643/2213