Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 22 0 2025 07 27 5201 5201 EN Sara Abtahi 1. Department of Dental Biomaterials, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran 2. NanoTech Laboratory, School of Engineering, Faculty of Science and Engineering, Macquarie University, Sydney, Australia Sajjad Omidian Faculty of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran Yasaman Sherafatmand . Department of Dental Biomaterials, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Golnaz Tayebi Department of Dental Biomaterials, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Alireza Ranjbar Hassani Department of Dental Biomaterials, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran 2024 05 12 2025 01 25 Objectives: This study aimed to comprehensively evaluate the mechanical and physical properties of six commercially available flowable dental composite resins, providing critical insights for informed material selection. Materials and Methods: Six flowable composite resin materials namely Edge Flow (EDF), Opallis Flow (OPF), Els Flow (ELF), Denfil Flow (DFF), DX Flow (DXF), and Charisma Flow (CHF) were tested according to ISO 4049 standards. Each material underwent evaluation of depth of cure, flexural strength, solubility, water sorption, and radiopacity. Statistical analyses with ANOVA and post-hoc Tukey test were conducted to identify significant differences among the six study groups (alpha=0.05). Results: Significant material-specific differences were noted in depth of cure and flexural strength among the six study groups (P<0.05). Solubility and water sorption profiles were also significantly different among the study groups (P<0.05). All tested composite resins met the required radiopacity standards, ensuring accurate radiographic diagnosis and monitoring. However, none of the composite groups achieved an exact color match with the A2 reference shade. Conclusion: This study revealed significant differences in mechanical properties of flowable composites, particularly in depth of cure and flexural strength, underscoring the importance of selecting the appropriate material. Shade matching presented ongoing challenges, emphasizing the need for careful material selection. Future research should explore long-term clinical performance and standardized methods for handling of pre-test failures. https://fid.tums.ac.ir/index.php/fid/article/view/5201 https://fid.tums.ac.ir/index.php/fid/article/download/5201/2177