TY - JOUR ID - TI - An Evaluation of Mechanical Properties of Different Types of Composite Resins (An in Vitro Study) AU - Shaymaa SH. Hassan PY - 2014 VL - 14 IS - 1 SP - 123 EP - 131 JO - Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان SN - 18121217 19980345 AB - The aim of this study was to evaluate the mechanical properties (compressive strength (CS), diametral tensile strength (DTS), flexural strength (FS) and modulus of elasticity (ME)) of different types of composite resins. Materials and Methods: Two flowable composites (tgflow, Tetric N-Flow) and two conventional composites (tgmicrohybrid, Tetric N-Ceram), were used in this study. For CS measurement, eight specimens of each material (3mm diameter x 6mm height) were prepared. For DTS measurement, eight specimens of each material (6mm diamerter x 3mm height) were prepared. For FS measurement, of each material eight bar shaped (2mm x 2mm x 25mm) specimens were prepared. The FS and ME were determined by three point bending method. The specimens were stored in distilled water at 37˚C for 7 days, then tested on a universal testing machine at a crosshead speed of 1mm/mint. Independent sample t-test and Duncan test were used for statistical analysis. Results: The CS, DTS and ME of flowable composites were significantly lower than that of the conventional composites, the FS of flowable (Tetric N-Flow) composite was significantly lower than that of the conventional (Tetric N-Ceram) composites but there was no significant difference between tgmicrohybrid composite and tgflow composite in FS. Conclusions: It can be concluded that the mechanical properties of two flowa-ble types composites were inferior than that of the two conventional types composites

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