1 2008-4676 دانشگاه ازاد اسلامی-واحد دندانپزشکی 1558 Prothesis Effect of changing connector area of three-unit fixed zirconia prosthesis in various silhouette and elliptical shapes on flexural strength Nourizadeh Amin ^b Kahyaie Aghdam Mina ^c Mahmoudi Aref ^d Shafiee Elnaz ^e Fakhrzadeh Vahid ^{f b} - ^c - ^d - ^e - ^f - 1 7 2025 22 2 99 106 22 12 2024 20 04 2025 Background and Aim: In multi-unit fixed prostheses, the connector areas are places where stress and failure accumulate due to thinness and need strengthening. The purpose of this research is to investigate the effect of changing the surface area of connectors of zirconia three-unit fixed prostheses on their bending strength. Materials and Methods:  In this experimental  - laboratory study thirty, first molar and first premolar teeth of the lower jaw were prepared as base teeth for the FPD prosthesis on the plastic model of the jaw. Zirconia FPD samples were made for them in two groups with silhouette and elliptical connector shapes, each group having three subgroups with connector areas of 8 mm2, 10 mm2, and 12 mm2, with CAD/CAM system. Finally, 5 samples were considered in these 6 groups. Then, the samples were cemented, and their bending strength was measured with the universal testing machine and a three-point bending test.Two-way analysis of variance and LSD post hoc test were used in SPSS version 22 software for statistical analysis. Result: Considering the significance level of P value (P< 0.05), there is no significant difference in bending strength between silhouette and elliptical shapes (P value = 0.339). The bending strength in the area of 12 mm square is significantly higher than the area of 8 and 10 mm square (P value = 0.001). Conclusion: In fixed three-unit zirconia prostheses, changing the area has significant effect on the bending strength, but the shape has no effect.