Background: Connectors of zirconia fixed dental prostheses (FDPs) play an important role in the fracture resistance of prostheses. The current study aimed to investigate the influence of connector dimensions on the fracture resistance of zirconia FDPs when cemented with two different types of cement.
Methodos: Sixty resin casts were divided into two main groups according to the length span of the zirconia FDPs: 3-unit (3U) and 4-unit (4U) FDPs. Each group was divided into three subgroups according to the connector surface area as follows: Subgroup U9 with surface area of 9 mm2 of each connector, Subgroup U12 with a surface area of 12 mm2 each connector, and Subgroup U16 with a surface area of 16 mm2 of each connector was 16 mm2. Each subgroup was divided into two subgroups according to the type of cement. Specimens were loaded in a universal testing machine, and data were statistically analyzed using 3-way analysis of variance (α = 0.05).
Results: The results showed that mean fracture resistance was significantly increased by increasing connector surface area (p < 0.001). The 3-unit fixed dental prostheses (FPDs) gave higher statistically significant fracture load values than 4-unit FPDs (p < 0.001). However, the cement type had no influence on the fracture resistance of zirconia FDPs.
Conclusion: The fracture strength of the zirconia FDPs was affected by the connector dimension. The 3-unit connector design was able to withstand occlusal forces more than the 4-unit connector design. Also, the 3-connector design with a cross-section of 16 mm2 was more able to withstand occlusal forces than those with the dimensions of 12 and 9 mm2.
Key words: Fixed dental prostheses, fracture strength, CAD/CAM, connector, resin cement, zinc phosphate cement
|
