Effect of Different Cements on the Biomechanical Behavior of Teeth Restored with Cast Dowel‐and‐Cores—In Vitro and FEA Analysis |
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Authors: | Carlos José Soares DDS MS PhD Luís Henrique Araújo Raposo DDS Paulo Vinícius Soares DDS MS PhD Paulo César Freitas Santos‐Filho DDS MS PhD Murilo Sousa Menezes DDS MS PhD Priscilla Barbosa Ferreira Soares DDS MS Denildo Magalhães DDS MS PhD |
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Affiliation: | 1. Biomechanics Group, Department of Operative Dentistry and Biomaterials, School of Dentistry—Federal University of Uberlandia, Uberlandia, Brazil;2. Biomechanics Group, Department of Periodontology and Implantology, School of Dentistry—Federal University of Uberlandia, Uberlandia, Brazil |
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Abstract: | Purpose: To test the hypothesis that the type of cement used for fixation of cast dowel‐and‐cores might influence fracture resistance, fracture mode, and stress distribution of single‐rooted teeth restored with this class of metallic dowels. Materials and Methods: The coronal portion was removed from 40 bovine incisors, leaving a 15 mm root. After endodontic treatment and standardized root canal relief at 10 mm, specimens were embedded in polystyrene resin, and the periodontal ligament was simulated with polyether impression material. The specimens were randomly divided into four groups (n = 10), and restored with Cu–Al cast dowel‐and‐cores cemented with one of four options: conventional glass ionomer cement (GI); resin‐modified glass ionomer cement (GR); dual‐cure resin cement (RC); or zinc‐phosphate cement (ZP). Sequentially, fracture resistance of the specimens was tested with a tangential load at a 135° angle with a 0.5 mm/min crosshead speed. Data were analyzed using one‐way analysis of variance (ANOVA) and the Fisher test. Two‐dimensional finite element analysis (2D‐FEA) was then performed with representative models of each group simulating a 100 μm cement layer. Results were analyzed based on von Mises stress distribution criteria. Results: The mean fracture resistance values were (in N): RC, 838.2 ± 135.9; GI, 772.4 ± 169.8; GR, 613.4 ± 157.5; ZP, 643.6 ± 106.7. FEA revealed that RC and GR presented lower stress values than ZP and GI. The higher stress concentration was coincident with more catastrophic failures, and consequently, with lower fracture resistance values. Conclusions: The type of cement influenced fracture resistance, failure mode, and stress distribution on teeth restored with cast dowel‐and‐cores. |
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Keywords: | Cast dowel‐and‐core finite elements analysis fixation cement materials fracture resistance |
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