Carlos López-Suárez1, Raquel Castillo-Oyagüe2, Verónica Rodríguez-Alonso1, Christopher D Lynch3, María-Jesús Suárez-García1. 1. Department of Conservative Dentistry and Buccofacial Prostheses, Faculty of Dentistry, Complutense University of Madrid (U.C.M.), Pza. Ramón y Cajal, s/n, 28040, Madrid, Spain. Electronic address: mjsuarez@odon.ucm.es. 2. Department of Conservative Dentistry and Buccofacial Prostheses, Faculty of Dentistry, Complutense University of Madrid (U.C.M.), Pza. Ramón y Cajal, s/n, 28040, Madrid, Spain. Electronic address: raquel.castillo@ucm.es. 3. University Dental School & Hospital, University College Cork, Cork, Ireland. Electronic address: Chris.lynch@ucc.ie.
Abstract
OBJECTIVES: This study aims to evaluate the fracture load of differently fabricated 3-unit posterior fixed dental prostheses (FDPs) with an intermediate pontic. METHODS:Fifty sets of two stainless-steel abutments were randomly assigned to five groups (n = 10 each) depending on the material and technique used for manufacturing the FDPs: (1) Metal-ceramic (MC, control); (2) Lava Zirconia (LZ, bi-layered); (3) Lava Plus (LM, monolithic); (4) VITA In-Ceram YZ (YZ, bi-layered); and (5) IPS e-max ZirCAD (ZZ, bi-layered). After being luted to the dies, all FDPs were submitted to thermo-mechanical cycling (120,000 masticatory cycles, 50 N; plus 774 thermal cycles of 5 °C/55 °C, dwell time: 30 s). Samples were then subjected to a three-point bending test until fracture in a universal testing machine (cross-head speed: 1 mm/min). Fracture load of the veneering ceramic (VF) and total fracture load (TF) were recorded. Microstructure and failure patterns were assessed. Data was analysed using one-way ANOVA and Tukey HSD post-hoc tests (α = 0.05). RESULTS: MC restorations recorded higher VF and TF values than did zirconia FDPs (p = 0.0001), which showed no between-group differences. Within the bi-layered groups, TF was significantly higher than VF. LM pieces registered lower average grain size than did LZ specimens (p = 0.001). Overall, the connector was the weakest part. CONCLUSIONS: All of the groups tested could withstand clinical chewing forces in terms of average fracture load. Zirconia-based samples performed similarly to each other, but showed lower mean fracture load values than did metal-ceramic ones. CLINICAL SIGNIFICANCE: Monolithic zirconia may be recommendable for solving the chipping problem.
RCT Entities:
OBJECTIVES: This study aims to evaluate the fracture load of differently fabricated 3-unit posterior fixed dental prostheses (FDPs) with an intermediate pontic. METHODS: Fifty sets of two stainless-steel abutments were randomly assigned to five groups (n = 10 each) depending on the material and technique used for manufacturing the FDPs: (1) Metal-ceramic (MC, control); (2) Lava Zirconia (LZ, bi-layered); (3) Lava Plus (LM, monolithic); (4) VITA In-Ceram YZ (YZ, bi-layered); and (5) IPS e-max ZirCAD (ZZ, bi-layered). After being luted to the dies, all FDPs were submitted to thermo-mechanical cycling (120,000 masticatory cycles, 50 N; plus 774 thermal cycles of 5 °C/55 °C, dwell time: 30 s). Samples were then subjected to a three-point bending test until fracture in a universal testing machine (cross-head speed: 1 mm/min). Fracture load of the veneering ceramic (VF) and total fracture load (TF) were recorded. Microstructure and failure patterns were assessed. Data was analysed using one-way ANOVA and Tukey HSD post-hoc tests (α = 0.05). RESULTS: MC restorations recorded higher VF and TF values than did zirconia FDPs (p = 0.0001), which showed no between-group differences. Within the bi-layered groups, TF was significantly higher than VF. LM pieces registered lower average grain size than did LZ specimens (p = 0.001). Overall, the connector was the weakest part. CONCLUSIONS: All of the groups tested could withstand clinical chewing forces in terms of average fracture load. Zirconia-based samples performed similarly to each other, but showed lower mean fracture load values than did metal-ceramic ones. CLINICAL SIGNIFICANCE: Monolithic zirconia may be recommendable for solving the chipping problem.
Authors: Stephanie Assimakopoulos Garófalo; Martin Wehner; Andreas Dohrn; Marin Dean Bilandžić; Christian Roos; Richard Johannes Wierichs; Hendrik Meyer-Lueckel; Ana Cecilia Corrêa Aranha; Marcella Esteves-Oliveira Journal: Clin Oral Investig Date: 2021-08-17 Impact factor: 3.606
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