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Fracture Load Before and After Veneering Zirconia Posterior Fixed Dental Prostheses
Author(s) -
Rodríguez Verónica,
CastilloOyagüe Raquel,
LópezSuárez Carlos,
Gonzalo Esther,
Peláez Jesús,
SuárezGarcía MaríaJesús
Publication year - 2016
Publication title -
journal of prosthodontics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.902
H-Index - 60
eISSN - 1532-849X
pISSN - 1059-941X
DOI - 10.1111/jopr.12357
Subject(s) - crosshead , chamfer (geometry) , materials science , universal testing machine , cubic zirconia , fracture (geology) , ceramic , flexural strength , cusp (singularity) , glass ionomer cement , composite material , orthodontics , dentistry , mathematics , ultimate tensile strength , medicine , geometry
Purpose To evaluate the fracture load of 3‐unit zirconia‐based posterior fixed dental prostheses (FDPs) before and after veneering the frameworks. Materials and Methods Forty standardized stainless‐steel master dies were fabricated (height: 5 mm, convergence: 6º, chamfer: 1 mm) and randomly screwed in pairs onto metal bases. The bases were randomly divided into two groups (n = 20 each) according to the zirconia CAD/CAM system used for constructing 3‐unit structures for FDPs: group 1 (L): Lava All‐ceramic, group 2 (Z): IPS e.max ZirCAD. Half of the zirconia structures per group were randomly selected and veneered, while the remaining half was left unveneered. The specimens were luted in standard fashion onto the stainless steel master dies using conventional glass ionomer cement. All specimens were tested for fracture load (FL). Specimens were subjected to a three‐point bending test until fracture by applying an axial compressive load at the central fossa of the pontics with a universal testing machine at a 0.5 mm/min crosshead speed. Wilcoxon's rank‐sum test and Weibull statistics were used for statistical analysis (α = 0.05). Results L structures recorded significantly higher values of load to fracture than the Z group both before and after veneering. Within each ceramic group, no differences were found between unveneered and veneered frameworks. Conclusions Although further studies are necessary to corroborate these findings, both zirconia systems could be recommended for restoring posterior teeth on the basis of the fracture load values recorded in this experiment (>1000 N). The veneering procedure did not affect the overall load to fracture in any group.