IADR Abstract Archives
Fracture Load of Zirconia Crowns Based on Preparation and Cement
Objectives: Limited research has been published evaluating the failure of cubic zirconia crowns with non-retentive preparations. The purpose of this study was to evaluate the effect of axial wall height and cement type on the fracture load of cubic zirconia crowns.
Methods: Ninety extracted maxillary human third molar teeth were prepared with standardized crown preparations with axial wall heights of zero, two, or four millimeters (n=10). The preparations were scanned and crown restorations were designed (Omnicam, Dentsply/Sirona). Cubic zirconia crowns (4Y-TZP, Katana STML, Kuraray) were milled (MCXL, Dentply/Sirona) and cemented with either a RMGI (RelyX Luting Plus, 3M/ESPE), self-adhesive resin (RelyX Unicem, 3M/ESPE), or adhesive-resin cement (Panavia V5, Kuraray). The specimens were stored for 24 hrs in 37°C distilled water, then subjected to thermocycling and cyclic loading. Each crown specimen was loaded to failure in a universal testing machine (Instron) at a 60-degree angle to the long axis of the tooth using a stainless-steel rod resting on the buccal incline of the palatal cusp. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests (alpha=0.05).
Results: Significant differences in fracture load were found between groups based on wall height and cement type (p<0.05). See table.
Conclusions: Regardless of cement type, the mean fracture load was significantly lower for the 0 mm wall height than with 2mm or 4mm wall heights, which were not significantly different from each other. Compared to the other cement types, the adhesive resin cement provided significantly greater fracture load with 0mm wall height.
The views expressed are those of the authors and do not reflect the official views or policy of the United States Air Force, Department of Defense, or its Components.
Methods: Ninety extracted maxillary human third molar teeth were prepared with standardized crown preparations with axial wall heights of zero, two, or four millimeters (n=10). The preparations were scanned and crown restorations were designed (Omnicam, Dentsply/Sirona). Cubic zirconia crowns (4Y-TZP, Katana STML, Kuraray) were milled (MCXL, Dentply/Sirona) and cemented with either a RMGI (RelyX Luting Plus, 3M/ESPE), self-adhesive resin (RelyX Unicem, 3M/ESPE), or adhesive-resin cement (Panavia V5, Kuraray). The specimens were stored for 24 hrs in 37°C distilled water, then subjected to thermocycling and cyclic loading. Each crown specimen was loaded to failure in a universal testing machine (Instron) at a 60-degree angle to the long axis of the tooth using a stainless-steel rod resting on the buccal incline of the palatal cusp. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests (alpha=0.05).
Results: Significant differences in fracture load were found between groups based on wall height and cement type (p<0.05). See table.
Conclusions: Regardless of cement type, the mean fracture load was significantly lower for the 0 mm wall height than with 2mm or 4mm wall heights, which were not significantly different from each other. Compared to the other cement types, the adhesive resin cement provided significantly greater fracture load with 0mm wall height.
The views expressed are those of the authors and do not reflect the official views or policy of the United States Air Force, Department of Defense, or its Components.
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