Comparison of Biaxial Flexural Strength of Ceramic/Composite Veneered Zirconia

Objectives:

To asses the Biaxial Flexural Strength of currently used ceramic and composite veneering materials when bonded to zirconia. To help optimise the composite- zirconia laminate bond.

Methods:

Zirconia (Group YZ) and Ceramic (Group MarkII) samples were prepared from CAD/CAM blocks using a diamond blade in a precision diamond saw. Two composite samples (Group LC and Group Sin) were produced. Two further groups of composite/zirconia samples were produced (Group LC+YZ and Group Sin+YZ). A universal primer was applied to the Zirconia surface prior to bonding the composite veneer.  For Ceramic bonded to Zirconia group (VM9+YZ), ceramic was added and fired according to the manufacture instructions.

All groups consisted of 10 samples of discs with the diameter of 12mm and 1mm thick. 0.5mm thickness of each material for laminate samples resulting in a 1.0mm thick sample. Test carried out using Lloyd 2000R universal testing machine with cross head speed of 1 mm/min resulting in a clean fracture through all tested samples.

Results:

The ceramic (MarkII) and composite (Sin) materials both showed similar BFS of about 170 Mpa. The ceramic/zirconia laminate structure showed and increased strength above 700 Mpa and the composite/zirconia structure a strength value of over 400 Mpa.  

Conclusion:

When comparing laminate structure to 1mm thickness of zirconia the study showed that when substituted with composite the strength decreased by 54.9% whereas ceramic resulted in a 27.3% derease.