To enhance strength properties of ceramo metal restoration, it is important to:
- A- Avoid sharp or acute angles in the metal structure.
- B- Build up thick layer of porcelain.
- C- Porcelain should be of uniform thickness and any defect of the preparation should be compensated by the metal substructure.
- D- Compensate any defect in the preparation equally by porcelain and metal substructure.
- E- A and b are correct.
- F- A and c are correct. ***
- G- B and d are correct.
You're correct, the optimal answer is F- A and c are correct. Here's why:
A- Avoid sharp or acute angles in the metal structure:
This is correct. Sharp angles create stress concentrations, making the restoration more prone to fracture. Rounded or smooth transitions between metal components are ideal for strength.
B- Build up thick layer of porcelain:
This is not always correct. While a thicker porcelain layer might increase overall strength, it can also create more internal stress within the restoration due to differences in thermal expansion between porcelain and metal. Optimal porcelain thickness should be determined based on the specific restoration and its location.
C- Porcelain should be of uniform thickness and any defect of the preparation should be compensated by the metal substructure:
This is correct. Uneven porcelain thickness creates internal stress points, and filling in preparation defects with porcelain alone further weakens the restoration. The metal substructure should primarily compensate for any preparation weaknesses to provide a more stable base.
D- Compensate any defect in the preparation equally by porcelain and metal substructure:
This is incorrect. As mentioned in point c, relying solely on porcelain to compensate for defects is not ideal. The stronger and more reliable approach is to use the metal substructure for this purpose.
Therefore, options a and c address both avoiding stress concentrations and proper defect management, making f. A and c are correct the best answer.
