Sunday, December 24, 2023

A low sag factor in a metal-ceramic FPD and cause.. Less deformation of bridge spans when fired



A low sag factor in a metal-ceramic FPD and cause:

  • Flow of metal under functional load.
  • High abrasion resistance.
  • Less deformation of bridge spans when fired.
  • Poor metal-ceramic bond strength.
  • Contamination of porcelain.

  • 1 only.
  • 1 and 4.
  • 2and 3.
  • 3  only***
  • 4 and 5.
  • All of the above.

The answer is 3 only.

A low sag factor in a metal-ceramic FPD (fixed partial denture) means that the metal framework is less likely to deform or sag under functional load. This is important because deformation of the metal framework can lead to a number of problems, including:

- Poor fit of the porcelain:

If the metal framework deforms, it can cause the porcelain to chip or crack.

- Stress on the abutment teeth:

If the metal framework deforms, it can put stress on the abutment teeth, which can lead to pain and discomfort.

- Fracture of the metal framework:

If the metal framework deforms too much, it can eventually fracture.


There are a number of factors that can affect the sag factor of a metal-ceramic FPD, including:

- The thickness of the metal framework:

A thicker metal framework will be less likely to deform than a thinner metal framework.

- The type of metal used:

Some metals are more resistant to deformation than others.

- The design of the metal framework:

A well-designed metal framework will be less likely to deform than a poorly designed metal framework.

By taking steps to increase the sag factor of a metal-ceramic FPD, dentists can help to prevent a number of problems that can occur with these restorations.

The other options are incorrect:

  • 1 only: Flow of metal under functional load is not a cause of a low sag factor.
  • 1 and 4: Poor metal-ceramic bond strength is not a cause of a low sag factor.
  • 2and 3: High abrasion resistance is not a cause of a low sag factor.
  • 4 and 5: Contamination of porcelain is not a cause of a low sag factor.
  • All of the above: Not all of the above are causes of a low sag factor.
So the answer is 3 only.