Abutment heights

[subrisi]

What is the minimum height of the cementable surface of a molar zirconia abutment where an emax cown has to be ceneted on?

 

[JohnWilson]

What is the minimum height of the cementable surface of a molar zirconia abutment where an emax cown has to be ceneted on?

Many factors go into why a crown stays on an abutment successfully. The height of the abutment is only one variable. Most documentation I have read state for a cemented retained restoration, the clinical height should be at least 5mm

I personally think that when the abutment has extremely parallel walls you can drop it to 4mm if you put a .4mm or more shoulder on the abutment.

The size of the occ table on the crown and how it relates to the bite "off axis contact" is more detrimental to having unit come uncemented. How you prepare the abutment to crown interface to be cemented also has a lot to do with the success or failure. Round abutments with no anti rotational grooves will not work with short abutment heights, no matter how precise the fit of the crown is.

With all of my opinions stated we are doing more screw retained restorations than anything else. Of course short clinical heights is where these restorations shine most.

 

[omarbhan]

I agree with you this answer.

reg.
Omar