Lab Life: The Multi-Abutment Case
A single implant arrived at our lab today. I noticed that it is a Nobel Biocare implant with a Multi Abutment. The model shows the analog. In essence, this is a conical abutment and we used to do these years ago.
I contacted my doctor and was told that the surgeon placed the Multi Abutment (17 degrees) to help the angle of the implant. I explained my concern: Multi Abutments are really only used for multiple, splinted implants, mainly bars, etc. If we restore this case using an UCLA type of abutment, it would have to be screw retained. Furthermore, there is no anti-rotational features on the Multi Abutment. The only way the crown would not “spin” is the interproximal contacts.
I decided to call Nobel Biocare technical support to see if I was missing anything. I explained the situation and the person at Nobel Biocare agreed with me. In addition, she reminded me that if we did use a UCLA type of abutment and made is screw retained, the maximum torque for the screw is 15Ncm. Certainly not enough torque to prevent the crowns from spinning eventually.
I could not figure out why the surgeon would place a Multi Abutment on a single unit. The only thing that I could figure is that the implant might be so far off angled, that a fixture level impression post may not be able to be placed, as the adjacent tooth may prevent the post from being engaged.
I called my doctor back and mentioned this. I was sent an Xray of the implant.
As you can see, the implant is angled quite a bit. I do think that we can get an impression post attached at the fixture level.
Here is the plan. My doctor will get the patient back in, remove the Multi Abutment and take a fixture level impression. We will make a Custom Abutment with a PFM crown. With a Custom Abutment, we increase our restorative options.
– Brent West