Dr. Beatrice Leung Dentistry Professional Corporation

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Prosthetically Driven Implant Dentistry: Are we really doing that?

Prosthetically driven implant dentistry is a term I have heard for the last twenty years. We should be aiming to place the implants where the teeth are but not where the bone is. We should be planning carefully so the implants are placed in a way that the prosthesis will be strong, functional, hygienic and aesthetic.
I find that this concept is often easier said than done, especially for full arch cases where the patient has a failing dentition requiring full mouth clearance. I myself have never really been a fan of immediate placement of implants for these cases. Yes, there are many tools and technology now to facilitate the extractions and immediate implant placement, and if indicated, even for immediate loading for full arch prosthesis. Patients love to hear that. They don’t have to wear a denture and immediately get to use the implants. From the business side of things, it definitely is more profitable if we can place the implants at the same time following the extractions.
But the planning is often done based on the patient’s existing dentition that is failing and inadequate. The question is should we plan our permanent implant placement based on the patient’s existing failing dentition…If so, what are we really sacrificing?
We all know that biology does not always allow us to do immediate implant placement…there are times with pre-existing infection, or inadequate bone in some cases, that we need to stage the treatment in a way that the patient may have to wear a provisional complete denture in the interim.
Prosthetically, sometimes I really just want to get rid of these teeth first and then do a proper set up before I commit myself to the final position of implants. Those who do enough immediate dentures on terminal dentition will appreciate how many built in errors there are from the steps of impression taking, inaccurate jaw relation records, to the lack of opportunity for a teeth try in, to finally all the tissue changes from the surgical extractions…..You are always hoping to have a miracle for the dentures to work out at delivery because there are so many limitations to immediate dentures…. And that’s why we always tell the patients that you may or will need a second set of dentures after healing….
So if you plan to do full arch immediate placement on a terminal dentition, what are some of the prosthetic risks you will be taking on. To me you are placing the implants based on a failing dentition where the incisal position, the occlusal plane or the vertical dimension may not be accurate. You can use digital pictures and CBCT to help assess these items…but ultimately if the patient has a failing dentition, these teeth are not healthy…they may have shifted out of the ideal location and that the patient may have an acquired bite that you may not be able to correct until these unhealthy teeth are removed.
I have learned from doing these full arch cases, you need to plan…but you also need to be fluid with your plan…sometimes my plan changes after doing a set up… after what I thought I would have the prosthetic space for a fixed zirconia turns out to be just a hybrid…what I thought I would be doing a bar overdenture, it turns out there is no prosthetic space after a new set up is done….My point is you can always plan but when you plan based on a failing dentition, your plan can change.…
This case I have been working on…..after staging the extractions and implants placement, I am finally at the tooth try in stage….I noticed that I don’t really like the occlusal plane on the right side. I have asked the lab to lower it a bit but was told there was not a lot of space….
Now looking back at the pre-op photographs, I followed the patient’s existing occlusal plane for implants placement….I should have noted that uneven occlusal plane on the right side and should have placed the implants a little deeper on that side. In any case, I developed the treatment plan to stage the extractions and implants placement because I thought I could use her failing dentition as my prosthetic reference in planning my surgical treatment. Well I planned wrong!