Shock Absorbing Intermediate Connections Between the Implant Prosthesis and Abutment?

Axel Kirsch developed an implant in the '80s which had the design features you are thinking about. The IMZ implant had an "intra mobile element" which was a shock absorbing silicon insert between the implant body and the abutment. Interesting idea...but lets leave that there. Maintenance nightmare. An expression comes to mind..."What is old is new again" ...but at least you are thinking...something to be said about that.

For removable overdenture, consider ERA abutments and housings for vertical resiliency without the maintenance nightmare that DK appropriately describes, above.

While myriads of implants seem to work well without such stress relief, I like to try to allow for some protection from extreme forces. Implant orientation, depending upon the design, could overload some designs, but most are pretty forgiving that way. I used composite crowns for heavy force situations over the years, and the old formulas did protect the implant and abutment, but could suffer wear and bulk modulus fractures. Still, they were easy to repair. The Bicon Lab makes one piece abutment/crown combinations and they claim that the composite bulk is not a problem and no need for the previous elaborate metal substructures. It is nice to be able to repair and "retread" old composite crowns over implants. Most composite crowns do not maintain that beautiful appeal of porcelains, etc., though. I am now using Parkell Retrieve, a fast setting caramel like, reversible cement that is easily cleaned up, even sub gingivally, on porcelain to gold and cast gold crowns. With extra die spacer, some movement is allowed in these cases. The problems with some of the old stress relieving devices include the unpredictable vectors of excessive loads and the cleaning, longevity problems of the designs. Placing porcelain on the implants is preferred by my patients and I caution them routing bite evaluation and occasional adjustment are to be expected. I mention that new crowns or even composite over the occlusals of posterior porcelains may be needed over the years. Occlusal design and function are critical to long term implant and supporting tissue survival and even stress relief schemes won't override that situation.

Wow! Like Dwayne Karateew says. You are thinking? thats great! You may come up with something new - keep it up :-)

It's good that you are thinking along the right line. Implants don't have the shock absorbing feature that natural teeth do.Implants occluding against natural teeth do have some shock absorbing effect of the opposing natural tooth/teeth, however.Implants occluding against implants have a much reduced shock absorbing effect than against natural teeth, but there is still some slight "give" in the surrounding bone. So this all has to be considered in designing the occlusion, to take into account the fact that you get slight intrusion of natural teeth on hard biting,but not with an implant.So the occlusion of the implant should take this into consideration.Also teeth can move due to orthodontic forces (they are in a state of dynamic equilibrium)but implants can't, and this slight movement may leave an implant in supra occlusion. Therefore the occlusion of implants should be checked on a regular basis, particularly if there is any sign of bruxing or clenching.If you are aware of these problems it is unlikely that you will experience any problems with the loading of implants in normal functioning occlusion.As mentioned previously,most attempts to build in stress breaking elements within the prostheses have ended in disater.

Dear Dr.H The stress breaking (shock absorbing) or cushioning or spring-action intermediate connections between the prosthesis and the implant abutment you mention, is quite different from the failed intra mobile element designed by IMZ. IMZ designed a "plastic" component inside the implant which wore out requiring replacement with a solid titanium element, eliminating any planned "cushion" and generating maintenance expense. Currently, the best shock absorbers are provided by O-rings, ERA and Locator attachments for removable prosthetics.

For Removable prostheses, Dr. Grossman hit the nail right on the head. You have the three most popular choices right there. For fixed prostheses you do not have any adequate choices. Your assumption is that stress breaking, intermediate connections would reduce bone resorption around the implants. I suggest to you that implants that are propperly loaded and have adequate bone around them, do not need stress breaking, and that cases where you see bone loss have a different etiology, such as infection, excessive load or inadequate bone circumferentially around it at the time of placement.

I'm working on anew implant design which will provide a shock absorbing mechanism nearly equal to that in natural teeth .

Dr. Ammar: IMZ did this back in the 80's and 90's. It did not work well! Who knows-you may have a solution!