Corrosion Around Dental Implants

This problem is one of the reasons that we have gone to Cad/Cam abutments made out of titanium as the basis for our SIMPL implant protocol. Cast alloys can contain a wide variety of trace metals that are used to enhance certain elements of the alloy ie flow, bond, etc. We occasionally get requests for base alloy crowns on top of our abutments from offices trying to keep cost down and we always convert them to a noble alloy at the very least. We feel going forward that the more abutments and restorations that can be done with a ceramic substrate the better. This is why we utilize Atlantis Components for our Cad/Cam abutment fabrication as they are the worlds largest supplier and have the most diverse offering in the all ceramic abutment market (zirconia). The entire abutment is zirconia, there is no metal adapter and the abutment is milled before sintering making them the strongest ceramic abutments available. We can then restore the coronal portion with a similar substrate material ie Lava, Procera Zirkon, Zircad, etc. By doing this the influence of the restoration of the fixture has been taken out of the equation. I'd be very interested in hearing from any researchers regarding the effects of "cast abutments" on long term implant retention with respect to galvanic reaction as well as interface adaptation and problems with micro gap leakage.

I couldnt possibly agree more with Mr Ackley. The only reason for corrosion is the galvanic difference in the potentials of the alloys. Titanium has a very stable oxide layer (that is why it does really integrate) and it is very hard to disturb it, but everything casted (except casted titanium) that you put on top of it will have corrosion potential, so precious metals or titanium if yo will cast, machined titanium would be better(smaller gaps and better fit less corrosion potential) and zirconia abutments and crowns would be best(great fit, small gaps and 0 corrosion potential... also mbetter in the cosmetic area).

Only comment from the preceeding posts is what about the matter of ' fretting ' , where the zirconia will actually wear the hex of the implant due to it being harder than the titanium ? Some ceramic abutments still have a metal collar for this reason . Any comments ?

On one level it seems to make good sense not to develope a couple between the implant and the restorative complex in a saline environment. However, one must ask to what extent is this a factor or a co factor in the breakdown process in a very successful mode of treatment and how is this putting our patients in danger? We speak of an overall average success rate these days of 97-98%. In the 2-3% of failure what part is stress corrision a real issue? I have no issue of going to 99% success, but is this the way? The skill of the restorative doc, the surgeon and the laboratory and the host factors of the patient seem to govern outcomes. How many angles do we need to dance on the tip of a pin? Materials are very important I do not under estimate the value of inteligent use of them, but to what end? Let us also remember that zircon is an alloy and a metal. It does have an energy signature. It is also very stiff and hard. Along with a zircon restoration there is more kinetic energy transfer to the fixture and the oxide interface to bone. Does this perhaps make a more deep seated issue? Stress release is important. I am not against reducing the potential for a couple, but to what end. I am not so sure about the need being built and the products being sold to cure a problem of unknown extent.

Corrosion is a big problem ofmetallic implants. They interact with any othe metal parts from the organism. The surface os the implants is a Ti oxid layer but stil porous. Ti-ions appear in the surrounding tissue and the concentrations grows by time. Prof. Ami Sandhous from Laussanne, Switzerland, a pioneer in metalfree implants has some case reports about implant related pigmentation and reactions in humans. The future belongs to metalfree implants, zirconia or composites.

Dr Mac: When will an all zirconia implant come into use in the USA? Are you aware of any companies that are currently seeking FDA approval in the USA for an all zirconia implant? If so, what is holding up the approval process? Are there any concerns about the all zirconia systems [eg., higher fracture potential, lesser osteointegration, radioactivity, etc]?

Agree, corrosion is an issue. Wrote an article some time ago that may help to shed light: Corrosion of implantable materials and aging of bone. J Dent Technol.1996 Jun;13(5):24-32. PMID: 9516274; UI: 98157004 ajvoitik@dentalartslab.com

Mr anton j voitik mdt: Thank you for the cite. Given that alot of the dentists here are very very busy and don't have a whole lot of time to pull the medical literature, could you give us a nutshell *Readers Digest* summary of what you found in your study on corrosion. In other words, give a *bullet* points. If we see the issues, it might make this thread even more interesting. In other words, bullets on (1) How big an issue is corrosion, (2) does corrosion raise any health concerns from the patient's perspective, (3) any way to avoide the corrosion, etc etc.

Are you aware of any companies that are currently seeking FDA approval in the USA for an all zirconia implant? Nobel Biocare has FDA approval for marketing its one piece zirconia implant since March 6th 2007. Other companies that might be interested in seeking FDA approval as they are already selling in Europe: - Z-Systems (Germany) - Bredent (Germany) - Incermed (Switzerland) - Ceraroot (Spain/Germany) - Paris Implants (France) Companies developing zirconia implants: - Biozircon (Switzerland) Advanced ceramic manufacturers that are able to develop and produce zirconia implants: - Maxon Ceramic (Germany) - Small Precision Tools (Switzerland) - Ceradyne (USA) - C5 Medical Werks (USA)

Here some basic info about zirconia. zirconia is not metal free! zirconia = metaloxid! it is a white metaloxid!

I have only seen corrosion when dissimilar metals are in proximity. This is usually when uses a np pfm crown over a Ti abutment. Also when there is amalgam in the bone such as from an apico etc.

I have a patient who wants to use a beauty product that makes use of galavanic currents to remove wrinkles... She has an implant supported mandibualr overdenture. What is the risk to the implants with long term use of said device? Thanks

Roy, I would not lose sleep on this one!