Magnetic retention to stabilize a distal ridge?

Very interesting question. At the IDS Show this year, we came across a product called MagDen, a magnetic implant overdenture system, developed by Shinwon Dental. We posted about it here: http://www.osseonews.com/magden-magnetic-overdenture-system/ Also, there is an excellent research paper in the J Can Dent Assoc 2010;76:a52 about this topic and the new magnetic systems, like that by MagDen, which imply new alloys and seals around a magnet to protect it from corrosion in the mouth. This is potentially a very interesting area of development.

Why do you feel the need to use a magnet? If there is room for an implant, there are other attachments that may provide more stability than a magnet. Why is the magnet a preferred attachment in this case?

Besides corrosion point there is another important, and yet to be solved, problem-to find the optimal mucose loading during a magnet pressure to prevent tissue ischemia.

How about changing the plan in prosthesis. Why not add one or two anterior mandible implant and make a bar on all the implants and add precision attachment to distal limib. Finally go for a castable clip and ball retained denture.

If can place posterior implants then try to re-plan for a fixed solution or a bar overdenture, if you leave it as a free standing terminal implant in say a 2-anterior implant overdenture scenario then those dital implants will take the brunt of any and all occlusal forces - class 3 lever

Yes, distal implants will predictably increase retention and function of a traditional tooth retained distal extension partial denture. It is a predictable and affordable options for many patients. I have about 12 patients with combination natural tooth/implant retained partial dentures, and all are very satisfied. It has been my experience that function is improved significantly regardless of where the implant is placed, so the second molar area would be good, but not necessarily better than an implant in the premolar area. Gordon Christensen wrote an article about a year ago showing implants in the mandibular first premolar areas in a patient with 22-27 remaining and a partial denture. I don't know anything about the magnet system you suggested. I share the concern of mucosal load. A combination of natural teeth/implant retention is acceptable for removable (where it is debatable in fixed) because the implant attachments are semi-precision and allow movement. Here are examples from my office: 65 y/o female, existing upper partial, natural teeth 6-11, 11 failed, extracted. Added denture tooth #11 to existing partial. Placed implant #12 with a Locator Abutment. One of the easiest implant cases I have done, patient and doctor thrilled with results. Patient inquired about adding implant #5 to upgrade her existing partial by eliminating clasp #6. 60 y/o male, bi-lateral four unit mandibular bridges (first premolar to second molar) lost to secondary decay. Immediate placement of implants in mesial root of each second molar extraction site. Delivered a traditional tooth retained partial. Placed two ball abutments and retrofit to partial at four months. Patient and doctor pleased with results.

corrosion is a real issue and hence why magnets aren't popular