Treatment Approach for Overdentures?

Why? If you've done the other cases with 4 or 5 implants and they've worked out,why would you undermine the prognosis with 2?Stick with the 4 or five on the maxilla nothing less. You're building the case to fail.If money is a problem don't do the case just yet but don't chince on the tried and true.

The first question that has to be asked is what is the purpose and objective of the implant placement? If it is for retention of the overdenture, then the forces degree and direction on the appliance has to be evaulated. There is no reason why two implants cannot sufice. If more retention and resistence is needed use four. One in the cuspid regions and one as far posteriorly on each side as pratical or possible. this will reduce anterior tipping from incisal forces. the concept of saving the case makes little sense to me. If one allows the fixtures to integrate and then applies a torque force of 35Ncm that is uneventful in motion or sensation, then the literature shows these fixtures have a success rate of greater than 99.9% if the surface is rough.

Unsplinted Implants Retaining Maxillary Overdentures with Partial Palatal Coverage: Report of 5 Consecutive Cases. Cavallaro/Tarnow International Journal of Oral & Maxillofacial Implants Vol 22 Number 5 2007 pp. 808-814. For use when very specific inclusion criteria can be met- see materials & methods section.

We should look at the skeletal relationship and envision the final prosthesis. If the patient is a class III skeletal, you can use two implants on the maxilla. If the patient is a class II skeletal, you should contemplate using three implants, with one in the anterior and one on each side in the premolar region. This will allow for anterior biting force. I found that when we use more than 3, we must make sure that the implant are relatively parallel, with maximally 15 degree offset. Moreover, when we use locator in our prosthesis, patient will have a hard time trying to remove the prosthesis in the more than three implants application.

I would not think 2 implants to support a denture in the maxilla to be appropriate as a rule of thumb . Whenever we talk about specific measurements with hardware we MUST also talk about context Just to say we have 2 implants is not enough ..D2/D3 or D4?? /we assume proper spatial relationship etc Bear in mind for overdentures the only force on the implant is when putting denture in and taking out This is the definition of IMplant Retained Otherwise the implants are over loaded as you have made a fixed bridge that is implant SUPPORTED Longer implants give greater resistance to pull out forces ..wider implants better resistance to lateral forces Over denture implants should have no lateral forces(at least minimal) This is why when placed properly the mini implants work well in the maxilla (but here you need 6...) The current thinking and long term efficient position I think is to have 3 implants minimum thus create a tripod of resistance There is a tendancy towards tipping with only 2 implants for an overdenture as the denture rotates around an axis

I use 4 to 5 3.75 mm implants and o ring attachment to retain a maxillary OD with no palatal coverage and seems to work great, also 6 mini's will work very well. I never tried to use only two in the maxilla, may be if you used them and didn't remove the palatal part of the denture it will be ok.. but any way try it and please keep us updated with your progress.