Implants Supporting Maxillary Overdenture: Prognosis?

Diameter and length look fine.....it's more about the spread of the implants...we like to see 6 implants in the maxilla. With 2 more more posterior. You can get away with 4 with a better spread...but 6 is best.

I think all we got was a preoperative pano. Is there more information about this case?

Dentist tend to make judgment based on what fits their imagination. I’m yet to see a calculation identical to an engineering evaluation of displacement forces based on anchorage. Biology and physiology are factors but very minimal. Physiological forces (those attributed to changes over time) are impossible to factor in the equation because they are unknown. If one would consider ending a hybrid bridge slightly past the most distal implant, the condition may last a long time. One thing for sure, forces applied to bridges or dentures past the most distal implant are detrimental to prognosis in terms of survival. The bone density, surface are of submerged implant, lateral occlusal forces are all factors to be considered. Length of implant is important but diameter of the implant and length is what determines anchorage. There is a reason why we were required to study math and physics when applying to dental schools.

4 implants on maxilla? Is it softer bone? A female? Why would you even consider 4 implants, when once I have the patient sedated, I would ALWAYS place at least 6 implants in this kind of case. Anyone that says otherwise, doesn't have 10 years of experience to prove why.

The question is regarding an over denture not hybrid nor six prosthesis Therefore, the load should be distributed on the bone and the soft tissue Not the implants. Getting more than four implants to engage a maxillary overdenture with locator type attachments is almost impossible. 4 is plenty to retain an over denture in the maxilla with a balanced occlusion.

Fixed. Sorry. Not six

We are giving advice based on scant information, but that won't stop me!🤓 I don't like the lateral locations. In the pano, those two teeth seem to have larger bony defects. This means the landing area on thae ridge may be anything but wide and flat. I suppose you might be successful with additional bone grafting there. I couldn't measure the amount of bone in the bicuspid area or the interocclusal space. Often these dentures are simply jacked open vertically to make room for attachments and substructure. You will notice all the pink they show in the smile photo. As for spread, more is better. Same for number of implants. If you have to sinus lift, you can go back further. I guess palatal implants are a consideration now for some patients. They can be permanent or provisional Finally, and thus won't be popular, but I like to reserve immediate loading for the most esthetically demanding cases. Why risk for a denture? Many times I am amazed at how difficult it is to pull a denture off a locator. Why not make the denture and attach later?

My suggestion would be to place the implants in the #4, 6, 11 and 13 areas in the maxilla. Placing your anterior implants in the lateral incisor area is dicey for two reasons: first, the position and height of the housings can create too many difficult restorative challenges in the lateral incisor area, and, two locator overdentures can fracture through the canine area of the anterior implants are in the #7 and and 10 positions

The following article may be of some help: "Unsplinted Implants Retaining Maxillary Overdentures with Partial Palatal Coverage: Report of 5 Consecutive Cases" Cavallaro J, and Tarnow, D. Int J Oral Maxillofacial Implants 2007;22:808-814 Best wishes, Jeff Tarlow, DDS

You want to read all of this You must take into consideration where your forces will be . They will be on the posterior teeth -the first bi back. If your implants are in the anterior segment as you describe then your highest occlusal forces will be distal to the most distal implant If an overdenture then you will compress the distal implant and rotate on it- and both vertical and horizontal pressure will be placed on the anterior implant due the soft tissue compression during function. And if you use Locators then you have used an attachment that is not made to function that way and you will over stress the system Think of a denture in function in your case and how it will move and this will show you how the forces will act on the implants. If this is fixed then your cantilever will have to act as described in the literature referenced to AP distance . You have 2 implant cantilevers in the maxilla both anterior and posterior AND you have poor bone I would reconsider the plan based on how you expect this to function not by how you can tie it down with the strongest longest implant. Consider possibly ALL on X to get your distal platform back as for as possible IF you don't want to do a sinus lift Also, in this case, to give you enough room for your attachments system you will need to remove bone. I think you would be better to remove the teeth and do no plasty work- -let it heal with an upper denture and reline in 3 months then use the reline to help you determine the amount of needed bone removal. This period of denture wear will help you evaluate the function that you will need to be aware of with the implant system as well as the type of restoration that will work JMHO

Having done hundreds of the case over the last 25 years I can tell you to always use 6 implants and I immediately load the cases 99.9% of the time. Of course I laser weld a metal frame splinting all implants and supporting all canilevers.