Thoughts on implant supported maxillary denture?

I do not provide full palate implant retained dentures any more. It seems to defeat one advantage of a denture being implant retained. Instead I provide a horseshoe- metal plate backed denture (ie a minimal area denture with Cr/Co palatal plate) which is implant retained. The best retention I feel is a CADCAM designed titanium or Cr/Co milled vertical bar with milled “dolder” bars which is supported on a minimum of 5 implants. This bar may use abutments direct to the implants, or if the path of insertion is not acceptable, using intermediary tissue level abutments which may be conical or flat abutments (depends on the implant brand as to the design) which the bar can screw onto. A milled “shoe” denture can then be constructed to fit over the bar. The stability and retention of such a designed denture is amazingly good. The problem with such a bar and shoe denture is firstly the accuracy required and also the cost. The laboratory fee is high and therefore the cost to the patient is high due to the level of expertise required and the high cost of parts. Secondly the degree of required oral hygiene is much higher – it is hard to properly maintain the soft tissues under the bar (although easier than a bridge). As well the mucosa can often become hypertrophic, and so expand into the space between the bar and the original tissue height – thus making maintenance more difficult. Therefore in many cases I often recommend a simple implant retained over denture on locator abutments (or occasionally I use ball abutments if the path of insertion is not close to parallel). In this case I usually recommend 4 implants are used (two in the 6 or 5 region and 2 in the canine-lateral incisor region). If cost is an issue, I will concede to 3 implants. I usually only place 2 retainer inserts in the denture initially because the retention is so good it is hard for the patient to remove the denture initially and it is therefore disturbing for them if more are used. The other inserts are therefore neutral inserts which allow vertical stability but do not add to the retention. After 2-3 weeks I review the situation with the patient and if they have learned the path of insertion and removal methods well enough I might add another retention insert to the denture. Quite often I never add the fourth retention insert because it would make it almost impossible for the patient to remove the denture (especially if they are old and their finger grip is not great). The reason I recommend the fourth one is placed initially - is as a “spare” in case one of the other implants fails (remembering in most cases the patients are over 65 years old and it would often be undesirable for more implant surgery at a later date if another implant placement was required after 5-10 years). To date I have never had a patient complain about these types of over dentures. They are easy to maintain and in many cases I have converted implant retained “hybrid” bridges to such dentures because the implants have peri-implantitis due to inability to maintain the implants properly under the bridge. Once the patients can easily clean the implants with a toothbrush, the implantitis problems generally resolve or are kept in check and the patient and I are happy with the long term result. The advantage with the implant retained denture (not the bar over-denture) is that if another implant is required later, it is relatively easy to add another retainer to the denture.

I do 4 implants wide spread. Horseshoe, retentive CrCo frame, full acrylic encased can be relined if necessary. Most important is to have a passive fit for locators attachments. Hader bars will work but aren't necessary and drive costs up.

What about Conus Copings on 4 implants? Since they have been surveyed and paralleled in the lab. It can be hard to correct the different angles on 4 implants in the maxilla with Locators. Example of implants in the sites of 4, 7, 10, 13. I'm just a treatment coordinator but I think of this restoration quite often and wonder what the professionals think about this? Don't beat me up too hard please. I've been wanting to ask this question for awhile but get nervous to ask in this group setting. Thanks in advance for your thoughts Sherri

Thanks for this discussion

Several comments: I am Leary of any attachment for maxillary free standing implants that are tissue supported, as this tends to put too much force on key implants. I agree with not covering the palate: one of the huge advantages to max OD I STRONGLY encourage you to avoid individual implants that have a resilient attachment to each implant: again this allows for uneven force distribution and I've seen countless cases like this in the process of failing. I am dishearted to hear of the use of a base metal for an attachment to an implant. The literature shows that a galvanic reaction takes places ( saliva is a great conductor) and it corrodes both titanium and the base metal. The standard of care is a Nobel metal or titanium bar. So going "old school" predictable, I'd suggest a titanium bar (with whatever attachments you prefer) that splints the maxillary implants together. With the lateral forces on free standing implants that can move, leave the reconstruction in jeopardy. As Dr Carl Misch taught years ago: "the price of failure in implant dentistry is so high (time, energy, money, team support, heart muscle and stomach lining) that it is prudent to OVERBUILD these cases with the number of implants and the method of stabilization. Painfully, 35 years of implant dentistry have taught me when I violate this rule,the patient, my team, the restoring dentist and I pay the price.