One of the most satisfying services I can provide a patient is stabilizing their complete denture with implants. I’ve done many of these and I’d like to share with you my thoughts on how I use them successfully.
(1) Implant-Retained, Tissue-Supported
This is a critical concept! The implants are offering retention that is far superior to suction and gooey adhesives, no question about that. But the prosthesis is still supported by the soft tissue. That means traditional denture concepts must be respected. A good implant overdenture always begins with a stable, well-fitting complete denture. Preferably I will make a brand new CD for the patient that I will fit for implant attachments. However if I have to use the patients existing denture I will at least consider a new chair-side reline before beginning treatment. If the CD does not fit well then there will be unexpected forces acting on the implant attachments which will compromise retention.
(2) Implant Location and Number
The standard of care is a minimum of two in the mandible. The mandibular implants are placed between the mental foramina due to the high quality of bone that is found there. It’s best to place them close together, roughly in the lateral incisor areas, rather than spread out in the canine areas. Why? Because the first option is better at resisting anterior-posterior rocking of the prosthesis.
The placement on the left will better resist A-P rocking of the denture.
Alternatively you can place a third implant in between the first two for additional retention. I’ll do this if the patient’s force factors are high (bruxer, strong bite, etc.)
Implant placement for an overdenture retained by three implants. The healing abutments are still in place.
Can you place more implants than three? Sure. But once you start getting to four and five implants, you’ll probably be leaning more towards a fixed, implant-supported prosthesis.
Two Locator abutments for an implant overdenture.
(3) Attachment Selection
There are O-rings, Hader clips, bars, and all sorts of mechanisms for making your overdenture click and snap into place. Personally, my method of choice is the Locator attachment. It’s simple to use and quite effective. I’ll use a bar if the implants have a severe angle discrepancy (greater than 20 degrees between implants) that would prohibit seating of the Locators. In that case, a bar would zero out the angles and provide a clean slate for other attachments to connect to. For more information on Locators, check out my next post.
You could take impressions and send everything to the lab for fabrication, but I think it’s better to do this procedure chair-side. Not only will it save you money, but you will be able to get a dynamic fit. A lab doesn’t have the benefit of muscled attachments, lips, and functional movement; all they have is a model. It’s super easy to pick up Locators chair-side. I’ll show you how in my next post.