Difficulty Seating Overdenture with Locator

Dr. F. asks:

I recently placed 4 regular platform dental implants in a patient’s mandible between the mental foramens. The dental implants are well integrated and stable. I placed Locator abutments on the implants and connected them to Locator male attachments in the overdenture.

For the first 6 months the Locators worked fine. Because the abutments were not exactly parallel, I used the Green Locator attachments for retention. After 6 months when I attempted to use the Blue Locator male attachments to increase retention, I had a great deal of difficulty seating the overdenture so I went back to the Green male attachments. I think the lack of parallelism of the dental implants is the problem.

Is there anything I can do to increase the retention of the overdenture? Any other comments?

13 Comments on Difficulty Seating Overdenture with Locator

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Dr. Michael Weinberg
The Locator attachments as you know have internal and external retention. The grren nylons are made for non-parallel implants as they are lacking the internal plug that goes inside the abutment. Find two implants that are parallel to each other and place pink nylons on them. Leave the other two in green. Hopefully this helps. It is very important to use paralleling pins during the surgery so you can see if all your implants are lined up parallel. Don't rely on the prosthetics to fix surgical errors. Take the time to ensure that the surgical placement is correct. If you were doing a bar overdenture then non-parallelism of the implants isn't really a factor. It is however with free standing implants. Good Luck!
evangelos mitsis
Why don't you try to use one or two blue with the rest green? Try to use the two most parallel or the two in the middle.
Richard Urban
The best answer so far with your dilema was "Good Luck". Locators and lack of parallelism don't mix well. You will also see them wear quickly when angled. Actually there is a way to fix this very easily with prosthetics. Install angle correcting abutments. There are couple out there to choose from. I've used the angle corrector ERA that Sterngold has several times when I have run into this.
Kirk A, Samann
How many degrees off-parallel were the implants? I guess the question is what is going on with the Locators that were initially working fine, then in six months you needed to fix the retention?
King of Implants
Did you have the metal housings processed with the denture or did you cold cure them chairside? If you had the lab process them they may not be seating over the abutments properly due to the acrylic shrinkage during processing... Remove them and deliver chairside one by one. Then follow the tips already given of finding two parallel abutments.
Nicholas Varras, CDT
I am a dental technician with Sterngold and I see this quite often. Any attachment will work, if they are parallel. If you can not physically correct the angulation of the attachments, you will notice premature wear of the attachments (both the nylon and titanium components). In the case of the locator attachments, the inner retentive button is missing to allow the nylon component to flex and engage the abutment that is non-parallel. The only problem is, that the nylon component remains in this extended position. The nylon component is now constantly getting worn in the same spot, and so are the metal housing and the abutment. This is what is causing the loss of retention you are experiencing. Eventually the nylon component will also wear a hole in the metal housing. The only way to avoid this is to physically correct the angulation of the attachments.
Scott Mullaly
It's funny that when ever a post is made on the Locator we get a mini infomercial on how ERA's can solve all of your problems. If that were true Zest Anchors would be out of business. The Locator Extended range males(green)were tested at a 20 degree angle and lasted over 30,000 cycles. And no it didn’t wear out the cap or the abutment. ERA's were tested on a perfectly parallel abutment and the male lasted less than 3,000 cycles. The Locator male pivots in the housing allowing for divergent angles. Unless your implants are more then 15 degrees off you really didn't need the green males. If you email me I would be happy to help you with your case. Scott Mullaly Zest Anchors Inc. scott@zestanchors.com
Nicholas Varras, CDT
Scott, Isn't it also funny that there is no mention of ERA in my post. I just merely stated that the implant divergence needs to be physically corrected and not compensated for. As for the metal housing wearing, I have spoken with several prosthodontists who ran into this problem.
If you have a severe difference in angulation. I would recomend using the Locator castable thread and create a " Custom Locator Abutment".
How many locator attacments exist on the market?
Hi, Please advise. I attempted to deliver a lower denture with 6 implants 19,30,20,29,23,24 area all processed in lab. It would not go down. I removed all the nylon from the housings and one by one tried in the denture. #24, 19 snapped in but could not place anymore. I would like to know if removing the housing from the denture of the remaining four and picking up in the mouth is the best way to go? If so how would I do this so as not to lock in any particular order? how to remove housing if 2 of the 6 implants not parallel can I pick up the others and use the green nylons. I get the concept but this is the first time I will be picking up in the mouth and want it to go well. Should I remove the housing before she arrives and try in the denture to make sure it goes down ( she said it feels high not touching gums). Please advise what is the steps? Thank you Mel
Richard Hughes, DDS. FAAI
Reimpres and send to whole thing back to the lab. Chair time is too valuable.
elie warde
try the 15' angled locators

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