Locator Attachments for Implant Overdentures: Part 1

In a prior post I discussed the”4 Core Concepts for Mandibular Implant Overdentures“.  One of those concepts is that Locator attachments are a simple and effective way to retain your overdenture.  Incorporating these babies into a well-fitting denture is easy once you know how.  Let’s dive in!

So the patient arrives in your office with healing abutments and full integrated implants.  Where do we start?  We don’t need any impressions since we’ll be doing everything chair-side.

Measure the deepest part of the tissue with a perio probe to determine your minimum collar height for the Locator abutment.

(1) Take off the healing abutments.  Measure with a perio probe from the platform to the height of the gingival collar.  If the tissue depth is not uniform all the way around we record the deepest measurement.  This is what determines the collar height of the Locator abutment.  If you’re not sure, err on the side of a taller abutment.  The goal is to have the abutment completely clear the soft tissue so that the male attachment doesn’t pinch the tissue.

If you’re concerned about the angulation, insert some impression copings and make sure they are less than 20 degrees divergent.  Locator makes an attachment that will also work with up to 40 degrees of divergence if you need it.  Replace the healing abutments and we’re done.  That’s all we need for the first visit.

(2) Order Locator abutments.  You can get this through your implant company sales representative.  We’ll need the correct size platform for the implant diameter, of course.  We’ll also need the appropriate collar height for the depth of tissue.  Make sure you also order the attachments.

(3) Okay, it’s your second visit.  Show time!  Remove the healing abutments and insert your Locator abutments.  These are inserted with the special Locator driver and torqued to 10 Ncm (or implant manufacturer’s instructions).

Locator driver… don’t leave home without it. This should be interchangeable between implant systems.

Now we’ll snap on the metal housing.  Look at your tube of attachments and take out the silver and black thing and the white ring.  The metal part is what will become encased in acrylic inside the denture.  The black part is a weak male attachment used to snap into the Locator abutment during processing.  The white ring just fills in any space between the metal collar and the abutment to keep acrylic from flowing where it doesn’t belong.

So we place the ring on and snap on the metal housing.  You will feel a snap!

Locator attachments. The white block-out ring is place around the abutment and then the metal collar and black processing male attachment are snapped on.

(4) Next we need to modify the denture to make room for the metal housing and Locator abutment.  I like to paint the housing with a Thompson’s marking stick to show what areas of the denture need grinding.  Go to town with that acrylic bur until the denture seats fully over all the abutments/housings.

A Thompson’s Marking Stick applied to the housing will show us where we need to adjust the denture.

(5) You may choose to poke a hole through the acrylic to the other side.  This will allow excess acrylic to escape.  Now it’s time to pick up the metal housings.  DO THIS ONE AT A TIME!  I do not recommend trying to pick up all the attachments at once.  It’s harder to control the final fit.  So we’ll mix a small batch of acrylic and place it in a relived area.  As we seat the denture, we’ll see the excess spill out the other side.  You can remove the excess at this stage or wait until the end.  Have the patient bite into gentle occlusion; not a heavy bite.  Once the material is set, remove the denture and pop out the white block-out collar.  Trim any excess and fill in gaps with more acrylic.

The relieved area is filled with hard acrylic. As it is seated, excess flows through a hole on the other side. After setting, the white block-out collar is shown retained with the denture.

Repeat the process for the additional Locator abutments/housings.  I like to leave the patient with the black processing male attachments initially.  This gives them a chance to get accustomed to the added retention.  Older patients with diminished dexterity may find that the black male attachments are perfectly suitable and won’t request an upgrade.  Bring the patient back in a week to see how they’re doing.  The denture will fit them differently now, so don’t be surprised if they develop a sore spot somewhere.

How do we swap out the male attachments for the stronger ones?  Stay tuned for Locator Attachments for Implant Overdentures: Part 2.

 

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7 Comments

  1. Pingback: 4 Core Concepts of Mandibular Implant Overdentures | The Curious Dentist

  2. tim says:

    Great post. I like the pick up idea, but have you ever taken a pickup and had the denture lock in after the acrylic set? Are there any techinques you know of to avoid this?

    • Chris says:

      Great question, Tim. Using the locator system, the white rings help block out any undercuts and prevent acrylic from flowing into the Locator abutment. I haven’t had problems with locking in yet, thanks to this little part. This is all the more reason to pick up one attachment at a time. It there is a locking problem, we’d at least know which abutment is the problem!

  3. Hannah says:

    Hi Chris, your site is awesome and all your articles have been very helpful! I was working on an overdenture case recently, picking up the metal housing and black processing male attachment for two locator abutments. I did them one at a time like you advised and the left side picked up perfectly fine but I’m having problems with the right. I hollowed out the denture, placed the white spacer over the abutment and the metal housing snapped on the abutment, I tried the pick up with different consistencies of acrylic to see if that would do it but the right side just wouldn’t pick up in the patient’s denture. The right abutment is slightly shorter with a slight angulation than the left side and I was wondering if that has anything to do with it? I will try again. Any suggestions?

    • Chris says:

      An interesting question, Hannah. There could be a few reasons why this happened. First, it could be the acrylic. Either the consistency was too soft or you may have taken it out too soon before it fully set. My next post will be on a new material I’m using to pick up the processing attachments and I think you’ll like it.
      Second, make sure the denture can passively and fully seat over the attachment, snapping into the left one without any interference. The patient should be able to bite comfortably. If the bite is off, then we need to relieve the denture for more clearance before trying to pick it up.
      As an aside, the shortness and “slight” angulation of the Locator abutment shouldn’t interfere with picking up the attachment. If the abutment is too short, you wouldn’t be able to snap in the attachment. If the angulation were too severe, you would still be able to pick up the attachment but would find it difficult to remove the denture after setting. Severe angulation discrepancies act like a “fish hook” and prevent a path of removal/insertion. Locator makes special attachments for these cases that are more forgiving.
      Good luck and let me know how it goes!

  4. Jack says:

    Chris,
    What acrylic material/kit are you using for your chairside pickup of the locator attachments? The kit from Zest that we’ve been using is no longer being produced. Thanks, love the site.

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