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.
(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).
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!
(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.
(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.
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.