Severely resorbed lower mandible: implant locator overdenture?
This is the most resorbed mandible I have ever had to deal with and wondering whether I could help the patient out by placing 2 anterior implants for a 2 implant locator over-denture. However the bone has resorbed to the point the IAN is exposed, and I can't even locate the mental foramen! Patient has seen the oral surgeon and has ruled out any major block grafting etc. As per my planning, there is just enough room for implant in the LR2 LL2 area, but I would have to impinge into the anterior branch of the IAN. As the CBCT scan is not clear on where the mental foramen is due to the severe resorption, will my current implant position give a good safe zone to not impinge on the mental nerve? Thanks for all your thoughts.
6 Comments on Severely resorbed lower mandible: implant locator overdenture?
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prosthodontist
9/21/2020
you have done a good work up.
i am not sure of your qualifications or expertise but i would suggest referring this one off.
OMFS
9/22/2020
You are likely to fracture this mandible if you attempt implants. Don’t do it.
mwjdds, ms
9/22/2020
Thank you for your nice images! In my residency we looked at spontaneous mandibular fractures after implant placement. We had 10 fractures that we evaluated. (none involved a pool cue to the jaw).
The height of the mandible is not the critical factor it's the width. We routinely went through the inferior border of the mandible with the old 7mm long Branemark fixtures. To avoid a fracture, there needs to be at least 2mm of bone surrounding the implant. Also, all fractures occurred within the first 3 months of implant placement and none after loading.
So... with that being said, it appears you have enough bone for implants without grafting. In the severely resorbed mandible I try to get 4 implants in to retain a fixed hybrid. These patients have such an atrophied residual ridge that wearing a tissue borne denture even retained by locators, is frustrating so if you can get the pressure of the tissues it's a huge help.
I talked with my surgeon and he routinely goes through the incisive branch of the IAN since it's only function is innervating teeth, so don't worry about the branch, just watch for the mental foramina and try to get 4 implants in if you can.
Best of luck!
mark
10/8/2020
site 23 & 26 implant locator
Matt Helm DDS
10/27/2020
I love the "where is the mental foramen" who-done-it . :)) Hello? On a mandible this resorbed it has "migrated" to the edentulous crest! Palpate the edentulous crest carefully and you will find it. As for the rest: impinging on the IAN in the intercanine region in a fully edentulous mandible is not a problem. Causing a possible mandbular fracture is. That said, the best solution for this case, by far, is mini-implants with locators in the inter-canine region, and a denture with a soft tissue base. The mini-implant locators are only retaining (but not supporting, therefore not rigid) allowing the denture to "float" slightly when necessary, and the soft tissue-side of the denture will prevent IAN trauma and pain.
mark
11/23/2020
unless you have lots of experience you should refer out.
