Atrophied mandible: recommendations?

I’m planning a 2 implant overdenture for this patient and this is the ICAT scan. As you can see, the mandible is quite resorbed, the height from crest to lower margin of the mandible is about 9-10mm in the anterior region where I was considering placing the implant fixtures. Theoretically there is enough space to place an 8mm length implant- but this would be very close to perforating the outer cortex. Also are there any issues with potentially causing a fractured jaw? What are your recommendations?

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ICATICAT

15 Comments on Atrophied mandible: recommendations?

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Peter Fairbairn
7/1/2014
Should be good to use 4.5 by 8 mm Implants as jaw very wide and in the 3 area has nice flat table . No worry on fracture in this case . Peetr
nafees
7/1/2014
i think this is not a implant favored case.because there is a little chance of implant success for longer time.but if you are looking to provide a overdenture for shorter period of time then go ahead but please do take notice of bone resorption.put the patient on calcium + vitamin D supplement and call the patient for follow up after every 3 months.take x-rays and check bone density.
Dr L
7/1/2014
Hi, why don't you think there is a long term success with implants here? What is it that you are concerned with?
Richard Hughes, DDS, FAAI
7/1/2014
I agree with Peter, 4.5x8 will work nicely. A subperiosteal or ramus frame is also I order for those that have the skills to do so.
Dr L
7/1/2014
Thanks for your input Peter & Richard. Just a question- I was concerned a 4.5mm diameter implant will leave too wide a fixture/locator intra-orally, and thus start to interfere with the non-keratinized mucosa??? Would a 3.5mm implant work as well??
Richard Hughes, DDS, FAAI
7/1/2014
Dr L 3.5 will be fine.
CRS
7/5/2014
I would place these guided since you only have a few sections where it is safe to place the implants. The bone is dense basal bone if you push too hard it can be easy to perforate into the floor of the mouth or lingual. This is a challenging case and it will be easy to become disorientated if you know how to manage the significant complications you should be okay. I would recommend a radiographic/surgical stent to orientate the clinical to the radiograph otherwise you are just guessing. The atrophic mandible has pitfalls. Good Luck.
Richard Hughes, DDS, FAAI
7/6/2014
CRS, You made a good point about disorientation.
Carlos Boudet, DDS DICOI
7/8/2014
All good points above. Consider a CBCT derived surgical guide. It will allow you to optimize placement and make the case slightly less challenging. I would use standard diameter implants, although I agree with Richard and Peter above that the wider implants will work. A third implant close, but not on the midline may offer less movement and more stability to the prosthesis. This is a case that years ago I would have treated with a subperiosteal, but having done them, I rarely recommend them. I will try the less extensive surgery whenever I can. Good luck!
Ernest
7/12/2014
In this case one might consider placing 4 minis between the mental foramina. If the area is type two bone, as the scan suggests, and if the insertion torque is greater than 30Nc there should be the same degree of success as conventional implants. Some may consider this approach "cheap" dentistry but it will meets the patient's needs in the most expeditious manner. I am not aware of any studies that show that two convention implants are better than four minis in a case of this type. If any one knows of such study please blog the reference.
Richard Hughes, DDS, FAAI
7/12/2014
Ernest, Why place minis when standard implants will fork so much better! Even two 3.75 by 8 mm. Can integrate and support a ball retained OD.
Richard Hughes, DDS, FAAI
7/13/2014
This is a case where two Quantum implants with ball attachments will work nicely. Two Bicons will also work.
K. F. Chow BDS., FDSRCS
7/16/2014
Earnest is right. 4 mini Oball heads with Orings and Housings cold cured into the lower full denture is the treatment of choice in this case. There is more than enough evidence based studies. Why place large diameter implants that will compromise the already compromised atrophied mandible when you can place 4 minis that are only 2.5mm diameter compared to the 3.75 - 4.5mm diameter conventionals? A sharp blow to the mandible and guess where it will fracture? Also 4 minis with cold cure of the full denture takes about 1-2 hours to place whereas conventionals will easily take 3-6months. Give the patient a choice and you will know which one he/she chooses. Observe a case of mine ......very atrophied mandible that even had a repaired fracture of the right body of the mandible and how satisfied the patient is up to today after 6 years or so. The initial treatment time took about 2 hours:http://smalldentalimplants.blogspot.com/p/singapore-academy-of-medicine-gives.html
Richard Hughes, DDS, FAAI
7/17/2014
Another treatment for this arch is the use of two Quantum implants placed in the symphysis with ball "O-Ring" attachments.
Dr B
7/22/2014
Interesting but a little difficult case Dr L - the placement might be tricky - u wouldnt be sure where u are in a completely edentulous case , definitely calls for a surgi guide ( a cbct derived one would be better). But if costs are prohibitive, i would suggest something - mark the prospective implant sites in old denture of the patient , preferable to place at both the canine regions in this case. Mark it on the tissue surface of the denture , make a cavity there using any bur, add composite, seat and adjust, then cure. Make it a solid regular shape, not too thin and hairy. Repeat for any number of sites. Ask the patient to wear it during CBCT. Now you can relate to the sites clinically from the radio-opoacities seen in the cbct. Just duplicate this denture using clear acrylic and make access holes as per your cbct findings for orientation and angulation - thats your cheapest surgical stent. :) Even though its just two implants, we are more concerned here owing to the age of the patient ,the mandible is frail may be subject to fracture and you want to avoid complications in general. From the looks of it, 8 mm should be fine, but as a safer bet, try for Straumann 6 mm if available. You could use 4.1 dia, tissue level and follow it up later with locators or whatever suits you. Lot of people would protest vehemently about short implants, but i think 6 mm implants are fine here considering you want to go conservative on the patient in terms of surgery and otherwise. Not only that , 6 mm implants are nothing, when u compare them to the new 4 mm series!!! Subperiosteal - i am not old school, so never tried it and i dont think i ever will. Mini implants yes, but again do you want them as permanent implants for this case..? 4 minis with immediate load, i have seen it work, but am skeptical because i have seen a bit of failures too. Dr B

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