Atrophic mandible: Advice?

I have a patient who is pretty desperate for some added retention in her mandible. Therefore, I have recommended two implants between the inter-canine region. She does have a severely atrophic ridge with dense cortical bone. On the CBCT scan, there is hardly any cancellous bone and also it is pretty difficult to visualize the mental foramen as this is almost at the height of the crest. Medically she has COPD, but does not take any medications which may affect her dental treatment.

A few concerns I have raised:
1) Will implants still heal in dense cortical bone with little bleeding?
2) Any issues penetrating branches of the inferior dental nerve between the incisor region?
3) The inferior alveolar nerve appears on the alveolar crest. Which flap design should I use to avoid incising this?



23 thoughts on “Atrophic mandible: Advice?

  1. NY OMFS says:

    I assume you are a GP. Please refer this to an experienced OMFS – a Marx Tent Pole procedure is probably what is best (Google it).

  2. Dale Gerke - BDS, BScDent(Hons), PhD, MDS, FRACDS, MRACDS (Pros) says:

    This a tricky case and NOT one for you to start with. There are also many prosthetic considerations as well as surgical. Refer patient to an OroMax specialist and better to request 3 implants if possible. It also might be prudent to ask if repositioning the mental nerve is possible as this could avoid issues in the next few years (follow their advice).
    Successful results for implants is all about case selection and having the right person do the the necessary in the appropriate situation.

  3. Frank says:

    I agree that you shoule refer this patient if you have so important questions.
    However it is a stright forward case if you can place four 6mm implants .
    Use a larger diameter bur so that the implants have a low insertion torque.
    They will intergrate.
    Read previous posts about incisal canal. No problem.
    Flap design: on the crest from cuspid to cuspid the dissect under flap and incise again once you are clear from the nerves. There will be lots of adherences. You will need to take you time. It is the longest step. 20 minutes at least.
    Then the rest is straight forward.
    Patient will be on soft food 3 months.
    That treatment is a life changer.

  4. mjdds, ms says:

    this should be reasonably straightforward. 4-5 implants between the foramina. When I was in my Pros residency we routinely placed 7mm implants through the inferior border of the mandible. The real risk is 1) overheating the type 1 bone. 2) potential lack of integration due to minimal osteoblasts for healing (no trabecular bone) so implants most likely will be mechanically retained.
    3) make sure there is adequate width of the mandible! If you perforate through the superior and inferior cortices then the only bone keeping the mandible from fracturing is the labial and lingual cortical plates. The width should be at least 4mm wider than the diameter of the proposed implants. I did a study in my program. We had 3 spontaneous mandibular fractures with these severely resorbed mandibles. They all occurred before loading and all occurred because of minimal width.
    Leave the surgeries with this type of mandible and bone type to the experts! it is definitely a tricky situation but one that will be highly satisfying when your patient gets a nice implant supported hybrid restoration.

  5. Richard Hughes says:

    Can you show the pano?

    A sub may be a viable option.

    The bone is very dense. One needs some bleeding into the osteotomy.

    Perhaps 4 root forms and a fixed detachable restoration can be considered.

  6. Dennis Flanagan DDS MSc says:

    This case may be best treated with 4-6, 2.5X13 implants placed between the foramina and immediately loaded. A lingualized occlusal scheme on a well fitting intaglio is important. A definitive soft intaglio may be an option as well.

  7. FES, DMD says:

    You have recommended only 2 implants for an atrophic mandible? Im not sure where you learned this principle, but it is wrong. The final prosthesis will be implant supported and retained, not just implant retained. There is no alveolar ridge to offer any support of the final prosthesis, whatsoever. 2 implants will not suffice and be woefully inadequate. Best thing to do with this case is refer…..

  8. david adams says:

    I received some Interesting advice from a master implantologist about dealing with very dense bone with poor vascularity.

    Four weeks before placing implants he creates a mini- osteotomy at the sites ( (1 mm narrower than eventual implant diameter).

    The response to the wound is increased vascularity at the site so that when the implants are placed healing is more predictable.

  9. roadkingdoc says:

    Ok, I will use dirty words mini implant. This is one of the few situations. I have used minis with success. I usually use four fixtures and load on the day of placement. Generally these are elderly patients. I have on occasion perforated the inferior cortical plate with little consequence. I am note a big advocate of minis but I will use them in the scenario. Good luck

  10. Matt Helm DDS says:

    In the interest of preventing spontaneous fracture of this mandible — whose excessively dense bone can be very deceiving in that regard — mini-implants are the only sensible solution for this case. Yes, they may not be the perfect solution because the denture will only be implant-retained, but not implant-supported. But in the long run minis will provide a safer, more predictable outcome for the patient, while providing a stable denture for mastication. In dense bone like this you can even get away with placing only two minis, if you don’t have sufficient room for 4. (One secret to success is to have symetrical placement in relation to the midline!) I have done precisely that (only 2 mini-implants), in many cases where bone was nowhere near this dense, and those minis are still chuggling on perfectly more than 10 years later, with happy and satisfied patients who continue to thank me to this day.
    A few caveats however: first, if you have no experience placing minis, then this case is not for you! Minis in a case like this are not for the faint of heart — they will be difficult to place to say the least, and they will definitely depart from the standard mini implant protocol in every aspect: from osteotomy (which will have to be deeper than the usual 1/2 the length of the mini) to speed of insertion (which will have to be very slow, with 15-second pauses between turns, even with all the irrigation in the world).
    According to your scans you should not exceed 8mm length — you don’t want any threads left exposed. Lastly, don’t use the minis with the very dense threads, but use the 2.4 mm “max-thread” in which the threads are further spaced apart, like they are on root-form implants. Good luck.

  11. Sergio says:

    As much as some here or anyone outside of this forum want to deny minis, minis were originally created by FAR for this purpose, which is to give retention to a loose lower denture.
    Yes, in a dense bone, placing minis might be a bit more difficult. Use 2.0 or 2.1mm implants.

  12. roadkingdoc says:

    I like to place more than two minis for stability and insurance reasons. If one fails we are still in the game. Two as stated can work great. I give the patient a choice explaining the benefit of an addition fixture or two. I usually have two sizes on hand and I for lack of a better term go to full depth and wallow the oesteotmy out some. If the mini resist little in screwing in, I may go to then next larger size.

    • Matt Helm DDS says:

      @Roadkingdoc, the recommended scheme is 4 minis in the incisal region, keeping them at least 5 mm mesial from the mental foramen. It is the ideal and what gives the best result. Sometimes however, for various reasons (space, cost) only 2 or 3 can be placed. In that case the ideal is for the minis to be placed symmetrically in relation to the midline, so that the denture will have symmetrically even retention.
      Minis have important caveats like: 1) the ideal is to engage the opposing cortical plate with the tip of the mini. 2) if the implant doesn’t torque to the desired 30-35 Ncm you must take it out and find a new site for it — it will never osteointegrate in that particular site and is considered an immediate failure. 3) The osteotomy is never made the full length of the implant and they must also be inserted very slowly (much slower than root-forms) to avoid bone overheating.
      But, roadkingdoc, your last sentence is confusing and the complete opposite of what should be done, i.e., the mini should oppose resistance to insertion, and if it opposes too much resistance then the next larger size will only oppose even more resistance. The correct thing to do if it opposes too much resistance depends on the amount of resistance and how deep the mini has already been inserted when it opposes resistance. If excessive resistance is encountered during the first phase of insertion, before it has been inserted less than 1/2 to 2/3 of its length, you should deepen the osteotomy a little. If excessive resistance is encountered after it has been inserted 2/3 of its length the proper technique is to back it out one quarter turn and resume insertion.

  13. roadkingdoc says:

    Dr Helm,thanks for the reply. Your post is excellent clinical advice. I may not have made myself clear in the last sentence. If the mini screws in too easily I will go to a larger size. I think after so many placements a clinician develops a “feel” if I can use that term. That feel in my hands tells me what mini to go to. It also tells me if the osteotomy needs to be further manipulated. Slow insertion is always nice!LOL Thanks again!

  14. roadkingdoc says:

    I might also add ( in my hands) placing a mini implant in an trophic mandible with very little if any medullary bone differs very much from placing one in the “average” mandible. Usually a deeper osteotomy is needed as the cortical bone at the apex of the prep is not very penetrable to end of the implant.

    • Matt Helm DDS says:

      Roadkingdoc, I knew you had misswritten that last sentence unintentionally, LOL. Heck, we all do that. But you are definitely right about that “feel” which, in my opinion, is much more crucial when placing minis than when placing root form implants. Root forms are easier to place, by comparison. Minis almost never follow one single protocol, because they are much more affected by the bone density and the absolute requirement to obtain a torque of 30-35 Ncm on the first shot. Also, unlike root form implants which have a drill size sequence to full length, minis only have two osteotomy drill sizes, 1.1 and 1.7 mm, and you can only prep the osteotomy to 1/2 length, or 2/3 at most, depending on the bone density. if you overprep the osteotomy, specially in terms of diameter you’ve already messed it up. And yes, you are absolutely right that inserting them in a mandible with little medullary bone differs greatly from the “average” mandible and poses a whole different set of challenges.
      But by far the most essential is to insert slowly, by hand, with pauses, to avoid overheating the bone. If you overheat the bone you’ll deffinitely end up with a failure in 2-3 months even if you obtained the required torque.
      I’ve done over 200 cases of minis, both mandibular and maxillary, in all kinds of combinations (even to stabilize maxillary full-quad unilateral cast PUD’s) and never had one failure. Why? Because I respect very rigorously that slow insertion protocol, and I’m prepared to overtorque, if I have to. It works like a charm.
      By the way, and unrelated, your id tells me you’re a motorhead, like me. Am I right? Ever done any racing? *wink*

  15. Asja Celebic says:

    It seems to me that the alveolar height is less than 10 mm. Try with 4 x Dentium mini dental implants intraforaminally of 2.5×8 or 2.5×6 mm . If they do not osseointegrate, at least it is not likely that the mandible will fracture. If the mucosa is not flabby, you have a great chance for success. We have good experience with short but slim implants.

  16. Andris Bigestans says:

    I would definately think about soft tissue quality and quantity first , then about implants and sorry in these cases implant diameter doesnot matter.If it is dense use ceramic drills and it goes easily.

  17. roadkingdoc says:

    After doing dentistry for 40 yrs and seeing many things in my office, if you are new to implant dentistry the atrophic mandible is a great referral to your oral surgeon. I always ask myself if something goes south can I fix it. I have placed larger than minis in atrophic mandibles with sucsess. It involves drilling and thread tapping the bone to achieve stability and integration . My heart beats out of my chest in these cases. I am always fearing that snap, loose implant and fractured mandible. I can’t fix that and it makes me look incompetent. In general the surgeon can fracture a mandible and not have many legal consequences. It was a difficult case, thats way the specialist referral. Complications are expected. The GP fractures a mandible and it is because he has a lack of education. I am very busy in my practice and secure in what it do. My guiding light has always been do whats best for the patient, not what will increase my monthly productivity. I post this for the younger guys starting out their practice. Treat the patient as thought they are your sister or brother, not how can you make a buck off of them. Just an old dentist ready to give it up. Roadkingdoc

    • Matt Helm DDS says:

      I hear ya roadkingdoc– on every count. Have dealt with the atrophic mandible and almost just about everything else under the sun myself. I’m very adept at surgery, never had a major mishap because I’m very deliberate and I always take my time, and I will still refer cases I’m not comfortable with, more for patient risk reasons than pure clinical difficulty level. Been doing it 32 years myself, and I think exactly like you. I always ask myself what I would want done in my own mouth, if that were me. And I am sometimes appalled at some of the younger guys’ lack of knowledge, and even lack of good clinical sense and feel. That’s why I also post here, in the hope they’ll learn something. But I’m not ready to give up just yet. Still love it, believe it or not. Just curious: what part of the country are you in? I hail from NY. Matt

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This entry was posted in Clinical Cases, Regenerative, Surgical and tagged .

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