Grafting the Posterior Mandible?

I am planning on placing a 4.8mm tissue level Straumann implant in the edentulous 36 (FDI) site. Since the bone is inadequate towards the crest to accommodate a 4.8mm implant I would like to place some particulate graft material and membrane at the time of implant placement. What has everyone’s experience been in terms of grafting in this manner for a posterior mandibular site? And would the choice of a titanium or Roxolid (TiZr) implant make any difference?
Thank you

18 thoughts on: Grafting the Posterior Mandible?

  1. Dr K says:

    You could get a way with 3.5mm implants. Any thicker implants , you would need block bone grafting as a 2 stage measure . Not a beginner job.

  2. st says:

    Hi, several points to consider
    1- angle the implant 2- smaller size, say 4.5 mm (if your system doesn’t have may consider a new one with more choice of sizes, it’s the system that should accommodate the pt, not the other way around. 3- consider bone expansion with osteotomes, ridge split or densah burs. 4 -what’s happening to the premolars, they appear almost shot, consider their longevity, support to your proposed restoration and if they may need extracting? 4- what is the opposing dentition, e.g. if edentulous of acrylic denture than even a 3.5 may be sufficient.

    It won’t harm to place some particulate but don’t expect miracles, bone expansion is more predictable. Furthermore, you are limiting natural blood supply from periosteum.
    hope this helps


  3. Greg Kammeyer, DDS, MS says:

    Block bone grafts and ridge splits are surgeries that require much training. Neither are optimal even when well done. GBR will work. You do need 2mm of buccal bone so a smaller diameter implant, a shorter one that is placed after a minor alveloplasty would help. Be sure the soft tissue is thick enough too. It appears on the x-ray that you have some apposing teeth that are unsupported. How will you deal with those?

  4. Dorian Hatchuel says:

    Since the ridge is edentulous I assume the bone is the same distally. (Siebert class 1).
    You will not get bone to develop vertically. It is not a horizontal augmentation once the implant is in. Do not try to “get away” with it.
    First graft horizontally with the technique you feel comfortable with (or refer), then place your implant in its rightful prosthetic position.
    If you perform the procedure as you propose you will wind up with soft tissue against the implant buccally within a short time.
    Be sure you have enough fixed keratinized tissue surrounding your implant as well.
    I hope this helps.

  5. David Jin DDS says:

    Great answers from all of the above, just like to point out one more thing, your proposed implant is bi-corticating, which is a major No-no.. so go with a smaller diameter, and may have to change the angle of approach. Remember, you can’t fight physics and biology.

  6. Robert Wolanski says:

    Dorian ‘s comments are spot on
    Bone grafting in the mandible is CHALLENGING
    If you do not know the answers to the questions you are asking you are at very high risk to do both your patient and yourself a diservice
    We could also suggest cheating by angulating the implant and reducing the diameter as st advised more lingually and using a custom cast abutment. The most predictable long term is site engineering with grafting first, then the placement of an implant later so you know what you have to work with.
    This would be a great case to partner with a mentor and learn about grafting such sites rather than trying to complete everything in one shot by yourself

  7. Marcusdoc says:

    Great answers people! By the way, I don’t know how the heck you can split the ridge here without it fracturing off. That, by the way, is a very advanced technique. Also, adding bone to dehisced buccal implant threads is not identical to vertical grafting as you still have bone mesially and distally extending superiorly adjacent to the graft. This technique has been published extensively in texts repeatedly and reproducibly (including by myself). I don’t think you NEED a 4.8 mm implant here. You can easily do a 4.1 mm RN Straumann here BUT, you still need to augment the buccal aspect as per your original question/concern. Because the mandibular cortex is so damned dense, mesenchymal stem cells have a hell of a time populating the graft medially. Yes, the other source of these cells is the periosteum but that doesn’t help at the bone-graft interface. I would strongly advocate making cortical perforations down to cancellous bone in the area of your grafting. You may need a more rigid membrane along the lines of Ti-reinforced ePTFE, tenting screws or Ti mesh or prevent graft collapse.

    You may want to consider removing the #35 and save the headache of your original dilemma and place a larger implant here and contour/extend out the final crown distally. Considering this patient’s bone stock, I’m sure you could get a 4.8 mm WN implant here with no trouble. What else are you going to do with the #35? It’s a mess. Also, I’d be worried that any implant or grafting you do at #36 with that #35 still there places this work at risk for contiguous spread of infection from the apex of #35. Remember if you have an implant failure for absolutely no obvious reason; check the adjacent teeth!

    Anyway, I think that’s how I would handle the situation you asked about. Unless you are the only DDS in 300 miles I would strongly suggest you offer this patient the option for specialty evaluation as, as others have pointed out, this is not a slam-dunk case. How would you treat your most loved one? Always consider that standard of care 🙂

  8. Dr. Robert Wolanski says:

    Holy Cow
    I got so caught up in the actual implant area that I neglected to comment on the other teeth
    THANK YOU Marcusdoc for pointing that out
    Upon looking at that second x-ray we also must consider what looks like moderate to severe parafunction.
    The few teeth we can see have been heavily damaged ( generalized attrition effects restorative space as well potentially complicating the restorative predictability) and we do not know how many teeth there are on the entire arch and what the opposing arch is. These are KIND of important bits of information to know if a long term success is hoped for
    Parafunction and hyperocclusion are killers in the implant world

  9. Mike Saso says:

    Use a slightly narrower implant, angle it a bit, remove 35 and place an immediate implant if possible. Splint the two final restorations. I dont think it is that complicated.

  10. mihai frunza says:

    I would do a 3.5-4 mm diametre implant. Some angulation and probably no grafting. 10 years will work fine. 20 maybe …

  11. Leo A. says:

    A lot of great suggestions! Firstly, graft first, place the implant later. The most critical aspect of this case will be soft tissue management. If you have wound dehiscence, then your graft will be compromised or lost all together. You must make sure you have adequate width of gingiva and the ability to achieve tension free primary closure. If you don’t have the skills to manipulate soft tissue, as this takes some experience, I would refer the GBR to a specialist and save yourself a lot of heartache. By the way, you will NOT get graft material to turn into vital bone against your implant surface. Just consider the biology, you need vital osseous cells and a continuous blood supply to maintain vitality. If you sandwich your allograft against titanium and a collagen/Teflon membrane, where is the blood supply going to come from? It will never turn into vital bone. Always make your decisions with sound biological principals in mind. Hope that helps.

  12. Dr. Bill Woods says:

    I would ridge split that area. Wait 4 months. Place a wider diameter tapered implant so threads parallel the lingual plate. If it is slightly angulated to conform to the plate then that is ok. Pay attention to what’s anterior andcaddress that. JM2C.

  13. Aj says:

    Hello all, thanks for all your comments and feedback. In response to some of the concerns regarding the premolar, it is sound and appears the way it does as it has rotated about 90degrees over the years. I have decided to graft the site and assess for a 4.8 or smaller implant in 6months.

  14. Faruk Surbehan says:

    I would go for a smaller implant diameter and angle it so that I have the implant threads in the spongeous bone all the way. There is no clear cut answer to how big a implant should be but we know that you need 2mm of bone circumferencially around the implant to give it the best prognosis. That way is the only way to know that you did what you could to not lose peri-implant bone height right away. This means you will have to have a angled custom abutment. It is way worse to end up with a implant with bad prognosis and a unhappy patient.

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