Predictability of GBR?

Dr. H asks:

I am periodontist with two years experience with dental implants.
Recently I placed implants in a 36 year old female,healthy, with no
parafunctional habits, who had lost tooth numbers 19 and 30 several
years ago. She has buccal-lingual bone resorption, so I decided to
place the dental implant and do guided bone regeneration (GBR) at the same time.

I used a bioactive glass (fillerbone) and a membrane (Membracel). During the healing process, the flap opened exposing the membrane and the graft which eventually was lost, leaving an exposed dental implant. I waited for the healing process to close the wound completely before taking a course of action.

Two months now since the surgery and there is a complete closure of the wound, leaving only the head and the cover screw exposed. The patient has shown excellent oral hygiene and has followed all the indications given (eg, brush gently, with a gentle toothbrush with a .20% chlorhexidine gel).

My questions are: Should I try to regenerate again or can I load the dental implant knowing that I have at least a 30% vestibular dehiscence on the implant? Lingually, there is no implant bone defect. Will I have tissue problems, especially plaque control, and how predictable is GBR after the implant has osseointegrated? How can I be sure that I have a “tension free” flap, which is, I think, is my biggest problem?

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7 thoughts on “Predictability of GBR?

  1. When you bulk out an area, the primary closure must be tension free. To achieve this, you will need vertical releasing incisions. You must cut through the periosteum with a sharp scalpel. You will feel the tissue stretch as you are cutting the periostium. As to where to place the cut, my preference is as deep into the vestibule as possible, where the soft tissue overlying the periostium is nice and thick. You do not want to cut through the periostium AND the soft tissue.

    If you are planning an uncovery procedure, and just want to ensure that the soft tissue does not migrate apically on you in the future, it is not a bad idea to place a healing abutment, perforate the host bone around the implant to get some real bleeding, and place bio-oss or nu-oss (ace surgical) without a membrane. Release the periostium and suture with horizontal AND interrupted sutures to achieve a nice snug seal around the healing abutment. Chlorhexidine rinse starting the next day until sutures come out. I recommend 6-0 nylon or PTFE sutures to minimize wicking. Nylon is much cheaper. By the way, 1 gram of amoxicillin or 300 mg clindamycin 1 hour prior to uncovery. Chlorhexidine rinse 1 minute TWICE immediately before procedure. Aseptic technique.

    You will not get back significant bone growth, but you will create a recession resistant zone around the cervical area of the implant, as well as, nice esthetic ginigival contours instead of the sunken look.

    For more info, look up Sascha Jovanovic in UCLA.

  2. Dear Dr. H.:
    Since you are a recent grad, I am sure that you attend most of the better Implant meetings. What I have noticed is that many presenters show us, the audience, miracles which they have performed. We assume those “miracles” are standard of care and a routine in their offices. I happen to be a garduate and and now, a faculty member at the NYU Post-Graduate Implant program, where we, too, perform “miracles” everyday. However, most of my teachers, and colleagues stay away from performing such “miracles” in their private practice. For the future, try and do “one miracle at a time” It is safer and way more predictable. In your particular situation, it is also more biologically sound. Nevertheless, there is plenty of literature out there that will describe repair of implants as in your situation. Some advocate decontamination of the implants with citric acid, others advocate removal of the threads with a high speed high speed. I have done both with moderate success… that means some worked, some didn’t. Dr. Kim’s recommendation of a passive flap is of paramout importance, and the treatment of the implants is dependent on the type of surface. Bio-Oss, and a Bio-Mend Extend memberance works well for me.
    Just remember that when you are starting a practice, it is better be known as safe and effective, then a cowboy. Patients and colleague like that much better.
    Good Luck

  3. If you just have the collar exposed, leave the implant as it is: you won’ t have any sort of problem.
    In my opinion, you should perform a GBR procedure only in case of lack of aesthetics or poor oral hygiene or, as Dr. Kim said, if you want to ensure that the soft tissue does not migrate apically in the future.

  4. A good idea will be to remove the implant wait three to five months an place another one in sound bone.

    It is very difficult to regenerate bone over any avascular (Implant) surface, and it will be even harder if the bone you want to regenerate is located outside the current bone architecture (one or non walled defect). If In addition to these drawbacks the inert surface where you are planning to regenerate new bone has been previously exposed (contaminated) the chances to succeed are beyond our current knowledge therefore you are performing another non predictable procedure (miracle) on your patient.
    If you decide not to extract the implant,tell the patient you are not satisfied with the performance of the implant and discuss with her the pros and cons of leaving it in place. If he agrees with your point of view, have him place the crown.If you appreciate any further problem you have to remove the implant and start again the way you should the first time, first regenerating new bone and later placing the implant in sound bone. The only additional surgical treatment I would perform is a free gingival graft or a CTG to ensure a favourable enviroment around the implant an therefore maintain the current soft tissue integration of the implant.

  5. I would suggest leaving well enough alone. Many clinicians do the same procedure, including, myself, yet, never know how successful they are with bone fill because they do not attempt to
    raise a flap to evaluate bone fill post implant surgery.

    You state that two months now since the surgery and there is a complete closure of the wound, leaving only the head and the cover screw exposed. The patient has shown excellent oral hygiene and has followed all the indications given (eg, brush gently, with a gentle toothbrush with a .20% chlorhexidine gel).
    That is a remarkable come back as the patient has demonstrated excellent healing potential. You do not mention the length and width of the implant but it sounds to me that an adequate degree of osseointegration occured. There are tests in the literature to test the relative degree of osseointegration but with most
    clinicians finding greater than 90 percent implant take success, you probably will be in that range as long as you can maintain the bone levels, eg. check adequacy of attached gingiva, over the area of the suspected bone dehiscence. Consider soft tissue grafting if there is reason to believe the gingiva may recede. In this case, I found it is much easier to manage now before the recession develops than try to to cover an exposed implant surface which you state you do not have yet. Thank you for sharing your case and I always welcome feedback and suggestions.

  6. If the implant is stable you can also watch and see, but use only a temporisation, which you can load in a slow way: out of occlusion and articulation, later in light occlusion and then in normal occlusion. If the implant will expose in the mouth you can always try to do a miracle. I have seen a good cleaning by using laser ( Er-YAG), but there are also some other ways to do this if you don’t have a laser. Then I would build it up whit Bio-oss ( slow resorbing material, propably a life-time event!) and a free gingival graft. The soft tissue will stabilise your GBR graft. An other way is since you have temporise your restoration, you can do the above gbr en free gingival graft ann put the implant to sleep again under your tension free flap. For the intergration you should make some wholes in the bone to get BMP’s and blood in your GBR.
    I hope this will help you.

  7. Late post but I just read this string. I like the idea of a FGG first over the whole implant and buccal – get some great tissue there – then graft the buccal of the implant with bone of choice. Yes, you CAN graft bone over an exposed implant and there are situations that are not difficult. In this way you will guarantee 1ry closure for the bone grafting and simplify both procedures. One miracle at a time. Were you in a hurry to succeed? Tell us what you ended up doing and how it turned out. just my conservative thoughts. Bill

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