Misangled Implant Case: Best Course of Action?

Dr YC Unless the angulation is extreme, you can still work with the malpositioned implant by correcting the angulation with the abutment. Depending on your preference, you can use a prefabricated angled abutment, a custom abutment waxed and cast to the correct angulation by the laboratory, or a cad-cam abutment such as the Atlantis abutment. The easiest thing is to take a fixture level impression and let your laboratory make you a custom abutment. You may have to play a little with the healing abutment after exposure, but it is very doable. Good luck.

Yes, a fixture level impresson is the best course.

Dear Dr. YC, Please consider discussion with, or referral to the specialist if you can. I honestly think there was minimal bone width to start with. You may lose furher facial bone in the future. A good course of action is to carefully analyze the anatomical situation and plan accordingly, rather than correcting issues. I wish you luck.

Dear DR.YC Angled implants are seeing all times . however certain steps should be addressed before placing implant 1- study the case even if it is seemed simple as one unit implant such study will avoid implant malposition 2- Use tow surgical stent system the first stent will give you the location of the osteiotomy site and the second stent will give you the direction of the implant buccolingually and mesiodistally it is very simle and easy to do 3-xray the guiding pin from time to time and use the assistant's eyes to verify the angulation 4- if the angel for any reason is not ideal custom abutment will correct the angulation for the final abutment and final restoration . it is advisable for severely angled abutment is to but the restoration in light occlusal contact and eliminat all the functional working and balancing sides contacts. note good lab will give you acceptable angled abutment and restoration , also how long is the implant is an issue too Good luck DR.Ali New York

Dear Dr.YC-Several points. Your labial bone plate is quite thin, and I do agree with Dr Delgado's observation. Treatment for this would be to do a bone graft (which really should have been done at time of placement) over the labial of the 2 implants to make sure you buttress the thin cortical plate. I use cortico-cancellous bone, 250-1000 microns, for this purpose, and cover with a collagen membrane. I would do this prior (by several months) to uncovering for your impression. As to the impression: I agree with those comments that stated to use an angled post. The issue is whether you can get by with the manufacturer's angled post, or whether you need a custom post. If you can use the former, and prep as needed, obviously it is much more economical for the patient. If money is no object, then the custom post is superior. But let's go back to the beginning of this. Today's standard in implant dentistry is the Catscan. If this had been taken, you would have seen the width of bone for the 2 implants, been able to choose width and length correctly, and have known to prepare for a bone graft AT THE TIME OF IMPLANT SURGERY. That would have provided the best analysis before starting the surgery, and made your life a lot easier. In the future, I recommend it be done for any implant patient, for both legal and diagnostic reasons. Hope the above has been of help.

The misalignment should be the least of your concerns.There doesn't seem to be any bone buccally at and immediate sub-crestal.It is also too late to graft now and the best way to cut your losses would be to explant,graft,and as Dr.Marshall advised re-enter after adequate diagnostics.

The placement of immediate implants requires a predrill to the lingual or palatal of the apex of the socket. A regular drill will be deflected by the cortical bone of the socket guiding it towards the apex and causing encroachment of the thin labial bone. What is needed is to start the purchase point towards the lingual wall with a Kirshner or Lindeman type burr. From the photo as I see it, you may have been better off to remove the implant, redirect it and then graft the buccal defect. A fixture level angulated abutment will help positioning, but I don't feel the labial plate as it is shown in the photo will hold up without having done a guided tissue regeneration procedure.

If you use freeangled abutment, you can retrieve the prosthesis at any time,with lingual hole. It is better than conventional angled abutment.

The best course of action, and certainly the most conservative is to do a small segmental osteotomy and reposition the implant. Use a piezo surgery unit with the most narrow saw-toothed tip. Raise a facial flap, split the ridge between the central/implant and on the other side implant/implant. DO NOT raise a palatal flap or cut through the apical bone. Cut the bone through to the palatal side into soft tissue. Maxillary bone is plastic enough so that you can gently puch the bone segment containing the implant to the palatal side until the axial orientation is correct. Then take small bone screws and place them in the cuts to hold the segment in place. Close the flap and re-enter in 2-3 months to retrieve the screws (very often by simply finding the screw heads, incising at the slot, and then backing out. Then learn how to place implants more ideally in extraction sites. RJM

Nice suggestion Rob.

Sir, why don't you just remove the off-axial implant, wait another four months and then replace it in a correct position? Those OMF surgeons who are familiar with single tooth osteotomy, are quite aware of its complications and avoid it as far as they can.Amicalement.

The AAID meeting in Boston this year will have a main podium presentation on the use of segmental osteotomies to realign implants. This will include final reconstructions. Don't know why your guys are having so much trouble with complications. We have achieved outstanding results using this technique. RJM

I agree with dr. Miller (segmental osteotomy) to align the implant, furthermore since the buccal bone is too thin , it is much better to do a GBR for long term stability of the buccal plate. In nobel biocare implants , you can take a fixture level impression and a zirconia custom abutment can be fabricated and an all ceramic JC to finish the case, if you have augmented the labial plate during surgery . Good luck.

As far as I recollect, Dr. Danesh is an endodontist and I am very eager to know how many segmental osteotomies he has ever done on the jaws!?!?!?.Regarding Dr. Bob Miller, I have no idea about his specialty(or whether he is a specialist or not)but, if his specialty is something rather than OMFS, then I sincerely request him to discuss the matter of single tooth segmental osteotomies with any orthognathic surgeon of his confidence.I am sure that he will receive fruitful and invaluable information.Merci beaucoup.

There is a huge difference between a single tooth osteotomy and a segmental implant osteotomy. First is proximity of the roots. Most surgeons are unable to split the difference between teeth without damaging the root. Second is technique. They tend to cut the apical portion as well. This will devascularize the segment resulting in a non-vital tooth and have a potential endodontic complication. Implants are generally placed farther apart and we do not make an apical cut. There is no danger of an endodontic problem and we do not get a freely moving block of bone, thereby maintaining apical blood supply. Perhaps you should send some of your surgeons to our meeting so we can share our experiences. Vous etes bienvenu. RJM

Dear Dr.Jafari; I will finish my master in implantology by next month from UCLA. Anyway I think we should respect the ideas of each other, and as long as any idea has a scientific background ,would be logic and respecful.

Sir, Please teach me how to cut between the implants when their distance is not supposed to be more than 3 mms, without exposing or stripping their threads.How is it possible to make your osteotomized segments movable by making only two mesial and distal cuts from the buccal and keep the apical part uncut? Please do not forget that you are not going to reflect any flap from the lingual side.Assuming your osteotomy is complete by now, how do you plan to fix your osteotomized segments considering the tiny amount of bone remained around the implant and the limitations regarding screw fixations.You may well know that in cases of single tooth or segmental osteotomies, we take advantage of arch bars or lingual/palatal splints for fixation of the mobilized segments when the teeth crowns exist.That is what you can never do with the fixtures buried inside the bone. Now, I would like to ask my original question again.Why not removing the misangled fixture, graft the area,wait for 4 months and re-insert it,(this time)in the right position. Au fait, merci pour votre invitation, mais, ce n'est pas possible a cause de U.S. visa qui est tres difficile pour les etrangers.

Dr. Miller, I am still waiting for your wise answer.I hope you are not eluding this critical topic.Je vous attendrais, mr.

If your implant is simply misaligned, why put the patient through a series of surgeries that will involve new grafting, membrane placement, new implant placement, and a potential soft tissue problem? I can't understand why you are so resistant to using a more minimally invasive approach to correct this type of problem. We are not suggesting that segmental osteotomy is appropriate for every case. I have elected to remove and replace far more implants than we have saved by using the osteotomy approach. Dr. Tremblay will present cases of mutiple segmental osteotomies in the premaxilla at the AAID this year (with exquisite restorative finish). I understand that getting visas from your country can be difficult. You can order the DVD set from AAID after the meeting and learn about the technique, from case selection, to preparation of the segments and the way we use compression screws to hold the segements in place. RJM

Howard Marshall states that all implant patients should have a catscan (presume he means CBCT)before any implant placement. This is nonsense and completely unecessary. The WHO has recently reported a huge rise in thyroid cancers, most likely linked to radiation form dental imaging techniques. We have a responsibility here to minimise radiation. If you are worried about bone thickness after taking your normal film (a good periapical is more accurate in 2D than a CBCT in any case)make sure you have lots of different implant sizes in stock and your patient already consented in case you need to do a spot of GBR. I understand that those who don't do many implants may want to order their implants for each case and a CBCT would allow them to do this more accurately, but this means exposing a patient to radiation for purely commercial reasons. Would you do this sort of thing to your mother or wife?

Dr. Chadge: I agree with you. A CBCT is not needed in most cases. For those that say that CBCT is the standard of care are for now, out of their minds and full of BS. You have to count how many CBCTs are sold in the USA or around the world and do the math. We all learned the basics or should of learned the basics as per diagnostic skills. Such as reading radiographs, palpation, use of mounted study models, use of bone calipers and a basic understanding of anatomy at the doctoral level. To quote Dr. Leonard I. Linkow, "I know what I am dealing with when I open up the patient." Let's face it most docs do not have the skills of Dr. Linkow and I was fortunate to be influenced and mentored by him. I have used CBCT, it's nice to have when you need it but not for every case. The cost to buy one is out of site. I refer my patients to an orthodontist for the CBCTs that I need and let him pay the bill for it. Most dental offices are still like mom and pop operations and cannot afford the cost of ownership.

If the case is not too bad off, why not take a fixture level impresson and let the lab figure it out!

I don't know about you gentlemen, but personally, I don't find Dr. Miller's answer, scientifically convincing.

As we moved along from the 1990's to the early 21st century, the thinking process graduated towards achieving more alternatives and finding more solutions to situations that were hitherto not "implant-salvageable" ! We devised more advanced techniques to rehabilitate patients with implants, when nothing else seemed possible. As the thinking gravitated towards tissue-engineering to generate a recipient site that was more suitable for implants; we then began to use those sites thus created by GTR techniques, for predictable implant placement. Predictability became the buzz word. The first decade of the 21st century has had its share of scientific contributions from Drs Hom-Lay Wang to Esposito; Jan Lindhe; Lars Sennerby; D Buser to U Grunder; N Lang...countless other lumineries in the legion of researchers...ALL of whom spoke at some point (in the 21st century) about creating a 3-D peri-implant environment before placing an implant. The commonality was that, they were all based on "Load acceptance" criteria.. on the need to plan prosthetically and basing Implant choice (Length & Diameter) and Implant Position on simulating the final prosthesis and using it as a guide for Implant surgery. Micheal Pikos, Michael Block, Hernandez Alfaro are three names (all Maxillofacial Surgeons of world wide repute who are considered contemporary), have all dabbled with Segmental osteotomies and have endorsed their not-so-predictable behaviour. As we get into the second decade of the 21st century the paradigm shifts towards affording simpler solutions, those that are geared towards rehabilitation options that are conservative and yet offer greater versatility in more compromised situations!! In the light of such progress, attempting a Segmental Osteotomy in the region of the anterior mandible (I believe the discussion was about tooth #27, a Mandibular Canine), when the Buccal plate has already freed itself off the rest of the parent bone (will at best work as a free graft, if the rest of the vascularity is in place), between the roots and moving the whole complex (with the implants) Lingually (arbitrarily without a Prosthetically guided position), would be attemting 2 miracles (that of Osteogenesis between the OSteotomized bone fragments, and another of Osseointegration of the Implants in situ) at the same time. One that would surely be fraught with the risk of UNPREDICTABILITY ! It is the opinion of the scientifically inclined community at large that a procedure or technique not be adopted because it works with a certain individual or a group of people for whom it is "possible" to accomplish such a deed! Being able to carry off the procedure is one thing and being able to stand up and look back at the work in 10 years and say it was truly path-breaking is another! Safer to worry about the Buccal plates re attaching and staying there under load after the implants are loaded ..! Cheers

Like was stated before a fixture level impression have the case mounted and then selection of either an angled stock abutment or a custom abutment to correct the angulation. I think the picture is a little deceiving on the buccal plate and with the lingual angulation of the fixtures there's probably adequate buccal bone.

DR Y C, 1. SHOULD HAVE CHECKED WIDTH OF BONE BEFORE. 2. WORRY ABOUT LABIAL BONE AS LABIAL PLATES ARE LOST. 3. DONT WORRY ABOUT ANGULATION, AS EVEN UP TO 15 - 25 DEGRESS ANGULATION ,IT IS OK. 4. TO REGERATE BONE USE THE TITANIUM MESH AROUND. WILL DO THE JOB IN 4 MONTHS.

Dr. YC, Let's talk treatment plan first. It looks like your patient is missing other lower teeth. I'm assuming she(?)is wearing a partial? What kind of clasps are retaining the partial. Did you think about using the implant(s) to retain the partial? You could get rid of some of the clasps and reduce trauma on the abutment teeth. You would get better esthetics result in this case too. Now about the bone width, I'm not comfortable with the facial bone thickness. 1) This is typically the best bone in the mouth, you might have used smaller diameter implants. 2) Learn to use a rear exhaust high speed to help position your implants. General dentists are great with high speed hand pieces. What to do now? You can add the teeth in the area of the implants, so you don't need to rush. At this point you want to pursue the most predictable treatment, take the implants out and graft. Let the patient know that her facial bone thickness wound up thinner on these implant than ideal. Let her know that you want these implants to be around for a long time, and although the implants there could be restored, you would feel much better with more bone facial to the implants.