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Perforated the Lingual Cortical Plate: Expect Complications?

posted in Treatment Planning & Complications, Active Posts, advice

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Dr. O. asks:
While placing a dental implant fixture in #19 area I perforated the lingual cortical plate. The lingual half of the last few threads are showing through the lingual bone. The buccal half of these threads are firmly engaged in bone. Should I have unscrewed the implant and drilled the hole oriented more towards the buccal and then re-inserted the implant to its new buccal orientation? I left the implant as is and closed the flap. Should I expect complications in osseointegration? Could I have placed a bone graft over the exposed threads?

28 Responses to “ Perforated the Lingual Cortical Plate: Expect Complications? ”

• DRMA November 17th, 2008

  
  

  There can be a periosteal pain by tong movements.
  I think bone graft will not help in this case.
  (if you are lucky, there will be no symptoms)
  I would wait one month before reimplant and use gelatin foam after explantation.

• eric-sb oms November 18th, 2008

  
  

  Obviously the key here is prevention. The lingual undercut is different in each patient, many times surprisingly severe. It is even worse in the second molar region. I think it is a bad idea to leave an implant in that can be felt under the periosteum. Although it does not represent pathology within itself, it may become a source of irritation for the patient. If the mucosa ulcerates, you could be in big trouble. It would be unlikely to heal and could cause the patient and you a lot of grief. There is no realistic way to fix this with a bone graft. The anatomy would not allow it, plus it would be quite an invasive surgery. Another thought is the concept of bacterial invasion. The implant osteotomy is a contaminated hole, as much as we think it is sterile. By introducing bacteria into the floor of the mouth or submandibular space and then sealing it in with an implant, you could cause trouble.
  I would have taken the implant out and re-drilled. You may have had to delay your re-entry depending on the thickness of the mandible.
  You can never be faulted by removing a fixture and trying to do it better. By leaving this one in, you will certainly spend a lot of your time thinking about it. Again, early implant removal is always easier than 2 or 3 months down the road. The important lesson here is not letting it happen again.

• Jeffery B. Wheaton DDS,MD November 18th, 2008

  
  

  I think the implant will integrate and there will be no symptoms and you’ll be fine. You can go a couple mm into the sinus with the apical portion of an implant and be O.K., likewise you can go through the cortical plate a little and be fine. We do it all the time with bi-cortical rigid fixation plates for trauma. Infection is a possibilty but the osteotomy is now plugged with an implant, as long as you were covered peri-operatively with antibiotics infection is a low risk. Just follow the patient, if asymptomatic in a couple of months- restore.

• Dr Frank Moloney November 18th, 2008

  
  

  I am assuming the #19 area is the lower left first molar? I Australia and most other parts of the world we use a different numbering system. How do you know you have perforated? Perforation of the lingual plate will probably not compromise osseointegration, but you might get a nasty surprise one day if you do that again, as I did this year, when I hit the lingual artery and watched an “oil well” coming up the socket of tooth#28 (your system), which was easily tamponaded by immediate insertion of the implant BUT was followed by serious swelling in the neck and floor of mouth. Luckily she was having a GA so we kept her intubated and sent her to ICU for 3 days until CT scans showed that the trachea had returned to a central position and was no longer obstructed. She was able to have her intubation tube removed on day 04 and she went home. At stage 2 implant surgery the implant was osseointegrated and my Dentist has gone on to successful crown preparation and finish—but that was a potentially life-threatening situation. Cheers Frank Moloney MD DDS Oral and Maxillofacial Surgeon, Brisbane, Australia.

• Joseph Kim, DDS November 18th, 2008

  
  

  Next time, make sure to feel the type of bone you are penetrating. Cortical bone has a distinct feel to it, especially when following cancellous bone. Don’t push the drill in areas where significant undercuts are present without being sure about the angulation of the bone and drill relative to it.

• Dr. Bill Woods November 18th, 2008

  
  

  How do you know you perferated the plate? How could you see it, under the tissue? Im not a specialist, but I think if I perferd, I would take it out, period. Cant be at fault for doing so. Dr. Maloney’s comments are pretty graphic as to what can happen. Measure twice, cut once. Did you have an implant length in mind and if so, how did you determine how long to go? I know how long my implants are going to be before I do the osteotomy. It doesnt sound like you knew how long to go and when to stop. Do you have depth markers or guards on you surgical burs? I have backed up an implant when I thought I was in the safety zone (

• Dr. Gerald Rudick November 18th, 2008

  
  

  This is a very interesting situation, and quite unpredictable, if only a 2 dimensional panorex or periapical film were taken in the initial diagnostic stage.

  When installing implants in the lower posterior region, our main focus is to be sure that the implant lies safely between the crest of the bone and 2-3 mm short of the inferior dental canal.

  It is rare that a less experienced implantologist would consider the possibility of a lingual perforation, when the concentrated effort is to stay within the boundaries for safety.

  Years ago, I used the open flap approach, visualized a sufficently wide crestal ridge,to place the implant in a comfortable position and had plenty of room to avoid the mandibular canal.

  I inserted the implant, which was an HA coated press fit Calcitek Integral, which fit snugly into the osteotomy up to 60% of its length, and then had to be gently tapped into its final resting place.

  Radiographs were taken throughout the creation of the osteotomy, and everything seemed fine.

  Upon placing two gentle taps on the implant, the entire implant virtually disappeared from my sight!!!

  A radiograph was taken immediately, which showed the implant lying horizontal and directly in the mandibular canal!! I was not sure if I should call my cardiologist for the heart attack I was sure I was about to have, or call my lawyer!!!

  Instead, I called the dental expert at Calcitek, who calmed me down and told me that I had in fact perforated the lingual plate, and not to worry.

  I extended the lingual flap apically with a periosteal elevator and was able to see the implant lying on the outside of the cortical bone, secured in place by the lingual mucosa. I fished out the implant with a college plyers, and was able to place the implant back into the osteotomy….only this time, instead of tapping….I just gently pressed the implant into place so the cover screw appeared at the crest of the ridge.The implant fit securely into place, and would not be affected by forces of chewing.

  The advise of the Calcitek implant expert was to suture the area, keep the patient on the medication originally prescribed for a couple of days longer…. and leave it for six months.

  This story is 25 years old and this implant has been supporting a fixed bridge all this time,without any problems and minimal bone loss.

  The message here is that before considering placing a mandibular implant without the benefit of a CT scan…. run your index finger along the Mylohyoid line with your thumb on the buccal plate and try to feel if there is a deep concavity on the lingual side below the mylohyoid ridge.

  When drilling the final depth, keep a finger on the lingual plate and you will feel the vibration of the drill if it is close to the cortical platebefore it has the chance to perforate the cortex.

  Occasionally in endodontic therapy, a strip perforation may occur through a wall of a root without the operator being aware of it, because the radiograph will not pick it up, unless there is a huge excess of the sealant, and pain and bleeding occurs.

  By feeling the vibration of the drill on the lingual, the perforation can be avoided, and a shorter implant can be substituted.

  Best advise is to wait, as you say a very small portion of the apical end of the implant is actually coming through.

  Good luck Dr. O.

  Gerald Rudick dds Montreal

• R. Hughes November 18th, 2008

  
  

  Dr. Wheaton is correct. However, be careful.

• Leopoldo Bozzi, MD Italy November 18th, 2008

  
  

  Dr. Rudick wrote:
  “The message here is that before considering placing a mandibular implant without the benefit of a CT scan…. run your index finger along the Mylohyoid line with your thumb on the buccal plate and try to feel if there is a deep concavity on the lingual side below the mylohyoid ridge.

  When drilling the final depth, keep a finger on the lingual plate and you will feel the vibration of the drill if it is close to the cortical platebefore it has the chance to perforate the cortex.”

  While agreeing with the first part of dr. Rudick comment and suggestion, because your’s was an incomplete diagnosis before surgery, and the one suggested by dr. Rudick it is the easest way to check the mandibular lingual anatomy if you’re using only a bidimesional x-ray examination, You should never place your finger below the inferior border of the mandibula “to feel the bur apex” perforating the plate, because of the higher risk to provoke this way a laceration of the eventually lying there blood vessels, kept against the bur by your fingers. So in any case you may want to place an implant in the mandible or in the full thickness of the mandible, and ovbiously here I’m thinking of an athophic, seriously atrophic mandible, it is far better never place your finger below the expected exit point of the bur. Use ever a new bur to have the best cutting capacity with the lowest pressure you may place on it, and be careful. Mandible is a completely different implant situation, respect to the maxillary sinus.
  So, in absence of any image of you clinical case, my advice is to take out the implant, you may place a shorter one in the same position if the available bone housing is sufficient to host -say- a 7mm long implant, or let it heal undisturbed (no gelatin sponge into it) wait three month and redo the surgery after a in-depth preliminary examination.

• Don Callan November 19th, 2008

  
  

  This can happen to any of us, learn what not to do so this will not happen again, there is some good advice above. TAKE THE IMPLANT OUT, GRAFT, WAIT 3 MONTHS AND PLACE ANOTHER IMPLANT. If the implant is left there, it will be a problem–I have been there.

• Dr. Kimsey November 19th, 2008

  
  

  I agree with Dr Callan to remove this implant if for no other reason that some other dentist will one day say how you placed it poorly and you could have killed the patient.

• Jeffery B. Wheaton DDS,MD November 19th, 2008

  
  

  I think it is irresponsible to just say “take out the implant.” Dr. Callan, exactly what problem have you experienced like this? That is a rather vague statement. As for subjecting this patient to more trauma because you are worried what some other dentist may say in the future, I think that is a little silly. I think this all depends on to what degree of perforation you are talking about. Get a CT, if it is barley through, bone will form over the apex and you will be fine.

• Dr S. November 19th, 2008

  
  

  Amazing thread going on here, with the most experienced implantologists giving their valuable inputs based on experience.

  However I think the question here is mis-understood. The dentist here tipped the last drill too lingually and the lingual cortical plate perforation that is being mentioned is obviously in the gingival 1/3rd of the implant not the apical 1/3rd. I haven’t done too many implants to qualify to comment here, but I guess it is going to make the prosthesis construction challenging probably needing special abutments. Secondly the patient is going to complain about the prosthesis encroaching on the tongue space.

• Dr S. November 19th, 2008

  
  

  On a lighter note.

  A lifeguard on the beach got frantic SOS call from a group of hyperventilating youngsters who wanted him to help their friend get out of the quicksand on the beach.

  “How much deep is your friend stuck in?” asked the lifeguard.
  “About ankle deep” retorted the victim’s friend.
  “Then you don’t need my help, you can pull him out yourself if he is just stuck in ankle deep” said the life guard.

  ” No he is stuck ankle deep UPSIDE DOWN! His ankles are sticking OUT of the quick sand and not sticking IN the quick sand, Please rush!”!!!!!!!!

  It helps to understand the question first.

• Jeffery B. Wheaton DDS,MD November 19th, 2008

  
  

  Dr. S. Good point, I was thinking ( as I think a few others were as well) about apical perforation, mainly because that is something I have experienced before. I agree with you, it does not sound like this implant is ideally placed restoratively. If that is the case then I would remove, graft, and replace in a few months…my point is I think alot of the concerns about periosteal inflammation, infection, etc. are unfounded.

• JAV November 19th, 2008

  
  

  The problem with this case is that it was not treatment planned. If you have exposed threads on the lingual your osteotomy is off. You probably did not have a stent and tried to free hand it. If you take it out and try to redrill the osteotomy you could easily perforate the lingual more apically. Take it out, graft the site, and then treatment plan the implant with a surgical stent or guide.

• Dr. Bill Woods November 19th, 2008

  
  

  I think that perfing the lingual plate, whether immediate or later consequence, is setting you up for some very unwanted misadventures in clinic or court. Period. Neither will be fun. No CT + later infection that is now sublingual with a fixed connection that would be an extremely difficult surgical situation to resolve, I just cant see it. Maybe that would get some bone over the apical portion of the implant. Havent seen that as “what to do” in any CE I have participated in, including AAID courses or Pikos or Callan. There isnt any schnederian membrane there as a boundary for a bone graft. Would you do a Summers procedure and just graft there? I dont think so. Not me. I have seen many lingual cortical plates that I intentionally place the threads for initial stability. Others thin and something to avoid. Sublingual is just somewhere I dont want to be with final placement. I completely agree with those that share the philosophy to take the implant out and place another later. Perfing a lingual plate is not a “no balls…no blue chips” situation. I’ll go by what I was sensibly taught and sleep better. “Surgeons whistle in the graveyard way too soon”. JM2C. Bill

• Dr S November 20th, 2008

  
  

  I have posted a case in osseonews cases section. Please opine urgently

• R. Hughes November 20th, 2008

  
  

  You can prevent this by careful planning, ample surgical exposure etc. You can determine if there is a perf by palpation, and probing.

• ddsyoon November 22nd, 2008

  
  

  I’d better remove it unless I am free of being charged misplacing it at the court.

• Dr. Scott Kareth November 26th, 2008

  
  

  Dr. Moloney,
  Here in the U.S. I assure you that we all know the rest of the world uses the International Charting System. I not only assume, but know that you are fully aware that #19 is in fact the lower left first molar (or rather 36) but in addition you feel the need, due to an Ausie or OMFS derived insecurity,to point out this obvious fact. The reason that I feel the need to call this out, is that I truely enjoy this site but believe many including myself are distracted by observations, such as your “lower left molar” revelation. Please leave the ego at home and let us all focus on the spirit of this site LEARNING.

• satish joshi November 26th, 2008

  
  

  Dr.Rudick’s advice to place finger under lingual plate during drilling is very dangerous and irresponsible.
  I would rather face the consequences of being sued for malpractice than placing my finger in the path of blood ridden drills and subject myself to be a victim of HIV,hepatitis B, hepatitis C,or other dangerous diseases.
  We must understand that all patients are not honest in revealing their medical history.

• toothdoc December 5th, 2008

  
  

  I agree with Satish Joshi.Is it worth to take a chance on your safety or well being?

• R. Hughes December 7th, 2008

  
  

  If you learn the bone expansion techniques as per Dr. O. Hilt Tatun, you will be disinclined to perforate the lingual plate.

• Chan Joon Yee December 28th, 2008

  
  

  Taking the implant out is the last thing that the dentist should do in this situation. Regardless of whether you try to graft the osteotomy or not, your re-entry will find a situation many times more challenging with higher risks of perforation than the first attempt.

  Personally, I would, as far as possible, avoid removing the implant. If there is primary stability and the perforation is small, there should be no problems with integration. Even with significant perforation, the mucosa is unlikely to be stretched to such an extent that dehiscence will occur. I would place a rigid membrane covering the perforation and close up for at least 4 months.

  I’ve found that grafting is always more predictatble with the implant in place. I have managed to achieve 3mm vertical ridge augmentation grafting over super-crestally placed implants. Doing it without implants in place has seen little success.

  Yes, a little bump will be visible on the lingual mucosa, but the fact that most people don’t complain about their tori should be an indication that it doesn’t really matter.

  As far as ideal positioning is concerned, most dentists perforate precisely because they want ideal placement and drilled straight down, right beneath the upper arch. If the dentist had drilled parallel to the concavity, he may not perforate but the implant would indeed be difficult to restore.

  I just had a case like that recently. I advised the patient to take a chance and she’s now glad that she did.

• Dr. Guy Levi December 30th, 2008

  
  

  I’d better remove it and manage the case like
  Dr Callan said. The main reason is extremely high risk
  of prosthetic complications and prosthetically -related surgical complications,as well. I am sure , in such cases, implant position is far away out of opposite dentition. Getting back the buccal bone volume and
  creation of surgical stent prior to implant placement is mandatory, especially in a such situation.

• Dr. Guy Levi December 30th, 2008

  
  

  … not saying about a highest risk of lingual cortical
  plate resorption with consequent soft tissue and other
  problems.

• Dr. Gerald Rudick December 30th, 2008

  
  

  I left an earlier comment on November 18th 2008 about preventing a lingual perforation by placing thumb and index finger over the buccal and lingual sides of the mandible while drilling; when not having the advantage of a CT scan.

  I described a situation of an event 25 years ago, which has turned out to be completely successful.

  I thought I was perfectly clear that when drilling the depth of the osteotomy, when your index finger is placed below the mylohyoid ridge, the vibration of the rotating drill can be felt….thus avoiding the possiblity of perforating the lingual cortical plate.

  Dr.Leopoldo Bozzi did not fully understand what I said….in that he commented ” you should never place your finger below the inferior of the mandible “to feel the bur apex” perforating the plate.

  I said that the index finger should be placed on the lingual plate below the mylohyoid ridge… certainly not the inferior border of the mandible, and certainly before it has a chance to perforate…..if too close, you will feel only the tip of the pointed drill before it has a chance to do any damage.

  Dr. Satish Joshi also criticized my comment by saying “Dr. Rudick’s advice to place finger under the lingual plate during drilling is very dangerous and irresponsible…etc.”

  Once again, this clinician read through the lines too quickly and without thinking, as I said ” when drilling the final depth,keep a finger on the lingual plate and you will feel the vibration of the drill if it is too close to the cortical plate before it has a chance to perforate the cortex”

  So my advice is to be respectful of the anatomy, and feel the vibration of the rotating drill before you can do any damage.

  Remember the case I referred to was 25 years ago when CT scans were not used as frequently or as routinely as they are today.

  I certainly take no offence to my collegues Dr. Bozzi & Dr. Joshi, and am glad they took the time to read what I had to say.

  Gerald Rudick dds Montreal

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