Can one salvage a crestal bone loss case?
Editor’s Note: This case has been updated with a one-year follow up, please follow the link to see the updated image.
Placed these three bone level implants in the posterior mandible sized 4.1 x 10, 4.5 x 10 and 5.3 x 12 in the LL first premolar, first molar and second molar regions in this 56 year old male patient; non-smoker, non-drinker and without a remarkable medical history, without augmentation. The patient went out of country and we could only have him back after seven months. The post op OPG revealed mesial and distal ditches to the middle implant. Clinically, we could only find a hole directly over the top of the middle implant. We raised a flap again, placed healing abutments on the LL 5 and 7 implants. The LL 6 implant (with the bone loss) was perfectly integrated, with granulation tissue pockets on each side measuring less than 3 mm. We gently curetted the area, irrigated it thoroughly, placed a bit FDBA (with intact lingual and thinned buccal cortices) with an allogeneic resorbable membrane inserted into buccal and lingual pockets. Then after three weeks, replaced the healing abutments with solid abutments and made a provisional three unit bridge, with clearance on LL 6 area. Here are my questions:
1. What would be the possible cause of this bone loss?
2. How can one salvage this bone loss; if at all one attempts it? Should one attempt it, or remove this integrated implant with difficult, regraft and redo it?
3. If some of the bone graft actually takes up, would it be a good idea to make three independent crowns or splint them, considering the history of bone loss in LL 6 area?
Thanks
Pre op OPG
![] https://osseonews.nyc3.cdn.digitaloceanspaces.com/wp-content/uploads/2014/02/20130417_140256-Copy-e1391704499545.jpg)Immediate post op periapical
Editor’s Note: View a one-year follow up to this case
30 Comments on Can one salvage a crestal bone loss case?
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k
2/7/2014
As you've mentioned, the soft tissue opening over the healing screw caused an infection and the bone loss. It's well documented in studies that replacing the healing screw with a transmucosal healing abutment as soon as you notice the opening (most likely the soft tissue never closed from the day of implant placement surgery) will prevent the bone loss. You've done the right thing by disinfecting the implant surface and placing graft material. I'd keep the crowns seperate just in case you get more bone loss around the implant so that you can take out the implant and place another one. Another option is to splint all 3 crowns (and make them all screw retained) so that if the bone loss gets worse which I doubt will happen you can simply remove the crowns and the implant and modify the middle implant crown's gingival shape to turn it into a pontic and just place it back on the implant. You are essentially making a three unit bridge. Thank you for posting.
Peter Fairbairn
2/7/2014
Hi the above report is correct as the small hole a spontaneous exposure is associated with this loss.
I assume these are DIO SM Implants and the flared head with the micro threads can be a problem if not correctly counter sunk and excess force is applied on insertion.
You seem to have done the correct action with the materials you like to work with .
Peter
CRS
2/10/2014
I absolutely agree with the treatment, however I would like to point out one 20:20hindsight. I feel drawing the conclusion that the pinhole was the culprit may only be a guess since the patient was not seen for seven months and a lot can happen in that timeframe. If there is some wound shrinkage and a screw becomes exposed I like to maintain it by having the patient dab it with peridex depending on when it happens. The pinhole may have been similar to a fistula relieving a small infection. I think the important part is to focus on the granulation tissue and bone loss vs a technical issue in placement and honestly I don't truly know why these things happen just a small SWAG!
k
2/10/2014
CRS, as I mentioned on my earlier comment, the early bone loss around exposed healing screw is well documented in literatures, and I'd like to site few of them.
1. Clin Oral Implants Res. 2010 Dec;21(12):1327-33. doi: 10.1111/j.1600-0501.2010.01952.x.
Cehreli MC, Kökat AM, Uysal S, Akca K.
Spontaneous early exposure and marginal bone loss around conventionally and early-placed submerged implants: a double-blind study. In this study, the authors concludes that, and I quote, "There is a direct relation between spontaneous early cover screw perforations with early crestal bone loss."
2. J Periodontol. 2009 Jun;80(6):933-9. doi: 10.1902/jop.2009.080580.
Influence of early cover screw exposure on crestal bone loss around implants: intraindividual comparison of bone level at exposed and non-exposed implants.
Kim TH, Lee DW, Kim CK, Park KH, Moon IS.
In this study, the authors concluded that, and I quote, "The early exposure of the cover screw that results in breakdown of the mucosal seal seems to accelerate early peri-implant crestal bone loss. Periodic follow-up after the first surgery may be critical for minimizing the influence of early exposure."
Here is yet another study that shows early exposure results in bone loss around implant. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008 Jun;105(6):702-6. doi: 10.1016/j.tripleo.2007.08.026. Epub 2008 Mar 4.
Influence of premature exposure of implants on early crestal bone loss: an experimental study in dogs.
Yoo JH, Choi BH, Li J, Kim HS, Ko CY, Xuan F, Jeong SM. In this study, the authors recommend replacing the healing screw with healing abutment as soon as the perforation is detected to minimize bone loss.
Yet another study published in 2008 showed same results.
J Clin Periodontol. 2008 Jan;35(1):76-9. doi: 10.1111/j.1600-051X.2007.01158.x.
Correlation between early perforation of cover screws and marginal bone loss: a retrospective study.
Van Assche N, Collaert B, Coucke W, Quirynen M. This study's conclusion is: "The unintentional perforation of two-stage implants resulted in significant bone destruction, probably because the biological width was not considered."
This is just a small portion of studies done on early soft tissue exposure and its effect on bone around implant. I agree that the implant placement technique may have contributed to the bone loss, but when you look at the other two adjacent implants which were placed at the same time by the same clinician, and there is a perforation only over the implant with the bone loss, then I'd be more incline to assume that there wasn't any problem with the implant placement technique but rather the early soft tissue exposure was the culprit.
CRS
2/10/2014
As I stated before this case had not been followed for seven months so what actually happened is just speculation. I follow my cases during healing and have not had a problem with exposed screws which are stable, movement and hygiene can be a problem however. While literature can be helpful I like to rely on the clinical situation which can have more variables and may not have a direct correlation. Thanks.
Peter Fairbairn
2/11/2014
Agreed k but what CRS was pertaining to I suspect was , was the spontaneous exposure just that or was the "pin hole " the result of another issue .
Peter
AAslamOMS
2/11/2014
Thank you everyone for your valuable comments. I had in fact followed the patient for about 3 and a half weeks post placement and I can vouch that there was no wound exposure till atleast ten days post implant placement at suture removal. Though I try to have the insertional torque vary between 35 and 50 N by using crestal drills in mandible, I might have had this one placed a little too tight. 7 months later, the opening was no more than pin hole large. So I wonder if the pin hole was an effect rather than the cause of bone loss. As CRS said, we also manage our early exposure with CHX mouth washes or gel application and even though there might be a literature support for exposures leading to bone loss, it might have been the opposite in this case as a low grade problem draining spontaneously through the pin hole. Do you guys believe in compression necrosis?
AAslamOMS
2/11/2014
Or as Peter Fairbairn rightly picked out the manufacturer, these particular screws always need to be submerged?
By the way, it is quite a decent biotype patient.
k
2/11/2014
Smaller the hole, bigger the bone loss. There is no mystery here guys. The mechanism is exactly the same as pericoronitis around partially soft tissue impacted 3rd molar. The soft tissue with a small exposure is just like having operculum over the head of implant. Whenever I see a pin hole exposure over submerged implant there always is a chance for low grade infection. If you had 30-50 NCm of insertion torque you could've just replaced the healing screw with a healing abutment. What would've been even better was to just place the healing abutment at the time of implant placement and make it a single stage surgery. You had more than adequate final insertion torque. Why did you not place the healing abutment when you noticed the soft tissue opening. The healing abutment would've sealed the soft tissue and you could've prevented the bone loss. I placed thousands of tapered implants well over 50 NCm over the years, and never had problem with bone loss such as yours.
Whenever I get 30NCm or better in insertion torque, I always place the healing abutment. In many occasions, I immediately connect temp crowns when the case is appropriate. Thanks.
AAslamOMSAslam
2/11/2014
I agree with K here. We now use healing abutments especially in posterior implants, whenever possible. However, inserting a healing abutment when a small soft tissue opening is encountered in the first few weeks might be risky in causing some movement of the implant healing
K
2/11/2014
LIteratures are means of disseminating valuable information to other clinicians around the world. As you know, literatures are basically other clinicians and researchers sharing their experiences and findings. Literatures also set the Standard of Care.
As of today, there is a general consensus in the scientific community and in dental schools that when there is early soft tissue exposure over a submerged implant that has at least 30 NCm or 70 units on Osstell ISQ, you are expected to replace the healing screw with a healing abutment so that you give the soft tissue an ability to seal around the healing abutment to prevent bacterial invasion into bony surface. If you don't follow this universally accepted procedure that's founded upon careful research, you may be considered as practicing below the Standard of Care.
CRS
2/11/2014
Boy that is a really big stretch since the standard of care is determined by what a reasonable clinician would do as determined by a jury. That said, conflicting views in literature can usually be found and actually can be used against a well meaning practitioner. What I suggest is reading the literature and evaluating it in regards to the clinical situation and evaluating it's relevancy. I feel that is critical thinking. My point is that there are many possibilities. I use healing heads or screws depending on the situation and do find literature helpful but not absolute. Glad to see the passion in the post but it could be a hygiene issue or even as simple as trauma from a flipper or occlusion. I like the way it was handled hope it heals nicely.
k
2/11/2014
if a patient walked into your office with a pericoronitis on a 3rd molar, you wouldn't just advise the patient to dab it with peridex. that's all i'm saying.
k
2/11/2014
one of the studies was a split-mouth design where they observed implants placed at left and right side of jaw. implants at one side had soft tissue opening and the authors maintained them using CHX, and the implants at the other side received healing abutments as soon as the soft tissue openings were created. when the authors evaluated the bone level, the side with soft tissue opening left alone but maintained with CHX, bone loss was much more than the other side that received healing abutments. And, I see the same results in my own practice. maintaining a soft tissue dehiscence over an implant is against the original Branemark's surgical protocol. i recommend either placing a transmucosal healing abutment if the implant's stable. if the implant's not stable enough, then i'd advise pt to apply CHX.
CRS
2/11/2014
I am really confused with what a pericoronitis has to do with an exposed implant screw since the disease entities are different. My point is that if there is no inflammation or pathology the screw issue can be addressed at the proper stage of implant healing. I would treat the case as the poster did which I stated before. And frankly I find your comments unprofessional and disrespectful, so I will not try to explain the difference with third molar infection, anatomy, occlusion or fascial space infection and not get baited into an inflammatory discussion just for the sake of argument. Let's just agree to disagree based on different viewpoints.
k
2/12/2014
you are comparing apples and oranges. there is a big difference between healing screw exposed out of soft tissue and pin hole exposure over the implant where there is 3 mm or more of soft tissue thickness. often, the hex on the top of healing screw harbors bacteria and it triggers inflammatory responses. the process is not unlike that of pericoronitis. we can agree to disagree, but you have to remember that you are disagreeing with me along with all the other authors who published the papers on this topic.
AAslamOMS
2/11/2014
Well; if it didn't appear in the first three weeks, the pin hole might not have been a cause, and indeed an effect, but then I might have failed to pick it up as it had formed just a bit. I now take home positive messages from this post because of an anecdotal evidence of thousands of tapered implants being handled this way by K, and also his pointing our attention to the literature now forming a standard of care about handling such situations in this way. Thank you for that.
Could compression necrosis have been a cause?
Thank you CRS too, and I would really want to place a follow up for the case when the patient comes back. He has unfortunately left again and at three weeks again, it was doing fine, but then it is too soon to comment on the salvage strategy.
Would you have used a thicker membrane like Alloderm or a thinner one like Lyoplant for this salvage?
k
2/11/2014
thank you for sharing your case!
CRS
2/11/2014
I think a resorbable membrane is fine to keep the epithelium at bay. I keep as much tissue around even at exposure, no more tissue punches if possible I would rather have too much tissue and drape it around the healing head. If I have a protected area and thick tissue I'll go with a short healing head. It is really a judgement call. I hate when this bone loss happens even before loading but better to fix it at the get go. I would be concerned in the future on this patient's worn occlusion, bruxer? He 'll be banging on these implant crowns! Perhaps an early healing head would prevent him from chomping on this edentulous space ;)! Thanks for posting!
Peter Fairbairn
2/12/2014
Yes nice debate here , but there is another critical factor being ignored and that is patient physiology variation .
Most cases of spontaneous exposure if fact have no issues with bone loss like this but some do and this possibly due to variation in host auto immune response to resident bacteria .
As we all know some patients with dreadful oral hygiene have no bone loss and others with impecable OH can have extesive periodontal bone loss .
k , I too am a big Osstell fan .
Peter
CRS
2/12/2014
Great point Peter Thanks for your perspective
Riaz
2/12/2014
I being the prosthodontic member of the rehabilitating team for the particular case would like to thank all for such an informative discussion.
Other concerns regarding the patient were his habits (nocturnal bruxism) and lesser crown height space (CHS).for this we have done elective endodontic treatment of the opposing first molar and second premolar and given him full coverage metal crown on molar and PFM crown on premolar.
I would like to ask that after how much time we should decide giving the definitive prosthesis as some crestal bone will be prone to resorption after prosthetic loading as well?
Wasiq Riaz
2/12/2014
I am not by any means a true expert in oral surgery or implantology but I think what K said that soft tissue clinical presentation of operculum in pericoronitis is referable or comparable to soft tissue clinical presentation of mucosa perforated in cases of cover screw exposure in periimplantitis is agreeable.
Faisal Moeen
2/13/2014
It is important to draw attention to the fact that under high stresses caused by a high insertion torque, significant alterations can occur in the angiogenesis dynamics impairing the formation of new blood vessels, causing hypoxia in the peri-implant tissues, thus inhibiting bone formation and favoring bone loss. Bone tissue is formed by a complex three dimensional tubule network filled with an interstitial
fluid that supplies bone cells. This fluid would be able to transmit external stresses to bone cells through a mechanism known as mechanotransduction, which refers to the conversion of mechanical energy from external stresses into bioelectrical and biochemical signals that modulate the bone cell metabolism. Therefore,
when this mechanical energy is too high, osteocytes are induced to death, followed by recruitment of osteoclasts and bone destruction. I am not saying that its all about mechanics but its almost all about mechanics. If the thickness of the buccal cortex reduces from 2mm to 1.75mm the compressive stresses at the same level of insertion torque increases by 35%.
Cortical bone does not dissipate stresses well but cancellous bone does. Do follow up and let us know if you get progressive bone loss as I doubt you would. Best of luck!
Richard Hughes, DDS, FAAI
2/13/2014
Yes, high insertion torque causes avascular necrosis. Open the site and degranulate, detoxify and decorticate and pack in a particulate graft material such as .....OsteoGen.
Cover and give it some more time.
Marik Guizot
2/14/2014
dont you think is better put it flapless with healing abutment or advanced early prosthetic, since the diameter of the implant is 4.1 , 4.3 , 5.3 mm, it means the bone is very good, why open the flap ? the vascularise in flapless is better than with flap. and if the tissue thick you can measured with x ray for the height of the neck.
k
2/14/2014
I only do flapless when the bone is wide enough and also when there is enough keratinized tissue. Reviewing a ct scan is highly recommended. Better yet, a guided surgery because you cant see the bone thickness at the top. Studies show there is less risk of bone and soft tissue loss with flapless sx.
David Vaysleyb
3/21/2014
Couple thoughts
1) Great implant positioning and placement
2) Great management protoccol. Very solid. For all GPs, torque down the non-problem abutments and make a temp bridge. Most labs will make an esthetic acrylic bridge. Cement w/ temp bond or 50% temp bond/50% vaseline (for easier removal).
3) I would wait 2-3 months to monitor the bone-loss on the middle implant. As is, I think you will have good success. 1 minor quibble, I would recommmend, is that you soak sterile gauze w/an antibacterial agent, and leave it around exposed bony structure prior to grafting. This is just a precautionary step. I personally like hydrogen peroxide, but CHX will also do well.
4) If possible, try to have regular checkups to verify no fistulas, peri-implantitis or tissue openings happen on your implant cases.
David Vaysleyb
3/21/2014
@K- Flapless is one of those things that SOUND WONDERFUL but in reality are TERRIBLE.
Let me explain. Bony surfaces are irregular and often irregularly angled. Often in the mandibular area, the crestal bone resembles a tree-top (wide at the bottom, narrow at the top).
Flap allows one to visualize the area and reduce any irregularities to provide predictable, even bone-levels.
Just my 2c. Cheers!
Dr. Gerald Rudick
10/12/2016
There seems to be a lot of opinions, and some very valid ones at that. '''MAKING A BIG ISSUE ABOUT A LITTLE BIT OF TISSUE".
From the radiograph posted, we can see that the work was well done. Peter Fairburn brings out a good point when he mentioned "avascular pressure necrosis" which can crush the tiny blood vessels and cause hypoxia to the living tissues when excessive torque is applied screwing in the implants.
Another factor I always like to take into consideration is the history of the patient, and what was the reason for the loss of the natural teeth . In the process of extracting the offending natural teeth, some harmful granulomatous type cells may have remained behind, and laid dormant in the edentulous ridge for many years . When the bone is traumatized by drilling into it later, these obnoxious cells awaken and proceed to interfere with osteogenesis.
In this case, the offending cells seem to be lying around the top of the implant, and can probably easily be scrubbed off with a tiny titanium rotary brush, laser technology, or other instruments, and the area gently rinsed with Chlorhexidine, citric acid, and a final rinse of sterile saline. Producst like Ostigen or BioOs can be placed in the cuffed out defect, and then covered with a collagen membrane and the soft tissues sutures .......wait four months and then expose again...should be well healed
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