Implant Seems to Have Protruded Through the Sinus Floor 2 to 3 MM – Best Approach?

Obviously you have perforated into the sinus with your bur since it is 1 mm longer than the depth indication. I have placed many-many implants in a similar way but without using curettes (there is a special round ended instrument to probe) and I had never experianced any problem. Business us usual!

Maybe a scan will show a clearer picture in 3D.

upto 4mm into sinus - using summers method is ok >4mm then use lateral window technique

It seems the x-ray appearance does not correlate with your clinical observation. It is possible it is not perforated to the degree it appears on X-ray (as it's a 2-dimensional image and there can be transposition of sinus floor). An icat would be the only way to evaluate its position. Even if it is perforated by a mm or two, I personally recommend to leave it alone. It usually does not cause any problems. Doing CL and elevating the membrane for a predictable regenerative procedure at this time is very difficult.

Should not be a problem. You have obturated your perforation with a non-resorbable material. Just like the old gold foil oral antral closure technigue. Your 12 mm of bone intergration should be fine. If you used a wide body implant even better. I have formed a new floor of the sinus several times without problems. As for I-cat or scans less radiation is better and it wont change the situation.

I have a few comments: Firstly, I believe that almost everyone who has inserted implants into sites such as you have described has at one time or another had similar experiences with a tactile feel of a drop into a perforation. Since you are dealing with a fairly long volume of bone at about 13 mm length it is possible at that moment to switch out your implant for a slightly shorter one with the likelihood that the antrum floor will reform. My second comment is that it is highly unlikely that there will be a negative outcome even if the implant is sitting a short distance up into the sinus vault. You may even get lucky and get a redevelopment of a new sinus floor position which would cover the implant apex. Thirdly, I do believe there is real value in obtaining a CBVT small field image even after the fact. It may be as previously posted that you have not had a perforation in which case you will feel better. More importantly, this type of imaging is extremely low in radiation and you will have the benefit of a learning outcome instead of wondering what happened.

First of all, I think that you may not perforated the sinus membrane. You may placed your implant under the elevated membrane. I would complete the implant osteotomy with the round ended osteotomes, after once I feel the slight drop of pilot drill, with a 1 to 2 mm lower lenght of implant than preoperatively planned.

There are studies which have documented implants penetrating the sinus without complications. If it is 1mm or less, typically a new membrane will form around the apex. Greater lengths will have titanium protruding into the sinus, but it doesn't seem to ever be a problem even though endoscopy shows them covered in debris. Have you guys seen zygomatic implants? They completely go through the sinus, often times without any grafting material placed around them. Titanium is extremely biocompatible and lives quite happily in the antrum. As for the CT scan business...harmless radiaton? Perhaps you should read some literature (See ROBERTS et al 2009) on chance of developing a malignant tumor per scan taken. What would the scan tell you that you don't already know?

I have hundreds and hundreds of implants a millimeter or two into the sinus. Not only is it not a problem, but you gain bicortical stabilization which is a good thing...

I refer you all to Ole T. Jensen's text book "The Sinus Bone Graft", which will clear up alot of the guess work. As one gets more experienced they will be able to push the boundries more and more, within their own comfort zone.

I have placed many implants protruding into the sinus to get bi cortical anchorage, when i do so, i prefer getting a scan or ICAT to be sure the sinus is clear. i got some cases where i protuded 3mm or so also by error by misinterpretation of the height... In all cases i did not get any problem.the experience in the litterature and mainly the one of Misch confirm that. i got occasionaly an ICAT or scan of the protruded implants, i never found the implant protruding into the sinus, in all the cases i found either the membrane laying normal with normal thickeness around the implant or sometimes the implant surrounded by a localized thickening of the sinus membrane... I said that i take a scan or ICAT if i have the intention of protruding into the sinus because if the sinus is infected there will be a risk of infection of the implant site and loose the implant and maybe getting an oro antral communication. I hope my little experience help.

After the drop of the bur from the sinus cortical wall and negative testing for perf....(this is ideally what we look for when doing an internal sinus lift, althought, using different instrumentarium) as to prevent such membrane perfoartion. Now, I follow to 1-2mm short of the drop of your original length, and finish my osteotomy,follow by collaplug first push short of the final lenght and gradually fill and push in with your bone graft material, place your implant,and you will see great bone formation and results...hope this help.

It is disconcerting to read the misinformation on radiographic imaging when it comes talking about CT scans. Firstly Cone Beam Volumetric Tomography (also sometimes known as CBCT) (e.g. an iCat moderate volume scan) has very small uSv exposure and is equivalent to about 8 days of background radiation. A small field CBVT such as can be obtained by a Kodak 3500 for example, has the equivalent of about one day of background radiation. CBVT's should not be confused with Medical CAT Scans which have radiation equivalent to 1000 days of background exposure and which generate very significant radiation exposure. In dentistry what is needed are Cone Beam imaging not CAT Scans (which for most dental applications are better than spiral medical CT's anyways). If you live in the high plateau of Denver for example you are getting a whopping greater amount of natural radiation per year than you will from 20 small volume CBVT's. The information derived from CBVT's is of very significant diagnostic value and before long I suspect this type of imaging will legally be a requirement before implant placement surgery is undertaken. It seems some of the respondents in this blog just don't understand what is what.

a shorter implant could have done the job.if u have choosen a 12 mm implant,u would have been no where close to sinus floor.i normally treatment plan implant lenghts 2mm away from critical organs like sinus and nerves when abundent bone is available.you had 14mm of bone and a 12mm implant was more than enough to resotre a molar.but perforation of this lenght heals with time and bone forms at te apex.sinus bone graft by ole t jensen describes it nicely.

Great blog, Gurus! Was worth reading all the way through !

I found this info really interesting. Thanks for posting!

In response to Nimchuk's rather inaccurate explanation of CT vs CBCT and his conclusions re xray use. Dr. Nimchuk it appears that it is you who does not understand what is what. There is no absolute safe limit of xray exposure. This is called the STOICHIOMETRIC effect. As someone who obviously likes his CBCT machine (and needs to recoup his financial outlay) you really ought to be familiar with the physics before bombarding your patients with what is probably unecessary radiation. In some countries you get struck off for unecessary xray use.

Do absolutely nothing. What will occur over time is the following: 1-the sinus membrane will reform over the implant. 2-bone will eventually creep up the exposed sides of the implant. Will it ever completely cover the implant? Never checked, but it doesn't seem to matter if it does not. 3-the only caveats are if the sinus is currently actively infected or particulate graft (usually ceramic or Bioss) has managed to migrate up into the sinus. Sometimes these particulates will get infected, but that is rare. In my opinion, the vast majority of sinus lifting is unecessary, whether it's a fully open a la Caldwell-Luc or through the osteotomy. If you have 4-5 mm of type 1-2 bone, you're OK. You might add 1-2 mm to that minimum in 3-4 types or postmenopausal women. Also, in my humble opinion, zygomatic implants are an abomination and should never be done. If there is a true indication for a traditional sinus lift, it is this type of patient, particularly in light of the fact that the grafting materials available today are so versatile. Most Caldwell-Luc type sinus lift approaches are drawn incorrectly in much of the literature I've seen. What I mean by that is the inferior aspect of the osteotomy is too high (typically minimum 5-6 mm or more from the alveolar crest). This approach makes it too easy to perforate the sinus lining (it is thinnest here), and to diffucult to accurately place the graft material (too hard to see it). It is far better to make the osteotomy 2 mm from the crest. Why? 1 - the alveolar bone is thicker here, making it trivial to elevate intact 2 - the sinus lining is thickest in this area, also making it trivial to elevate intact 3- better visualization of the placement of the material. Have to seen some of the severely over-packed maxillary sinsuses on this forum? If you use this approach this is unlikely to happen. Remember that the entire volume of the sinus is 15 ml, so you should rarely exceed 5 mm of graft material. Should you happen to tear the lining, it's no big deal. Just place a suitably sized resorbable membrane between the sinus lining and graft, and things will heal just peachy. A final note: In my experience (14+ years), osseointegration is rarely the 100% bone to implant surface area contact we've all been led to believe. My educated guess is that successful osseointegration is somewhere between 50-60% bone to implant surface truely osseintegrated in the classical sense, and may be even less. We've all seen 10 mm dental implants with 3-4 mm actually still remaining in the bone, and yet they're *amazingly* still in function and rock solid stable. Not always of course, but enough to make you wonder. So there it is in a nutshell. Relax, keep it simple, and everything will work out just fine.

I have had this circumstance and clinically it has not presented a problem several years out in at least 5 cases that I can recall.

Thank you very much doctors for sharing your experiences. The patient still has no signs or symptoms of sinusitis 3 weeks post-op. I am a little worried about having complications at the prosthetic phase though (after reading another posted comlication "implant crown sunk into..." . Dr. Jon W. could you please post the full name of the article you cited regarding CT scan radiation and increased risk of developing malignant tumors? Thank you.

Dear Dr. A. I am going to give you two pieces of information when performing posterior maxillary osteotomies. Rule 1. After initial penetration into the bone to not more than 10mm depth with a rotary instrument, switch to ostetotomes to achieve any further depth safely. Rule 2. Never forget rule #1.

DO NOT WORRY AT ALL. even if a perforation of the membrane happened, it is safe to insert the implant in to the sinus but WITH OUT GRAFT MATERIAL in case of perforation. I advise you to read the sinus augmentation chapter of the clinical periodontology and implant dentistry, volume 2, written by Prof. Niklaus Lang, it is very evidence based and answer this question.

i had a similar case and colplug,graft combination seems a good,viable and easiest and reliable solution

hi, i hav a similar case, post op x ray showed 2-3mm of implant in the sinus. even i am waiting to know how the implant is going to respond.

Dear Jon W or any one who can help, where do I get hold of the studies that have documented implants penetrating the sinus. Thanx for all the comments.

Dr GP Nel, You can find arbitrated article abstracts in Pubmed

A perf of 2 to 3 mm. is no big deal.

No worries! It will be fine! Sterile implant, nonperfed membrane. A little nasacort, zithromax, and away you go.