Abutment Fractures with Ankylos Implant System?

Could you post some pictures? Was the patient a clencher? Did the failure result from excessive occlusal forces? Under-engineering the case? What was the crown-root ratio? What was the diameter of the implant? Thanks,

I think you mean the abutment retaining screw is broken. I had 1 case like that about a year ago with the Ankylos system. There is always excess load issues when you have a broken abutment screw. However, in the Ankylos system, you have to be careful to not overtorque. The recommended torque for the Ankylos implant is 15-20Ncm, which can be acheived without a torque driver. Your lab has to buy an Ankylos lab tool so they dont overtighten the screw to prevent metal fatigue. The design of the Ankylos system allows for the same abutment on the 3.5 mm, 4.5mm, and 5.5 mm diameter implant fixtures. The screw in not a load bearing screw, it only allows the abutment to seat and engage the morse taper in the implant. So, the previous post about implant diameter is not as important in this case. The ankylos abutment retaining screw is part of the abutment. The company uses laser welding to connect the threads to the shaft of the implant abutment retaining screw. They should consider other design where the screw is milled instead of laser welding the shaft to the threads.

Dr H. Additional information would be an asset. -did the fracture occur upon surgical placement of the implant into the prepared osteotomy site? Was it the Placement Abutment which fractured? -did the fracture occur in the prosthetic abutment proper? -did the fracture occur in the floating prostheic screw? A separation of the threads from the shank? All three scenarios are quite different, both in causative factor and resolution. Clarification would be helpful The previous poster is (close to) correct on a few items of note. The prosthetic platform is universal in all Ankylos implants regardless of implant diameter. The floating prosthetic screw is torqued to 15Ncm (not 20). The lab MUST invest in a lab torque limited hex driver (the lab driver is limited to 10Ncm). If this is not used and finger tightening is utilized the laser weld of the thread/shank joint can become stressed and fracture upon insertion. Published studies have shown that the Ankylos abutment proper is able to withstand occlusal loading (failed to fracture at 5 million cycles, 4 cycles/second, 200N force).

Please clarify if you are referring to the fixture mount during placement of the fixture or to the actual abutment after the crown has been placed. Very unusual for the abutment to fracture as it's a cone connection, the floating screw in the abutment has very little incidence of fracture. The new ANKYLOS C/X abutment fits incredibly tight and if the conical reamer and tap aren't used correctly, it's possible to fracture the "fixture mount" screw...there is however a retrieval tool and you should not need to explant..........please clarify and provide pictures if you have them.

That is the problem what I have with severe platformshifting in the molar area. Why make your connection smaller in an area where you need a wide emergence profile and strength? In my office platformshifting is for esthetic areas and 1-stage implants (Straumann, ScrewPlus) are used for the molar region.

Hello every one. I was really surprised reading that topic, and i leave my post immediately. I use Ankylos for 5 years. Last year i experienced two abutment fractures. Abutment not just screw fractures. Both first lower molars. The abutment broke at the level of the implant. I retrieved the cap with half of the abutment inside the cap and part of the screw. having the knowledge of the conical connection of ankylos i am sure tha the abutment fracture occured in the first place and the screw broke consequently. I called my supplier and assured me that he had never heard it before. He send me the Ankylos repair Kit and i retrieved both the the screw and the abutment remnants. (Very difficult procedure). I used both implants with new abutments. I am very worried since then. Everybody is thinking about occlusion problems. Unfortunately it is not tha simple. I think that platform swithing reduces the diameter of the abutment at the implant level significantly. Give your comments

It's interesting that your supplier never heard of any screws fracturing in the Ankylos system, but just happened to have a screw and abutment retrieval kit on hand. Add that to the Straumann bone level screw fracturing problems from a previous post and we see a recurring theme here; severely platform shifted implants have an inherent weakness at the point of attachment. Better to use a moderately platform shifted implant (i.e. Intra-Lock International or Astra). You will get the benefits of a medialized platform with a more robust abutment to prevent fracture. RJM

Any implant can fracture, period. Just last month, I had a patient that fractured an overdenture bar! The mouth is a hostile enviroment.

-did the fracture occur in the prosthetic abutment proper? yes The fracture occurred in the abutement not the screw. The fractures have occurred with anterior, balance and standard abutement. The size of the implant is irrelevant as the abutement connection is the same for all sizes. I think Dentsply is well aware of this problem. They have a design flaw. I will post photos later this week

Abutment fractures are extremely rare. Screw failures are more common (but not very common in the global prespective), most likely due to over-torquing past 15 NCm. The captured screw design, with a 1 mm diameter screw shaft and a 1.8 mm diameter screw thread, allows for a thicker side wall for a stronger abutment. Without a submission of broken parts to Ankylos for analysis of failure, or knowledge of the oral dymanic environment, insertion/preparation protocols,it is extremely difficult to make any intelligent commentary as to exactly what might be happening.

Dear Dr H, As Mr Hoffman has suggested above, an actual fracture of the abutment itself is incedibly unusual without error of placement of prosthetic components. I have placed over 2000 Ankylos and Straumann Implants and have not seen this once. I have had screw fractures with both, but less than 0.5%. The platform switch machanism works to maintain bon leves. I believe that after 20 years of clinical evidence a problem would have been identified. I think most likely poor planning and occlusion forces have caused this to happen 5 times!

Platform shifting is not the issue here. An implant design that has an excessive medialized platform with a smaller diameter abutment in the submergence profile and then a screw that maintains the abutment connection is asking for this kind of untoward event. Ankylos had a better track record when they had a cone fit abutment that was solid. As soon as they (and Straumann) added a screw so that the abutment could be indexed like all modern implant systems, the problems began to manifest themselves. You cannot retrofit an older design without singificant design modifications. It is always the clinician who lives with the responsibility for the failure. RJM

We have seen the screw break, in one case, on a balanced abutment. We are very aware of the guidlines on torqueing the balanced abutment. On three we have seen the abutment break at the abutment implant interface, the screw still intact. We have seen one straight standard abutment break. I have photos but don't kmnow how to post here.

Dr Miller, Ankylos has always had a screw for retention regardless of the index implant or the older model that was non-indexed. Your point is completely invalid. As you mention the Cone fit is solid. This has remained the same. I also use Straumann too. The issue with their bone level implant which i do not like is that the torque and force is on the screw. With Ankylos, the force is on a long Morse Taper that handles this much better - except for Dr H, who has experienced an issue which is most likely a prosthetic placement error.

We can certainly disagree; however, I have not seen a fracture of an Intra-Lock or Astra implant which are similar in design but more robust. Intra-Lock does not have a screw retrieval kit as this issue has not manifested itself. I stand by my assessment of a severely medialized platform with small submergence diameter being far more prone to fracture. I refuse to utilize implant designs whose engineering is suspect and where reports of fractured components are reported with regularity. RJM

Dr. H. Let me identify myself. I am the Specialist, Implant Prosthodontics for Ankylos Implants, DENTSPLY/Tulsa Dental Specialties, so I have intimate knowledge with the Ankylos implant system. Nobody else I’m aware of or who’s posting here has experienced the problems such as you report. I suggest you submit all broken parts to Tulsa Dental Specialties for analysis. Your local representative can assist you in this manner. Thanks!

Skinny little abutement neck hollowed out for an abutement screw, molar final prosthetics that increases mesial distal class 1 lever forces, impossible abutement screw retrieval when fractured all spells a formula for failure, not if but when!Use an approiately sized implant for the tooth you are replacing think about the final forces that the entire complex is getting when in function. DO NOT BELIEVE ANYTHING THE MANUFACTURER STATES READ THE INDEPENDENT RESEARCH!

Dear Frank, I place a number of different implant systems but, according to the distributer, my practice also happen to be the largest user of Ankylos in the UK. We place many hundreds of Ankylos implants each year and simply have not experienced lots of the problems you have suggested above (otherwise we'd change to one of our other systems). My colleague who I work alongside here has had one abutment fracture and one screw fracture - I have not had any. Ankylos DOES make a very comprehensive and easy to use "Screw-Retrieval Kit" which I have used to retrieve a fractured screw from a clinician elsewhere so it is incorrect to say that they are "irretrievable". I have no financial interest in any implant system other than that I place lots of them. Kind Regards, Bill Schaeffer

Mandibular implants,in general, can be vulnerable because of the discrepancy in the ratio and proportion of the occlusal table in relation to the implant, the magnitude of forces directed against them, their proximity to the hinge axis and the parafunctional habits a patient may indulge in. Considering the basic morphology of a mandibular molar; narrow Bu-Li and wider M-D, I'm wondering, why is there no implant design available to meet these SPECIFIC DIMENSIONS? OR, am I just missing them? Why go through the process of RE-STRUCTURING bone morphology by grafting, trying to fit a wide circular design, if it is possible to avoid it by simply having another design that is more proportionally shaped to fit in? For practical reasons, would it not be a better choice to modify the implant to fit into the structures than the other way around? Of course there will be instances where grafting cannot be avoided. I would appreciate a logical explanation to this situation... Thank You,

I've been using Anklos since it was introduced into the UK around 12 years ago and have placed thousands of Ankylos implants. Screw fracture is a recognisable but rare complication. The screw retrieval kit is really there for implant carrier screw fractures which can occur if the implant is over-torqued into D1/D2 bone by operators who haven't prepared the site fully. It can also be used for the removal of fractured abutment screws. This can happen, usually prior to loosening of the abutment causing stress fractures, thankfully it doesn't happen very often

Dear Dr H, I am an Ankylos user for many years and have not had any fractures all this time. I also use other makes, so it may be an issue of numbers. Most of the time, I try to place the fixtures aligned such that only straight one piece abutments without a floating screw is used. Could be you took a bad batch that somehow were defective and tended to fatigue easily and fracture. You have been using them for 3 years with no problems and then suddenly a series of fractures.... bad batch. Thus it may be a question of quality control and testing.

i would like to ask the dentist who had this problems with the Screw fracture how did they solve it and how they removed the broken part ....

It is clear from this above discussion that: 1. The screw fracture is not so unusual; 2. It is likely to happen if one doesn't work with the appropriate device (Max 15 Ncm); 3. screw retrieval remain an issue of this process; It is not clear: 1.Is the kit retrieval a useful device or not? 2. Is it possible that the producer of the ankylos don't make some improved in the kit to solve this issue? 3. In case it is not possible to retrieve the screw what is the best solution? 4.is the Removal of the plant a possible solution? Or it may cause irreversible problem to the bone? My main concern of this issue is 5. According to your experience is it a good solution to leave the scew inside and to cement the conic part in some way to the structure? Considering the fact that the plant is part of a couple consecutive plants and only one of theme with this problem. I will appreciate any suggestion or comments. An

I have been placing and restoring implants for 18 years. I have been using Ankyloss almost exclusively for the last 10 years. Up until last year I had never seen an abutment fracture with any implant system, and I a have placed well over 1000 implants. I have now seen four fractures in three patients, one patient fractured a second abutment in the same implant. In all cases I checked the occlusion carefully and found no fault, although all patients were large muscular males,in the molar region, but none exhibited signs of occlusal dysfunction, such as excessive wear. Two of these cases involved implants which had standing molars be hid them in normal occlusion. Yes Ankyloss has a problem, and it is very sad to see some of the comments posted here from their clinical representatives which attempt to lay the blame at the door of the clinician, instead of acknowledging the problem and offering some potential solutions. That is a very cheap shot, and if it continues I will investigate an alternative to ankyloss for my patients in future. This would be sad because I have been very pleased with the system previously and I have been very vocal in my support of it. I am no novice, I hold the DipImpDent from the Royal College of Surgeons of England and I have been an examiner for this diploma for several years. I will be at the EAO in Athens tomorrow and I will be seeking answers from Ankyloss there. Audoen Healy, B Dent Sc, MGDS, FDS DipImpDent RCS Eng

I have had quite a few Ankylos titanium and zirconia abutments fracture at the fixture interface with and without screw shaft fracture. Typically it is without a screw shaft fracture. At least when the screw fractures you can easily remove the crown. The usual instance is that the abutment fractures and the screw is still threaded into the fixture. Even if you back the screw out of the fixture threads, one cannot get the threads at the distal end of the screw to pass through the lodged fractured abutment, stuck in the Morse taper. So you have this miserable wiggling crown cemented onto a broken abutment that you cannot easiy remove from the fixture. You have to either find access to the screw shaft and severe it apical to the crown and free portion of the fractured abutment, or you can try and reverse hammer the crown to try and usually unsuccessfully pop up the broken abutment fragment stuck in the taper, or get the screw shaft and threads to separate at their welded junction. It's a really bad situation and one reason I am not placing Ankylos implants in my patients anymore. The other reason was that the manufacturer never mentioned an inherent contraindication for single unit crown restoration in the non-C/X system. That is rotation of a single crown in clinical service. I have had several distal molars and other single units cemented on non-C/X morse taper screw retained abutments be clinically non-mobile or not rocking but have gradually rotated on their axis like a cork in a bottle that can be turned but won't come out. The indexed C/X later design eliminated this but I have hundreds of non-C/X single units in function that have this potential of coming back to haunt me. One has to drill into the crown to get access to the set screw and then dislodge the abutment and rotate the crown back into place and retighten the screw and wait for it to happen again.

I am currently facing this problem with an abutment fracture on tooth area #31. Is this a design failure with this implant system? GH

I'm a patient and I had an Ankylos implant placed in July, 2013. It loosened 2 or 3 times and my dentist drilled through the crown to re-tighten the screw. In April, 2018, the screw broke during flossing. My dentist wants $1,800 to try to repair the implant. I feel that Ankylos should pay to repair/replace this implant. Thoughts from others would be appreciated.