Roundhouse Implant Supported Bridge: Use Minis or Conventionals?

Dr. WL asks:

I have a patient who wants me to do a roundhouse, implant supported bridge on his maxilla. However, he still has some teeth which are maintainable: #4 [maxillary right second premolar; 15], #6 [maxillary right canine; 13], #10 [maxillary left lateral incisor; 12] and#11 [maxillary left caine;23]. I would like to preserve these natural teeth and would like to do a roundhouse bridge combining natural teeth and implants. I have seen cases where IMTEC mini implants have been used for this purpose. What would you recommend? Would you recommend minis or conventional implants? Should I use a segmented roundhouse with non-rigid precision attachments? How do I achieve parallelism because the anterior teeth are flared to the buccal and if I place more anterior implants because of the bone geography they will also have to be flared to the buccal? I do not see how I will be able to achieve parallelism of the natural teeth and implants.

22 Comments on Roundhouse Implant Supported Bridge: Use Minis or Conventionals?

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Dr. Dennis Nimchuk
6/8/2010
I think you have pointed out very effectively the folly of contemplating a roundhouse combining natural teeth and implants. Your have rightly stated the draw problem. The other problem is one of combining ankylosed implants with natural teeth which will have intrusion and other displacement movements. It is possible under some instances to join natural teeth to implants but this application is not one that I'd recommend. Non-rigid connectors should be avoided. Better to use segmented zones. If you use mini-implants with the inferior engineering they provide and couple them to natural teeth, it seems to me they will have a hard time surviving as they will bear the brunt of load when the natural abutments are displaced. Actually, I get the feeling you are pulling our collective legs on this one.
Joseph Kim, DDS
6/8/2010
Please don't try this with minis! Conventional implants are perfect for this type of situation. However, why do you want to keep the natural teeth? This makes the restoration much more difficult, and not many labs in this country can handle restoring this case. Having said that, Phillipe LeClerq of Paris has been doing this for decades, even immediately loading them. When the implants outnumber the natural teeth, and are placed in as wide a triangle or rectangle pattern as possible, you should have no problems. My concern is, what are you going to do when they have recurrent caries on the natural abutment? Draw is not a huge problem, so long as the natural teeth draw, and you place the implants deep enough and within the maximum divergence of your platform. An alternative is to make custom abutments for each implant and fabricate a one piece PFM restoration, but this will only add to the patient's future maintenance costs and be a pain for you when you try to retrieve it.
Dr. Samir Nayyar
6/9/2010
Well i wud suggest u 2 remove the remaining teeth & go for All-on 6/4 technique from nobel biocare. This wud b d best solution.
Richard Hughes, DDS, FAAI
6/9/2010
Depending upon the periodontal status, crown root ratio, and the ammount of coronal tooth structure remaining and if the bi and lateral were not endo tx, you may keep them. My rule of thumb is to look at the # of teeth restored then divide by two and add one. This is a modified Anti's Law. It has never failed me. I do deviate and use less abutments if the patient is small in stature or has a small mouth.
jg
6/9/2010
uhmmmmm.....mini implants in the maxilla, attached to natural dention....We dentist sure like to push the envelope!!!!
Carlos Boudet, DDS
6/10/2010
Dr WL From the opinions posted so far, you can tell that this is not a simple case, and if you don't base your decision on sound biologic and engineering principles, it will be more likely to prematurely fail. If you have to redo a case like this, it will not be profitable. Make sure that you use properly mounted study models to treatment plan the case and consider the following: 1 -Segmentalizing the case would make it simpler, both in terms of procedural difficulties and servicing in the future. 2 -The case has no posterior support, and if you do not plan adequate posterior support for this case, it is doomed to fail. 3 -Consider keeping implants and natural teeth separate for reasons such as angulation, lever arms, direction of load forces, etc... 4 -Consider placing conventional implants in the posterior regions, and not minis. Most of our colleague will agree that they are not engineered for that application. Thanks for posting and good luck with your case.
Paul
6/13/2010
Refer...take some good CE...start with predictable cases...implantology can quickly turn into a loss leader without proper education - not to mention it's in the patient's best interests to have someone who isn't looking for a treatment plan on a chat board...sorry to be critical but it's obvious you're not ready for this case, imo fwiw, minis in the maxilla suck (and they're not a whole lot better in the mandible)
Richard Hughes, DDS, FAAI
6/13/2010
Do not do it. Mini's have a place, but not for this. It is a function of how much metal from the implant(s) is interfacing with the bone. You do not have enough with minis. Tripoded pins worked well for crowns. You will have to go back--way back to the old literature and chat with some of the pioneers to un derstand. Do not listen to a bunch of promotional BS.
Amayev
6/14/2010
Don't Don't Don't do it. No mini's for full roundhouse bridge. Minis not design for this the diameter only 1.8-2.00mm not enough to stand that pressure. They going to break or get loose. ( minis excellent for dentures) The minis, dentist can use for denture stabilization or use them for temporaries during transitional period, when you place conventional implants at the same time you can also place minis and place temps over. After healing time is over and you ready to place permanent bridge you must remove them. Do not make this mistake that will cost you a lot later.
sergio
6/15/2010
Amayev, you say it like you have so much experinces with minis or are you one of those who just says so because some implant gurus say minis don't work. Have you done any roundhouse case with minis? If not, don't make it sound like it's the fact.
ssargent
6/15/2010
For the expense involved and considering the extreme loss of maxillary teeth so far, I would not do a roundhouse connected to any sort of implant. I see two choices. One, if the patient is frenetic to keep her remaining four teeth, I would place a traditional implant at the Maxillary right first premolar (#5), right lateral incisor (#7), left central incisor (#9), left second premolar (#12) and the left second premolar (#13). This assumes not enough bone at the left first molar (#14) for an implant. Then I would restore #5 singly, a bridge on #7 to #9 and a cantilevered bridge on #12 & #13. That way if the remaining teeth are lost, you only have to place one additional implant at #11 and restore with an implant supported fixed hybrid denture. Alternatively, and my preference, would be to remove the remaining 4 teeth and do the implant supported fixed hybrid denture to begin with. I don't think the patient has a real problem with losing the remaining 4 teeth or he wouldn't be in the position he is in now.
Amayev
6/15/2010
Sergio: Yes i do have experience with minis and conventional implants. And I make sound because I know. If you done full roundhouse with minis then tell me how long do you expect your patient to have this case in his or her mouth 1year ,2 ,4 5, 10, 20 years. Give me your number. Anything possible, you can place minis. place bridge over and it will look nice. Your patient will be happy for now and you will think that you a god. But you must also think what you will get in a long run not today or tomorrow but think years ahead. If you trying to place this implant charge a lot of money and run way in a year or two that's different if this is your way of practicing but if this is your office and you will continue practicing at the same location for years then you must seat down grab your head and start thinking. I hope you got my point. Don't you think that if you do roundhouse with minis how much load will be applied to this implants??? Also I don't think that any patient want to spend 20K or more for only 3-5 years or less. Would you want it? Dear Sergio from your respond I think you have no clue about implant. Just make a hole in the bone monkey can learn too.
Isavesmiles
6/16/2010
Don't do it. A lot of promotional stuff is just that promotional stuff, stretching the envelope so to speak. It will fail. Start with lots of straight forward cases and when you feel experienced whether with minis or regular implants, then stretch the envelop. Dr Sergio, I see lots of these failing cases. They were done outside of the USA for financial reasons and then they show up to me to fix the problem of the failing implants.
sergio
6/16/2010
Amayev I place both conventinal and minis. I ve done all on 4 and mini roundhouse. As far as amount of load is concerned, more minis will distribute the occlusal forces as much as 4 or 5 conventional implants do. have you ever taken out ankylosed lateral incisors? Probably not and that's why you come off very rude and ignorant about this topic. Those might have very small root but not easy to extract. Same thing apply to implant once they integrate whether mini or conventional. Learn some and experience some then tell other peole you don't have clue about something. And you still didn't answer the question; have you done any roundhouse with minis, 3 to 5 years? Where the heck did you come up with the numbers? Any studies you ve done or just ignorant wild guesses.
sergio
6/16/2010
Oh, just one more thing. There were and are claims that minis don't on upper, lower, or anywhere.. Now, in my hands they have been working. Does that somehow validate as fact? NO IT DOESN"T. you might have seen it failing somewhere. I know some dentists who do this and not getting much of failure at all. I actually see happier patients on many occasions with minis. All Im saying is if you are going to talk about science and studies, then talk about sciences and studies in both minis and conventional. I see a big trend when minis are discussed here by some, they talk about their experiences not studies and then compare that to studies done on conventional impants. Im not advocating minis over convention. Just don't think youve seen it all and make something sounds like facts when it's entirely based on your own experiences.
Amayev
6/16/2010
How long do you expect them to last when you do roundhouse case. I am just wondering???
K. F. Chow BDS., FDSRCS
6/17/2010
The patient has 4 remaining maxillary teeth which are flared buccally, indicating that there is some over closure of the bite. We should remember that no matter how good our dental implants seem to be, they are not teeth and are only poor imitations of the real teeth! As such, Dr WL is wise to insist on keeping the real teeth as far as possible. Treatment planning is vitally important especially in complex cases. It is a derivative of the patient's local and systemic condition, the patient's preferences and budget and the dentist's knowledge/skills and materials available. Having all this in mind, I would like to offer a possible solution. The bite can be raised and corrected with some posterior implants, either conventional or minis. Once the posterior prostheses are in place, they can be used to orthodontically align the remaining right 3 and 5 and left 2 and 3 to its correct position and height. Alternatively, do a bridge on the right 3 and 5 and splint crowns on the left 2 and 3,if rapid results are required. At the same time, the necessary implants can be placed between the canines and restored. Minis or conventionals can be used. Extractions of the remaining teeth should be a no no as far as possible, especially the two canines which are considered as keystone teeth and should never be extracted as far as possible. In most complex cases, I trinity treatment plan with both minis and conventionals in mind. In general, I find that I can complete a case faster this way, mainly because the healing and loading of minis can be done much faster, not because it is a better or cheaper implant but merely because it is smaller and therefore is minimally invasive and present a much lesser healing challenge to the body. And if placed judiciously with due attention to the biomechanics involved, should be quite durable. At present, there are not enough studies and analyses of minis to provide anything definitive, just like the conventionals at one time. As such, we have to fall back on our knowledge of basic sciences of osseointegration and biomechanics and try our best to err on the conservative. At no time should we discount an alternative like minis unless proven otherwise. The history of dental implants have shown that we should not write off individuals like Linkow, Chercheve and Professor Branemark. These individuals have been severely ostracised and criticised in their time but have been proven substantially correct to all our current benefit! Cheers.
DR KURIEN
6/20/2010
if you can place conventional type why placing minis , the theory says use if bone permitting place the longest and widest implant .minis if placed should be more in number so extra drill and cost wise will be same or more .conventional one will be the best for round house and its better not to tie implant with natural teeth as you know about the periodontal difference.if am wrong please correct me
Dr S
8/4/2010
The question is rather surprising to be a realistic clinical situation? Would you go to a car lot and wonder wether you will buy the Top end Mercedes or the Toyota Yaris ? Any way, both will work... notwithstanding anatomical factors. I would prefer the conventional implants in my mouth but i would expect to pay 3 times the price or more for sure. Minis are a great thing for patients ,inexpensive, minimally invasive reasonable/acceptable aesthetics etc Some people just cannot afford the best ...is this not obvious? In good hands minis are very predictable..but my only warning is that they are not very forgiving nor flexible if you screw up as the operator ....you need to ace the placement protocol and the biomechanical design has to be carefully considered. Building pyramids and roman colosseums are considered very wasteful and totally over engineered by todays standards..today we can build huge structures with properly designed engineering with much less material...Minis are no different. I have done many roundhouse cases with Imtec MDI ,several are into the 5th year now . no discernible change, patients very happy. I have been doing conventional for much longer and they are good too..they do look better in many cases ..but they were much more expensive and multi staged and I had to have a lot of experience before I did round house conventional implants in the maxilla I am inclined to agree with Sergio..if you understand what you are doing and follow tried and tested principles there is no reason that Minis will not work and thus make fixed maxillary arch prosthetics available for many more people.i really do not see what is wrong with that?
Dr SenGupta
8/4/2010
Further to the above We really should not see the cost of treatment as a taboo. I can count on one hand the number of patients in my office that really do not care what the cost of a maxillary roundhouse bridge is.There is a place for everything ...however as stated above Minis are a cheaper option but not necessarily a clinically easier option
gpkaralis dds
9/22/2010
Based on the idea of keeping 4,6,10 and 11, tells me that you have bone @ 3, 7-9 and distal to 11. By placing 7-8 conventional implants and doing the case in a segmented fashion now, you are going to largely ensure bone preservation and have largely engineered a permanent long run implant supported solution. Also on big multi unit cases, it's plenty hard enough, with the option of angled and custom abutments to correct divergences, so I guess anecdotally I'd be wondering why add to the difficulty? Finally does the natural dentition that is being retained need full coverage?
David R Powers
4/13/2011
Wow, all of the above comments are very interesting. I would have to first check my individual experience and figure out what I feel comfortable doing, anyone who has placed any implants knows that problems can come about at anytime during, and after the treatment is completed. We as dentists deal with this in every aspect of restorative dentistry from a broken filling to failed endo, yet when these issues are presented to us by our patients we do our best to correct them. My point is we really do not know what problems could arise in either scenario ,only what has happened to our patients in the past (traditional or mini's), So my suggestion would be to present these options to the patient informing them of the possible future issues. Last, I think it is important to point out also that the use of mini's would be substantially less invasive, and less costly in both time and money. I am a dentist that places and restores both traditional and mini's. I have had my share of issues with both, but my successes out-weigh those and I have dealt with every problem and been able to solve them. I would suggest not keeping the remaining teeth in this case as in my experience they are the weak link in the restoration. Regardless of whether they work with implants or not the potential for "tooth problems" to occur in the future is high and could sabatoge the entire treatment later on. Just my opinion, Good Luck

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