Topics of the day:
1. Re: Bonded lingual retainer causing teeth to shift
As a practioner with a career's experience with fixed retention, the > following thoughts go through my head:
1. you are probably either now or have in the past not been bending the wire off a model. You are bending it (or a chairside is bending it) without a model and then they are using dental floss to hold the wire against the lingual surfaces to be bonded. If the wire is not dead passive, there is enough residual energy to eventually cause the wire to flair the 3s or to move the 2s.
2. if the above does not apply because you have been very careful, then it is possible that somehow the patient is distorting the wire somehow and this is causing the teeth to move. If you are using a twist -o- flex type wire (coax), this is a real possibility particularly between the upper 2 & 3 where the lower canine occludes.
My preference, and I learned it from Dr. Zachrisson, is to bond a bar on the canines only and allow the lower incisors to rest against the bar but not to be held to the bar. I would be happy to send you a copy of BZ's article on the subject.
If you want to attach to every tooth, then consider the gold twist wire available from Gold N Braces (on the lower this works nicely since I don't believe there is much chance of distortion) or Ortho Flex Tech from Reliance. The gold twist requires a model and the Ortho Flex Tech is dead soft white gold and does not require a model. The OFT is a Dave Musich creation specifically to avoid post tx movement due to patient distortion.
2. In the upper arch, only bond 2-2 and use a slip cover type retainer worn only sleeping as a supplement to the 2-2. This will basically eliminate your breakage and your residual movement. Use the OFT if there is not significant pre tx spacing but the gold twist if spacing was a problem.
Don't give up on fixed retention. It is the answer for almost all ortho retention problems.
Try using an .032 TMA wire bent to fit from 3-3 contacting each incisor as high to the incisal as possible and boned only to the cuspids. The ends of the wire are bent downward and ground to a feather edge. The enamel on the lingual of the cuspids is prepared first with a small football shaped diamond to remove the shiny surface. We have used this routinely on nearly all patients for over six years and rarely have relapse or breakage. The TMA allows for flexion and cuspid mobility without breakage. Bonding to only the cuspids allows for much better hygiene and avoids that problem of having one of the teeth come loose from the retainer. The key to its success is to have the wire bent as accurately as possible and to have heavy pressure against the incisors while curing the composite. We do this by bonding one cuspid first and then pulling the wire very, very tight against the incisors with a floss between the centrals and laterals while bonding the second side. This has become a very routine and fast process for us and has made lower incisor relapse a thing of the past. The only time I used to see relapse is when I did not pull tight enough on the floss.
Bonded lingual retainers made of twist wire or braided wire predictably twist over the years, torquing the right lateral labially and the left lateral lingually. The solution is to make the retainer of single strand .016 stainless wire.
An excellent and inciteful comment. I too have seen this occur only on a coaxial .0195 wire. Again, like you I thought passivity was key and reviewed these concerns with our lab tech and our staff. Now as a result of your email, I would have to agree with you or at least give it strong consideration. john
john kalbfleisch DDS., D.Ortho., M.Sc., FRCD (C)
direct line: (416) 580-5034
Dr Jen Salzer,
As an answer to your question: anyone else seeing a phenomenon of teeth shifting in a very unique way after a period of time in fixed lingual retainers?
We have seen the situation you describe and have found that multibraided wires and alike have a tendency to twist when one or more of the incorporated wires have broken (it is hard to see clinically). We have ongoing reasearch on lingual retainers at our University.
Recent postings have asked questions about various retainers and retention problems. Dr Gabriele Floria, editor of the VJCO in Florence, Italy, has graciously granted permission to reprint my article on bonded retainers here> I hope this will help answer many of the questions. If you haven't signed onto the VJCO, you may paste this into your browser and sign up.
This article will open as a .pdf file in Adobe acrobat, unless you are the lucky owner of a Mac. Mac opens .pdf files automatically
Hello fellow members, Several years ago one of our members posted an invaluable resource for bulk clear pressure formed retainer material from Cope Plastics. It was virtually indestructible, very accurate and easy to work with. Cope has since stopped distributing the material (.040 clear polyethylene). Has anyone found a good alternatvie source for this material? Thank you!
Duane Erickson, DDS
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