Monday, February 18, 2013

Orthodontic retention



Q. What is the biggest misconception about orthodontic treatment?

A. If I could just tell people one thing about orthodontics it would be this:
      Teeth are NOT like fence post that are set in concrete.  With a fence post, you place it where you want it, pour concrete around the base, hold it in place (retain) and, when the concrete sets up, the fence post is stable and should never move. 

Now this is NOT what happens with teeth!  Teeth are never fixed to the jaw bones. 

They always have the capability to move.  So why don’t they; why do crooked teeth stay crooked until the orthodontist moves them; why do straight teeth stay straight if a patient is blessed with straight teeth and never needed orthodontic treatment?  The answer is that, in both cases, the teeth still can move…they just don’t “want” to move, at least not right then.  

        In both cases, the teeth are stable (crooked and straight) in their respective positions because the forces on them from the bite, tongue, lips and cheeks balance out.  Change the forces with braces, or with just normal aging, and the teeth will move. This is why we never tell a patient to stop wearing their retainers.  Even if the teeth might stay straight for years, forces change over time, and the teeth will move. Retainers will hold teeth in position because they can overcome any unbalanced forces that might affect the teeth.

         Now all of this is not to say that it makes NO difference where the orthodontist puts the teeth.  Ideally, we try and find the most stable position possible for each patient.  If we do this, then the teeth will tend to stay straight, with or without retainers (not that we recommend not wearing retainers). 

         This is where diagnosis comes in.  Let’s say a patient has extremely crowded teeth due to very large teeth and a small mouth. The teeth are stable in their crooked position, but if we just expand the arches to make room for all the teeth, are we not moving them out to an unstable position?  But if we extract some teeth (so we can leave the remaining teeth in the arch, but straight), then the final result should be much more stable.
           
           My wife had orthodontic treatment 50 years ago and, like many people, she stopped wearing her retainers after a few years.  Yet, because she had teeth taken out for crowding, her final result was stable and, even 50 years later, her teeth look great.  Now this doesn’t happen for everybody, but this is what we try to achieve, and this is the reason why we try so hard to get everything perfect and why we reluctantly are forced to extract teeth in some patients.

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