Did my wisdom teeth make my other teeth crooked?

I often have parents of patients ask about wisdom teeth and when they should be removed.  One concern people have is that the wisdom teeth are going to come in and ruin the orthodontic result.  While the wisdom teeth get a lot of blame for the recurrence of crowding in the dental arches, how much of it is really warranted?  Do the wisdom teeth really cause that crowding?  And if not, what does?

Usually the wisdom teeth start to come in (if there is enough room for them) in the late teenage years or early 20s.  Research done at the University of Iowa has shown that as these teeth erupt, they do not put enough force on the adjacent teeth to cause crowding to occur.  Pressure sensors were placed between the teeth to measure the pressure on the teeth with and without wisdom teeth being present, and there was no difference.  Other studies have shown that crowding in the adult teeth will occur with or without wisdom teeth ever being present, and whether they are extracted or not.

So if wisdom teeth aren't to blame, then what causes the teeth to crowd up in these cases?  Orthodontists have a few ideas.  One is that as the lower front teeth wear a bit on the edges, the upper teeth exert a bit more pressure on them pushing them back toward the tongue.  Another possibility is a small amount of late jaw growth which puts a bit of extra pressure against the backs of the upper front teeth.  Also, as we get older there are natural, yet undesirable changes that tend to occur.  One such change is a narrowing of the lower arch as the canines tip in slightly.  This takes away some of the space for the lower incisors causing them to shift.

So what can be done to prevent this relapse from happening?  Although there are valid reasons for removing the wisdom teeth if there is not room for them, preventing the teeth from crowding up shouldn't really be one of them.  The secret to keeping our teeth straight long-term is really no secret.  The answer is long-term retainer wear.  Permanent, bonded retainers are a great way to do this (and will be addressed in a future post) but removable retainers will work just as well, assuming they are worn as directed.  I think the main reason that patients see shifting when they are in their late teens and early twenties is not due to wisdom teeth coming in.  I think it's because they have stopped wearing their retainers and one of the other factors mentioned is in play.  Wear your retainers and your teeth won't move, and you will preserve that beautiful smile for as long as you like.