The average human mouth has a total of 32 permanent teeth in the adult dentition. Of these 32, the wisdom teeth are 4 teeth of much renown. In orthodontics, they are often vilified as the cause of the anterior teeth crowding in our late teens or early 20s. I cant tell you how many times I hear, My teeth were straight until my wisdom teeth came in. Is this actually what happened? Do all wisdom teeth need extraction? Will these latecomers into the mouth ruin the hard work you and your orthodontist put into creating your perfect smile? Luckily, the situation is not as dire as many people may think.
The wisdom teeth, or 3rd molars, are the last teeth to erupt into the mouth. Like I mentioned above, most of us will have 4, but through genetic variation, others will develop extras or may be congenitally missing up to all 4. Similarly, genetic variation allows for some of us to have enough room for our wisdom teeth, while others do not. Typically they erupt, or break through the gum tissue around 16-20 years of age.
For most of us, at some point in our lives, our wisdom teeth will be removed. As for whether or not wisdom teeth need to be extracted, I usually base the decision on 2 factors:
1) Is there enough room for the wisdom teeth?
2) Are the wisdom teeth angled in a way that they will be able to erupt into the mouth correctly?
Radiographs taken during treatment help orthodontists to determine if the wisdom teeth are present, and to evaluate the likelihood of their eruption into the mouth. Sometimes, due to one or both of the factors above, the wisdom teeth stay impacted (under the gums and/or bone of the jaw). At other times, the teeth can erupt into a partially impacted position (only part of the tooth erupts into the mouth).
Impacted and partially impacted 3rd molars are most often extracted due to complications that can arise. Impacted wisdom teeth can put pressure on the roots of the 2nd molars next to them, and cause root damage. Partially impacted teeth can become decayed and/or infected, even when oral hygiene is ideal, because part of the tooth is still under the gums and cannot be cleaned properly. For these reasons, among others, we routinely refer impacted and partially impacted wisdom teeth for extraction.
As a last point of discussion, I wanted to touch on the common belief that wisdom teeth cause the front teeth to crowd. Multiple studies have been conducted to investigate if the eruption of the wisdom teeth does in fact force the teeth in front of them to crowd. From their results, it has been determined that the force of 3rd molar eruption is not great enough to cause the crowding of the anterior teeth that we see in the late teens to early 20s. This phenomenon is seen even when the wisdom teeth have been extracted early on. So why do the teeth crowd in this way? Although we are not certain, multiple factors have been suggested, including genetics (the mouth is programmed to try to make space for the wisdom teeth) and the anterior component of force put on teeth during function (biting and chewing push the teeth forward). The result is the crowding of your previously straight teeth.
This is why retainer wear is so important. Your best bet to keep that smile looking as beautiful as the day we take off your braces is long-term retainer wear, which will counteract the forces that tend to cause crowding. And remember, your teeth can always move, whether youre 16 or 60. Make sure to protect your investment, and wear those retainers!