Teeth shift unpredictably throughout life. They always have. After teeth erupt into the mouth you’ll notice that through the years and decades these teeth will not stay in the same spots. If your teeth do, you’re very fortunate. Tooth position stability — even after braces — is the exception, not the rule. We wish teeth would stay straight: the way we placed them after braces or the way Mother Nature put them if you naturally have straight teeth.
Teeth shift before braces. If you get braces at 55, for example, you’ll recognize that your teeth were not in the same positions in your 40s as they were in your 20s. Braces allow teeth to shift into ideal positions. And teeth — if retainers aren’t worn or are lost — shift out of ideal positions after braces.
So, that’s why we advise you wear your retainer the rest of your life. Usually, the day we take the braces off we instruct you wear retainers 24/7 for a few weeks to months. After that, only wearing at night should be sufficient to maintain/retain your nice smile.
Many retainer types are used, depending on your original condition. A fixed or glued wire is used in some cases. In other cases, we use a variety of removable retainers.
Teeth don’t shift into bad positions after skipping your retainer for a single day. However, it often won’t take too long and your teeth can shift in ways you and mom won’t like (see image below). So, please wear your retainer. And call immediately if a dog eats it, a train runs over it, etc.