Yes. Remember, if your teeth can be moved into their correct alignment using aligner treatment, they can easily shift back to their original position without proper maintenance. 

After you complete your aligner treatment, you will enter the “retention” phase.  The idea of the retention phase dates back to 1945, and has proven to keep your hard-earned results of treatment in good shape. The retention phase is crucial to maintaining the desired outcome and avoiding risk of further orthodontic care.  

There are 3 primary reasons that your teeth may move after a completed orthodontic treatment, all of which can be prevented by wearing a retainer:

1. Gum and bone tissues supporting the teeth remodel in response to tooth movement.

These tissues require an adequate time to fully restructure in their new shape and position. Retainers hold teeth in their new optimal position and provide enough time for the remodeled supporting tissues to mature.

2. Typical growth and aging result in changes in the bone tissue supporting the teeth, resulting in unfavorable tooth movements.

But the good news is that wearing your retainer is a highly effective way to prevent crowding of the lower front teeth. Many people intuitively assume that once their wisdom teeth come in, it will cause crowding of the lower front teeth, but research studies rejected this idea. Remodeling of the front part of the lower jaw bone as a part of aging is often the main reason for the lower teeth crowding.

In some rare scenarios, the late growth of the lower jaw changes the bite after the already completed orthodontic treatment. Wearing retainers is not efficient in preventing unwanted skeletal growth. In other words, a successfully treated bite could turn into an underbite if the lower jaw keeps growing.

3. Moving teeth into an unstable position during an orthodontic treatment causes relapse as well.

Retainers would only hold teeth in this position if they are worn for life time. Teeth are mostly stable as long as they are in their bony housing. This notion is very critical in patients with severe crowding who were treated without removing teeth. This is a fundamental concept justifying removal of healthy teeth in patients with severe crowding.

A range of retainer types are available, including removable and permanent appliances. You will be evaluated by your orthodontist to determine which type is best for you based on your specific goals, your lifestyle, and the amount of tooth movement during your orthodontic treatment.