Orthodontic retainers are devices that we orthodontists give our patients to keep their teeth as straight as possible after their braces come off. I say “as possible” because as I’ve explained in several other blog posts, there is no retainer that can prevent all tooth movement. Even retainers that are glued to every tooth allow some change. The goal is keeping these changes to a minimum. Some movement following the removal of braces is not only acceptable, it is welcome. “Settling,” as we call it, means that the teeth erupt and drift slightly so that they actually fit BETTER than the day the braces were removed. This is desirable on the back teeth, but not up front where people will notice. Retainers that do not cover the chewing surfaces of the back teeth allow settling. Wearing two full-coverage retainers at the same time does not permit settling.

Your retainer should fit well on the first day
We deliver our retainers on the same day that patients’ braces come off. We do not let them out the door unless their retainers fit correctly. Retainers might feel snug at first, but they will loosen up the same way that a new pair of slip-on shoes loosen up with wear. If a retainer doesn’t fit right on removal day, we either remake it or change the kind of retainer completely. Some patients have naturally short teeth or puffy gums that make the retainers less retentive than patients with longer teeth. Although not every design works for every patient, we keep at it until every patient has retainers that will work for them.

Sometimes the retainers change shape
When a patient reports that his or her retainer is no longer fitting, there are only two things that could have happened. The first occurs when a patient does something to a retainer that distorts its shape. This can happen when a clear plastic retainer is cleaned in water that is too hot. Essix retainers are made from thermoplastic that is heated and formed to a patient’s model using high pressure. Washing or soaking them in water that is too warm can cause the heat sensitive plastic to “relax” and lose its shape allowing the underlying teeth to move. Water used with clear aligner-type retainers should be only luke warm. Retainers with acrylic and wires can be deformed by being inserted or removed incorrectly (using the front wire as a handle for example) or by being slept on, stepped on, or in the case of my own assistant, run over by a jeep! Once a retainer has changed shape, it must be adjusted or replaced. Only your orthodontist can tell you which will be necessary for you.

Retainers stop fitting if they are not worn as prescribed
The second and most common cause of retainers not fitting is that they are not being worn as prescribed. There are different regimens for holding teeth straight, so I can’t dictate here what is appropriate for you. I can say however that if your retainer fit when you left your orthodontist’s office but it no longer does, chances are you have not worn it enough and your teeth have moved. If the change is recent and minimal (and your retainers still fit but are tight) you can try wearing them full-time to see if the teeth will move back where they were before. If the teeth don’t realign within a couple of days however, you’ll need to see your orthodontist right away. If you stopped wearing your retainer more than a few days and your retainer won’t fit at all, you’ll also need to see your orthodontist. Waiting too long will only allow more movement and increase the likelihood that you’ll need your braces put back on.

When a patient returns to my office with a fit problem, the first thing I do is evaluate the condition of the retainer. If it looks good, I then look to see how much the teeth have moved since the braces came off. If the front teeth still look good and only back ones that have moved, I try to adjust the retainer to match the new position of the back teeth. If, however, the teeth have moved so far that retainer adjustments aren’t enough, replacing the retainer or getting your braces back on may be your only options. Prevention is the best medicine and noticing that your retainer feels tight is the first sign of trouble. Good luck!

NOTE: The author, Dr. Greg Jorgensen, is a board-certified orthodontist who is in the private practice of orthodontics in Rio Rancho, New Mexico (a suburb on the Westside of Albuquerque). He was trained at BYU, Washington University in St. Louis, and the University of Iowa in the United States. Dr. Jorgensen’s 25 years of specialty practice and nearly 10,000 finished cases qualify him an expert in two-phase treatment, extraction and non-extraction therapy, functional orthodontics, clear aligners (Invisalign), and multiple bracket systems (including conventional braces, Damon and other self-ligating brackets, Suresmile, and lingual braces). This blog is for informational purposes only and is designed to help consumers understand currently accepted orthodontic concepts. It is not a venue for debating alternative treatment theories. Dr. Jorgensen is licensed to diagnose and treat patients only in the state of New Mexico. He cannot diagnose cases described in comments nor can he select treatment plans for readers. Because he has over 30,000 readers each month, it is impossible for him respond to all questions. Please read all of the comments associated with each article as most of the questions he receives each week have been asked and answered previously. The opinions expressed here are protected by copyright laws and can only be used with written permission from the author.