Orthodontic treatment successfully aligns teeth into a new position, but the conclusion of the braces phase does not end the process. The retention phase, which requires wearing a retainer, is mandatory for long-term success. Teeth have a natural tendency to shift back toward their original positions, a phenomenon known as relapse. The retainer is an indispensable tool for stabilization, ensuring the investment made in straightening the teeth is preserved.
The Biological Reason for Tooth Relapse
The tendency for teeth to shift, or relapse, is rooted in the biology of the surrounding support structures. Teeth are not rigidly fixed in the jawbone; they are suspended within the socket by the periodontal ligament, a dense network of fibers. When braces move a tooth, these fibers are stretched and compressed, and they retain an elastic “memory” of their former, misaligned state.
The periodontal ligament acts like a stretched rubber band, creating a pulling force that guides the tooth back to its starting point once braces are removed. Simultaneously, the jawbone undergoes alveolar bone remodeling during tooth movement. It takes time for the newly formed bone to fully solidify and stabilize the tooth in its final location. The residual tension in the fibers, combined with the incomplete stabilization of the alveolar bone, creates the environment for relapse.
How Retainers Counter Bone and Tissue Memory
The retainer’s primary role is to act as a passive stabilizer, providing a fixed barrier against the forces that cause relapse. By holding the teeth firmly in their corrected alignment, the retainer prevents the stretched periodontal fibers from pulling the teeth back to their original spots. This passive force allows the surrounding structures to complete their long-term stabilization process without disruption.
The retention phase is a healing period for the jaw structure. The retainer gives the alveolar bone adequate time to fully mineralize and mature around the tooth roots in their new position. While the teeth are held steady, the fibers of the periodontal ligament and the gingiva gradually reorganize and adapt to the new dental arch form. Consistent retainer wear locks in the orthodontic correction by providing the necessary stability for permanent tissue adaptation.
Understanding Retainer Options and Wear Schedules
Retainers fall into two main categories: fixed and removable, and the wear schedule progresses from full-time to part-time use. Fixed retainers consist of a thin, custom-fitted wire bonded to the back surface of the front teeth, typically from canine to canine, and they offer continuous retention. A benefit of this type is that they cannot be lost, though they require meticulous cleaning with floss threaders to prevent plaque buildup.
Removable retainers include the classic Hawley retainer and the clear plastic retainer (Essix retainer). Clear retainers are popular for their near-invisibility, but they may wear out or discolor faster than Hawley retainers. The initial wear schedule for removable retainers is full-time (12 to 23 hours a day) for the first four to six months after braces are removed. After this initial stabilization period, the patient transitions to a nighttime-only wear schedule, which is often recommended indefinitely to guard against the natural, lifelong shifting of teeth.
What Happens If You Stop Wearing Your Retainer
Failing to wear a retainer as prescribed immediately risks undoing the alignment achieved through orthodontic treatment. Teeth can begin to shift back toward their initial positions within weeks or even days, a process known as orthodontic relapse. This movement can result in the re-emergence of gaps, crowding, or crookedness, compromising the aesthetic outcome of the smile.
Stopping retainer use can also cause original bite problems to return, potentially leading to pain while chewing or jaw discomfort. If teeth shift significantly, the old retainer may no longer fit, and forcing it can cause damage. In cases of substantial relapse, the only solution is often re-treatment, requiring additional time and expense to wear braces or clear aligners again.