If you do not wear a retainer, your teeth will definitively move back. Orthodontic treatment relies on a period of stabilization to maintain the corrected alignment. This stabilization process, known as the retention phase, is critical. Without consistent retainer use, natural forces within the mouth will cause the teeth to gradually shift out of position.
The Phenomenon of Orthodontic Relapse
The tendency for teeth to return to their original, pre-treatment positions is called orthodontic relapse. This movement is a standard biological expectation, occurring because surrounding tissues need time to adapt permanently to the new tooth location. Relapse can begin quickly, with minor shifting noticeable within weeks or months after braces or aligners are removed if the retainer is neglected.
Studies suggest that a significant percentage of patients, potentially 30 to 50 percent, will experience some degree of relapse within a decade if retention protocols are not followed. Consistent use of a retainer is the only reliable method to counteract this natural, long-term tendency toward misalignment.
Biological Mechanisms Driving Teeth Movement
The movement of teeth back toward their former positions is driven by several biological structures that maintain a “memory” of the original alignment. One primary structure is the periodontal ligament (PDL), a network of fibers that anchors the tooth root to the jawbone. These fibers are stretched and compressed during orthodontic treatment and, like a rubber band, exert a continuous pulling force as they attempt to return to their original, unstrained length.
The jawbone is involved in the continuous process of bone remodeling, which allows teeth to move. This process involves bone-forming and bone-resorbing cells constantly reshaping the socket around the tooth. After the orthodontic appliance is removed, this remodeling continues, and without a retainer holding the tooth still, the process may favor a return to the previous position.
The pull from the gingival and transseptal fibers, which are connective tissue fibers in the gums and between the teeth, is another powerful mechanism. These fibers take an extended period to fully reorganize and lengthen in the new tooth position. The elastic recoil from these tissues acts as a constant, gentle force, pulling the teeth together or apart, which is why indefinite retention is often recommended to stabilize the outcome against this soft tissue memory.
Factors Increasing the Risk of Relapse
Several factors beyond biological memory can accelerate or increase orthodontic relapse. Continued growth and maturation of the jawbones, especially in younger patients who have not fully finished developing, can exert pressure that shifts the alignment of the teeth. This ongoing change means even perfectly aligned teeth are subject to new forces as the facial structure changes over time.
Daily, repetitive forces from detrimental oral habits also increase the risk of movement. Habits such as tongue thrusting (pushing the tongue against the front teeth during swallowing) or bruxism (grinding or clenching) apply unnatural pressure. These forces can easily overcome the stability of the recently moved teeth.
The initial severity of the malocclusion is another predictor of relapse, as patients with severe crowding or spacing before treatment often have a greater underlying tendency for their teeth to revert. While the role of erupting wisdom teeth in causing late-stage relapse is a common concern among patients, the consensus is that they contribute less to misalignment than the forces from growth and soft tissue memory.
Retainer Options and Long-Term Care
To prevent relapse, the retention phase utilizes custom-made appliances to hold the teeth in their corrected alignment. Removable retainers are a common option and typically include the Hawley retainer, which features a metal wire and acrylic base, or the clear plastic Essix retainer, which is less noticeable. The wear schedule for these is initially full-time for several months, followed by an indefinite transition to nightly wear.
Many patients also use fixed, or bonded, retainers, which consist of a thin wire permanently cemented to the back surface of the front teeth, often on the lower arch. This option provides constant, passive retention and eliminates the risk of forgetting to wear the appliance. However, fixed retainers require meticulous hygiene, using floss threaders or water flossers to clean around the wire and prevent plaque buildup.
Both removable and fixed appliances require long-term care and maintenance to remain effective. Removable retainers may need replacement every few years as they wear out or become ill-fitting, and fixed retainers must be checked regularly for breakage or bonding failure. Consistent adherence to the prescribed wear schedule and proactive replacement are the most effective ways to ensure the long-term stability of the orthodontic result.