Retainers are a common follow-up to orthodontic treatment, maintaining the alignment achieved by braces or clear aligners. This article explores how these devices keep teeth in their corrected positions.
The Purpose of Retainers
After orthodontic treatment, teeth have a natural tendency to shift back towards their original positions. This phenomenon, known as orthodontic relapse, occurs due to the “memory” of the periodontal ligaments and the surrounding bone structure. Periodontal ligaments connect the tooth root to the jawbone, and while they adapt during tooth movement, they possess an elastic recoil that can pull teeth back to their starting points.
The alveolar bone and gingival fibers also undergo remodeling during tooth movement, and these tissues require time to stabilize in the teeth’s new positions. Retainers provide the necessary support to hold the teeth firmly in their corrected alignment while these surrounding tissues reorganize and solidify. Without this stabilization, the effort and investment made during orthodontic treatment could gradually be undone.
How Retainers Achieve Stability
Retainers work by physically holding teeth in their desired alignment, preventing unwanted movement. Various types are available, with the choice depending on individual needs and orthodontist recommendation.
One common type is the Hawley retainer, a removable device with a custom-fitted acrylic base and metal wires. The acrylic rests against the roof of the mouth or along the tongue-side of the lower teeth, while a thin metal wire, known as the labial bow, extends across the front teeth. This wire applies gentle pressure to prevent shifting, with clasps gripping the back teeth to keep the retainer securely in place.
Clear plastic retainers, often called Essix retainers, are a discreet option. These vacuum-formed, transparent trays fit snugly over the entire arch of the teeth, similar to clear aligners but typically thicker. Essix retainers encapsulate the dentition, providing continuous pressure across all tooth surfaces to prevent movement. They are removable for eating and oral hygiene.
Fixed, or bonded, retainers offer continuous retention because they are permanently attached to the teeth. These usually consist of a thin wire, often stainless steel or a flexible fiber composite, custom-contoured and bonded with dental adhesive to the tongue-side surfaces of the front teeth, typically from canine to canine. This type of retainer provides constant, invisible support, effective for long-term stability without daily removal and reinsertion.
Consequences of Not Wearing Retainers
Failing to wear retainers as prescribed can lead to orthodontic relapse, where teeth gradually shift back towards their original misaligned positions. This regression can begin almost immediately after braces are removed if retainers are not worn consistently, with noticeable changes sometimes occurring within weeks or months. The risk of relapse is highest in the first year following treatment.
Common issues from neglecting retainer wear include re-crowding of teeth, reappearance of spaces, and return of bite problems. Forces from daily activities like chewing, tongue pressure, and natural aging can contribute to this shifting. This undoes the progress and investment made during orthodontic treatment.
In cases of significant relapse, further orthodontic intervention may be necessary to correct shifted teeth. This can involve additional time, effort, and financial cost, with re-treatment costs potentially ranging from $1,000 to $5,000 depending on complexity. Consistent retainer wear is a practical measure to maintain a straight smile and avoid subsequent treatments.