The last stage of orthodontic treatment is a multi-phased transition designed to secure the results. This period focuses on meticulous refinement and stabilization, rather than active tooth movement. Understanding these final steps is fundamental to preserving the corrected alignment against the natural tendency for relapse. The final stages involve precise adjustments, the physical removal of the appliances, and the commencement of the retention phase.
The Final Adjustments
Before the appliances are removed, a finishing phase takes place, often lasting several months, to ensure every tooth is in its ideal location. This detailing process focuses on achieving functional occlusion, which is how the upper and lower teeth meet. The orthodontist often switches to lighter, more flexible archwires to manage these subtle movements with precision.
Minor spaces between teeth are closed using elastic power chains, which apply a continuous, gentle force. Another element is the use of elastic wear, where small rubber bands are hooked onto brackets in specific patterns to settle the bite. This ensures the cusps of the back teeth interlock correctly, creating a stable fit. Before removal, the orthodontist verifies the roots are correctly angled and the bite is fully corrected, often confirmed with final X-rays.
Removal of Appliances
The physical removal of the braces is known as debonding, which marks the end of active treatment. The orthodontist uses specialized metal pliers to gently squeeze the base of each bracket, causing the adhesive bond to break. Patients typically feel pressure or a slight popping sensation, but the process is not painful.
Once the brackets and wires are off, the remaining dental bonding glue, or composite resin, is removed from the tooth surfaces. This is accomplished through careful polishing to ensure the enamel is smooth and clean. Following the removal and cleaning, a final impression or digital scan of the newly aligned teeth is taken. This mold is necessary for the laboratory to fabricate the custom-fitted retention devices.
The Retention Phase
Retention is the final stage, as teeth have a biological tendency to shift back toward their original, pre-treatment positions, a phenomenon known as relapse. This movement is driven by the memory of the periodontal ligaments, which are the connective tissue fibers anchoring the tooth root to the jawbone. These fibers are stretched and rearranged during tooth movement and require time to reorganize and stabilize in the new position.
The forces exerted by the surrounding soft tissues, such as the tongue and cheeks, and ongoing growth also contribute to the instability. For this reason, retention is a commitment to maintaining the corrected alignment. The initial wear schedule is often full-time for several months, typically 20 to 22 hours per day, before transitioning to nightly use for an indefinite period.
Types and Care of Retainers
Retention is maintained using either fixed or removable appliances, both designed to hold the teeth in place. Fixed retainers, often called bonded retainers, consist of a thin, custom-fit wire cemented to the back surface of the lower, and sometimes upper, front teeth. They are constantly in place, eliminating the risk of forgetting to wear them.
Removable retainers come in two main styles: the Hawley and the Essix retainer. The Hawley retainer uses a metal wire wrapped around the teeth embedded in an acrylic base. The Essix retainer is a clear, vacuum-formed plastic tray that fits snugly over the entire arch, offering a discreet appearance. Removable retainers must be cleaned daily with a soft toothbrush and cool water to prevent plaque buildup. If a retainer breaks or is lost, immediate contact with the orthodontist is necessary to prevent rapid tooth movement.