An orthodontic retainer is a custom-made appliance prescribed after braces or clear aligners are removed. Its primary function is to maintain the newly corrected position of the teeth, preventing them from shifting back toward their original alignment (relapse). Consistent use is necessary for long-term success because the bone and soft tissues surrounding the teeth need time to stabilize after active movement. The specific retainer used for the top or bottom jaw depends on the hardware chosen and the patient’s individual needs.
Understanding the Main Types of Retainers
Orthodontists use three main types of retainers, differing in composition and design. Clear plastic retainers, often branded as Essix or Vivera, are custom-molded, vacuum-formed trays made from thin, transparent thermoplastic material. These removable appliances fit snugly over the entire arch of the teeth, holding them passively in place.
The Hawley retainer is readily identifiable by its combination of metal and acrylic. This removable device features a durable acrylic plate that rests against the roof of the mouth or the tongue side of the lower jaw. A thin, stainless steel wire, known as the labial bow, wraps around the front six teeth to maintain alignment.
The third type is the fixed, or bonded, retainer, which patients cannot remove. This device consists of a thin, braided or solid wire permanently cemented to the tongue-facing surface of the teeth. The wire is typically bonded across the front teeth, often spanning from canine to canine, providing continuous retention without requiring patient compliance.
Retainers Commonly Used for the Upper Jaw
The upper arch primarily uses removable retainers, such as the Hawley or clear plastic Essix types. Removable appliances are preferred because the palate and the nature of the bite make permanent wires more challenging. A fixed retainer bonded to the back of the upper front teeth carries a higher risk of interference with the lower teeth, potentially causing the wire to break or debond.
Clear plastic retainers are a popular choice for the upper jaw due to their near-invisibility, which is aesthetically pleasing. They offer full coverage of the teeth and effectively maintain alignment when worn consistently. The classic Hawley retainer remains a viable option because its metal wire component allows for minor adjustments if a small amount of shifting occurs.
The design of the Hawley retainer allows the back teeth to settle naturally into the final bite position. This is an advantage over full-coverage plastic trays, which can prevent the upper and lower teeth from meeting fully. The choice between a clear plastic or a Hawley retainer for the top arch often depends on the orthodontist’s preference and the patient’s desired level of aesthetics and compliance.
Retainers Commonly Used for the Lower Jaw
The lower arch has a higher propensity for post-treatment movement, making it the most common location for a fixed retainer. The lower front teeth, especially the incisors, are susceptible to relapse and crowding due to natural forces from the tongue and lips. A bonded retainer placed on the tongue-side surface of these teeth provides stability twenty-four hours a day, eliminating the risk of relapse in that segment.
This thin lingual wire is effective because it is constantly in place, requiring no effort from the patient. While the fixed retainer is excellent for the front teeth, it only protects the teeth to which it is bonded (usually the six anterior teeth). Therefore, patients with a fixed lower retainer are often prescribed a removable retainer, such as a clear plastic tray, to wear at night.
The removable lower retainer ensures that all teeth, including the back molars, are held in their corrected positions, supplementing the bonded wire. This hybrid approach is frequently recommended for the lower jaw, combining the stability of a permanent wire with the full-arch coverage of a removable device. Successful performance depends on following the orthodontist’s instructions precisely.