A retainer is a customized orthodontic appliance designed to maintain the position of teeth following the conclusion of active treatment, such as with braces or clear aligners. The primary function is to prevent relapse, which is the natural tendency of teeth to shift back toward their original positions. These devices must be worn consistently because the bone and tissues surrounding the teeth need time to stabilize in the new alignment. The appearance of a retainer varies, depending on the specific type prescribed by the orthodontist to suit the patient’s aesthetic preferences and clinical needs.
Clear Plastic Retainers
Clear plastic retainers, often known by brand names like Essix or Vivera, offer a nearly invisible option for retention. These devices are fabricated from thin, transparent, biocompatible plastic material using a vacuum-forming process over a model of the straightened teeth. The resulting appliance is a custom-fitted sheath that fully encases the entire dental arch, covering the biting surfaces and wrapping slightly around the gumline.
These retainers are highly transparent, allowing the natural color and structure of the teeth beneath to remain visible. They are aesthetically preferred because they minimize the visual impact on the wearer’s smile compared to other retainer types. While virtually unnoticeable when first placed, the plastic can become cloudy, stained, or discolored over time due to exposure to food, drinks, and normal wear, making them gradually more visible. A clear retainer should look like a smooth, seamless extension of the teeth, conforming precisely to the contours of the dental anatomy.
Traditional Wire Retainers
Traditional wire retainers, commonly referred to as Hawley retainers, are characterized by their visible metal and acrylic components. This removable appliance consists of an acrylic base plate molded to fit against the roof of the mouth for the upper arch or along the tongue-side of the lower teeth. The acrylic portion can be customized and comes in a wide variety of colors or designs.
The most visually prominent feature is the labial bow, a thin, stainless-steel wire that runs horizontally across the front surface of the six anterior teeth. This wire is clearly visible when the wearer smiles or speaks. The wire connects to clasps, often Adams clasps, that anchor the retainer to the back teeth, ensuring a secure fit. The combination of the colored acrylic base and the prominent front wire makes the Hawley retainer the most noticeable type.
Fixed or Permanent Retainers
Fixed retainers, also known as lingual or bonded retainers, are designed to be entirely discreet and are the least visible option. These retainers consist of a thin wire that is permanently cemented with a dental adhesive to the tongue-facing, or lingual, surface of the teeth. The wire typically spans the front teeth from canine-to-canine, which are the teeth most susceptible to shifting after orthodontic treatment.
The wire itself is often braided or straight and made of stainless steel or nickel-titanium, custom-contoured to fit snugly against the inner tooth surface. The retainer is completely hidden from view during normal conversation or smiling. The only visible aspect might be the small amount of clear or tooth-colored bonding material used to affix the wire, which is only noticeable to the wearer looking closely in a mirror.
Recognizing an Improper Fit
A correctly fitting removable retainer should look like it is resting perfectly flush against all surfaces of the teeth and gums. For clear plastic retainers, a proper fit is indicated by a snug, uniform contact with the teeth, showing no visible air pockets or gaps between the plastic and the tooth surface. There should also be no white stress marks in the plastic, as these can signal that the appliance has been warped or forced into place.
Signs of an improper fit involve visual cues of damage or poor alignment with the dental arch. A loose retainer may visibly wiggle or fall out easily, or there may be noticeable gaps between the edges of the retainer and the teeth. For both clear and Hawley retainers, visible cracks, fractures in the plastic or acrylic, or a broken or poking wire indicate that the device is damaged and no longer functioning correctly. A retainer that is too tight might also cause the edges to visibly dig into or irritate the gum tissue, leading to noticeable redness or swelling.