If you stop wearing your retainer after completing orthodontic treatment, your teeth will almost certainly move out of alignment. This phenomenon is known as orthodontic relapse, which is the natural tendency of teeth to shift back toward their original positions. A retainer is a custom-made appliance designed to hold the teeth firmly in their newly corrected locations. The retention phase is just as important as the active phase with braces or aligners, as biological forces will otherwise undo the time and effort invested.
Why Teeth Seek to Return to Their Original Position
The movement of teeth back to their previous positions is driven by the internal biological structures that surround them. Every tooth is suspended within its socket by a network of specialized tissues, primarily the periodontal ligament (PDL). This ligament is composed of collagen fibers that connect the tooth root to the jawbone.
During active orthodontic treatment, pressure from braces or aligners triggers bone remodeling, allowing the tooth to move. When the active force is removed, the stretched collagen fibers of the PDL maintain a kind of “memory” of their former position. These fibers naturally recoil and exert a persistent force on the teeth, encouraging them to return to their original, pre-treatment locations.
This tendency to revert is compounded because the surrounding bone tissue takes time to fully mature and stabilize around the new root positions. Although the teeth are visually straight immediately after treatment, the supporting bone structure remains pliable for approximately nine to twelve months. Unfavorable muscle pressures from the tongue, cheeks, and lips, along with the forces of chewing, also contribute to instability. A passive appliance like a retainer is required to counteract the relapse tendency until the surrounding tissues have completely adapted to the new dental alignment.
Understanding Retainer Types and Wear Schedules
To successfully combat the biological drive toward relapse, orthodontists prescribe one of two main types of retainers. Removable retainers offer flexibility and are custom-made in two common forms: the Hawley appliance (metal wire and acrylic base) and the clear plastic retainer (Essix or vacuum-formed). The effectiveness of a removable retainer relies entirely on a patient’s consistent adherence to the wear schedule.
The typical wear protocol begins with a full-time schedule, requiring the retainer to be worn for 20 to 22 hours per day, only removing it to eat, brush, and floss. This intensive phase usually lasts for the first three to six months following the removal of braces or aligners, when the teeth are most vulnerable to shifting. Once initial stability is achieved, the schedule transitions to nighttime-only wear.
In contrast, fixed retainers consist of a thin, braided wire bonded to the tongue-side surface of the front teeth, most commonly the lower arch. This type offers continuous, passive retention, eliminating the need for patient compliance. Fixed retainers are not visible and provide ongoing support. They require careful oral hygiene, including the use of floss threaders or water flossers, to clean around the wire.
Most orthodontists recommend some form of lifelong retention, regardless of the type chosen. This often involves wearing the retainer only a few nights a week to prevent gradual, age-related shifting.
How Quickly Relapse Occurs and Retreatment Options
The speed at which teeth begin to shift without a retainer can be rapid, often starting within days or a few weeks of discontinuing wear. This initial movement is typically a minor “settling” as the teeth respond to the immediate loss of external support. During the first six months post-treatment, when tissues are actively remodeling, even a brief lapse in retainer wear can result in noticeable changes.
If a patient notices their retainer fits too tightly or cannot be seated fully after a short period of non-compliance, it indicates that minor relapse has already occurred. For these small movements, the orthodontist may recommend immediately increasing the wear time back to a full-time schedule for a few weeks to passively nudge the teeth back into alignment. If the movement is more significant, such as a noticeable gap opening or crowding returning, the existing retainer may no longer be usable.
In cases of moderate relapse, where the teeth have moved too far for the old retainer to correct, retreatment is necessary. This often involves a short course of clear aligners or limited braces to correct the movement. Severe relapse, especially if left unaddressed for months or years, may require a full second round of comprehensive orthodontic treatment. Consistently wearing the retainer as instructed is the most practical and cost-effective approach to maintaining alignment.