An overbite, or deep bite, is a common condition where the upper front teeth excessively overlap the lower front teeth. While orthodontic treatment is highly effective at correction, the overbite can return. Teeth naturally tend to drift back toward their original alignments, making the retention phase just as important as the active treatment phase.
The Biological Reality of Orthodontic Relapse
The tendency for teeth to shift back, known as relapse, is rooted in the biological memory of the tissues supporting the teeth. Teeth are suspended within the jawbone by a network of fibers called the periodontal ligament. When braces move a tooth, these fibers are stretched and compressed, retaining a memory of the tooth’s initial position and seeking to pull it back after the appliance is removed.
This memory comes partly from the dense transseptal fibers, which connect adjacent teeth across the bone. While the periodontal ligament fibers generally remodel within a few months, the supracrestal fibers in the gum tissue can take a year or longer to fully reorganize. This extended stabilization period means the first year after braces is the most vulnerable time for relapse. The bone surrounding the tooth also needs time to harden and stabilize around the new root position, a process called bone remodeling.
Specific Factors That Drive Overbite Recurrence
Beyond biological mechanisms, several ongoing forces and habits contribute to overbite recurrence. Continued growth and maturation of the jaw and facial bones is a factor, particularly in patients who finish treatment before they reach skeletal maturity. Even in adults, the natural aging process involves subtle, lifelong changes to the jawbone structure that can cause gradual shifting.
Myofunctional habits, involving the muscles of the mouth and face, place constant, repetitive pressure on the teeth that can undermine the orthodontic result. A tongue thrust, where the tongue pushes against the front teeth during swallowing, or an improper resting posture of the tongue can apply enough force to push the teeth out of alignment. Persistent habits such as teeth grinding (bruxism) or clenching also create excessive force that destabilizes the bite.
The most common cause of overbite recurrence is the failure to consistently wear a retention device as prescribed. Skipping retainer wear allows natural and habitual forces to act unchecked on the teeth. This gives the teeth an opportunity to surrender to their biological memory and begin moving toward their original misalignment.
Maintaining Alignment with Retention Devices
Retention is the phase of orthodontic care designed to hold the teeth in their corrected positions while the surrounding tissues stabilize. The prescribed wear schedule typically begins with full-time wear for the first several months, followed by a transition to nighttime wear indefinitely. This initial full-time period is when the risk of immediate relapse is highest due to the tissue memory.
Orthodontists generally use one or a combination of three main retainer types to manage this phase. The Hawley retainer is a removable device made of acrylic and metal wire, which is durable and can be adjusted to correct minor movement. Clear aligner-style retainers, often called Essix retainers, are vacuum-formed plastic that fits over the entire arch, offering a more aesthetic and discreet option.
For long-term stability, particularly of the front teeth that correct the overbite, a fixed or bonded retainer may be used. This device is a thin wire permanently cemented to the tongue-side surface of the front teeth, which eliminates the possibility of forgetting to wear it. While fixed retainers are excellent for preventing movement, they require diligent cleaning to prevent plaque buildup and must be checked immediately if the bond breaks or the wire loosens.
Addressing Minor Tooth Movement After Treatment
If minor shifting is noticed, contact the orthodontist immediately for an evaluation. Prompt intervention often allows for a simpler and less extensive correction than waiting until the relapse is severe. If the movement is minimal, the orthodontist may recommend wearing the existing removable retainer more frequently, sometimes full-time for a few weeks, to guide the teeth back into place.
For more noticeable movement, the solution often involves limited orthodontics, which focuses only on the specific teeth that have shifted. This may involve a short course of clear aligners or limited braces, typically lasting six to nine months. This is significantly shorter than the original comprehensive treatment. Attempting to force an old retainer onto teeth that have shifted significantly is not recommended, as it can cause damage or pain.