Orthodontic retainers are custom-made appliances created after active treatment, such as braces or clear aligners, is complete. They hold the teeth in their newly corrected positions. The primary purpose of using a retainer is to prevent orthodontic relapse, which is the natural tendency for teeth to shift back toward their original alignment. Retainers provide stability while the supporting bone and ligaments around the teeth adapt to the change.
When Retainers Affect Occlusion
While retainers are engineered to stabilize the final alignment, they can inadvertently affect a person’s occlusion under certain conditions. They are passive devices, intended to maintain a position, not actively move teeth. When a bite problem arises, it typically signals that the device is no longer functioning as designed, or that the teeth have already begun to shift.
Misalignment occurs when a retainer is ill-fitting, damaged, or used inconsistently. Introducing a foreign object into the mouth can temporarily alter how the upper and lower teeth meet, causing temporary discomfort. However, a persistent change in the bite suggests a genuine mechanical or biological issue requiring attention.
Specific Causes of Bite Misalignment
Damage or distortion to the retainer is a mechanical cause of a shifting bite. Exposure to excessive heat can warp the thermoplastic material of clear retainers, changing the internal mold and causing uneven pressure points. This distortion can force teeth into a slightly incorrect position, actively disrupting the established occlusion.
Certain retainer designs, particularly the vacuum-formed clear type (Essix), can create issues related to the chewing surfaces. Because these clear retainers cover the entire biting surface, they introduce a thin layer of plastic between the upper and lower arches. For individuals who clench or grind their teeth, this plastic layer can cause a slight intrusion, or sinking, of the back teeth. This effect leads to an altered bite where the front teeth strike first when the retainer is removed, known as a posterior open bite.
Non-compliance with the wearing schedule is another common trigger for bite changes. If a person does not wear their retainer enough, the teeth may experience minor relapse. Forcing a retainer back over teeth that have already moved slightly places unintended pressure on certain teeth, potentially locking them into an incorrect post-relapse position. Furthermore, some Hawley retainers contain active components that, if not properly adjusted, can exert force that continues to move teeth beyond the intended final position.
Recognizing Signs of Bite Changes
The most immediate sign of a bite problem is an altered sensation when chewing. The teeth may feel uneven, or the jaw might instinctively try to find a new, uncomfortable way to close. This can manifest as new, premature contacts between individual teeth.
Another clear indicator is pain or soreness, particularly upon waking after wearing the retainer. A tight-fitting retainer should feel snug, but if it is difficult to seat fully or causes persistent discomfort, it may indicate that significant shifting has occurred. The change in occlusion can also place strain on the temporomandibular joints (TMJ), leading to jaw pain, clicking sounds, or headaches.
Necessary Steps When Your Bite Feels Off
If you suspect your retainer is causing a problem, immediately stop wearing a device that is visibly cracked, broken, or warped. Continuing to wear a damaged appliance can lead to unwanted tooth movement or injury to soft tissues. For removable retainers that feel uncomfortably tight but are not damaged, reduce wear to the minimum necessary to keep them reinsertable, and then seek professional guidance.
Contact the orthodontist who managed the original treatment for a consultation. Only a professional can accurately assess the retainer’s fit and determine if the bite change is due to a mechanical issue, natural post-orthodontic settling, or a serious underlying dental concern. They can often make minor adjustments to a Hawley retainer or recommend a new impression for a replacement clear retainer. Never attempt to fix, bend, or modify a retainer at home, as this will worsen the problem. Proper care, including avoiding heat and using non-abrasive cleaners, helps prevent the initial warping that causes fit issues.