Teeth commonly shift after orthodontic treatment, a phenomenon known as orthodontic relapse. This post-braces movement is a natural biological process. Understanding its causes helps manage expectations and highlights the importance of post-treatment care.
Reasons for Post-Braces Tooth Movement
Teeth are held in place by a dynamic system of soft tissues and bone that constantly adapt. Orthodontic treatment remodels these structures, allowing teeth to move. After braces are removed, these tissues need time to stabilize, contributing to shifting.
A primary reason for tooth movement after braces is the “memory” of the periodontal ligaments. These elastic fibers connect the teeth to the jawbone and, after being stretched and reformed during orthodontic treatment, they retain a tendency to pull teeth back toward their original positions. This “memory” can cause noticeable shifting if not counteracted. Additionally, the bone surrounding the teeth undergoes a process called remodeling. During orthodontic treatment, bone is removed on one side of the tooth and built up on the other to facilitate movement. After braces are removed, this bone needs time, often months or even years, to fully solidify and support the teeth in their new alignment.
Beyond these immediate post-treatment biological factors, teeth also undergo continuous, subtle movements throughout life, known as physiological drift. This occurs due to everyday forces like chewing, swallowing, and tongue pressure. Aging can change jawbone shape and density, leading to gradual shifting, especially of lower front teeth. Habits like teeth grinding (bruxism) also contribute to movement.
Erupting wisdom teeth can contribute to shifting, though their impact on alignment after treatment is less significant than once thought. The most common cause of post-braces movement is insufficient retainer wear. Retainers hold teeth in new positions while bone and ligaments stabilize. Without consistent use, teeth can shift back quickly, sometimes within weeks.
Preventing Tooth Movement After Braces
Maintaining orthodontic results relies on consistent post-treatment care, with retainers playing a central role. Retainers are custom-made devices that hold teeth in alignment, allowing surrounding bone and soft tissues to stabilize. Adhering to wear instructions is important, especially in the initial months after braces are removed, as this is the most unstable period for tooth position.
There are two main categories of retainers: removable and fixed. Removable retainers, such as Hawley retainers with a wire and acrylic base, or clear Essix retainers resembling clear aligners, offer flexibility as they can be taken out for eating and cleaning. Essix retainers are often favored for their near invisibility, while Hawley retainers are durable and allow for minor adjustments. Fixed retainers, also known as bonded or permanent retainers, consist of a thin wire custom-bonded to the back surfaces of the front teeth, typically the lower ones. These remain in the mouth continuously, providing constant retention and reducing the risk of non-compliance.
Proper care of retainers ensures their effectiveness. Removable retainers should be cleaned daily with a soft brush and non-abrasive soap, using cool water to prevent warping. Fixed retainers require diligent oral hygiene, including careful brushing and flossing around the wire. Regular dental check-ups monitor oral health and retainer integrity, catching any potential issues early.
What to Do When Teeth Move
If teeth shift after orthodontic treatment, contact an orthodontist promptly. Early intervention can address minor movements before they become significant. The orthodontist will assess the movement and determine the best course of action.
Several interventions are possible depending on the shifting degree. For minor movements, increasing retainer wear or a new custom-made retainer might be recommended. New retainers can sometimes guide teeth back into position if the shift is minimal.
For more noticeable movement, limited orthodontic treatment, such as clear aligners, may be recommended. In severe relapse, full re-treatment with braces or aligners might be required. While discouraging, re-treatment is often shorter than the initial process. Addressing shifted teeth early is important, as delaying action can lead to more extensive treatment.