Orthodontic treatment, commonly involving braces, is primarily used to correct dental misalignments and improper bites. The direct goal is to reposition teeth for better function and aesthetics, which often results in a secondary but noticeable alteration in facial appearance. Because the teeth and supporting bone structure provide a foundation for the overlying soft tissues of the face, moving the teeth can harmonize the facial profile. These changes are generally seen as an improvement, shifting the face toward a more balanced and proportional look.
Orthodontics and Skeletal Remodeling
The ability of braces to move teeth relies on the dynamic and continuous process of skeletal remodeling within the jawbone. Orthodontic appliances exert a controlled, gentle force on the teeth, which is transmitted through the thin connective tissue known as the periodontal ligament (PDL). This application of pressure initiates a biological response within the surrounding alveolar bone.
The PDL acts as a sensor, transducing the mechanical force into a chemical signal that triggers specialized bone cells. On the side of the tooth where the PDL is compressed, cells called osteoclasts are activated to resorb, or break down, the adjacent bone tissue. This creates the necessary space for the tooth to move in the desired direction.
Conversely, on the side of the tooth where the PDL is stretched, osteoblasts are stimulated to deposit new bone material. This synchronized process of bone resorption and deposition allows the tooth to migrate incrementally through the jawbone. This constant remodeling ensures the tooth remains securely anchored in its new position once the treatment is complete.
Specific Impacts on Facial Profile and Features
The most distinct facial modifications resulting from orthodontic treatment are observed in the lower third of the face, impacting the lips, jawline, and overall profile. Changes in tooth position directly influence the posture and appearance of the lips, which drape over the underlying dental foundation.
When teeth are significantly moved backward to correct protrusion, the lips follow the movement of the teeth, often becoming less prominent or “retruded.” For a patient with protruding teeth, this retraction can create a softer, more relaxed lip posture and a better seal at rest. Studies have indicated that when upper incisors are retracted, the upper lip may follow by about 60% to 70% of the distance the tooth was moved.
Correcting a severe malocclusion, such as an overbite (Class II) or underbite (Class III), can indirectly enhance the definition of the chin and jawline. In cases of a deep overbite, moving the lower jaw forward allows the upper and lower teeth to meet correctly, which can make the chin appear less retruded. This repositioning of the mandible improves the projection of the chin and provides a clearer separation between the neck and the jawline. The overall impact on the facial profile is a straightening of the side view, leading to a more harmonious balance between the nose, lips, and chin.
Factors Influencing the Outcome
The degree of facial change experienced from orthodontic treatment is highly variable and depends on several individual factors. Age is a major determinant; treatments performed during adolescence, while the jawbones are still growing, allow the orthodontist to guide skeletal development, often resulting in more pronounced and stable facial changes. In contrast, adult treatment primarily focuses on dental movement, as skeletal growth is complete, meaning the facial changes tend to be more subtle.
The severity and type of the initial malocclusion also dictate the magnitude of the facial transformation. Patients with significant dental protrusion or skeletal discrepancies will experience the most substantial aesthetic improvements when these issues are corrected. A minor crowding correction, conversely, is less likely to produce a noticeable change in the facial profile.
The treatment plan, specifically whether it involves the extraction of teeth, plays a considerable role in the soft tissue outcome. Extraction of premolars, for instance, is sometimes necessary to create space to pull protruding front teeth backward, leading to a greater retraction of the lips. Non-extraction treatments, which aim to make space without removing teeth, typically result in less dramatic changes to the lip profile.
The patient’s individual anatomy, such as the natural thickness of their soft tissues, influences the final result. Thin lips are more likely to show the effects of tooth movement than naturally thick lips.
Temporary Changes During Treatment
Beyond the permanent structural and profile adjustments, patients often experience several temporary changes while wearing orthodontic appliances. The physical presence of brackets and wires adds bulk to the mouth, which can initially push the lips outward. This temporary change may make the lips appear fuller or slightly strained, affecting the resting lip posture until the patient adapts to the hardware.
The process of speaking and closing the mouth can also change as the facial muscles adjust to the new appliances and the initial movement of the teeth. Some patients may experience temporary difficulty in achieving a natural lip seal or minor alterations in their speech patterns. These muscular adjustments are part of the adaptation period and usually resolve as treatment progresses.
Some patients report temporary changes in facial fullness or weight loss due to discomfort or difficulty chewing certain foods. This is a behavioral change, not a structural one, and the facial contour returns to normal as the patient becomes accustomed to the braces and resumes a regular diet. These effects are distinct from the long-term changes and typically disappear once the patient is acclimated or after the appliances are removed.