Crooked teeth can contribute to facial asymmetry. Facial asymmetry means the left and right sides of the face are not mirror images of each other, a condition almost everyone has to some minor degree. When teeth are severely misaligned—a condition known as malocclusion—the structural balance of the lower face can be noticeably affected. Understanding this connection involves looking at how the dental structure influences the underlying skeletal and muscular systems.
How Misaligned Teeth Affect Jaw Structure
Dental misalignment, particularly in severe forms like a crossbite or a pronounced underbite, forces the jaw to move into an unnatural position to achieve a functional bite. This is a compensatory movement, often called a functional shift, where the lower jaw slides laterally or forward to allow the upper and lower teeth to make contact. Over time, this habitual shifting can lead to structural changes in the jaw joint and surrounding tissues.
The body’s attempt to find a comfortable bite results in an imbalanced use of the facial muscles responsible for chewing, such as the masseter and temporalis muscles. Consistent overuse or underuse of these muscles on one side can lead to uneven development. The overworked muscle may become more prominent or bulkier on one side, causing that area of the jawline to appear fuller and creating visible asymmetry.
This constant strain also impacts the temporomandibular joints (TMJs), which act as hinges connecting the jawbone to the skull. When the jaw is habitually shifted, it places uneven pressure and wear on the TMJ on one side. This can contribute to or exacerbate a temporomandibular disorder, which may further shift the jaw out of alignment and increase the facial imbalance. A significant malocclusion can therefore alter the contours of the chin and jawline over time.
Other Common Causes of Facial Asymmetry
Not all facial asymmetry is rooted in dental issues, as the condition can stem from a variety of developmental, acquired, or genetic factors. Many cases of asymmetry are considered skeletal, meaning the underlying jawbone or skull grew unevenly due to genetic programming or developmental variation. Congenital conditions, such as hemifacial microsomia or cleft palate, are examples of developmental causes that result in significant facial differences from birth.
Acquired causes of asymmetry include physical trauma, such as a fracture or injury to the face, which can lead to uneven healing of the bone and soft tissues. Lifestyle factors like prolonged sun exposure or smoking have also been correlated with increased facial asymmetry over time. The natural aging process contributes to asymmetry as skin elasticity decreases and facial fat and bone density diminish unevenly.
Neurological and muscular conditions are another category that can lead to acute or chronic facial asymmetry. Conditions like Bell’s Palsy, which causes temporary facial nerve paralysis, or certain myopathies that weaken facial muscles can cause one side of the face to droop or appear less expressive. Because multiple factors influence facial symmetry, a professional assessment is necessary to determine if dental alignment is the primary cause or a contributing factor.
Correcting Asymmetry Caused By Dental Issues
For asymmetry that results from a functional shift due to misaligned teeth, the primary treatment involves correcting the underlying dental structure. Orthodontic treatment, typically using traditional braces or clear aligners, is designed to reposition the teeth into proper alignment. This change in the bite allows the lower jaw to close and rest in a more centered, symmetrical position, reducing the need for compensatory muscle action.
In younger patients whose jaws are still developing, early intervention is effective because an orthodontist can guide the growth of the jawbones and teeth. Specific appliances like palatal expanders can be used to widen the upper jaw to resolve a crossbite, preventing the lower jaw from shifting laterally. This early guidance can mitigate the development of long-term facial asymmetry.
When dental misalignment has resulted in a fixed skeletal problem, especially in adults where growth is complete, a combination approach is often necessary. This involves orthodontics to align the teeth, followed by orthognathic surgery (corrective jaw surgery) to physically reposition the jawbones. The surgery realigns the upper and lower jaws to their ideal anatomical relationship, providing a stable, symmetrical foundation. The goal is to establish a stable bite and allow the jaw to function without strain, promoting a more balanced appearance of the lower face.