The correction of an underbite using braces depends heavily on the severity of the misalignment, the patient’s age, and the underlying cause of the condition. An underbite occurs when the lower teeth extend beyond the upper teeth. The total time required to correct this bite issue typically ranges between 18 and 36 months of active treatment, not including the subsequent retention phase. The overall timeline is personalized, differing significantly from one patient to the next.
Defining the Underbite and Treatment Approaches
An underbite is clinically classified as a Class III malocclusion, where the lower molars are positioned too far forward relative to the upper molars. This misalignment can be either dental or skeletal in origin, which determines the approach and complexity of the treatment required. A dental underbite involves misaligned teeth, but the underlying jaw structure is generally correct, making it the simpler type to treat. Treatment for a dental underbite typically involves using braces and specialized elastics to reposition the teeth.
A skeletal underbite involves a structural discrepancy in the jawbones, where the lower jaw (mandible) is either overgrown or the upper jaw (maxilla) is underdeveloped. This type of malocclusion is more complex and often requires a multi-phase approach that extends beyond simple braces. For growing children, specialized appliances like a palatal expander combined with a reverse-pull headgear are often used to guide the upper jaw forward. For adults whose jaw growth is complete, a severe skeletal underbite may require orthognathic surgery (jaw surgery) in conjunction with braces to permanently realign the jawbones. Braces are used before and after the surgery to fine-tune the final alignment of the teeth.
Factors Influencing Braces Treatment Length
The duration of underbite correction is heavily influenced by several key biological and behavioral factors. Age plays a large part because the jawbones are still malleable in children and adolescents, allowing orthodontists to modify growth patterns. Treating a young patient with a Phase I approach while their jaws are still developing can prevent the need for more invasive procedures later on. Conversely, treating an adult with a skeletal discrepancy is more challenging because bone growth has ceased, and tooth movement is slower.
The severity of the malocclusion directly correlates with treatment length; a more pronounced underbite necessitates a longer period of force application to achieve the desired correction. Patient compliance is a major variable that can shorten or lengthen the timeline dramatically. Specialized appliances like rubber bands (elastics) or headgear are often necessary to apply the specific forces needed to correct the underbite. Failing to wear these prescribed accessories consistently can stagnate progress and significantly extend the time a patient must wear braces.
Typical Treatment Phases and Duration Estimates
Orthodontic treatment for an underbite is generally broken down into two distinct periods: the active treatment phase and the retention phase. The active phase is the period during which braces or aligners are worn to physically move the teeth and correct the bite. For mild to moderate underbites corrected solely with braces, this phase typically lasts between 18 and 36 months. In complex cases that involve preliminary jaw-modifying appliances, the total active treatment time may extend beyond three years.
Following the removal of the braces, the retention phase begins, which is necessary for long-term stability. The jaw and surrounding bone need time to solidify around the newly positioned teeth. Initially, patients typically wear a retainer full-time for several months, often between six and twelve months, to prevent the teeth from shifting back toward their original position. Due to the nature of Class III malocclusions and the tendency for the lower jaw to continue forward growth, retainer wear must often be maintained indefinitely, usually nightly, to ensure the results are preserved.