An underbite, clinically known as a Class III malocclusion, is a condition where the lower jaw or teeth protrude beyond the upper jaw or teeth when the mouth is closed. This misalignment arises from genetics, which influences jaw size and position, or certain childhood habits like prolonged thumb-sucking. Correcting an underbite requires addressing the skeletal or dental discrepancy to establish a balanced and functional bite. While traditional metal braces are a common orthodontic solution, numerous effective treatments exist to correct this condition without fixed brackets and wires.
Early Intervention: Growth Modification in Children
For children whose jawbones are still actively growing, typically between the ages of seven and ten, non-brace treatment focuses on orthopedic growth modification. The goal is to redirect the development of the upper and lower jaws to correct the skeletal imbalance. This approach is time-sensitive, as it is only effective before the growth plates in the jaw bones have fully matured.
A common appliance is the reverse-pull headgear, also referred to as a facemask. This extra-oral device rests on the forehead and chin, applying a gentle, controlled forward-pulling force to the upper jaw (maxilla). It uses elastics connected to an intra-oral appliance, often a palatal expander. By stimulating forward growth of the maxilla, the headgear helps align the upper jaw with the lower jaw, which can reduce the need for more invasive treatments later.
Another tool is the chin cap, often indicated in the early mixed dentition phase to restrict the forward growth of the lower jaw (mandible). Functional appliances, such as the removable mandibular retractor or the Reverse Twin Block, also work by posturing the mandible backward to improve the jaw relationship. A specialized palatal expander is often an integral part of this treatment, as it widens the upper jaw and facilitates its forward movement, helping to unlock the bite.
Discreet Orthodontic Alternatives for Teens and Adults
For mild to moderate underbites in teenagers and adults, where the issue is primarily dental or requires only limited skeletal change, discreet, non-brace alternatives can be highly effective. These treatments focus on moving the teeth to achieve the correct alignment rather than dramatically altering the jaw structure. Clear aligner therapy, such as Invisalign, is a popular option, utilizing a series of custom-made, transparent plastic trays to gradually shift the teeth.
Clear aligners work by applying constant, controlled pressure to the teeth, digitally planned to move the lower teeth slightly backward and the upper teeth forward. To achieve the necessary force for underbite correction, the aligners are often used in conjunction with small, tooth-colored attachments and elastic rubber bands. These elastics connect the upper and lower aligners, providing the orthopedic force required to correct the front-to-back bite relationship.
An additional fixed alternative that avoids visible brackets is lingual braces, which are attached to the tongue-side (lingual) surface of the teeth. Their placement makes them virtually invisible from the outside, offering a highly aesthetic solution for comprehensive tooth movement. In cases where the underbite is very mild, cosmetic dental procedures, such as reshaping the teeth and placing veneers on the upper teeth, can visually camouflage the misalignment without moving the teeth or jaw.
Surgical Correction for Significant Skeletal Discrepancies
When an underbite is severe and caused by a significant skeletal discrepancy in adults, orthognathic surgery, or jaw surgery, is typically required for correction. Since the bones are mature, growth modification is no longer possible, making surgery the definitive fix for the skeletal problem. The procedure involves an oral and maxillofacial surgeon physically repositioning the jawbones to achieve proper alignment.
The most common surgical approach involves performing a planned cut in the bone (osteotomy) to set the lower jaw back or to advance the upper jaw forward, or a combination of both. While the surgery corrects the bone position, a preparatory phase of orthodontics is often necessary to correctly align the teeth over the jawbone before the procedure. This preparatory phase may use clear aligners or lingual braces to position the teeth optimally for the final surgical bite correction, ensuring a stable and functional result.