The question of whether braces alone can fix an underbite is common, and the answer is complex. An underbite, where the lower jaw sits noticeably ahead of the upper jaw, is a complex alignment issue affecting a person’s bite and facial profile. The effectiveness of treatment relies heavily on two primary factors: the severity of the underbite and the age of the person being treated. For mild cases, braces may be sufficient, but more significant issues often require specialized appliances or surgical intervention alongside traditional braces.
Defining the Underbite Condition
An underbite is the common term for a condition medically known as a Class III Malocclusion, which occurs when the lower teeth overlap the upper teeth when the mouth is closed. Distinguishing between a dental and a skeletal underbite is important because it dictates the treatment plan.
A dental underbite is less severe and is caused by the misalignment of the teeth themselves, where the jawbones are correctly positioned but the teeth are tilted. In contrast, a skeletal underbite arises from a discrepancy in the size or position of the jawbones, such as an underdeveloped upper jaw (maxilla) or an overdeveloped lower jaw (mandible). Skeletal problems, which involve significant bone imbalance, are far more challenging to correct without intervention that addresses the bone structure.
Orthodontic Correction Methods
Braces are a consistent component in nearly all underbite corrections, but they primarily serve to align the teeth, not to correct major bone discrepancies. For cases rooted in bone structure, braces work in conjunction with specialized appliances designed to adjust the jaw position. The goal of non-surgical orthodontic treatment is to restrict the forward growth of the lower jaw or to encourage the forward growth of the upper jaw.
One common appliance is the reverse-pull headgear, or facemask, which applies gentle, forward-directed force to the upper jaw. This external appliance uses pads on the forehead and chin, connected by elastic bands to a dental appliance cemented to the upper teeth. The constant, light pulling force stimulates the growth of the maxilla, helping it to catch up with the lower jaw, making this treatment highly effective during childhood growth spurts.
Often, the reverse-pull headgear is used alongside an upper jaw expander (palatal expander), which is fitted across the roof of the mouth. This device gently widens the upper jaw to ensure the upper arch is wide enough to accommodate the lower teeth once the jaw has been moved forward. The final phase of orthodontic treatment, involving traditional braces or aligners, is then used to refine the position of individual teeth and ensure a perfect bite alignment. This comprehensive approach addresses both the skeletal imbalance and dental alignment issues without the need for surgery.
The Role of Age in Treatment Strategy
The timing of underbite correction is a significant factor, as a child’s developing bone structure allows for treatment options unavailable to adults. For children, typically between the ages of 7 and 10, orthodontists employ a technique called growth modification, often referred to as Phase I treatment. This method uses appliances like the reverse-pull headgear to guide the growth of the jawbones.
The bones of a growing child are pliable and responsive to the forces applied by these orthopedic devices, making it possible to achieve substantial skeletal changes. This early intervention can successfully resolve a skeletal underbite, potentially avoiding the need for more complex procedures later in life. If growth modification is successful, a second phase (Phase II) of treatment with braces is initiated in the teenage years to finalize the alignment of the permanent teeth.
Once a person has finished their adolescent growth spurt, the jawbones become fused and rigid. At this point, growth modification is no longer an option because the skeletal structure cannot be changed with appliances. Treating an adult skeletal underbite with only braces may correct tooth alignment, but it will not fix the underlying jaw discrepancy, resulting in a limited change to the facial profile.
When Surgery Becomes Necessary
When a skeletal underbite is severe, or when the patient is an adult whose jaw growth is complete, orthognathic surgery (jaw surgery) becomes the most reliable solution. Surgery is necessary when the lower jaw protrudes significantly and causes problems with chewing, speaking, or breathing. Braces alone are insufficient to correct severe bone misalignment because they can only move teeth within the existing jaw structure.
The orthognathic procedure physically repositions the jawbones to achieve proper alignment, involving moving the lower jaw backward or the upper jaw forward. This major procedure is carefully planned by both an orthodontist and an oral surgeon. Even when surgery is required, braces are still a necessary part of the overall treatment plan.
The orthodontic treatment is divided into pre-surgical and post-surgical phases, with braces used before the operation to align the teeth so they fit together correctly once the jaw is moved. Following the surgery and recovery, braces are worn for several more months to fine-tune the bite and achieve the final result. This combined surgical and orthodontic approach is the only way to correct a significant skeletal underbite in a non-growing adult.