Braces are a common method used to correct an overbite, a dental condition where the upper front teeth vertically overlap the lower front teeth excessively. While a slight overlap is normal for a healthy bite, an excessive overlap, often called a deep bite, can cause functional issues like uneven tooth wear and jaw pain. The goal of orthodontic treatment is to achieve proper alignment and balance between the upper and lower arches. Understanding the root cause of the overlap determines how braces will be used for correction.
Defining the Types of Overbite
Overbites are categorized based on whether the issue stems from the position of the teeth or the structure of the jawbones. This classification dictates the complexity and approach of the treatment plan.
A dental overbite occurs when the jawbones are correctly aligned, but the front teeth are misaligned or over-erupted. This type is often easier to correct using braces alone, as treatment focuses solely on repositioning the teeth within the existing bone structure.
A skeletal overbite, or Class II malocclusion, is more complex and involves a discrepancy in the size or position of the upper and lower jaws. This usually means the upper jaw is positioned too far forward or the lower jaw is positioned too far back. Treatment requires moving the teeth and influencing jaw growth in younger patients or surgically correcting the bone structure in adults.
The Mechanism of Overbite Correction with Braces
Braces correct an overbite by changing the vertical relationship of the anterior (front) teeth and leveling the arch. This process involves two reciprocal movements: intrusion and extrusion. Intrusion is the movement of a tooth further into the bone socket, used to push over-erupted front teeth.
This movement is achieved using specialized archwires that are initially bent into a curve, known as the reverse Curve of Spee, before insertion into the brackets. As the wire attempts to return to its original flat shape, it exerts continuous forces on the teeth. This force simultaneously pushes the anterior teeth into the bone (intrusion) and pulls the posterior (back) teeth out of the bone (extrusion).
Extrusion, the movement of teeth out of the bone, is used on the back teeth to open the bite and create vertical space. The combination of intruding the front teeth and extruding the back teeth flattens the lower arch curvature, or Curve of Spee, leading to a flatter, more stable occlusal plane.
Role of Auxiliary Appliances and Elastics
For many overbite cases, especially those with a skeletal component, fixed braces require auxiliary appliances to generate directional force. One common component is the use of orthodontic elastics, or rubber bands, stretched between specific hooks on the upper and lower braces. Class II elastics are worn from an attachment point near the upper canine to a molar bracket on the lower arch.
This diagonal placement applies a continuous force that pulls the upper teeth backward and the lower teeth forward. This action encourages the lower jaw to move into a more forward position relative to the upper jaw, improving the skeletal relationship. Patient cooperation is important, as these elastics must be worn nearly full-time to be effective.
Bite Turbos
Bite turbos, also called bite blocks or ramps, are small, bonded platforms placed on the back of the upper front teeth or on the chewing surfaces of the back molars. The purpose of the bite turbo is to prevent the patient from fully closing their bite.
Preventing full bite closure is necessary when the upper front teeth are hitting the lower brackets. These turbos protect the lower braces from damage and remove physical interference that prevents desired tooth movement. This temporary separation allows the posterior teeth to erupt (extrude) more freely, which helps open the deep bite.
Treatment Options for Severe Cases
In cases of severe overbite, especially those involving a significant skeletal discrepancy, traditional braces may not be sufficient. For children and adolescents whose jawbones are still developing, functional appliances are often used before or alongside braces. Devices like the Herbst appliance or Mandibular Advancement Appliances are fixed to the teeth and hold the lower jaw in a more forward position to stimulate growth.
Clear aligners can correct mild to moderate dental overbites, often by incorporating features like bite ramps molded into the plastic. However, aligners have limitations with severe skeletal or complex deep bite issues, where the continuous, fixed force of traditional braces is more predictable.
For adults with a severe skeletal overbite where jaw growth is complete, the discrepancy may be too large for tooth movement alone. In these instances, orthognathic surgery, commonly known as jaw surgery, is required to physically reposition the upper or lower jawbone. This surgical procedure is performed in conjunction with braces, which align the teeth within the newly corrected jaw structure.