Braces are primarily designed to move teeth, but the field of orthodontics encompasses a range of appliances that can, under the right circumstances, influence the development and position of the jawbones. The ability to correct a jaw discrepancy is directly related to whether the patient’s facial skeleton is still growing or has reached adult maturity.
The Primary Function: Dental Alignment
Standard fixed braces are mechanical tools used to correct the position of individual teeth within the jawbones. The system uses brackets bonded to the tooth surface and an archwire that runs through them, secured by small elastics or ligatures. The archwire applies a constant, gentle force to the teeth. This continuous pressure initiates a biological process known as bone remodeling, where bone tissue is broken down on one side to allow movement and rebuilt on the other side to stabilize the tooth in its new position. This mechanism is highly effective for correcting dental malocclusion, or a “bad bite,” which includes crowding, spacing, or rotated teeth. In these cases, the underlying jaw structure is generally well-aligned, and only the teeth need repositioning within the alveolar bone that supports them.
Distinguishing Skeletal and Dental Alignment Issues
Orthodontic problems are classified based on the relationship between the upper jaw (maxilla) and lower jaw (mandible). It is crucial to differentiate between dental and skeletal issues. A dental malocclusion (Class I) involves misaligned teeth despite a relatively normal jaw relationship. A skeletal discrepancy, however, involves a structural mismatch in the size, shape, or position of the jawbones themselves. This includes Class II malocclusion (overbite), where the lower jaw is positioned too far back, and Class III malocclusion (underbite), where the lower jaw protrudes beyond the upper jaw. Diagnosing the precise nature of the problem requires specialized X-rays, such as cephalometric analysis, to measure the exact relationships between the facial bones. This imaging allows the specialist to determine whether the bite problem is rooted in the position of the teeth or in the underlying jaw structure.
Non-Surgical Jaw Modification Techniques
Non-surgical jaw correction, known as “growth modification,” is possible for children and adolescents whose jawbones are still actively growing. This treatment, often called interceptive orthodontics, aims to harness the body’s natural growth to guide the development of the maxilla and mandible. It must occur during a child’s growth spurt to be effective. Specific functional appliances are used to influence skeletal development. For instance, a palatal expander is used to widen a narrow upper jaw by applying gentle outward pressure on the bones of the palate. Appliances like the Herbst or Twin Block are used to correct a Class II overbite by encouraging the lower jaw to grow forward into a better position. For a Class III underbite, a facemask appliance may be used, which employs elastics to apply forward-pulling force to the upper jaw. These devices redirect the growth trajectory of the jawbones, potentially preventing the need for surgery later in life. Success depends highly on consistent patient compliance and the age at which treatment begins.
The Role of Orthognathic Surgery
For adults with severe skeletal discrepancies, non-surgical growth modification is no longer an option because the jawbones have completed their growth. In these cases, correcting the jaw structure requires orthognathic surgery, often referred to as corrective jaw surgery. This procedure is performed by an oral and maxillofacial surgeon to physically cut and reposition the maxilla, the mandible, or both. The treatment is a combined effort that typically begins with orthodontic preparation using braces, a process that can take 12 to 18 months. This initial phase involves moving the teeth into the correct position relative to their respective jawbones, which may temporarily make the bite look worse. The surgery then aligns the jawbones, followed by several more months of braces to detail the final tooth positions. This comprehensive approach is reserved for the most pronounced skeletal misalignments that affect function, breathing, and facial symmetry.