An underbite, clinically known as a Class III malocclusion, is a common bite issue where the lower teeth and jaw sit forward, extending past the upper teeth. This misalignment makes the lower jaw appear more prominent and affects how the upper and lower teeth meet. While braces are a primary tool for correction, the length of treatment depends heavily on the specific nature and severity of the individual’s condition. Understanding the phases of orthodontic care and the unique factors influencing tooth and jaw movement helps determine the timeline for fixing an underbite.
Understanding Underbites and Treatment Objectives
An underbite results from a discrepancy between the upper jaw (maxilla) and the lower jaw (mandible). This imbalance can be purely dental (misaligned teeth) or skeletal (disproportionately sized jaw bones, often a large lower jaw or a small upper jaw). Correcting this condition is important for both aesthetics and oral function.
The primary goal of using braces and related appliances is to achieve proper alignment of the teeth and establish a correct bite relationship, known as occlusion. This correction improves functionality, such as the ability to chew food efficiently and speak clearly, while minimizing abnormal wear on the tooth surfaces. Successful treatment ensures the long-term health of the teeth and jaw joints.
Key Factors That Determine Treatment Length
The duration of underbite treatment is highly variable, generally ranging from 18 months to three years for the active phase. This range is influenced by several individual factors that determine the complexity of the case.
Severity and Type of Malocclusion
The most significant factor is the severity and type of malocclusion. A mild dental underbite, involving only teeth alignment, is quicker to resolve than a severe skeletal underbite, which involves underlying bone structure issues. Skeletal discrepancies require more complex and lengthy intervention because they involve bone movement.
Patient Age
The age of the patient is another major determinant of treatment length and method. Treating a younger patient whose jaw is still growing allows for growth modification techniques, guiding the upper jaw forward or restricting the lower jaw’s growth. In contrast, an adult with a fully developed skeletal underbite may require orthognathic surgery to reposition the jaw bones, substantially extending the total timeline.
Auxiliary Appliances and Compliance
Treatment complexity increases when auxiliary appliances are necessary. Devices like palatal expanders, reverse-pull facemasks, or temporary anchorage devices (TADs) are often used to address skeletal issues before or during the active phase of braces. The time required for these separate appliances, which can be six to twelve months, is added to the overall duration. Patient compliance is also critical; following instructions for wearing elastics, maintaining good oral hygiene, and attending all adjustment appointments directly impacts how efficiently the teeth move.
The Typical Timeline of Active Braces Treatment
The active phase of underbite correction follows a structured path aimed at progressively moving the teeth and correcting the bite.
Early Intervention (Growth Modification)
For growing patients with a skeletal issue, the process may begin with an early intervention phase focused on growth modification. This initial stage, often lasting six to twelve months, uses appliances like a reverse-pull facemask to encourage forward growth of the upper jaw before fixed braces are applied.
Alignment and Leveling
Once fixed braces are placed, treatment transitions into the alignment and leveling phase, which focuses on straightening the teeth within the arch. Initial, flexible archwires are used to gently position the teeth, a process that typically takes about three to six months. Wires are periodically changed to increasingly stiffer materials to move the teeth into their desired positions.
Working Phase (Bite Correction)
Following alignment, the working phase concentrates on correcting the bite relationship itself. This involves using bite correction mechanics, most commonly through elastics worn between the upper and lower arches to move the jaw into a proper Class I relationship. This phase is often the longest, usually requiring six to twelve months or more, depending on the magnitude of correction needed.
Detailing and Finishing
The final stage, detailing and finishing, involves making minor adjustments to the position of individual teeth and ensuring the upper and lower teeth interdigitate perfectly. This can take an additional three to six months before the braces are ready to be removed. The total active time in fixed braces for an underbite typically spans from 18 to 36 months, depending on the severity established in the initial diagnosis.
The Necessary Phase of Post-Braces Retention
The removal of braces marks the end of the active treatment phase, but retention begins immediately after. Retention is necessary because the newly corrected teeth and supporting bone must stabilize in their new positions to prevent relapse. The soft tissues surrounding the teeth require time to adapt to the changes made during active treatment.
Retention devices, or retainers, are custom-made to hold the teeth in the achieved position. These include:
- Removable retainers, such as the Hawley retainer or clear plastic aligner-style retainers.
- Fixed retainers, which are thin wires bonded to the back surface of the front teeth.
Initially, removable retainers are often worn full-time for several months to ensure maximum stability, then the wear schedule is reduced to nightly use. Retention is a long-term commitment, often indefinitely, because natural physiological changes can cause teeth to shift throughout life. Consistent retainer wear is the only reliable way to preserve the final results and prevent the need for re-treatment.