A crossbite is a form of dental misalignment (malocclusion) where one or more upper teeth fit inside the lower teeth when the mouth is closed. This is the reverse of a typical bite, where the upper arch should slightly overlap the lower arch. If left uncorrected, a crossbite can lead to uneven tooth wear, gum recession, and jaw joint issues. Addressing this misalignment is necessary for long-term oral health, and patients often prioritize understanding the total time required for correction.
Understanding Crossbite Classifications
Crossbites are broadly categorized based on their location, which helps determine treatment complexity. An anterior crossbite involves the front teeth, where one or more upper incisors are positioned behind the lower incisors. This differs from a full underbite because it affects only a select group of teeth.
The second major category is the posterior crossbite, occurring in the back of the mouth, involving the premolars and molars. The upper back teeth bite inside the lower back teeth, which can be unilateral (one side) or bilateral (both sides). Crossbites are also classified by origin: a dental crossbite is a tooth position issue, while a skeletal crossbite indicates a structural mismatch between the upper and lower jaws. Skeletal discrepancies, such as a narrow upper jaw, often represent a more severe issue that impacts treatment time and complexity.
Orthodontic Tools for Correction
Correction typically requires a combination of appliances, with fixed braces serving as the core component for final alignment. For posterior crossbites, especially those with a skeletal component, a palatal expander is frequently used first. This fixed appliance is attached to the upper back teeth and uses a screw mechanism to gently widen the upper jaw by applying force to the mid-palatal suture.
This initial expansion creates the necessary width for the upper teeth to fit correctly over the lower teeth. Fixed braces are then applied to move individual teeth into their final corrected positions. Removable appliances, such as plates with springs, can also be utilized for simpler anterior crossbites or in growing patients.
Orthodontic elastics (rubber bands) are a common adjunct tool used with braces to fine-tune the bite. They are strategically hooked between the upper and lower braces to apply consistent pressure, helping shift the arches into a proper relationship and ensuring the upper and lower teeth meet correctly.
Average Treatment Duration and Influencing Factors
The total time needed to fix a crossbite varies significantly, ranging from six months for minor dental issues to 18 to 30 months for complex skeletal cases. A simple anterior crossbite involving one or two teeth might take five to seven months for initial correction. However, this is often followed by a period of full fixed braces to complete the alignment of all teeth, extending the total treatment time.
Patient Age
Patient age is a primary factor influencing the timeline, as early intervention in children is faster than adult treatment. Treating a skeletal crossbite in a growing child allows the orthodontist to use a palatal expander to modify jaw growth. This process is much more challenging once the mid-palatal suture has fused in adulthood. Treatment started in patients under 11 years old can average around eight months, substantially shorter than the average of nearly 15 months for those starting between 11 and 16 years old.
Severity and Compliance
The severity of the crossbite is directly proportional to the duration of treatment. Cases requiring a two-stage approach—starting with an expander or partial braces before moving to full fixed appliances—average around 17 months, compared to about 11 months for single-stage treatments. A patient’s compliance with wearing prescribed elastics or removable appliances is also a major factor, as appliances only work when worn as instructed. Poor compliance can easily add several months to the overall treatment plan.
The Importance of Retention After Braces
Once the active phase of treatment is complete and the crossbite is corrected, the braces are removed, transitioning to the retention phase. This passive period is important because surrounding bone and gum tissues require time to stabilize around the teeth’s new positions. Without retention, teeth have a high tendency to shift back toward their original misalignment, known as relapse.
Retention involves specialized appliances, including fixed retainers (thin wires permanently bonded behind the front teeth) or removable retainers. Removable options include clear vacuum-formed retainers or Hawley retainers, worn full-time initially and then typically only at night. While active correction may take a year or two, the retention phase is considered indefinite. Continued retainer use ensures the long-term stability of the corrected bite.