The field of orthodontics is dedicated to correcting misaligned teeth and jaws, a complex process that relies heavily on precision and mechanical forces. Patients often hear technical shorthand in the clinic, and one term that frequently comes up during treatment is “repo.” Repo is the abbreviation for repositioning, an adjustment procedure necessary to ensure the best possible movement of the teeth. This process involves altering the placement of the fixed appliances that deliver the gentle, continuous forces needed for alignment.
Defining Orthodontic Repositioning
Repositioning in orthodontics refers to the act of removing a fixed appliance, such as a bracket, button, or aligner attachment, and re-gluing it in a new location on the tooth surface. The core function of any orthodontic appliance is to act as a handle through which the archwire or clear aligner delivers force to the tooth. If this handle is even slightly off its ideal position, the resulting tooth movement can be incorrect or inefficient.
Brackets are engineered with specific angles and depths, called prescriptions, that dictate the final position of the tooth. Repositioning a bracket corrects its angle or vertical height on the tooth’s crown to better express this prescription. In clear aligner therapy, repositioning attachments involves placing a small, tooth-colored composite shape in a new spot to improve the grip and force transfer from the plastic tray to the tooth.
Reasons Why Repositioning Becomes Necessary
Repositioning becomes necessary for several reasons, including initial placement errors, appliance failure, or unexpected treatment progression.
Initial Placement Errors
When the appliances are first bonded to the teeth, minor errors in placement can occur. Even a small deviation, such as a bracket being half a millimeter too high or low, can significantly impact the final tooth angulation and height.
Appliance Failure
Appliance failure is a frequent trigger, most commonly when a bracket or attachment debonds or falls off due to chewing hard foods or sustaining an impact. When this happens, the appliance must be re-bonded, and the orthodontist will ensure the new placement is perfect.
Treatment Progression Adjustments
Repositioning can be a planned adjustment midway through treatment when the teeth do not move exactly as predicted. This is often done to correct the angulation of the tooth root, which may require a panoramic X-ray evaluation to assess its position within the jawbone, a process sometimes called a “pano-repo” appointment.
The Repositioning Procedure
The repositioning procedure begins with the careful removal of the existing appliance. For brackets, a specialized plier is used to gently flex the bracket base until the adhesive bond breaks, which may cause a brief sensation of pressure.
The next step is tooth conditioning, where any residual adhesive is removed from the enamel surface using a slow-speed bur or polishing disk. The tooth is then prepared for the new bond through a process of etching and priming, which creates a surface that allows the new adhesive to grip securely.
The orthodontist uses a precise gauge or specialized instrument to place the new bracket or attachment at the correct height and angle on the tooth. The appliance is secured with a light-cured dental composite, which hardens almost instantly when exposed to a bright blue light. Once the new appliance is bonded, the archwire is re-tied into the bracket slot, or a new clear aligner tray is seated over the fresh attachment, immediately activating the new, corrected force.
Impact on Treatment Timeline and Outcome
Repositioning is a necessary adjustment that contributes positively to the final outcome. Repositioning is a common, built-in part of treatment, and one or two such events are typically factored into the overall treatment plan. The goal of the procedure is to ensure that the teeth finish in their ideal positions, preventing minor alignment issues that could compromise the bite or smile aesthetics.
However, frequent or repeated repositioning, particularly when caused by patient non-compliance such as eating hard or sticky foods that break the bond, can extend the overall treatment timeline. Research suggests that each repositioning event may add about 0.3 months to the total treatment duration. Repositioning is a fine-tuning technique that allows the orthodontist to achieve a superior result, correcting subtle root angulations and preventing the need for tedious archwire bends later in the process.