A dental crown is a protective cap, typically made of porcelain or metal, that covers a damaged tooth to restore its shape, size, and strength. Orthodontic braces use brackets and wires to apply continuous pressure to move teeth into alignment. Having an existing crown does not prevent orthodontic treatment, but combining the two requires specialized planning and techniques to ensure a successful outcome.
Initial Dental Evaluation
The process begins with a thorough diagnostic assessment by the dental team. The orthodontist must carefully evaluate the crown’s material, which dictates the necessary bonding technique and resilience to treatment forces. The examination checks the stability and integrity of the restoration, particularly the crown margins. If a crown is damaged or loose, the dentist may recommend repairing or replacing it before starting orthodontic movement to ensure it can withstand the forces applied by the braces. The underlying tooth structure must also be assessed, often through X-rays, because teeth with root canals can move more slowly than vital teeth.
Methods for Attaching Brackets to Crowns
Attaching traditional brackets to a crown requires different materials and protocols than bonding to natural tooth enamel. Standard orthodontic adhesives rely on the micro-porosity created by etching the enamel surface, a process that is ineffective on the smooth, non-porous materials of a crown. Specialized surface preparation is necessary to create a strong, yet controlled, bond. For porcelain crowns, preparation involves specialized etching or sandblasting, followed by the application of a silane coupling agent. Metal crowns require mechanical roughening and the application of a metal primer. The goal is to achieve a bond strong enough to withstand treatment forces, but weak enough for easy removal without fracturing the crown.
Non-Bracket Orthodontic Solutions
When direct bracket bonding to a crown is not ideal, alternative orthodontic solutions are available. Clear aligner therapy, such as Invisalign, is frequently recommended because it eliminates the need for direct bonding to the crown surface. The custom-made plastic trays fit over the entire tooth structure to facilitate movement. While aligners avoid bonding the main appliance, they sometimes require small attachments secured with specialized adhesives on crowned teeth. Another option, particularly for molars with full coverage crowns, is the use of orthodontic bands, which are metal rings cemented around the crown to provide a robust anchor point for the archwire.
Maintenance and Risks During Treatment
The combination of braces and crowns introduces specific maintenance challenges and potential complications. A primary risk is bracket debonding or failure, which is more likely on a crown surface than on natural enamel and may extend treatment time if not promptly re-bonded. Oral hygiene is extremely important because crowns remain vulnerable to decay at the margins, and brackets create additional traps for plaque. Meticulous cleaning, including special brushes and floss threaders, is required to protect the crown’s integrity for the long term. The most significant risk occurs when brackets are removed, as the process can potentially create microcracks or surface damage on porcelain crowns, necessitating specialized debonding techniques to minimize stress on the crown material.