A dental crown is a custom-made cap placed over a damaged or weakened tooth to restore its shape, size, strength, and appearance. While crowns are built to be a long-term solution cemented with durable materials, they are not permanently fixed. Dental crowns can be removed, and this is a common, necessary procedure undertaken by dentists to preserve the underlying tooth structure and overall oral health.
Primary Reasons for Crown Removal
The most frequent reason a crown needs removal is the development of recurrent decay beneath its margin. Bacteria can penetrate any minute gap between the cap and the tooth structure, leading to a new cavity that requires removal for treatment access. This decay often starts near the gum line where the natural tooth is exposed.
A poor fit or margin issue is another clinical necessity for removal. If the crown’s edge does not create a proper seal with the prepared tooth, it can allow oral fluids and bacteria to leak in, leading to sensitivity, infection, or decay. Crown damage, such as a chip, crack, or fracture, will compromise the protection the crown offers, leaving the underlying tooth vulnerable and necessitating a replacement.
Crowns can also become loose over time if the cement bond degrades or the underlying tooth structure is compromised. Beyond clinical issues, an existing crown may be removed for aesthetic reasons, such as upgrading an older metal alloy crown to a newer ceramic or zirconia material. Additionally, if the tooth underneath requires a subsequent procedure, like a root canal re-treatment, the crown must be removed to allow proper access to the pulp chamber.
Methods Used by Dentists to Remove Crowns
The technique used depends on the crown material, the strength of the cement bond, and whether the goal is to save the crown. One common and definitive method is crown sectioning, which involves using a high-speed dental bur to precisely cut the crown into two or more pieces. This approach is necessary for strong, firmly cemented crowns made of metal, porcelain-fused-to-metal, or zirconia, as it sacrifices the crown to preserve the underlying tooth.
Dentists can also use specialized instruments, sometimes called crown pullers or removers, to apply controlled force. These tools apply leverage or a controlled, rapid impulse shock to physically break the cement seal between the crown and the tooth preparation. This approach is best suited for crowns that are already slightly loose or for those where the underlying tooth is stable enough to withstand the force.
A less destructive method involves ultrasonic devices, which generate high-frequency vibrations against the crown’s surface. These vibrations are transmitted through the crown material to the cement layer, helping to loosen the bond without requiring the crown to be cut. This technique is effective for crowns bonded with resin-based cements and is preferred when the dentist hopes to remove the crown intact for potential reuse or examination.
Post-Removal Care and Next Steps
Following the crown’s removal, the dentist first thoroughly assesses the underlying tooth structure. This inspection checks for any signs of decay, fractures, or damage that necessitated the crown removal. Any decay or compromised material is cleaned out and treated to ensure the remaining tooth is healthy and stable.
The prepared tooth must then be protected, as it will be highly sensitive and vulnerable to damage and bacterial invasion. A temporary restoration, usually a temporary crown or a large filling, is placed over the tooth to shield the dental preparation and the exposed dentin. This temporary restoration also helps maintain the correct spacing and prevents the neighboring teeth from shifting while the permanent replacement is being fabricated.
If a new permanent crown is required, the next step involves taking an impression or digital scan of the now-treated and prepared tooth. This mold or scan is sent to a dental laboratory, which uses it to fabricate the new, custom-fit crown. The waiting period for the permanent crown to be returned from the lab and cemented into place usually ranges from one to three weeks.