Dental crowns are fitted to teeth to conceal something, or to reinforce the tooth (or often, for both reasons). A tooth might be permanently discolored and unresponsive to external whitening, so a crown may have been fitted to conceal this discoloration. When the tooth has deep decay beyond what a simple filling can strengthen, a dental crown can be used to reinforce the tooth. What can you expect if a dentist ever has to remove your crown?
In most cases, a dental crown stays in place until it's time for it to be permanently replaced. This can happen after years of wear and tear, leading to the crown becoming permanently discolored and tarnished. On average, a crown lasts for around ten years. They can last longer with a high standard of care, so crown replacement isn't going to be a regular concern. Why would a dentist need to remove a dental crown long before it needs to be replaced?
Treatment for the Underlying Tooth
Dental crowns sometimes need to be removed when the underlying tooth needs treatment. For example, it's possible for a cavity to develop beneath the crown. The tooth's pulp (which is its nerve) may also have become infected—and this can require root canal treatment. Your dentist will need to look beneath the crown, and so the first step is generally an x-ray. This allows your dentist to diagnose the problem and determine treatment.
Through the Crown
Minor, uncomplicated cavities can often be treated through the crown. Your dentist will drill through the crown to access the natural tooth beneath. The access hole made in the crown will then be patched with a composite dental resin. More complicated problems mean the crown must be removed. Your dentist may decide to arrange a safeguard for this removal.
A Tooth Impression
Prior to removing the crown, your dentist may take an impression of it. For a manual mold, you'll be asked to bite down on a piece of dental putty. Some dental clinics can perform digital modeling, where your dentist moves a small scanning wand over the target site to create a 3D digital model of the tooth and its crown. This data is used to make a temporary crown—which is usually acrylic.
Permanent, ceramic dental crowns can be damaged during removal. Their placement is supposed to be permanent, and so even with the utmost care, prising a cemented dental crown away from a tooth can damage the crown. Without the crown, your tooth is more sensitive and vulnerable to decay. This allows your dentist to treat your tooth, and then immediately fit a temporary crown, which will serve your purposes until a new, permanent crown can be manufactured.
Hopefully, once a dental crown is fitted, it will stay in place until it needs to be permanently replaced. But if the crown ever needs to be removed to treat the underlying tooth, there's a process in place to make sure that your tooth stays protected.