Even if a tooth is slated for a crown, dentists need to protect it while the permanent crown is being made and delivered to the dental office in two to three weeks. And although the color of a temporary crown might not match that of the natural tooth, patients can often continue to eat and speak normally during this interim period.
Temporary cement is used to fix these crowns so that they are easy to remove later. Here's why you might need one.
Crowns provide a protective cover for both natural teeth and dental implants. The American Dental Association (ADA) explains that when a tooth is discolored, badly shaped or weak due to a large filling, crowns provide an attractive fix. Dentists might simply recommend a crown when there is little or no tooth remaining. They may also be used to anchor bridges, which replace missing teeth or those that needed extracting.
How They're Made
According to Cleveland Clinic, dentists fit temporary crowns at the first of two appointments. During this visit, the dentist takes an x-ray of the problem area and treats any lingering decay. To make room for the permanent crown, the natural tooth is filed down over the sides and top. The dentist then takes an impression of the filed tooth – as well as those above and below it – and sends these impressions to a dental laboratory for the creation of a permanent crown. Because this can take two to three weeks, he or she places the temporary crown onto the tooth to protect it until the next visit.
At the second and final visit to the clinic, when the permanent crown has arrived, the dentist removes the temporary crown and fits the permanent crown in its place.
What Makes It Permanent?
There are a few differences between temporary and permanent crowns, but it comes down to the cement dentists use to fix them. Keep in mind that temporary crowns are made to last only a few weeks, whereas permanent crowns last five to 15 years with good care. The former is made of either metal or plastic, according to the Vanderbilt University Medical Center, but the latter can be made of high-grade porcelain or porcelain bonded to gold.
The cement used to fix temporary crowns should be fairly easy to break, because dentists must be able to remove them to attach permanent crowns. Restorative Dental Materials mentions that zinc oxide-eugenol cement – made from zinc oxide powder, eugenol and olive oil – is a common adhesive for temporary restorations. In contrast, glass ionomer and resin-modified glass ionomer cement are two tough, durable glues used to fix permanent crowns, according to dentists in Inside Dentistry.
Caring for Temporary Crowns
Normal brushing with a fluoride toothpaste such as Colgate® Total Clean Mint actually helps to care for temporary crowns just like normal teeth. MIT Medical offers similar advice: Immediately after the crown is fitted, don't eat for 30 minutes, while the cement sets. Sticky foods might pull temporary crowns off the teeth, so these should be avoided as well. If the crown does come off, the patient can fix it back in place with personal denture cement until he sees the dentist again.
It's important not to leave a temporary crown out of the mouth for long periods of time either, because teeth can move – which makes fitting the permanent crown difficult.
Having temporary crowns fitted is nothing to worry about. On the contrary, without their protection, natural teeth are exposed to decay and changes in position. Treat a temporary crown carefully while waiting for a permanent crown to arrive, and it shouldn't cause you any problems.
Learn more about the types of dental crowns in the Colgate Oral Care resources.