All About Crowns
A crown resembles a tooth, but is a cover put on a damaged or decayed tooth. A crown is also known as cap.
Crowns may be required for numerous reasons. The most common one being covering broken or severely decayed tooth that can’t be repaired with a filling. A crown does the perfect job of holding the cracked parts of a tooth together and they can also hold a bridge in the right position. Crowns are ideal for improving the overall appearance of your smile as they allow cover up of misshapen or discoloured teeth.
Crowns can be prefabricated or customised in a laboratory. Prefabricated crowns are for temporary use until a permanent crown is ready and they are usually made of plastic or stainless steel. Crowns can also be made of metal, zirconia, porcelain fused to metal, porcelain fused to zirconia, and ceramic.
Every crown has its advantages and disadvantages. Which type of crown is best for your teeth can be decided in part by your occlusion and whether or not you grind your teeth. The final decision is up to you and your dentist.
Crowns usually last a minimum of 7 years. In most cases they last a lot longer, may be up to 40 years or so. In many cases, the crown stays intact, but the tooth beneath it develops a cavity. Hence, it is important to maintain a good oral hygiene to ensure your crown lasts longer.
How to prepare the tooth for a crown?
Before getting a crown for your tooth, you are most likely to get an endodontic or root canal treatment done. However, this isn’t necessary. Root canal treatment is a must only if the cavity is deep and is reaching the tooth’s pulp, where the nerve of the tooth is situated. If there isn’t too much of tooth left, the dentist will have to build up a foundation to support the crown. If the crown is being placed after a root canal treatment, the dentist will insert a post-and-core foundation.
Placing a crown requires your dentist to first file down the tooth and make space for the crown. If you have opted for an all-metal crown, not much of the tooth has to be removed as these crowns can be made thinner than the ceramic or PFM ones.
Once the tooth is filled, there are 2 ways to create a permanent crown. The majority of crowns demand two visits to the dentist. At the first visit, you will receive a temporary crown, and at the next visit, you will get a permanent one. Several dentists use a machine to make a crown in the first visit, so you don’t have to visit them the second time.
The traditional approach to making a crown involves using a piece of thread or cord to drive the gum away from the tooth. The dentist will then make an impression of your tooth utilizing a rubber-like material. The impression material sets in about 5 minutes and then it is removed. A few dentists are eliminating this traditional technique and are making use of digital technology to take the impressions of the tooth.
The dentist will not just take the impression of the tooth that requires a crown but also of the teeth above or below it. The objective is to ensure that the crown fits perfectly into your normal bite.
The impressions will be sent to the lab, so the crown can be made. Till the time your crown gets ready, you’ll have a temporary crown placed. Crowns are typically made of plastic and they can either be made in advance by the laboratory or by the dentist while your preparation visit.
Temporary crowns are not intended to last long. Sometimes, however, a temporary crown may be placed for a year or more. If it needs to be placed for long, it is best to use a lab-made plastic crown as it is stronger and will endure longer than a temporary plastic crown created by the dentist.
A special type of temporary cement is used to keep the crown in its place. This cement is weak, so it allows your dentist to easily take away the temporary crown to be replaced with a permanent one.
At the second visit, your dentist will take away the temporary crown and check if the permanent one works well for you. Sometimes, the crowns may require more polishing or glazing or some kind of adjustment before they are fixed. Once the crown is ready, it will be cemented on your tooth permanently.
If your dentist has a Cerac or CAD-CAM unit, you won’t have to wait too long for your crown as it will be made in just one visit. First, the dentist will feed a 3D image of the prepared tooth into the unit, and then a computer will prepare the crown using a block of porcelain. The dentist will then place the crown during the same visit.
What happens after a crown is placed?
You won’t feel any discomfort or sensitivity once a crown is fixed. However, if your tooth dint get a root canal treatment, it’s going to contain the nerve. You might hence feel some temporary sensitivity. If you discover pain or sensitivity when you bite down, it is best to speak to your dentist. This may mean that the crown is fixed too high and on bitting, you are first hitting the crown. In this case, the crown will have to be adjusted.
There are chances of you seeing a thin, dark line near the gumline on your crowned tooth if you see closely in the mirror, specifically if you have a PFM crown. This dark line is nothing but the crown’s metal showing through. This shouldn’t be a trouble unless it appears on the front teeth and is noticeable. You may require an all-porcelain crown having no metal base to replace this crown.
A crowned tooth remains safe from decay, excluding the gum line. Your dentist may suggest a high-fluoride gel to be used every night if you’ve got possibility of developing cavities. A crown doesn’t prevent gum disease. Hence, you must continue to brush and floss two times a day.
Crowns can chip, especially the ones made of all-porcelain. At times, they can be repaired in the mouth by etching the porcelain with a special agent and then using a composite resin to bond it and fix the chip. Porcelain repairs may not last for very long. If there’s plenty of chipping, you might need a replacement crown.
If the crown doesn’t fit perfectly on the prepared tooth, it’s likely that the cement washes out from below the crown. However, the crown will certainly not fall out immediately. In such situations, bacteria will leak in and lead to decay. If your crown feels loose while chewing, or if you notice an unusual odour around the tooth, it is important to consult your dentist.
Crowns at times drop out. This may be because of washed-out cement or an incorrect fit. Should this happen, you must keep the crown in a secure, zip-top plastic bag before bringing it to your dentist. In such cases, a new crown will have to be made. The old crown may serve as a temporary crown in such a situation.