Understanding Porcelain Crowns and How They Are Used
14 November 2014, setve dentistrty
Dentist eugene has said he wants to give you a porcelain crown
. You've heard of crowns, but not porcelain. Is that even possible? Looking it up online only makes things worse: veneers, metal and porcelain hybrids, machine milling versus hand shaping, it goes on and on. What does all this mean, and how do you make the best decisions?
A dental crown is a cap that sits on top of a damaged tooth. It generally looks like the tooth it's replacing, and is made of metal, porcelain (also called ceramic), resin, or a combination of metal and porcelain. There are lots of reasons why a crown is a good choice. The most common is to protect a tooth that is already broken and needs to be held together, or is in danger of breaking or other damage without the protection of a crown. Crowns can also be used to anchor a larger dental appliance, like a bridge. They can also be used for cosmetic reasons, to mask deformed teeth, to hide a dental implant, or just to make a prettier smile.
When your dentist talks about a porcelain crown, he can be referring to one of several types. A porcelain fused to metal crown is just what it says: porcelain is permanently fused to a metal shell. The porcelain can cover the entire shell, called a PFM crown. Alternately, the porcelain may only cover part of the shell, usually the part that is visible; this is called a porcelain veneer. Then there is the crown that is made entirely of ceramic / porcelain. There are also variants called "onlay" or 3/4 crowns; normal crowns completely cover the tooth, where the onlays and 3/4 crowns only cover part of the tooth.
Each of these types have their own advantages and disadvantages. Both the veneer and the porcelain-and-metal crowns are much stronger than most of the alternatives, thanks to the metal shell. However, they don't look entirely natural. Both the veneer and the full porcelain and metal crown can have metal showing, usually at the gum line. For that reason, they're not well suited to front teeth replacement. Moreover, metal crowns can cause wear on adjacent teeth. If you're sensitive or allergic to certain metals, such as nickel, then crowns with metal content are out of the question.
Full porcelain teeth look entirely natural, which makes them perfect to replace front incisors or any tooth that is visible to others. They can be color-matched to your natural teeth and can even be molded to match shape and even apparent alignment. The downside is that porcelain is not as strong as the metal alternatives, and can be prone to chipping or breaking. Sometimes chipping can be patched. But if it's chipped too badly, it would have to be replaced.
To apply a crown, first the tooth has to be prepared. Your dentist will make molds of the target tooth, and find the color that best matches your natural teeth. Sometimes, if the tooth is in very bad shape, or is in danger of further damage, he might want to perform a root canal first to strengthen things. Then he will form the tooth into a shape that will fit the crown and hold it safely in place.
The next step is to apply the crown and cement it into place. Normally, this requires a second office visit (usually about two weeks later; you'll be fitted with a temporary crown to protect the tooth during that waiting period). Placing the crown requires only dental cement, but your dentist may want to numb the area first, to minimize any discomfort. Some dentists offer same day crowns. This means that he has the shaping equipment in his office to make the crowns on site. Either way, the end results are the same.
A crown requires no special care. But a crown, whether full porcelain or metal and porcelain, does not protect the tooth beneath from decay, nor does it protect against gum disease; bacteria can get underneath the crown. You will still have to brush and floss the same as before. If you have bad habits, like grinding your teeth, biting your fingernails, or crunching ice, you should break them, because they can damage your crowns (they're not good for your real teeth either!) Assuming that you take good care of the crown, and there is no unusual wear and tear, a porcelain crown can last anywhere from five to fifteen years.
Porcelain crowns, either a full porcelain piece or a metal and porcelain fusion, require no special procedures to install, are as strong or stronger than the alternatives, and they don't need any special care once they're in your mouth. They look natural, making them perfect for visible teeth. Your dentist can help you decide whether porcelain crowns are the best choice for you.