Dentistry is an art as well as a science; dental crowns offer a perfect example of this. A dental crown or “cap” is a covering that fits over a damaged, decayed or unattractive tooth. It can even replace a tooth entirely as part of dental bridgework.
A crown completely covers a tooth above the gum line. This is in contrast to a dental veneer, which only covers a tooth's front surface and needs natural tooth structure to support it. Therefore, if a tooth is missing a significant amount of structure above the gum line, a crown would be the restoration of choice.
Crowns strengthen damaged teeth, allowing them to function normally again. When crafted from today's high-tech porcelains (dental ceramics), crowns are virtually indistinguishable from natural teeth. They can even be designed to improve upon a tooth's original appearance.
There are other materials besides porcelain that we can use to make dental crowns, depending on what qualities are most important. For durability, cast gold can't be beat. However, this is not always the most aesthetic choice — especially towards the front of the mouth. Other possibilities include porcelain-fused-to-metal crowns (PFM), which have a metal interior for strength and a porcelain exterior for a more natural appearance, and all-porcelain crowns with zirconia, representing the strongest ceramic. We would be happy to discuss the pros and cons of these various options with you.
Crowning or capping a tooth will usually take two to three visits. At the first visit, your tooth is prepared to receive its new crown. First, it is shaped to fit inside the new covering. This will involve some drilling to give the tooth a uniform shape. The tooth and the surrounding area will be numbed beforehand. If there is very little tooth structure left to begin with, the tooth may have to be built up with filling material, rather than filed down, to support the crown.
After the tooth is prepared, impressions of your teeth are taken, either digitally or with reliable, putty-like impression materials, and sent to the dental laboratory. There, the impressions will be used to make models of your teeth for the creation of a crown. The models will serve as guides to the highly skilled lab technicians, who will ensure that your new crown is designed to enhance your smile and function well within your bite.
Before you leave the office, a temporary crown will be attached to your tooth to protect it until the permanent crown is ready. At the second visit, your permanent crown will be attached to your tooth with either a resin that hardens when exposed to a special light source, or a type of permanent cement.
Crowns can also be used to create a lifelike replacement for a missing tooth. This is done with bridgework, which spans the space of the missing tooth and requires at least three crowns. Two of those crowns will be placed over healthy teeth on either side of the missing tooth; these healthy teeth are referred to as abutment teeth. The two crowned abutment teeth become supports for a third crown placed in between them; that third crown is referred to as a pontic. If more than one tooth is missing, more crowns will be needed to bridge the gap in between the abutment teeth.
The number of abutment teeth necessary to replace missing teeth is influenced by the number of missing teeth, the size and length of the abutment tooth roots, the amount of bone support each abutment tooth has, as well as where in the mouth the missing tooth is located. For example, if you have three missing teeth, four abutment teeth may be necessary, thereby creating a seven-tooth bridge. Engineering and designing of the bridge requires an understanding of how to replace teeth, as well as the biology of the supporting gum and bone tissue.
Crowns and bridgework require the same conscientious care as your natural teeth. Be sure to brush and floss between all of your teeth — restored and natural — every day to reduce the buildup of dental plaque. When you have crowns, it is even more important to maintain your regular schedule of cleanings at the dental office. Avoid using your teeth as tools (to open packages, for example). If you have a grinding habit, wearing a nightguard would be a good idea to protect your teeth and your investment.
Fillings do just what the name implies — seal a small hole in your tooth, i.e., a cavity, caused by decay. This prevents the decay (a bacteria-induced infection) from spreading further into your tooth and, if untreated, continue on to the sensitive inner pulp (nerve) tissue located in the root canal. Should that happen, you would need root canal treatment.
There are a variety of materials used to fill teeth these days, but the process of filling a tooth is similar regardless. The first step is a clinical exam of the tooth with x-rays, to determine the extent of the decay. Then the decayed area of the tooth is removed, usually with a handheld instrument such as a dental drill. Of course, your tooth will be anesthetized first, so you won't feel any discomfort. If you normally feel nervous about receiving numbing injections, it's possible that taking an anti-anxiety medication or using nitrous oxide can help you feel more relaxed. After removing the decay, the remaining tooth structure is roughened or “etched” with a mildly acidic solution; then translucent cement is applied to bond the tooth and the filling material together.
There are two broad categories of dental fillings: metal fillings and tooth-colored fillings. Each may offer particular advantages and disadvantages in certain situations.
Cast Gold — Among the most durable restorative dental materials, cast gold combines gold with other metals for a very strong, long-lasting filling. It is also highly noticeable, which can be considered a plus or minus.
Composite — A popular choice for those who don't want their fillings to show, composite is a mixture of plastic and glass, which actually bonds to the rest of the tooth. Composites are more expensive than amalgam fillings, and the newer materials can hold up almost as long. Less drilling of the tooth is necessary when placing composite as compared to amalgam.
Porcelain — These high-tech dental ceramics are strong, lifelike, and don't stain as composites can. They are sometimes more expensive than composites because they may require the use of a dental laboratory or specialized computer-generated technology. While considered the most aesthetic filling, they can also, because of their relatively high glass content, be brittle.
Glass Ionomer — Made of acrylic and glass powders, these inexpensive, translucent fillings have the advantages of blending in pretty well with natural tooth color and releasing small amounts of fluoride to help prevent decay. They generally don't last as long as other restorative materials.
The numbness caused by your local anesthesia should wear off within a couple of hours. Until then, it's best to avoid drinking hot or cold liquids, and eating on the side of your mouth with the new filling. Some sensitivity to hot and cold is normal in the first couple of weeks after getting a tooth filled. If it persists beyond that, or you have any actual pain when biting, it could signal that an adjustment to your filling needs to be made. Continue to brush and floss as normal every day, and visit the dental office at least twice per year for your regular checkups and cleanings. And remember, tooth decay is a very preventable disease; with good oral hygiene and professional care, you can make your most recent cavity your last!
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