Grinding your teeth, an improper bite, age, root canals, lost fillings and tooth decay can all be contributing factors in the wearing down, cracking or breakage of your teeth. Dental crowns cover the entire visible surface of your affected tooth and add strength, durability and tooth stability.
Crowns are made of natural looking porcelain and are made to improve your overall smile or to blend in with your own teeth. Your cosmetic dentist will usually be able to spot problem areas in your mouth that might lead to tooth damage and a need for crowns. Chewing patterns play a big role as well. By selectively grinding the tips of your middle and back teeth (called cusps) will alter your bite to reduce the stress on at-risk teeth. Crowns are dental restorations otherwise known as "caps" which are coverings that fit over teeth. Crowns are also used to improve the appearance of natural teeth that are malformed, malpositioned or discolored.
Who is a candidate for Tooth Crowns?
A dental crown is needed when a tooth is badly broken down - either a cusp has broken off, or there are large old fillings or a large portion of decay. A filling is used to fill a small portion of the tooth - a crown when the tooth has extensive damage.
A previously filled tooth where there now exists more filling than tooth. The existing tooth structure becomes weakened and can no longer support the filling. Fillings may develop broken edges which will no longer properly seal the tooth. If the filling is small enough, a new filling can be used. But if the tooth has a large filling and there is not very much of the original tooth material to attach the filling to, a crown may be a better solution.
Extensive damage by decay. If a tooth has decay so deep and large that a filling will not stay, or if the tooth structure is weakened, a crown must be placed on the tooth to save it.
Discolorations and compromised esthetics.
Fractures or Cracked Tooth:
A tooth that has broken is usually too weak to hold a filling. A crown will hold the tooth together and prevent it from breaking again. If the fracture involves the nerve, Root Canal Therapy may be required before the tooth is crowned. In some cases, a broken tooth cannot be saved and must be extracted. When a tooth is cracked, a filling will not seal the crack. A crown has to be placed over the tooth to hold it and the crack together. If a crown is not placed on the tooth, the tooth will become sensitive to chewing pressure, or will eventually break. It is important to crown a cracked tooth before it breaks, because in some
cases a broken tooth cannot be crowned and must be extracted.
After Root Canal:
Teeth tend to become brittle and are more apt to fracture. These teeth need to be protected by a crown.
When missing teeth are replaced with a bridge, the adjacent teeth require crowns in order to support the replacement teeth.
Types of Tooth Crowns
There are basically three types of crowns, those made of gold, ceramic crowns and ceramic-veneered gold crowns. Gold and metal-ceramic crowns are extremely durable and are normally used in molars, where the forces from chewing and grinding are most prevalent. Ceramic crowns are used primarily for front teeth, since they can best resemble the natural tooth color.
The following are the advantages and disadvantages
of the most common crown types;
1. Gold crowns
Gold crowns are appropriate when appearance is not a priority to you. The gold metal is very workable, gold crowns are able to have a more precise fit than any other type of dental crown. Gold crowns also eliminate the slight possibility of chipping that exists with anything that contains porcelain. For simple longevity, nothing beats gold.
The preparation of a tooth for a gold crown is the simplest and least complicated preparation as there is minimal tooth structure removal with as much as possible of the healthy tooth structure remaining untouched. While porcelain is hard by comparison, it may cause wear on opposing teeth over the years where gold is not as likely to do so. Gold is also easier to fit to the area where the tooth and crown meet for a better fit. Gold is also a healthier environment for the gum tissue.
The biggest disadvantage to gold crowns is the cosmetic aspect, unless it is being used in the back of your mouth.
2. Resin and Porcelain Crowns
The new reinforced resin or bonded all-porcelain type of crown has the nicest appearance. This crown can be made from pure ceramic or a new reinforced composite resin, and is almost indistinguishable from natural teeth. The new bonding technology involved provides an exceptional bond your tooth. It is metal-free, and thus satisfies the needs of patients with metal sensitivities.
The Empress crown is also a variation of an all-porcelain crown which uses the Empress pressed ceramic material. Other ceramic crown materials are Procera, In-Ceram, and feldspathic porcelain. A cosmetic dentist will be familiar with all of these materials and will use the best crown for each clinical situation. They all have their advantages and disadvantages.
|Advantage: Porcelain crowns or new reinforced resin are considered to be the most aesthetically pleasing, as it is so easily matched in color to the surrounding teeth and no metal shows.
Disadvantage: The thickness of the porcelain required for pleasing aesthetics also requires that more tooth structure needs to be removed. Gingival inflammation appears to be more common with porcelain crowns than gold crowns.
3. Porcelain Fused-to-Metal Crowns
For a very natural appearance, porcelain fused to metal crowns are the answer. Because they have a metal substructure, they require the use of an opaquer under the porcelain, which makes it impossible to re-create the translucency of natural teeth. They can also show a dark line at the edge of the crown, next to the gum. Dentists try to hide this line under the gum, but sometimes they are unable to do this; and sometimes the line doesn't show when the crown is first placed but shows later, as the gum recedes But porcelain fused to metal is stronger than the all porcelain crown.
|Advantage: Porcelain fused-to-metal crowns have a very natural appearance. They are the strongest type of esthetic crowns and don't fracture or chip as easily as alternative esthetic type crowns.
Disadvantage: They have a metal substructure and require an opaque below the porcelain. This can make the translucency of natural teeth difficult to replicate. Occasionally a darker line will be visible at the edge of the crown, near to your gum when it recedes with age. Metal may be visible if tissue is thin, may affect color of porcelain and possible bluish tint of gum if gum tissue is thin and metal shows through. Porcelain margin more susceptible to chipping than metal.
In situations where there is a high amount of concern about appearance, a bonded all porcelain crown (metal-free) is the nicest restoration. For the front teeth, the advantage is its natural, lifelike translucency and not having to deal with the possibility of the potentially unsightly dark line at the gum line of the tooth. For back teeth, the advantage of a porcelain crown or onlay is the conservation of healthy tooth structure and kindness to the gums.
Where appearance is no concern to you, a gold crown is a logical choice, because it has the best fit and the best chance of lasting the longest. It will never crack or chip.
For teeth that are toward the back but that still show when you smile, a porcelain fused to metal crown is a good choice. Because it isn't in such a prominent position, it usually looks very natural, and although it's not indestructible, it's strong enough to resist the heaviest biting stresses.
It takes two appointments to restore your tooth with a crown. This is because the crown must be custom hand-crafted in a dental laboratory to precisely fit your tooth and bite.
These are the steps necessary to produce your new crown:
- Your tooth is numbed with topical and local anesthetic.
- Any decay is removed.
- The tooth is shaped with a handpiece.
- We take a precise impression of your teeth. You will be fitted with a temporary crown while the dental laboratory crafts your permanent crown. These plastic (acrylic) restorations are placed on teeth to protect them and the gum tissues between dental visits. The temporary cementing medium used is designed to allow the easy removal of the temporary at your next scheduled visit. This usually takes about one week.
There are a couple of additional facts you should know about regarding the care of your temporary crown:
- Home care is extremely important while your temporary crown is in place. The health of your gum tissue and the success of your final treatment restoration depends upon it. PLEASE do not be afraid to clean your teeth between visits.
- Sometimes, even with meticulous care, temporary crowns may become loose between visits. If this should occur, please place the temporary crown back on your tooth immediately and hold the temporary in place until you can schedule an appointment. Once again. If you can not replace the temporary crown yourself, put it in a safe place and call the office. We will be happy to recement it for you at the earliest possible moment.
It is not unusual for the new crown to be mildly sensitive to cold temperatures for a few weeks. However, if the sensitivity is severe, does not subside, or if the bite feels uncomfortable, contact your dentist. Further adjustments to the crown may be necessary.
|Second Appointment |
- On your next visit to the dentist, your temporary crown is removed and your new permanent crown is fitted. Your dentist will fit the final crown, check for accuracy, adjust for any bite discrepancies and evaluate the esthetics
- When you and the dentist are satisfied with the fit and bite. If all of these factors are acceptable, the crown is cemented to your tooth
How long do crowns last?
Crowns should last approximately 5-8 years. However, with good oral hygiene and supervision most crowns will last for a much longer period of time. Some damaging habits like grinding your teeth, chewing ice, or fingernail biting may cause this period of time to decrease significantly.
To prevent damaging or fracturing the crowns, avoid chewing hard foods, ice or other hard objects. You also want to avoid teeth grinding. Besides visiting your dentist and brushing twice a day, cleaning between your teeth is vital with crowns. Floss or interdental cleaners (specially shaped brushes and sticks) are important tools to remove plaque from the crown area where the gum meets the tooth. Plaque in that area can cause dental decay and gum disease.
Dental crowns can restore a natural-looking smile when accidents, disease or wear and tear cause damage to teeth. Porcelain or porcelain-on-gold crowns are extremely reliable for long-lasting repair of even the most severe dental problems, including permanent replacement of missing teeth to give you a complete smile and a functional bite. Crowns can also return full dental function and relieve unexplained pain due to hairline cracks in filled back teeth.
In front teeth, older fillings can both weaken the teeth and cause staining or chipping. Porcelain crowns and bridges are suitable in cases where porcelain veneers are not. In teeth with root canal fillings, crowns can prevent breakage. When done correctly, these treatments typically last 5-8 years as close to permanent as any dental treatment gets.
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