Dental Crowns are fixed
prosthetic devices. Unlike removable devices such as
dentures, which you can take out and clean daily, crowns are cemented onto existing teeth or implants. These restorations are permanently bonded to your natural
tooth or teeth. These restorations are used to correct your
bite and restore your teeth's strength and function, as well
as give you back a beautiful, full smile if you are missing
Before either a crown can be
made, the tooth (or teeth) must be reduced in size so that
the crown or bridge will fit over it properly. After
reducing the tooth/teeth, your dentist will take an
impression to provide an exact mold for the crown or bridge.
If porcelain is to be used, your dentist will determine the
correct shade for the crown or bridge to match the color of
your existing teeth.
Using this impression, a dental lab then makes your crown, in the material your dentist specifies. A temporary crown will be put in place to cover the prepared tooth while the permanent crown or bridge is being made. When the permanent crown is ready, the temporary crown is removed, and the new crown is cemented over your prepared tooth or teeth.
While crowns can last a
lifetime, they do sometimes come loose or fall out. The most
important step you can take to ensure the longevity of your
crown is to practice good oral hygiene. A Crown
can lose its support if the teeth or bone holding it in
place are damaged by dental disease. Keep your gums and
teeth healthy by Brushing with fluoride toothpaste twice a
day and flossing daily. Also see your dentist and hygienist
regularly for checkups and professional cleanings.
To prevent damage to your new crown, avoid chewing hard foods, ice or other hard objects.
How do Crowns Work?
A crown is a restorative that covers, or "caps," to strengthened a damaged tooth to restore it to its normal shape and size. Crown can be used to improve the tooth appearance, shape or alignment. Crowns are necessary when a tooth is generally broken down and fillings won't solve the problem. If a tooth is cracked a crown holds the tooth together to seal the cracks so the damage doesn't get worse. Crowns are also used to support large fillings when there is not enough tooth surface remaining to attach a bridge. Crowns protect weaker teeth from fracturing or restore fractured teeth and they also cover badly shaped or discolored teeth.
The porcelain teeth crown procedure
takes place over two office visits. During your first visit,
we will prepare your tooth, removing any decayed damaged
tooth and preparing the existing tooth for the crown.
prepare the tooth
for a crown, it is reduced so the crown can fit over it . A one to two millimeter dimension all around the tooth and on top is removed to fit the crown while strengthening and preserving the remaining natural tooth structure We will then take a precise impression or mold of the remaining tooth material, which will be used as a guide to creating your new porcelain crown. A temporary crown is fitted over the tooth until the permanent crown in made.This impression of your tooth will be sent to a specialty dental laboratory, where your natural looking porcelain crown will be fabricated to your exact needs. Once this process is completed and we have your finished porcelain crown, you will return to the office, where we will apply a special dental adhesive to bond your new crown to the existing tooth structure. Once permanently cured, this adhesive will create a strong, permanent bond, and your new porcelain crown will be complete and and it becomes your new tooth.
To prevent damaging or fracturing the
crowns, avoid chewing hard foods, ice or other hard objects
- just like you should avoid for your natural teeth. 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
Plaque in that area can cause dental decay and gum disease.
Crowns can be made in three different ways.
1. Gold crowns - Gold is very durable but obviously not as aesthetically pleasing as porcelain, which looks like your natural tooth. Gold is more durable than porcelain on chewing surfaces so it is sometimes preferable when a molar needs a crown. These alloys are generally stronger than porcelain and may be recommended for back teeth.
2. Porcelain fused-to-metal - These crowns have a metal,
sometimes gold, lining inside the porcelain exterior. They
are natural looking because the porcelain is on the outside
and more durable than porcelain alone because of the metal
lining. One caution for these types of crowns is that as the
years pass and your gums start to recede, the metal lining
can show as a dark line along the gum line, thus negating
the aesthetic look that you first wanted to achieve.
As mentioned, because of a metal lining, though covered with porcelain, on the aesthetic zone or on the front area of the mouth, If we can avoid using them, All Ceramic or Procelain Crown would give the best aestheitc result. When placed, they usually look opaque or "flat" because they do not let light pass through like a natural tooth. There is often a tell-tail dark line next to the gum-line that is undesirable (often the darkness invades the adjacent gum tissue as an adverse reaction).
3. Composite Crown - Composite crowns provide a good "temporary" cheaper alternative to porcelain crowns for the short term. They will eventually wear down or break and you should expect to have your composite crowns replaced or "upgraded" to a porcelain or gold crown.
4. Porcelain crowns - the most natural in appearance because of their transparent properties. They are strong and durable.
The most beautiful crown for a tooth is, without question, all-porcelain or all-ceramic. With porcelain fused to metal crowns, there has to be an opaque layer put over the metal to block out its color. This makes it impossible to have a translucent restoration that mimics the translucency of natural teeth. Only with pure porcelain or pure ceramic can you have such translucency.
There are various types of all-porcelain or all-ceramic crowns. Let's explain the differences between some of them:
1.The Procera crown - Procera is a milled ceramic on the inside with a more traditional porcelain baked onto the outside. The advantage of Procera is its exceptional strength. However, the milled ceramic core is opaque white, so many cosmetic dentists feel that it isn't as natural-looking as the more translucent materials. An advantage of Procera is that it doesn't have to be bonded to the tooth but can be cemented with ordinary crown and bridge cement.
2. The Lava crown - Lava is similar to Procera, but the milled ceramic on the inside is a more translucent Zirconia, rather than an opaque white material. The Zirconia is shaded, and then the final esthetics of the crown are achieved in the baked-on outer layer. The Lava crown can also be cemented with traditional techniques. However, any crown cemented with a traditional crown and bridge cement is going to be susceptible to a compromise in the appearance if that cement line ever shows.
3. Feldspathic porcelain is the
standard, traditional porcelain that is used for crowns.
Many cosmetic dentists feel that this is the most beautiful
The Empress crown - Empress is strictly speaking not a porcelain, but is more like a glass. It can be called a ceramic material. The Empress material is cast rather than baked as a feldspathic porcelain crown is. The fit of Empress is more precise than the baked feldspathic porcelain. However, the color in Empress is mostly baked on the outside. Empress can be very beautiful. For appearance's sake, some expert cosmetic dentists prefer the feldspathic porcelain, and some prefer the Empress.
4. The Cerec crown - Cerec is are also milled from a block of very hard ceramic material. What's unique about Cerec is that the crown is milled by a computer in the dentist's office rather than in a separate dental laboratory. Thus, the dentist doesn't have to send out for it to be made-it can be made on the spot. So, no second appointment is required, and no wearing of a temporary crown between appointments. Cerec is milled from a block of ceramic that is a single color, so it is generally not considered esthetic enough for demanding cosmetic dentists. A few exceptional dentists who are artists, however, are able to custom stain Cerec for front teeth so that they are truly beautiful. Some even make Cerec veneers that can be placed the same day. To be precise, Cerec is actually a technique and not a material. There are several companies that make ceramic materials for use in Cerec machines.
5.The InCeram crown - InCeram is made of a very dense and very
tough aluminous porcelain. It also has excellent esthetics,
but is more opaque than feldspathic porcelain. InCeram is
also strong enough to be cemented with traditional dental
There are other types of all-ceramic crowns. We're not going to list all of them here.
All-porcelain is generally not as strong as porcelain fused
to metal. It has to be bonded to the tooth in order to have
adequate strength for oral function. The bonding technique
is very demanding.
With porcelain fused to metal, the porcelain has to be opaque in order to block out the appearance of the metal underneath. They all also eventually develop an unsightly dark line at the margin where the edge of the crown meets the tooth.
Some of the all-ceramic systems that have an inner ceramic core with an outer layer of porcelain baked on require more tooth reduction. Grinding away more of the tooth is often not desirable.
Some of the ceramic materials that are very tough and fracture resistant are also quite abrasive against the opposing teeth. Of the crowns listed above, the Empress is the kindest to the teeth it chews against. There are several factors that need to go into the selection of a crown material: strength requirements, esthetic requirements, the abrasivity of the material against the opposing teeth, and the skills of the dentist.
There is not a single crown that is clearly superior for all situations. Many cosmetic dentists will have several types that they will use, each for a different situation.
If you are interested in learning more about porcelain Dental Crowns and Bridges, you can read more info on the link provided below or you can schedule for a FREE cosmetic consultation, by calling our office at (613) 9629-7664. For your convenience, you may also fill out our online contact form
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