Crowns: An Overview

Why would I need a crown (cap)?
1. A tooth has been so badly damaged by decay or so heavily restored by fillings that it can only be saved with cast restoration
2. A tooth has been treated endodontically (root canal treatment). These teeth are almost always restored with a cast restoration because they have lost a great deal of tooth structure from fracture, decay, or the drilling process. These teeth are prone to fracture under normal and light chewing forces.
3. The tooth needs to be used as an abutment (anchor) for a bridge to replace missing teeth.
4. Grinding your teeth, an improper bite, age, fillings and tooth decay can all be contributing factors in the wearing down, cracking or breakage of your teeth. 

What are dental crowns?
Dental crowns cover the entire visible surface of your affected tooth and add strength, durability and tooth stability. Click here to learn about the difference between crowns, bridges, and implants.

What kinds of crowns are there?
Expect to pay more for porcelain crowns because they are usually more time-consuming than gold crowns. Porcelain, porcelain over metal and gold crowns average between $600 to $3100 each in total cost. The new reinforced resin or bonded all-porcelain type costs more than other types, require more skill from your dentist and the lab, and may exceed your insurance plan coverage for crowns.

• Resin and Porcelain Crowns

• The new reinforced resin or bonded all-porcelain type of crown as the nicest appearance. This crown can be made from pure ceramic or a new reinforced composite resin, and is almost indistinguishable from natural teeth. Thew new bonding technology involved provides an exceptional bond to your tooth. It is metal-free, and thus satisfies the needs of patients with metal sensitivities. When correcting your back teeth with bonding, the cosmetic dentist will perform a tooth colored onlay. This type of procedure is used to correct only those parts of the tooth that are in need. This is a metal-free procedure. 
• 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
• Disadvantage: The thickness of the porcelain required for pleasing aesthetics also requires that more tooth structure needs to be removed. It is more difficult for your cosmetic dentist to get an ideal fit where your gum meets the crown. Gingival inflammation appears to be more common with porcelain crowns that gold crowns. All-porcelain crowns require a higher skill level from your dentist and lab.
• Crowns Made of Gold

• Gold crowns are appropriate when appearance is not a priority to you. The gold metal is extremely workable, making gold crowns a more precise fit than any other type. While there exists a slight possibility of chipping with porcelain crowns, gold crowns provide no such possibility.
• Advantage: 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 goal 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.
• Disadvantage: The cosmetic aspect, unless it is being used in the back of your mouth
• Porcelain and Metal Crowns

• For a very natural appearance, porcelain fused to metal crowns are the answer. However, 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. 
• Advantage: Porcelain fused-to-metal crowns have a very natural appearance
• 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
• Types of Porcelain
• There are two types of porcelain - felspathic and pressed ceramic porcelains. The felspathic type is the original method that has been around for 20 years. Ceramist in a dental lab bakes porcelain onto tin foil and then heats it in an oven. The Ceramist is able to create tints and opaques inside the porcelain to give the natural look we seek.
• Pressed ceramic is created from a single ingot. The single ingot is milled in one piece to create the desired shape. The stains and opaques are applied only to the surface of the porcelain to give a natural look.

How do I choose a color for the dental crowns - how white should it be?
Whiten your natural teeth to either the level of whiteness you want or to the brightest they can be. Your cosmetic dentist will then have the crowns made to that color. Teeth are of course not monochromatic, so typically more than one color is used to used a very natural look. This color variation is critical in avoiding fake or artificial looking teeth. It is the internal contrast of colors that help create vitality. The internal play of light on the porcelain in the restoration helps to create this vitality. Surface texture is also very important, and helps to break up light reflections and make the crown look more natural.

There is no one standard system in the dental field to measure and determine tooth color. The most often heard about, however, is the Vita shade guide. This guide divides tooth color into four basic shade ranges:

A (reddish brown)
B (reddish yellow)
C (gray)
D (reddish gray)

In the A range, there are five level of darkness. Ranges B, C, and D, each have four levels.

Not all of your teeth are the same natural color. Usually your eye teeth tend to be darker than the others, your front teeth are typically the whitest, and molars tend to be a shade between the two. The goal for everyone is to achieve their individual optimum whiteness while still looking natural.

Most dentists will show you a shade chart for your to pick from. Keep in mind, with a good cosmetic dentist, this is merely a starting point. Other considerations when determining the color of crowns for each patient are your complexion, hair color, the color of your natural teeth and even your eye color.

What is the procedure?
- Preparing (drilling) the tooth in an appropriate fashion for the type of crown chosen
- Making impressions of the prepared tooth, opposing teeth, and the occlusal (bite) relationships
- Selecting a shade for tooth-colored crowns
- Fabricating a provisional restoration that will remain in place while the crown is being constructed
- Cementing or bonding the completed crown into position. If the work to be done is extensive, there may also be several appointments needed for preliminary seating (try-in) of the crowns or castings

What do I need to do BEFORE I get the crown?
It is important for the ultimate success of the crown(s) that you understand and can perform thorough plaque removal. You should immediately begin following the oral self-care instructions that you have been given. It will make the procedure more comfortable and efficient, and the resulting restorations will look better. Final impressions cannot be taken until the gum tissue is healthy. Crown lengthening is an oral surgery treatment that involves removing excess gum tissue around the upper teeth to make them look longer. Your cooperation is appreciated and necessary.

What do I need to do AFTER I get the crown?
As is true with your natural teeth and especially with teeth that have been restored with any dental material, you should avoid chewing on excessively hard or sticky foods after the crowns have been cemented. It is especially important not to bite down on hard foods with just one tooth. The porcelain material can fracture from the metal substructure under extreme forces. Anything you chew that could break a natural tooth could break a crown!

Be sure to brush and floss daily as instructed. We also advise using a fluoride mouthrinse as part of your daily routine. Please be sure to return for your regular examinations and prophylaxis (cleaning) appointments at the time intervals we suggest.

After observing these types of procedures for many years, we note that the gingiva (gums) can recede from the crown margins and the surrounding tooth structure may become visible. This recession usually takes place over a period of several years and may require restoration replacements or a periodontal plastic surgery procedure to correct it.

We expect that you will receive many years of service from the cast restoration.

If you have any questions about crowns and bridges, call our office and ask or set up an appointment. We have 3 convenient locations around Austin.