Porcelain Crown

Introduction

The crown is a cap placed over a tooth for restoring its shape, size, strength and also for improving its appearance. These crowns totally enclose the visible part of the tooth lying above the gum line after cementing. One of their types is a porcelain crown.

Indications for a porcelain dental crown:

Permanent Porcelain crown is needed in the following conditions:

1. For protecting a week tooth from decay, from breaking or for holding parts of a cracked tooth.

2. For restoring broken or severely worn out tooth.

3. For supporting and covering a tooth with large filling.

4. For holding a permanent dental bridge between abutment teeth.

5. For covering a dental implant.

Types:

Porcelain crowns can be of two types:

1. All-porcelain: these dental crowns are the best natural color match than any other crown type. Also, they are suitable for people having metal allergies. But, they are not as strong as porcelain-fused-to-metal crowns and they wear down the opposite teeth more than metal or resin crowns. They can be used for front teeth.

2. Porcelain-fused-to-metal: in this type, the color of the crown can be matched to adjacent teeth. But the drawback is that the opposite teeth are exposed to more wearing. Also, there is a possibility that the porcelain portion of the crown can chip or break off. It gives more natural look than its all-porcelain counterpart. In some cases, the metal underlying the porcelain can show up through as a dark line. Particularly this happens at the gum line. These crowns are a good choice for front as well as back teeth.

Tooth crown procedure:

1. The cosmetic dentist prepares an impression of the tooth and sends it to a dental laboratory to make the permanent crown.

2. A temporary crown is given to the patient to wear till the permanent crown is ready.

3. After about two weeks, generally the crown is ready and the permanent crown is then cemented onto the tooth. Thus, only two visits are required for this procedure.

4. For stabilizing this structure, a filling is placed before placing a crown due to the loss of original tooth structure.

5. Make sure to discuss with the dentist about the color of the crown and also check whether it is same as temporary crown.

6. Sometimes, a Flipper appliance is used in the place of temporary crown till the permanent crown is placed. A Flipper is a false tooth attached via either a wire or a plastic piece to the roof of the mouth awaiting the permanent crown.

Color of the porcelain Crown:

Although the Porcelain crowns mimic the natural color of the tooth, the level of whiteness or brightness of the white should be decided prior to crowning. However, two factors govern the natural looking color of the porcelain crown. These are internal contrast of color and texture. The internal contrast or play of colors on the porcelain in the crown helps to create a sense of vitality. Surface texture is also very important in this case as the texture breaks up the reflections of the light giving a natural hue to the crown. The selection of shades of color with various levels of brightness is available with the dentist.

Problems with a porcelain dental crown:

1. Sensitivity: newly crowned tooth can be sensitive to extreme temperatures immediately after the procedure, as the effect of anesthesia begins to decrease. Too highly places crown can also cause sensitivity during bite. This can be corrected easily.

2. Chipping of crown: all porcelain crowns tend to chip. It is generally repaired by using a composite resin. But, if there is extensive chipping, the crown may need to be replaced.

3. Loose crown: Sometimes the cement washes under the crown gets dislodged causing loosening as well as infection. If a crown feels loose, contact the dentist.

4. Fall of the crown: due to lack of cement or improper fitting. This can be fixed or replaced.

5. Allergy to porcelain.

6. Cost of the crown must be weighed against the advantages.

On an average, the running life of the permanent porcelain crown is about ten to fifteen years.