A crown (or cap) is  used to cover the entire tooth surface for  restoring  the tooth  like  its original shape and size.  A crown protects and strengthens tooth structure that cannot be restored with fillings or other types of restorations. Crowns are necessary when fillings will not solve the problem due to the loss of substance in the tooth. Crowns are also used to restore partially fractured teeth or to cover badly shaped or discolored teeth.

Although there are several types of crowns, porcelaine crowns  (tooth colored crown) are the most popular, because they resemble your natural teeth.  They are highly durable and will last many years, but like most dental restorations, they may eventually need to be replaced.  Porcelain crowns are made to match the shape, size, and color of the teeth for  a natural, long-lasting beautiful smile.

Reasons for crowns:

• Broken or fractured teeth.
• Cosmetic enhancement.
• Decayed teeth.
• Fractured fillings.
• Large fillings.
• Tooth  that has  root canal treatment.
• What does getting a crown involve?
• A crown procedure usually requires two appointments.  Your first appointment will include shaping the teeth and taking several highly accurate molds (or impressions) that will be used to create your custom crown and a temporary crown which will stay on your tooth for approximately  until your new crown is ready.
• While the tooth is numb, the dentist will prepare the tooth by removing any decay and shaping the surface to properly fit the crown.  Once these details are accomplished, your temporary crown will be placed with temporary cement and your bite will be checked to be sure about your  proper biting position. After shaping the tooth and preparing it for the new porcelaine crown you will have the temporary  plastic crown at the same day.
• At your second appointment your temporary crown will be removed, the tooth will be cleaned, and your new crown will be carefully placed to ensure the spacing and bite are accurate.
• You will be given care instructions and encouraged to have regular dental visits to check your new crown.
• There are  a few different types of porcelain crowns like  e-max crowns,empress crowns,zirconia crowns,metal based porcelaine crowns,etc.

Metal- based  porcelaine  crowns

These crowns have a metal core, on top of which porcelain has been fused. The metal is first masked with an opaque layer of porcelain to give it a more tooth-like color, and then consecutive layers of normal porcelain are used to build up the final shape. The metal used is semi-precious or precious such as gold. Metal porcelain crowns are used when there is a need for high strength, normally in the molar region.

A PFM-crown can be made in such a way that the gum-portion of the crown has no metal at all. Instead this portion of the crown is made in porcelain. Therefore, only porcelain can be seen.
In a situation, where there is one or more teeth missing, a dental bridge literally bridges the gap. In its basic form, a dental bridge involves placing a crown on each tooth on either side of the missing tooth, with a tooth suspended between the two crowns. The two anchoring teeth are called abutment teeth. The suspended tooth is called a pontic. A dental bridge can also be supported by implants or even by a combination of natural teeth and implants.

B-PORCELAİNE BRİDGES

A dental bridge is a fixed (non-removable) appliance and is an excellent way to replace missing teeth.

There are several types of bridges.  You and your dentist will discuss the best options for your particular case.  The “traditional bridge” is the most popular type and is usually made of porcelain fused to metal.  Porcelain fixed bridges are most popular because they resemble your natural teeth.  This type of bridge consists to two crowns that go over two anchoring teeth (abutment teeth) and are attached to pontics (artificial teeth), filling the gap created by one or more missing teeth.

Dental bridges are highly durable and will last many years, however they may need replacement or need to be re-cemented due to the conditions.

Reasons for a fixed bridge:

• Filling the space of missing teeth.
• Maintain facial shape.
• Prevent remaining teeth from drifting out of position.
• Restore chewing and speaking ability.
• Restore your smile.
• Upgrade from a removable partial denture to a permanent dental appliance.

What does getting a fixed bridge involve?

Getting a bridge usually requires two or more visits.  While the teeth are numb, the two anchoring teeth are prepared by removing a portion of enamel to allow for a crown.  Next, a highly accurate impression (mold) is made which will be sent to a dental laboratory where the bridge will be fabricated.  In addition, a temporary bridge will be made and worn for several days until your next appointment.

At the second visit, your permanent bridge will be carefully checked, adjusted, and cemented to achieve a proper fit.

You will receive care instructions at the conclusion of your treatment.  Proper brushing, flossing and regular dental visits will aid in the life of your permanent bridge.

Traditional bridges are made of either porcelain (ceramic) alone or porcelain fused to metal (gold, semi-precious or non-precious).

Full porcelain bridges

Porcelain bridges are dental bridges made completely of porcelain. The core (framework) in porcelain bridges is often zirconium, especially when bridges are long (covers much of the arch), when bridges have longer hanging sections or when bridges are being used in the molar regions, where the bite forces are higher. The reason is the exceptional hardness of the material. The zirconium is veneered (covered) with more conventional porcelain. When properly seated, a bridge in zirconium is nearly as strong as a metal-porcelain bridge. Short bridges (one tooth missing) can be made in the front region or on the teeth immediately behind the front teeth (bicuspids or premolars), in an even more aesthetic material, IPS e.max ceramic.

Metal porcelain bridges

Porcelain fused to metal bridges have metal on the inside and porcelain on the outside. The metal inside adapts perfectly to the teeth and provides strength and resistance to biting forces. The porcelain outside provides the beautiful appearance, matching the color and shape of your other teeth.

The main advantage of a metal-porcelain bridge is its strength and durability. If there is any uncertainty concerning the level of chewing forces used on the back teeth, a porcelain fused to metal bridge is often recommended.