Crown & Bridges
What is a crown?
A crown, sometimes called a "cap", is a restoration that goes over a tooth to cover it completely. A crown is usually used to protect the tooth from a fracture.
A crown can be fabricated from various materials; porcelain, aka glass, zirconia, and a combination of metal and porcelain.
The crown is usually custom made in a laboratory; however, there is modern equipment that can create a crown while a patient is in the chair.
What is the process for the crown?
Laboratory made crowns are done within 2 appointments, 3-4 weeks apart. On the first appointment, the tooth is cut circumferentially with a minimal reduction required for the thickness of the crown, approximately 1mm. After the tooth is prepared, the mold is taken to the laboratory. The laboratory uses this mold to fabricate a custom-made crown that can perfectly fit and function only on that tooth.
While the crown is fabricated in the laboratory, your tooth is protected with a tooth-colored, chairside, custom-made temporary crown. Even though temporary crowns can feel and function as a natural teeth, some precautions have to be maintained as they are made out of flexible plastic-like materials and cemented with a temporary cement.
At the delivery appointment, the permanent crown will be carefully checked for its integrity, fit, function, and esthetics. Even though the crown is made out of materials foreign to the body, it should feel and function as a natural tooth. The crown is then cemented with a permanent cement. It takes up to 24 hours for cement to completely set; therefore, patients are usually asked to avoid eating on brand new crowns for 24 hours to protect it from shifting.
Why do dentists diagnose crowns?
Dentists in Las Vegas and Henderson diagnose crowns when a tooth is severely compromised or damaged by a large filling, cavity, or fracture. A crown is like a sleeve that holds a tooth in one piece to be safe to chew on.
Sometimes crowns can be placed for esthetic reasons to alter misshaped or discolored teeth.
What are bridges?
A bridge is a fixed, permanently cemented appliance that is used to replace one or more teeth. It is one of the common choices to replace missing teeth aesthetically. A bridge is fabricated by the laboratory by connecting crowns on both sides of missing teeth with a teeth-looking link.
Why would I want to replace missing teeth?
Even if the esthetics are not an issue, missing teeth must be replaced for an ideal harmony and function of the mouth.
Teeth like to touch each other, and if for some reason a tooth is lost, the surrounding teeth will shift in the mouth to find their mate; a top tooth will move down, a bottom tooth will move up, a back tooth will move forward, and a front tooth will move back. Unfortunately, teeth don’t shift evenly, they shift at an angle causing problems with your bite.
What are the different types of crowns?
There are three different types of crowns in the modern dentistr; porcelain crown, porcelain fused to metal, and zirconia crowns.
What are Porcelain Crowns?
Full porcelain crowns are restorations whose full thickness is made entirely of a glass-like substance, such as porcelain.
Advantages of placing an all-ceramic crown is their natural appearance. They are most esthetic crowns in the modern dentistry.
The single biggest disadvantage is their durability to chewing. Therefore, they are usually recommended in the front esthetic areas where chewing is not part of the function.
What is a Zirconia Crown?
Zirconia is a ultra strong ceramic. It is considered to be one of the strongest aesthetic crowns in the market. It would be an excellent choice for back teeth where chewing is essential.
What is porcelain fused to metal crown?
Porcelain fused to metal crowns, aka PFM, consists of a metal shell covered by a layer of porcelain.
Advantages of PFM:
- Great strength due to their metal structure.
- Usually associated with lower cost comparing to porcelain or zirconia crowns.
Disadvantages of PFM:
- The “dark line”. If changes such as gum recession occur, the appearance of a tooth that's been crowned with a PFM can be spoiled by its metal edge (dark line) that then becomes visible.