Crown & Bridges
WHAT IS A CROWN?
A crown, often called as a cap, is an artificial hollow cover resembling a natural tooth crown that restores a decayed or damaged tooth to its normal shape and size. It is fabricated out of metal or ceramic material by special procedure in a dental lab.
WHERE CAN CROWNS BE PLACED?
- All the teeth that have had root canal treatments done should be covered with crowns to prevent their breakage as they have lost their natural hydrating mechanism and tend to be brittle.
- Teeth that have been restored more than half by filling material should be crowned.
- Tooth with bad aesthetics can be reshaped with crown to improve the aesthetics.
- Damage to the tooth structure because of wear and tear can be restored with crown.
- Fractured tooth can be restored with crown.
- Teeth with wide spaces between them resulting in food lodgment or unpleasant appearance can be crowned.
A fixed bridge can replace one or more missing teeth. It consists of one or more artificial solid teeth suspended to crowns that are placed on two or more supporting teeth. Fixed bridge helps to restore normal function and proper position of your bite. A fixed bridge is made of various metals, porcelain, or a combination of the two.
WHERE IS IT INDICATED?
- If one or more teeth are missing it can be replaced with fixed bridge.
- If the jaw has generalized space in between the teeth, the fixed bridge can fill the gaps.
- Can be placed over implants to make implant supported partial or full mouth bridge.
WHAT ARE THE ADVANTAGES OF A BRIDGE?
- This is a fixed partial denture and patient does not need to remove it once fixed.
- If maintained properly, stays for a longer period.
- Less expensive as compared to dental implants.
- Do not require any surgery.
WHAT ARE THE DISADVANTAGES OF A BRIDGE?
- The supporting teeth needs to be trimmed.
- They are more expensive than removable dentures.
- Difficult to maintain oral hygiene.
- Does not prevent bone loss.
HOW ARE CROWN/ BRIDGES MADE?
- The tooth is trimmed in a proper shape to accommodate the crown/bridge.
- An impression is made with an impression material to replicate the tooth outside the mouth.
- Then a model is made from this impression with a special dental stone which will represent patient’s teeth.
- The model is sent to dental lab where a crown/bridge is fabricated.
- When a crown/bridge is ready, it is bonded with special type of dental cements to the trimmed tooth in the patient’s mouth by the dentist.
VARIOUS TYPES OF CROWNS/BRIDGES
There are various types of crowns/bridges which include:
- All metal .
- Porcelain fused to metal (tooth coloured)
- All porcelain (metal free )
- Zirconium based (metal free)
- Precious metal
- They are the most stable crowns available.
- There is no porcelain to chip or break and they are nearly indestructible.
- They can be made quite thin in areas in which there is little room.
- They require less tooth reduction.
1) The major disadvantage of this crown is its aesthetics. They are very unaesthetic and can’t be used in front teeth region.
PORCELAIN FUSED TO METAL:
- PFM’s are the strongest esthetic crowns in dentistry, and have the advantage of the added stability provided by the bevel at the finish line.
- They can be given in front teeth region also.
- The major disadvantage of this crown is, it requires more space to accommodate porcelain.
- Because of Metal inside, the gum line tattooing can be observed at later stage.
- Because of metal inside, it has to be masked by an opaquer making the overall look of the crown/bridge more opaque ( slightly artificial).
- All-porcelain crowns are esthetically the best choice for anterior teeth.
- They transmit light like a real tooth. So gives the best hue for front teeth and thus does not look artificial.
- The Main disadvantage of this crown is they are not strong enough to bear occlusal forces.
Can’t be give in posterior teeth.
ZIRCONIUM BASED CROWNS/BRIDGES
- Crowns with zirconium copings are almost as strong as porcelain fused to metal crowns.
- They are suitable for posterior, as well as anterior teeth, and they have nearly the same excellent esthetics as all-porcelain crowns.
PRECIOUS METAL CROWNS/BRIDGES
They are made from precious metals like gold and palladium.