Naturally, the tooth is made up of two basic components - the root (the part of the tooth inside the gums), and the crown (visible upper portion of the tooth). A dental crown is an artificial cap that is placed above the affected tooth to restore its form, strength, functions and improve its appearance. The dental crown should last for about 8 to15 years, under the normal circumstances.
When is the dental crown needed?
It is needed in the following conditions such as:
1. Large cavity in the tooth: In case of a large filling, the remaining part of the tooth becomes weak and may get fractured if not protected well. In several cases, large filling causes cracks in the surrounding area. In this type of a situation, filling is often replaced with a crown placement.
2. After root canal treatment: Root canal treatment sometimes leaves the tooth hollowed. So it often needs immediate dental crowns to avoid fractures and further defects.
3. Syndrome of cracked tooth: This is characterized by sharp pain when biting on a certain tooth which may get worse if the applied biting force is increased. This is due to the fractures inside the tooth which may or may not involve pulp. In this condition, the crown is placed to reduce the stress on fractures thereby relieving the pain. In this case the doctor may place a temporary crown for some time to help relieve pain.
4. Broken cusps due to trauma: Sometimes accidental injuries may result in a fracture and loss of tooth structure. To restore the tooth, a crown is needed. If the tooth is completely broken during the injury, the dentist may choose to do post & core build up sometimes accompanied by crown-lengthening procedure (this involves downward trimming of the bone and the gum below the edge of fractured part and placing the crown on a healthy base).
5. Unpleasant color or pattern of teeth: Can make the appearance of teeth unacceptable. In this case aesthetic dental crowns can improve the appearance.
6. Replacement of missing tooth: A bridge is multiple crowns joined as a single unit, used to replace the missing teeth by taking the support from adjacent healthy teeth.
Use of dental crowns in children:
- To protect a damaged/decayed tooth, when filling option does not work.
- To protect the front teeth with prefabricated aesthetic crowns
What are the types of dental crowns?
Based on the duration of its use, dental crowns are categorized as:
Temporary dental crowns: These are made up of acrylic or stainless steel and are meant to be placed temporarily until a permanent crown is available.
Permanent dental crowns: Made up of metals like stainless steel, gold or nickel-cromium alloy, porcelain-fused-to-metal and ceramic. These are made in a dental laboratory by experts and used for permanent restoration of teeth.
Based on the material used, following dental crowns are available:
- Stainless steel crowns: Usually these are preferred for temporary use either till the permanent crown is ready or in children to restore primary teeth. These are particularly used in children.
- Metal crowns: Include crown gold alloy, palladium or nickel-chromium alloy. They withstand the chewing pressure well and last longer. The only drawback is the unpleasant metallic color, so these are often preferred for off-site molars.
- Crown made up of porcelain-fused-to-metal: These are acceptable by appearance as it can be matched with the other teeth and looks like a natural tooth. They are often preferred for front line teeth.
- Crown made up of resin: Although these tooth colour crowns are cheap, they are weaker than porcelain-fused-to-metal crowns and can get fractured easily.
- Crowns made up of metal free ceramic: These provide most natural appearance than any other crown. Used by people with metal allergies and for front line teeth. However they are the costliest of the lot.
Which type of crown is best?
There is no ideal crown, so your dentist will make the right choice based on the needand desired benefits.
What are the steps involved in preparing the tooth before placing a crown?
You may be asked to visit the dentist twice to prepare your tooth for crowning.
Assessment and preparation of tooth for crown:
This involves the following steps:
- X-ray: To check for infection or injury to the root and the surrounding bone level
- Root canal treatment if needed
- Filling of hollowed part of the tooth to support the crown
- Anesthesia for the tooth and surrounding area
- Shaping of the tooth
- Making impression of the teeth to receive the crown
- Placing a temporary crown
- Manufacturing of the permanent dental crown
Placing a dental crown:
After the assessment and preparation, your doctor will take away the temporary crown and will fix the most suitable permanent crown chosen for you.
What type of care is necessary for a temporary crown?
The following precautions are necessary:
- Avoiding food that may grab and pull out the crown (e.g. chewing gum)
- Avoiding excess pressure on crown placed tooth, especially while chewing
- Avoiding hard foods that may break the crown
- Using slide flossing while cleaning the teeth
What are the risks after placing a dental crown?
Following may be some problems:
- Increased sensitivity and pain while biting.
- A porcelain crown may get chipped
- The cement used to fix the crown may get washed away leaving loose tooth behind and also increase the risk of decay
- Crown may fall off due to improper fitting or small tooth structure
- Experiencing allergic reaction to the material/s used for a crown
- Undesirable dark line near the gum line of crowned tooth may be observed
Is it okay to get a dental crown during pregnancy?
Materials used in crown preparation are safe and thus crowns can be placed during pregnancy, if it is truly urgent. However, it is recommended to avoid crown fixing unless absolutely essential during pregnancy to minimize stress on the fetus and the mother.