Crowns & Bridges
A dental crown refers to a tooth-shaped "cap" that is fitted over an existing tooth to restore its function, shape, or appearance. It can be made from a range of different materials depending on your functional and cosmetic needs.
The crown is a fixed prosthetic treatment, which means that it is cemented over your tooth, and unlike dentures it isn't removable.
Why may I need a Crown?
The dental crown is one of the most common prosthetic treatments and there are several reasons why somebody may need one.
1. Your tooth has a large cavity and it can not be restored with just a filling, as it may fail or further weaken the tooth and eventually fracture.
2. You've broken a tooth during an accident or chewed something hard and substantial tooth structure is missing. The tooth now is not restorable with just a filling and a crown is needed in order to protect the tooth from further damage.
3. You have had a Root Canal Treatment (RCT). After an RCT, the center of the tooth is weakened as the procedure requires removal of affected tooth structure for proper cleaning and shaping. So, in order to protect your weakened tooth from breaking (due to high forces during chewing) especially if it is a back tooth, a crown is required and considered as the best option.
4. You have had a large filling and now a part of the tooth fractured leaving your tooth even more weakened. This is a common issue observed with large amalgam fillings and should be addressed as soon as it is noticed because further damage is possible. Usually a crown in this situation is the best option as it will provide full coverage and protection of the weakened tooth.
5. Due to Cosmetic reasons. When you have a tooth that is discolored, or slightly misaligned (and orthodontics are not a desired option) restored with an old filling and you want a better looking smile, then a dental crown is an excellent solution.
What is a dental Bridge?
A dental Bridge is a fixed prosthetic treatment used to replace one or more missing teeth. It literally bridges the gap between two existing teeth, as the pontic (the fake tooth replacing the gap) is held in place as it is fixed between the crowns of the existing anchoring teeth called abutments. So, a bridge replacing one missing tooth will consist of two crowns and a tooth shaped pontic. A dental bridge is a fixed alternative to removable bridges or implants in replacing missing teeth. Unlike removable partial dentures, the bridge is fixed over your existing teeth providing excellent stability and you get used to it just in a few days.
Dental Crown/Bridge Materials
Dental Bridges and Crowns can be fabricated from a range of different biocompatible materials. Which material you choose depends on clinical indications, cosmetic requirements and quality.
Metal Crown
A Metal crown or bridge is an excellent material option as it can perfectly restore function and the form of teeth. One of the main downsides is that they do not imitate the colour of natural teeth, which is a cosmetic issue for some patients. A metal crown can be fabricated from low value non-noble alloys such as Chrome-Cobalt to high noble dental alloys such as Gold adding significant value to the crown. Gold even today, is considered one of the most biocompatible and long lasting restoration materials in dentistry.
Porcelain Bonded Crowns (PBC)
BC is one of the most common combinations of material used in dentistry for crowns and bridges as it is indicated to restore perfectly function and appearance, from front to back teeth. They consist of a metal core (noble or non-noble) and a tooth coloured porcelain coverage bonded over it. So, it combines the strength of the metal and exceptional esthetic properties of porcelain. As with metal crowns, there are different levels of qualities you can choose from. You can have a PBC made from a noble or non-noble metal core and the covering porcelain from standard or high quality porcelain.
Full porcelain crowns
These are crowns made only form tooth coloured porcelain material without a meta core. This gives an esthetic advantage especially when restoring front teeth. The absence of the metal core gives the technician the ability to create an esthetically superior crown. Full porcelain crowns are usualy indicated for front teeth and are avoided to be placed on back teeth as they lack sufficient strength.
Zirconia Crowns
These types of crowns are relatively new to dentistry and are made from an extremely tough material, Zirconia. This material can withstand very high chewing forces (higher than a PBC) without breaking. In addition to that, they are tooth coloured and can match any tooth shade. Zirconia crowns are a fantastic option for single crowns and small bridges. While Zirconia has superior mechanical properties (tougher), Porcelain or Emax are still the materials of choice when the priority is a highly esthetic result.
Emax Crowns
Emax crowns are made from lithium disilicate, which is a type of ceramic known for its durability and amazing esthetic properties. These crowns are strong enough to endure high chewing forces but also imitate the form, shape and natural colour of your teeth. So Emax are almost as strong as a zirconia and have esthetic properties very similar to those of porcelain crowns.