Brief Guide to Dental Crowns
A dental crown, sometimes referred to as a cap or replacement, is used to replace part or all of a tooth above the gumline. Most commonly a crown is used to repair a badly damaged tooth that would otherwise have to be extracted.
A well-made crown looks and functions just like a normal tooth and are coloured to match the existing colouring of the surrounding teeth. A crown is the best option available to a dentist in cases where a tooth is so badly damaged that it cannot be repaired by other methods such as a filling.
Constructing the Crown
- A dentist and dental technician work in tandem to create a dental crown. The dentist makes a mould of the tooth and the surrounding area so the replacement crown can be made to match the problem tooth perfectly. This initial mould gives the dentist a reverse record of the tooth and this mould is then filled with hard plaster to create a replica of the tooth which is exact in size and shape.
- After removing the damaged part of the tooth and clearing away any decay or debris, a second mould, called a “cast”, is taken which is used by the dentist for study and reference and also to make a third mould, an “investment”, which can withstand high temperatures and is used by a dental technician to create the actual crown.
- The dental technician plays a crucial role in creating the crown and ensuring it matches the exact size, shape and colour requirements for each individual case. Having created an “investment” from the mould supplied by the dentist, the technician coats the inside with a releasing agent before packing it tightly with the gold, porcelain, plastic or combination of metals which will form the actual crown. This is then hardened at high temperature and left to cool. The mold is then broken open and discarded leaving a finished crown that is a perfect match in size, shape and colour for the tooth being operated on.
Fitting the Crown
- While the dental technician is preparing the actual crown, the dentist will prepare the tooth for its installation. Having already pared down the tooth to the required size, the dentist places a temporary cap over the remaining tooth structure. This is made from acrylic and its purpose is to protect the underlying tooth from further damage as well as to keep it clean, protect from sensitivity to heat or cold, preserve the spacing between teeth and allow the patient to get used to the feeling of the finished crown.
- Once the crown is finished and returned, the dentist will inspect it thoroughly to ensure it complies with the size, shape, fit, material and colouring specified with the technician. Satisfied that all is in order, fitting the crown in place is a simple and straightforward procedure. The crown is coated on the inside with an adhesive cement and then placed over the remaining tooth structure. Although the two parts, the crown and tooth, should fit perfectly there may be some slight final adjustments to be made to ensure a tight and correct fit. Once in place, the surface of the crown may require some grinding to make sure it is smooth and even. Some dentists may additionally choose to apply an acrylic polymer coating to seal the crown and enhance its natural appearance.
High Success Rate
- Apart from necessary dental work, crowns are also quite commonly used in cosmetic dentistry. This is because they are almost indistinguishable from natural teeth and require no special care as is the case with dentures. The procedure is carried out under local anaesthetic and any pain or discomfort is minimal and short lasting.
- Crowns are extremely durable and function as well as natural teeth when eating, chewing, brushing or flossing. The success rate is high although crowns can fracture, loosen or come unglued but these are extremely rare occurrences with some crowns lasting as long as forty years without incident.