A crown is a cap that is placed over a tooth and held in place by dental adhesive or cement.
Crowns are used for several reasons:-
- as a protective cover for badly decayed teeth or fractured teeth
- as a permanent restoration for teeth with large fillings
- to correct problems in natural teeth like spacing, irregular shape or severe discolouration.
- as a temporary measure between the different stages of other treatments.
Materials used for Crowns
There are three main types of materials used to construct crowns:-
Porcelain bonded to metal alloyCrowns constructed in this way have been tried and tested over many years. In many situations, they give the best combination of aesthetics, strength and durability. They are particularly suitable when the bite is strong or the teeth are very discoloured.
Porcelain onlyThe main advantage of this type of crown is their ability to bond to tooth structure, giving it strength and support. It also gives a very natural-looking restoration. Recent developments in ceramic technology have led to improved strength using zirconia and pressed ceramics, and it is now possible to use porcelain-only restorations in both the front and back parts of the mouth.
Gold alloyGold is one of the best metals to use due to its inert properties. When combined with other metals to form an alloy, its strength and durability is improved. Gold restorations are known for their comfort and longevity. They are mainly used where aesthetics is not the main concern.
Stages of Crown Treatment
Initial Dental ConsultationThis could be a routine examination, or a patient wanting to discuss a solution to their dental problem. During this appointment we will discuss with the patient the possible solutions available.
Dental ExaminationA thorough clinical examination is conducted by the dentist. The suitability for crowns is assessed and any necessary photographs, radiographs and sometimes impressions for a diagnostic wax-up, are taken. Your dentist will also be able to advise on the choice of material, treatment sequence and any other concerns you may have. A detailed treatment plan will be developed, and the patient given time to consider their options.
Discuss different treatment options in complex casesIf multiple crowns are necessary, a separate appointment may be required to discuss options and choices after evaluating the photographs and diagnostic wax-up received back from the laboratory.
Preparation for CrownThe teeth to be crowned are prepared. This involves reduction of the tooth size (usually under local anaesthesia) followed by an impression or mould of the prepared tooth. This trimming of the tooth is required to create space for the crown to be fitted. The mould taken is then sent to a laboratory where skilled technicians will fabricate the crown. In the meantime, a temporary crown is made and fitted onto the trimmed tooth.
Fitting appointmentThe temporary crown is removed and the tooth surfaces cleaned. The completed crown is tried on the tooth for fit, bite and appearance. Finally, the crown is cemented or bonded onto the prepared tooth.
Care of your Crown
Crowns are made of inert materials that do not deteriorate over time. However, the underlying tooth is still prone to decay and gum disease.
- Daily brushing and flossing are essential for maintaining good oral health as well as keeping the crown trouble-free. Ceramic on the surface may chip or fracture: avoid chewing excessively-hard substances like ice or bones. The most vulnerable portion of the crown is the margin or the junction between tooth and crown.
- Regular dental and hygiene appointments will enable your dentist or hygienist to detect any problems with your crown and recommend necessary treatment.
- Correct dietary control is essential to prevent decay to the underlying tooth supporting the crown.