Teeth can require restoration for many different reasons and a crown is a tooth restoration that covers the entire tooth. It is essentially a tooth shaped “cap” that is placed over a tooth to restore it’s shape, size, strength and appearance.
When people are younger they are more prone to decay; decay in teeth is removed and usually replaced with some type of filling material. This can be done because the area of decay is normally a small or moderate sized hole inside a tooth. Over time, these fillings require replacing and there is less tooth remaining. In addition to this, teeth can crack or fracture or even suffer more significant injuries. Eventually, there is not enough tooth left to hold a filling and it is at this time that a crown can be made to fit over the remaining portion of the tooth. These crowns are made of ceramic or gold alloys. These are constructed at very high temperatures and therefore are made outside the mouth in a dental laboratory. To allow us to make crowns outside the mouth, we use either impressions or digital impressions.
What is the process for getting a crown?
Examination and Consultation
The tooth will need to assessed to ensure it is suitable for a crown and whether a crown is the best course of action for the damaged tooth.
A crown preparation appointment involves local anaesthesia, tooth preparation, final crown and bridge impression taking, bite recording, and the construction and placement of a temporary crown.
The crown is essentially like a sleeved fitted over a tooth. It requires a certain thickness in order to withstand chewing forces for a long period of time. Typically, the required thickness is approximately 1 or 2 mm. This needs to be removed from the tooth in a particular way so that the crown will not fall off or fracture over an extended period of time. This is typically done using a local anaesthetic injection with a dental drill. Whilst the crown is being constructed, a temporary crown that is approximately the same shape and size as the final crown is used over the tooth. It should be noted that temporary crowns are not as strong as final crowns and care should be taken with these.
Placing the crown
The crown is placed on the tooth after construction and the temporary crown is removed along with temporary cement. The crown is then checked to ensure that it is the correct shape, colour and size. The bite or occlusion is of high importance. If the crown is left higher than the other teeth, the muscles in the jaw with quickly fracture the crown or damage the tooth underneath.
For crowns that replace front teeth in an aesthetic area, we always place these on a temporary basis so that people have a chance to go home and check over several weeks that they are completely satisfied with the colour and shape. The dental laboratory that we utilise to make the crowns is in the rooms next to the office, so colours and shapes can be changed quickly (usually within an hour). The final crown is not cemented permanently until at least one month has elapsed with the crown in temporarily. This gives the patient enough time to decide if they are happy with the result.
We encourage opinions from other people. We also recommend that photographs be taken to ensure the final crown is correct in all situations. Using the photographs, it is possible to match the colour and shape of teeth exactly.
Usually following tooth preparation, patient’s feel discomfort which is caused by the drilling process as well as keeping their mouth open for 30/40 minutes. We encourage people to use Panadol or Neurofen before the local anaesthetic has completely worn off. Another mild analgesic before bed is usually enough to resolve most problems. Typical symptoms following crown preparation appointments are mild to moderate discomfort at most.
After crown placement
The care required for a crown is similar to that for natural teeth. Dental floss or using brushes to clean between teeth is an excellent way to maintain your teeth and crowns in the long term. We encourage the use of common sense in regard to the types of food patients eat after having a crown placement. Biting fingernails or similar small objects will increase the risk of fracture of teeth and crowns. In the past, aesthetics ceramic crowns have had a higher risk of fracture due to the developmental nature of some of the ceramics. Current ceramics are extremely hard and breaking them is difficult. The risk of fracture of these restorations is now quite small, however it is still a risk. Teeth and crowns fracture in a similar way so any incident which could break a tooth could break your new crown. The incidence of fracture in present times is minimal. We would see a fractured crown approximately once every one to two years.