The tooth has previously had a large filling that is now failing.  To replace the filling with a new filling will only provide a short term fix and put the tooth at risk of breaking beyond repair.

The nerve of the tooth has become infected forcing you to have a root canal treatment in an effort to keep the tooth.  A root canal procedure weakens the tooth, therefore, a crown may be recommended to bring strength and stability back to the tooth.

A hairline crack or fracture has developed on the tooth surface.  If left exposed and untreated, the crack could develop further causing the tooth to break beyond repair, pain on biting due to the tooth structure flexing when you chew, or with a significant crack, it may reach the nerve of the tooth causing it to become infected and die.

The tooth has been badly worn down from clenching and grinding and due to these intense pressures of a person with a bruxing habit, a regular composite filling will not be able to withstand these forces like an indirect dental crown can.

The outer layer of the tooth has eroded away from an acidic diet, improper tooth brushing, medical conditions such as reflux or regular medications and now needs a protective covering that can provide a sustainable barrier from these elements if the tooth is to survive long term.

How long will vary greatly on a number of factors such as diet and lifestyle, the position of the teeth and bite, bruxing habits, medical health and medications and overall oral health and home hygiene care. That said, if you maintain the health of the crown, the tooth and gum holding things in place you can expect to get up to 20 years out of a dental crown. It is important to note that dental tooth crowns are considered the most long term solution to keeping a fragile tooth strong and in your smile for as long as possible.

It can be difficult to identify and diagnose a cavity or infection under a crown in a visual examination or with an x-ray as the dental crown is radio-opaque meaning it blocks the radiation from passing through making it almost impossible to see what’s happening underneath and inside the tooth crown.  The majority of the time, the dentist relies on the patient’s feedback on symptoms felt by the tooth to diagnose a cavity under a dental crown.  In some cases, the dentist may suggest removing the crown in order to inspect the tooth structure and give a clear diagnosis. 

No teeth whitening gel or teeth bleaching products will change the colour of a dental crown of any kind, no matter what dental material has been used to complete the dental crown.  If you want to whiten your teeth, it is advised to do this prior to having your tooth crown procedure so that the dentist can match the tooth crown to the colour of your freshly whitened teeth.