A Failing Crown
Even though a crown protects and strengthens your tooth, you can still develop a cavity at the crown’s edge, where it meets the tooth. This area is very prone to developing plaque, and it can be one of the toughest spots in your mouth to keep plaque-free.
If the decay has barely started next to a crown, it’s easy to fix with a filling, unless it’s between your teeth where we just can’t get to
it. If the cavity penetrates the protective outer enamel layer and reaches the softer dentin layer, it progresses much more quickly and can cause an infection in the inner pulp layer containing your tooth’s nerves and blood vessels.

A more serious problem
When your tooth’s pulp is infected, the only way to treat the infection is by performing root canal treatment to remove the infected tissue. Without root canal treatment, the infection will continue to spread; pus from the infection may gather at the tip of the root and pass into the jaw bone, causing an abscess. An abscess can be excruciatingly painful, and can damage the bone
that surrounds your tooth.

For these reasons, if your crown has failed, we typically recommend removing it and the decay beneath it. We’ll then replace the old crown with a new one, which will re-seal your tooth and protect it from further decay and infection. By replacing the crown early, before the decay gets into the pulp chamber of your tooth, you can avoid discomfort, unnecessary damage to your tooth and more complicated, extensive treatment.

Your tooth’s anatomy	A cavity beneath a crown	A beautiful new crown

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Restoring a Large Cavity
Why does a large cavity sometimes need a crown?
We can usually restore small cavities with fillings. However, when a large portion of your tooth has been damaged by decay, we’ll need to remove a significant amount of the tooth in order to remove all the decay. When a tooth loses much of its natural structure, it also loses much of its support and strength. As a result, it can easily fracture, or a portion of it can break away entirely.

A cracked or broken tooth allows infection-causing bacteria into the vulnerable inner layer of your tooth, called the pulp. The pulp is comprised of soft tissue containing your tooth’s nerves and blood vessels, and an infection in this area can cause these tissues to die. Without its blood supply, your tooth can become brittle and break more easily. If this were to happen, we would need to perform root canal therapy to eliminate the infection within your tooth’s pulp. Without this treatment, the infection could easily spread to the root tips and into the surrounding bone, causing a damaging,
painful abscess.

A crown can prevent these problems
A crown prevents these problems by completely covering the portion of your tooth that extends above the gum line. Crowns cover and protect your tooth, adding strength and stability and restoring your tooth’s function and appearance.

Depending on where it will be placed in your mouth, your crown may be made from metal, porcelain bonded to a metal base, or entirely out of porcelain. Together, we’ll decide which kind of crown is best for your situation.

It takes at least two appointments to create a crown, because it’s custom-made to precisely fit your tooth. First, we’ll prepare the tooth, and then we’ll take an impression. Using this impression, a model of your mouth is created; your crown is fabricated on this model. You’ll wear a temporary crown to cover and protect the prepared tooth while your custom crown is being fabricated.

Large cavities weaken teeth	Tooth broken from large filling	Crowns strengthen and protect

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Crowns and Root Canals
How does root canal treatment affect a tooth?
Root canal treatment leaves a tooth brittle and weak. The tooth is weakened because we had to remove the center of it to get at the
infected nerve. This leaves only the sides of the tooth for support. The nerve and blood supply are also removed during root canal treatment, so the remaining tooth structure may become brittle over time.

Why is it essential to place a crown after root canal treatment?
A tremendous amount of force is applied to the edges of teeth when you bite together. If a tooth is not crowned after root canal treatment, that force can cause some of the tooth to break away. If a tooth breaks, it is much more difficult to repair. After root canal treatment, a crown is an important step that covers, strengthens and protects your tooth.

Symptoms of cracked tooth syndrome
You may have cracked tooth syndrome if:
• you find yourself chewing on only one side of your mouth because it's uncomfortable to chew on the other side;
• your teeth are sensitive to hot or cold temperatures, or to sweet or sour foods;
• you feel a sharp pain when you bite down;
• or the pain you feel is intermittent, rather than constant.

Your tooth anatomy	An infection in the pulp and root canals	Crowns strengthen and protect

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