How long do dental crowns last? Pain after a crown, care and when to replace

Why is a crown needed?

A crown protects a weakened tooth from fracture by covering it completely: heavily filled, root-treated, cracked or worn teeth; on implants; for aesthetic reasons. The tooth is reduced by 1–2 mm all round, an impression is taken and the crown made in the laboratory is cemented. On choosing the material: Zirconia or metal-ceramic crowns?

Average lifespan

Studies show high 10-year survival rates. Lifespan is decided less by the crown "wearing out" than by decay or fracture of the tooth beneath, exposure of the margin through gum recession, and fracture of the porcelain.

Pain and sensitivity after a crown

• Cold sensitivity in the first 1–4 weeks: Expected after preparation of a vital tooth; fades gradually.
• Pain on biting: The crown may be high; it needs adjustment and will not settle on its own.
• Prolonged, throbbing pain with heat: Pulpitis. Some vital teeth prepared close to the nerve may need root canal treatment even years later; in that case the crown is usually kept, with a small access opening.
• Pain on pressing the gum, bleeding: An overhanging margin or plaque build-up; cleaning and, if needed, margin correction.

Can decay form under a crown?

The crown itself cannot decay, but the margin between crown and tooth can. As the gum recedes the margin is exposed and plaque collects. Signs: a dark line at the margin, sensitivity to sweets, bad odour, floss catching, a feeling that the crown "moves". A yearly X-ray catches marginal decay early; at an early stage the crown is replaced and the tooth saved; late, root canal treatment or extraction may be needed.

If a crown comes off

Keep the crown; don't lose it. Clean the tooth gently and see the dentist within 1–2 days; most crowns are re-cemented if enough tooth remains beneath. A temporary cement from the pharmacy can be used to keep it in place; never use superglue. A tooth without its crown is sensitive and fragile — don't chew on that side.

To extend its life

• Brush twice a day, paying particular attention to the crown margin; floss or an interdental brush every day. Under a bridge, bridge floss.
• A night guard if you clench or grind — the number-one cause of porcelain fractures. Who needs a night guard?
• Don't bite hard objects such as ice, nut shells, pens or nails.
• A check and cleaning every 6 months; a margin X-ray once a year.

When is it replaced?

Marginal decay, recurrent gum inflammation and a grey margin exposed by recession, a fracture or extensive wear of the porcelain, loosening and leakage, aesthetic mismatch. A trouble-free crown is not replaced just because "it's old"; each replacement takes a little more tooth. The decision is made together with an examination and X-ray.