Crown Lifespan & Replacement Timing

A crown isn't a treatment that lasts a lifetime once placed. Zirconia, all-ceramic and porcelain-fused-to-metal crowns are reported in the literature to have a 5-year survival rate above 90%, but replacement is often needed because of problems at the tooth underneath and the gum margin rather than the crown itself. Boston Miso Dental Clinic fits the margin, bite and contact points carefully at placement to reduce the need for remaking it, and provides a 2-year crown warranty (conditional on regular check-ups).

What signs mean you should replace a crown?

• The margin looks dark, or food keeps getting caught there — this can be a sign of decay in the gap between the crown and the tooth. The crown itself can't decay, but the tooth underneath can.
• The gum has receded and the margin is showing — on front teeth this can look unsightly, and the exposed root can be sensitive.
• Chipping or cracking — if the porcelain chips off or cracks, it's repaired or replaced.
• It keeps coming loose — the cause (remaining tooth structure, bite) needs to be identified before re-cementing. A Case of a Crown Repeatedly Coming Loose.
• It hurts to chew, or the gum swells — this could be a problem with the nerve or root tip underneath, so we check with an X-ray.

What shortens a crown's lifespan?

• A poor margin fit — plaque builds up in the gap, causing decay and gum inflammation.
• A high bite — force concentrates on one tooth, which can crack the crown or fracture the root.
• Not enough remaining tooth structure — a root-canal-treated tooth without an adequate core and ferrule tends to come loose easily.
• Teeth grinding — a common cause of porcelain fracture.
• Poor cleaning at the margin — if floss or an interdental brush doesn't reach it, decay develops at the margin.

What do we check when replacing a crown?

1. The condition of the tooth after the old crown is removed — the extent of decay, how much tooth structure remains, and whether there's a crack. Some of this is only visible after removal, so we mention that possibility upfront.
2. The nerve and root tip — root canal treatment or retreatment comes first if needed.
3. Whether the tooth can be saved — if the root is fractured or almost no tooth structure remains, we compare other options instead of a crown. Saving Natural Teeth.
4. Bite and contact points — whatever caused the old crown to come loose or crack is corrected in the new one.

How do the materials differ, and what do they cost?

• Zirconia — high strength, the standard for back teeth. Back teeth ₩550,000 · front teeth ₩600,000.
• PFZ (zirconia core + porcelain) — translucency for front teeth. Front teeth ₩750,000.
• Gold — gentlest on the opposing tooth, worth considering if you grind your teeth heavily. Back teeth ₩850,000.

The full list is on our Fees page, and how to choose a material is on the Cosmetic Crowns & Veneers page.

The reasons the material differs between front and back teeth, along with five-year survival rates by material, are set out with references in Why Front and Back Teeth Get Different Crowns — How We Choose Between Zirconia, PFZ, and Gold.

If the colour does not match the neighbouring teeth and you are unsure whether to remake it, When only the crowned front tooth looks off-colour — what can be fixed without remaking it, and what cannot explains how we separate staining, the gum line and the shade of the restoration itself.

How do you care for it to make it last?

• Floss and use an interdental brush at the margin every day — this has the biggest effect.
• Regular check-ups every 6 months to a year — decay at the margin caught early can often be treated without removing the crown.
• A night guard if you grind your teeth.
• Don't bite down on hard things like ice or bone with a crowned tooth.

If a tooth filled with resin or an inlay (rather than a crown) has decayed again, the criteria for deciding whether to fix only that part or redo it are set out in When a filled tooth decays again — repair just that part, refill it, or move up to an inlay or crown.

FAQ

How many years does a crown usually last?

The literature reports a 5-year survival rate above 90%, and many crowns last 10 years or more, but this varies with decay at the margin, gum recession, and teeth grinding. Rather than promising a lifespan, we focus on creating the conditions for it to last, and the crown warranty is 2 years (conditional on regular check-ups).

What happens if a cavity forms under a crown?

In most cases, the crown is removed, the cavity is treated, and a new crown is placed. Early decay at the margin can sometimes be treated with the crown left in place, which is why regular check-ups matter.

Can an old metal crown be replaced with zirconia?

Yes. However, depending on the condition of the tooth underneath once the old crown is removed, a core or root canal treatment may be needed first — we let you know upfront that the plan may change after removal.

References

The treatment sequence and criteria described above are Boston Miso Dental Clinic's own principles; the frequency, mechanism and prognosis figures are based on the references below.

※ This guide is general information; risks and timelines vary with each person's oral condition, medical conditions, and habits. Whether it applies to you and your expected schedule will be explained by Dr. Lee, our Clinic Director, after an exam. Listed fees are base prices — see Fees for itemized details.