Dental crowns: when you need one, and what to expect.

A crown is a custom-made cap that fits over a prepared tooth, covering it down to the gum line to rebuild its strength, shape and appearance. To fit one, the dentist removes a layer of the natural tooth all around, takes an impression, and bonds the finished crown on top. Because that preparation is irreversible, a crown is the right answer when a tooth is too damaged for a filling — but the wrong answer when something less invasive would do.

Good reasons for a crown include a tooth that is heavily broken or has a very large filling with too little structure left to hold a new one, a cracked tooth that needs holding together, a tooth that has had a root canal (which leaves it brittle), or a badly worn tooth. Crowns also anchor bridges and cap implants. What is not a good reason is crowning a healthy tooth purely to change its colour or shape — a veneer or bonding preserves far more tooth for that.

The main options are all-ceramic / zirconia crowns — strong, metal-free and natural-looking, now the usual choice for most teeth; E.max (lithium disilicate) — highly aesthetic, favoured for front teeth; and older porcelain-fused-to-metal, strong but can show a grey line at the gum over time. The best material depends on the tooth's position and how much biting force it takes; we match it to the job rather than applying one type to everything.

Conventionally it takes two stages: the tooth is prepared and an impression taken, a temporary crown is fitted, and the lab makes the final crown for fitting on a second visit. With an in-house laboratory — as at our clinic — the gap between preparation and a permanent crown is much shorter, so a crown case can often be completed within one trip. Any underlying work (a filling build-up or root canal) is done first.

A well-made, well-fitted crown commonly lasts 10–15 years or more, and often longer, with good hygiene and regular check-ups. What shortens a crown's life is usually decay at the margin where it meets the tooth, or a heavy bite (grinding) — which is why cleaning around the gum line and a night guard if you grind matter. The crown itself doesn't decay, but the natural tooth underneath still can, so it is cared for like any other tooth.