Why a tooth might need a crown
Teeth are strongest when their outer walls are intact. Once a large part of a tooth has been lost to decay, fractures or old fillings, the walls that remain can flex and crack under chewing forces. A crown is usually suggested when a filling or onlay is unlikely to hold the tooth together on its own, for example:
- A tooth that is now more filling than tooth
- A cracked tooth, where a crown may stop the crack spreading
- A molar or premolar after root canal treatment
- Teeth worn down by grinding or acid erosion
- A badly misshapen or discoloured tooth that other options can’t fix
- Restoring the visible part of a dental implant
How a crown protects the tooth
A crown works a little like the metal hoops around a wooden barrel. It wraps around the tooth, holding the walls together and spreading biting forces across the whole tooth instead of letting them wedge cusps apart.
To make room for it, a layer is removed from every side of the tooth, so a crowned tooth will always need a crown from then on. That is why your dentist will usually consider a filling or onlay first and recommend a crown only when the tooth needs that level of support. Crowns are also used to anchor a replacement tooth across a gap, which is explained on our dental bridges page.
Ready to book a visit?
Porcelain, porcelain-fused-to-metal or gold
Each material is a balance of appearance, strength and how much tooth needs to be removed. Your dentist will recommend one based on where the tooth is, how heavily you bite, whether you grind and what matters most to you.
- Porcelain (all‑ceramic): the most natural looking, with no metal to show through. Modern ceramics are strong, but in heavy grinders some types can chip or fracture
- Porcelain-fused‑to‑metal: a metal shell with porcelain layered over it, used for decades with a long track record. If the gum shrinks back, a thin dark edge of metal may show, and the porcelain layer can chip
- Gold: a gold alloy that is very hard-wearing, needs the least tooth removed and is gentle on the opposing teeth. Its colour means it is usually chosen for back molars that don’t show
Crowns after root canal treatment
Once a tooth has had root canal treatment, it no longer has a living nerve to warn you when you bite too hard, and it has often lost a lot of structure from decay and the access opening. Back teeth in this state are more likely to split, and a crack that runs into the root can mean the tooth has to come out.
For that reason a crown, or sometimes an onlay that covers the cusps, is commonly recommended for root-filled molars and premolars, ideally soon after the canals have been sealed. The tooth may first need a core, a filling that rebuilds the inside of the tooth so the crown has something solid to sit on. Front teeth take less force, and a filling is sometimes enough.
Your temporary crown
While your crown is being made, you wear a temporary one made of acrylic. It protects the prepared tooth, keeps it comfortable and stops the neighbouring and opposing teeth from moving into the space.
Temporaries are deliberately held on with a weaker cement so they can be removed easily, so they need some care. Chew on the other side where you can, steer clear of chewy lollies and gum, and when you floss, slide the floss out sideways rather than lifting it up. If it comes away, hold on to it and ring us so it can be refitted, as the tooth can shift or become sensitive without it.
Risks and side effects to know about
Cold drinks may make the tooth twinge for a few days after each visit, and your gum may be a little tender where the crown edge sits. A crown that feels high can be adjusted.
Shaping a tooth for a crown places some stress on the nerve. In a small proportion of teeth, particularly those that have had deep decay or large fillings before, the nerve becomes inflamed, sometimes months or years later, and the tooth then needs root canal treatment. This can usually be done through the crown. Porcelain can chip, a crown can come loose, and decay can still develop at the edge where the crown meets the tooth.
Making your crown last
A crown itself can’t decay, but the tooth underneath can, starting at the margin near the gum. Brushing along the gum line, cleaning between the teeth every day and keeping sugary snacks to mealtimes all help protect that edge.
How long a crown lasts varies with the material, your bite and the health of the tooth and gums. Many give years of service, while grinding, gum recession and decay at the margin are common reasons one needs replacing sooner. If you grind, a night splint can help protect crowns and natural teeth alike, and regular check‑ups let us spot problems at the margin early.
What affects the cost
The fee for a crown is mostly shaped by the material, the dental laboratory work involved and whether the tooth needs a core build‑up first. Crowns are usually claimed under major dental on extras cover, and many funds apply a longer waiting period and an annual limit to that category, so it is worth checking both before your preparation visit.
Dental crowns, step by step
Questions about dental crowns
Can a tooth with a crown still get decay?
The crown itself can’t decay, but the natural tooth underneath can, usually starting at the edge near the gum. Daily cleaning at the gum line and regular check‑ups help catch it early, while it can still be repaired.
Why is there a dark line at the gum on my old crown?
This is common with porcelain-fused‑to‑metal crowns when the gum shrinks back slightly and exposes the metal edge. It isn’t harmful on its own. If it bothers you, your dentist can talk about whether replacing the crown is worthwhile.
Can I have a crown if I have a metal allergy?
Yes. All‑porcelain crowns contain no metal, so they are usually the choice for people with a confirmed metal allergy. Let your dentist know about any allergies before treatment is planned.
Will whitening change the colour of my crown?
No. Porcelain and gold don’t respond to whitening. If you are thinking about whitening, it is usually done first, so the new crown can be matched to your lighter shade.
My new crown feels high. Is that normal?
Your bite is checked carefully at the fitting, but numbness can make it hard to judge. If the crowned tooth seems to meet first once the anaesthetic wears off, call us, as a high spot is quick to fix and can make the tooth sore if left.
Do I really need a crown after root canal treatment?
For back teeth, a crown or cusp-covering onlay is usually recommended, because root-filled molars and premolars are more likely to crack. Front teeth sometimes need only a filling. Your dentist will base the advice on how much of your tooth remains.
How long is the preparation appointment?
It is usually one of the longer appointments, as the tooth is numbed, shaped, recorded and fitted with a temporary. We can tell you roughly how much time to set aside when we book you in, and you can pause for a break at any point.