When a tooth needs a crown instead of a filling

The reasoning is mechanical. A filling depends on the tooth around it to carry the load, and once the walls are thin, or a cusp has broken away, chewing forces flex them instead. Repeated flexing is what splits teeth, often below the gum line. A crown wraps the tooth so the load is resisted all the way around.

Where that line falls is a matter of judgment. What moves a tooth toward a crown is the width of the existing filling relative to the distance between the cusps, cracks that appear once the old filling is removed, pain on releasing a bite, and whether you grind. A crown removes a substantial amount of tooth, so when a bonded composite filling can still do the job, that's the option we prefer.

The situations that usually call for a crown

  • A fractured cusp. Once a corner has broken off, the remaining walls carry more load than they were designed to, and the next fracture tends to run deeper.
  • A large old restoration that keeps failing. Each replacement leaves a larger cavity and thinner walls, until more filling than natural tooth remains.
  • After root canal therapy on a back tooth. Structure has been lost, both to decay and to the access needed to reach the nerve, so the tooth needs coverage. Front teeth with small access cavities sometimes do not need it.
  • Cracked tooth syndrome. This produces sharp pain on biting, particularly on release. A crown holds the segments together. If the crack has extended into the root, a crown won't save the tooth, and we can't always know that in advance.
  • Severe wear, or a front tooth that is dark, chipped and heavily filled at once. These are the cases in which too little sound enamel remains for a veneer to bond to.

Crown materials, and where each one is used

The choice balances strength, appearance and the amount of tooth structure that has to be removed.

Zirconia
A very strong ceramic, used for back teeth and for people who grind heavily. Full-contour zirconia is more opaque than enamel, and the more translucent versions sacrifice some strength. It requires less thickness, so less tooth structure is removed.
Lithium disilicate
A glass ceramic, often known by the brand name e.max. It balances strength and translucency and bonds strongly, which makes it a common choice for front teeth and premolars.
Layered porcelain
A ceramic core with porcelain built up by hand, which gives a technician the most control over color, translucency and texture. The layered surface chips more readily, so it suits high appearance demands and moderate load.
Porcelain fused to metal
Porcelain baked over a metal substructure. It has a long track record and considerable strength. The metal is opaque, so more tooth structure is removed to make room for the porcelain, and if the gum recedes a dark line can show at the margin.

What to expect at a crown appointment

  1. Shade, then preparation

    We choose the shade before the tooth is prepared, since teeth lighten as they dry out during an appointment. Then we remove the old filling and any decay, and shape the tooth so the crown has even thickness all the way around.

  2. The impression and the temporary

    We take an accurate record of the prepared tooth, the margin at the gum, the bite and the opposing teeth. The temporary holds the gum in shape, so avoid sticky foods and slide floss out sideways rather than pulling it upward.

  3. Fitting the crown

    We check the fit at the margin, check the contact with the neighboring teeth using floss, and adjust the bite. You review the result in a mirror before anything is cemented, so please speak up with any concerns at this visit.

  4. Cementing and review

    We clean away excess cement, especially below the gum line, where it can cause inflammation months later. Tenderness for a few days is common. A bite that feels high is a quick adjustment, so call us if it doesn't settle.

Margins, gum health and how a crown ages

The margin is the junction where the crown meets the tooth, and it strongly influences how the crown performs long term. A crown that fits precisely gives plaque nowhere to accumulate. One with a gap or a ledge collects plaque, inflames the gum, and lets decay start underneath where it is difficult to see.

Gum health determines how a crown looks years later. Inflamed tissue bleeds, swells and can then recede, and recession exposes the margin and the darker root below it. That's why gum treatment through periodontal care comes first, and why daily cleaning at that margin matters. Porcelain itself doesn't decay, although the tooth beneath it remains susceptible.

Common questions about porcelain crowns

How long does a porcelain crown last?

Crowns often last many years, and some fail earlier than expected. What separates them is gum health, daily cleaning at the margin, and how much sound tooth was left underneath. Clenching and grinding at night put heavy load on porcelain, so if you grind, a night guard is likely to be part of the plan.

How much does a crown cost?

It depends on the material, the laboratory work, and whether the tooth needs a build-up or root canal therapy first. A crown needed to hold a broken tooth together is generally assessed differently by a plan than the same crown done to change appearance. Call (559) 683-4694 and ask, and see insurance and financing.

Will the crown match my other teeth?

Matching a single front tooth is among the more difficult tasks in dentistry, because the neighboring tooth is the reference. Careful shade mapping usually comes very close. A very good match is realistic, and an identical one is not always achievable, so we'll be honest with you about what to expect.

Should I whiten before having a crown made?

If whitening interests you at all, it comes first. Porcelain doesn't lighten, so a crown matched to your current shade will stand out if the teeth around it change later. See whitening.