A filling is finished in one appointment
Composite is built up in 2 mm layers, each cured for 20–40 seconds, so even a deep cavity is completed before the anaesthetic wears off. Typical service: 5–10 years.
Cracked tooth: filling or crown
The short answer: a crack that leaves thick, healthy walls around it can usually be rebuilt with a filling, while a crack that undermines a cusp — or a tooth already treated with a root canal — needs a crown that holds the tooth together. The choice changes your calendar: a filling is finished in one sitting, while a crown means 60–90 minutes of preparation and 2–3 weeks in a temporary before the permanent one is fitted.
01
Everything starts with how much tooth the crack leaves standing. Shallow cracks with thick walls keep the one-visit filling option open; cracks that run under a cusp do not.
02
A filling rebuilds from inside in a single sitting. A crown wraps the tooth across two visits with a 2–3 week laboratory wait. A root canal adds 1–2 visits of 60–90 minutes before the crown is even started.
03
Composite lasts 5–10 years, amalgam 10–15, PFM crowns 5–15 and zirconia 10–20. Cleaning recalls every 3–12 months are what catch a failing margin before it becomes a new crack.
The filling-versus-crown decision is made by how much sound tooth the crack leaves behind, not by preference or budget.
A shallow crack surrounded by thick enamel and dentine can be rebuilt from the inside. Composite resin is placed in increments no thicker than 2 mm, each layer cured under the lamp for 20–40 seconds, and the repair is completed in a single appointment. On typical ranges a composite filling serves 5–10 years; an amalgam filling stretches that to 10–15.
The picture changes when the crack runs under a cusp or leaves thin walls. A filling placed in that situation does not strengthen the tooth — it just occupies space while the weakened cusp keeps flexing under biting load. That is the mechanical argument for a crown: it wraps the tooth and holds the remaining structure together.
Neither option is a moral failing or an upsell by itself. They are answers to two different amounts of remaining tooth, and the checkup is where that amount gets measured.
Composite is built up in 2 mm layers, each cured for 20–40 seconds, so even a deep cavity is completed before the anaesthetic wears off. Typical service: 5–10 years.
Preparation takes 60–90 minutes, then the laboratory needs 2–3 weeks. You wear a temporary crown in between.
For 2–3 weeks it protects the prepared tooth and holds the spacing for the permanent crown. It is cemented lightly on purpose — sticky food can lift it.
Local anaesthetic outlasts the appointment. Chewing before sensation returns is how cheeks and tongues get bitten.
The canal is sealed over 1–2 visits of 60–90 minutes, then left for 2–4 weeks before the crown is placed. The crown is part of the treatment, not an extra.
Bitewing X-rays every 12–24 months; recall cleanings every 3–12 months by gum risk. Failing margins are found here, not in front of a mirror.
A filling rebuilds the inside of a tooth; a crown holds the outside together.
The numbness outlasts the appointment — chewing waits 2–4 hours until sensation returns.
| Repair or visit | Typical lifespan | Time in the chair | Appointments | Built-in waiting period |
|---|---|---|---|---|
| Composite filling | 5–10 years | Layered placement; 20–40 s light-cure per 2 mm layer | 1 | None — finished in the same visit |
| Amalgam filling | 10–15 years | Single-visit placement | 1 | None |
| Porcelain-fused-to-metal crown | 5–15 years | 60–90 min preparation | 2 | 2–3 weeks in a temporary crown |
| Full zirconia crown | 10–20 years | 60–90 min preparation | 2 | 2–3 weeks in a temporary crown |
| Root canal treatment | Tooth preserved, then crowned | 60–90 min per visit | 1–2 | Crown fitted 2–4 weeks after sealing |
| Routine checkup | — | 30–60 min including X-rays and scaling | 1 | Bitewings repeated every 12–24 months |
The values listed are standard published ranges for these procedures; individual cases vary with bite, hygiene and the tooth involved.