Both restore damaged teeth with lab-made ceramics — but crowns and onlays offer very different levels of coverage. A crown encases the entire tooth. An onlay covers only the damaged cusps, preserving more natural structure. The right choice depends on how much healthy tooth remains.
If your dentist has recommended a dental crown or an onlay, you may be wondering which is right for your tooth. Both are custom-made, lab-fabricated restorative treatments crafted from high-quality ceramics — but they cover very different amounts of the tooth.
A crown encases the entire visible tooth, restoring its full shape, strength and function. An onlay covers only the damaged cusps and biting surface, preserving significantly more natural tooth structure. The key distinction is how much healthy tooth remains: if the tooth retains enough structure to support a partial restoration, an onlay is the more conservative choice. If the damage is too extensive, a crown is the appropriate solution.
The right treatment always depends on a clinical assessment. Your dentist will examine the tooth, take X-rays if needed and recommend the most appropriate option. A new patient examination is just £30 — book online or call us on 020 7183 0527.
At a Glance
Dental crowns vs onlays — side by side.
| Feature | Dental Crown · From £995 | Onlay · From £995 |
|---|---|---|
| Coverage | Full — encases the entire visible tooth (360°) | Partial — covers the damaged cusps and biting surface only |
| Procedure Type | Full-coverage restoration — restores strength, shape and function | Partial-coverage restoration — reinforces the damaged portion |
| Treatment Time | 2 appointments over 1–2 weeks (45–60 min each) | 2 appointments over 1–2 weeks (45–60 min each) |
| Tooth Preservation | 1.5–2 mm removed all around the tooth | Only the damaged portion removed — maximum tooth preserved |
| Structural Support | Full reinforcement — protects entire tooth against fracture | Partial reinforcement — strengthens weakened cusps |
| Aesthetics | Excellent — all-ceramic, shade-matched | Excellent — porcelain shade-matched, virtually invisible |
| Cost at Our Clinic | From £995 (Zirconia or E.max) | From £995 (Porcelain or Gold) |
| Longevity | 15–25+ years with good care | 15–25 years (porcelain); 25–30+ years (gold) |
| Suitability | Severely damaged, broken, root canal-treated or heavily restored teeth | Medium–large cavities where the tooth retains healthy structure |
Treatment recommendations depend on individual clinical assessment. All prices confirmed before treatment begins.
Full-Coverage Restoration
A dental crown — sometimes called a cap — is a custom-made restoration that covers the entire visible part of a tooth above the gum line. It restores the tooth's original shape, size, strength and appearance. At Dental Clinic London, all our crowns are 100% metal-free, crafted from advanced dental ceramics.
We offer three types: zirconia crowns (from £995) — the strongest option, ideal for back teeth and patients who grind; porcelain (E.max) crowns (from £995) — offering the most natural translucency, ideal for front teeth; and layered porcelain (PFZ) crowns (from £1,195) — combining zirconia strength with hand-layered ceramist artistry for the premium result.
Crowns typically require 2 appointments over 1–2 weeks. At the first, the tooth is prepared (1.5–2 mm removed all around) and a temporary crown fitted. At the second, the permanent crown is cemented. With good care, crowns last 15–25+ years.
Partial-Coverage Restoration
An onlay is a custom-made, lab-fabricated restoration that covers one or more of the tooth's cusps — the raised points on the biting surface. Unlike a crown, it does not cover the entire tooth. Only the damaged portion is replaced, preserving the maximum amount of healthy natural tooth structure.
At Dental Clinic London, onlays are crafted from porcelain, ceramic or gold, all starting from £995. Porcelain and ceramic onlays are shade-matched to your natural teeth, making them virtually invisible. Gold onlays offer exceptional durability — lasting 25–30+ years — and are ideal for back teeth where aesthetics are less of a concern.
Like crowns, onlays require 2 appointments over 1–2 weeks. At the first, the damaged portion is removed and an impression taken. At the second, the custom onlay is bonded permanently. Because only the damaged area is prepared, significantly more natural tooth is preserved compared to a crown. With good care, porcelain onlays last 15–25 years.
Understanding the Difference
This is the most fundamental distinction. A crown covers the entire visible tooth — 360° — requiring 1.5–2 mm of structure to be removed all the way around. An onlay covers only the damaged cusps, preserving all the healthy, untouched tooth surfaces. When a tooth retains sufficient healthy structure, an onlay is the more conservative choice. Preserving natural tooth structure is always desirable — it maintains the tooth's long-term integrity.
Crown preparation is more extensive: the entire outer surface of the tooth is reduced to create space for the restoration. Onlay preparation is more targeted: only the damaged or decayed portion is removed. For teeth where both options are clinically viable, an onlay preserves significantly more enamel and dentine. Your dentist will always recommend the most conservative option that reliably restores the tooth.
Both are highly durable restorations. Porcelain crowns typically last 15–25+ years; porcelain onlays last 15–25 years; gold onlays can last 25–30 years or more. Both significantly outlast composite fillings (7–15 years). The choice between them should be based on how much tooth structure remains, not on longevity alone — both deliver excellent long-term results.
At Dental Clinic London, crowns and onlays both start from £995 (porcelain or gold). Layered porcelain crowns (PFZ) start from £1,195. Since the costs are comparable, the decision is driven by clinical need rather than price — your dentist will recommend whichever restoration is most appropriate for the extent of damage. 0% finance is available on selected treatments, subject to status.
For medium to large cavities where the tooth retains healthy structure, an onlay provides the ideal balance of strength and conservation. For teeth with extensive damage — large fractures, severe decay, failed large restorations, or root canal treatment — a crown provides the full coverage and reinforcement needed. Both options sit above a standard filling in strength; the deciding factor is how much tooth remains.
Weighing Up
Advantages
Limitations
Advantages
Limitations
Transparent Pricing
Prices at Dental Clinic London. View our complete fee guide for all treatment pricing.
| Treatment | Price | Visits |
|---|---|---|
| New Patient ExaminationFull examination, X-rays & treatment plan | £30 | 1 |
| Composite Filling (for comparison)Standard filling — suitable for small cavities | From £185 | 1 |
| Onlay — Porcelain / CeramicCustom lab-made partial-coverage restoration | From £995 | 2 |
| Onlay — GoldExceptionally durable — 25–30+ years lifespan | From £995 | 2 |
| Zirconia / E.max CrownFull-coverage all-ceramic crown | From £995 | 2 |
| Layered Porcelain Crown (PFZ)Zirconia core + hand-layered porcelain — premium result | From £1,195 | 2 |
All costs confirmed before treatment begins. 0% finance available on selected treatments, subject to status.
Making Your Decision
The right choice depends on how much damage the tooth has sustained and how much healthy structure remains. Here is a general guide — your dentist will confirm the best approach following examination.
If the tooth has lost a significant amount of structure — from a large fracture, severe decay, a failed existing restoration or root canal treatment — a crown is the appropriate option. It encases and reinforces the entire tooth, preventing fracture and restoring full chewing function. A tooth that is too weak for an onlay needs the full coverage only a crown can provide.
If the tooth retains sufficient healthy structure but the cavity or damage is too large for a standard filling, an onlay is the ideal restoration. It replaces only the damaged cusps, preserving all the healthy enamel and dentine. This conservative approach maintains the tooth's long-term integrity and avoids the more extensive preparation required for a crown.
Porcelain crowns and onlays both last 15–25+ years. Gold onlays can last 25–30 years or more. Both are significantly stronger and longer-lasting than composite fillings (7–15 years). When both options are clinically suitable, durability alone does not favour one over the other — the decision should be based on how much tooth structure remains.
Crowns and onlays are priced the same at Dental Clinic London — both start from £995 (porcelain or gold). Layered porcelain crowns (PFZ) start from £1,195. Since the cost is comparable, the choice should be based on clinical need, not price. For smaller cavities where neither a crown nor onlay is necessary, a composite filling from £185 may be the most appropriate and affordable option.
For smaller cavities, a composite filling may be sufficient. For teeth that cannot be saved, a dental implant is an option. Both form part of our comprehensive general dentistry services.
Common Questions
Have another question? Contact our team and we will be happy to help.
Book a new patient examination (just £30) at Dental Clinic London. Your dentist will examine your teeth, take any necessary X-rays and recommend the most appropriate restoration — whether that is an onlay, a crown, or a different treatment entirely. No obligation, no pressure.
Disclaimer
This article is intended for general educational purposes only and does not constitute personalised dental advice. Individual diagnosis and treatment recommendations require a clinical examination by a qualified dental professional. All treatment outcomes vary by patient. Prices shown are starting prices and may vary depending on complexity. Dental Clinic London is registered with the Care Quality Commission (CQC) and the General Dental Council (GDC).