Dental Inlays and Onlays: Costs, Types and What to Expect
When a filling is not enough but a crown is too much, an inlay or onlay could be the ideal solution. Here is a clear guide to what they are, what they cost, and whether they are right for you.
Dr Tristan Tinn
Founder & Clinical Director
Photo: Unsplash
If your dentist has mentioned an inlay or onlay, you might be wondering what exactly they are and how they differ from a regular filling or a crown. These indirect restorations sit in a useful middle ground: they are stronger and longer-lasting than large fillings, but they preserve more of your natural tooth than a full crown. This guide covers everything you need to know.
Key Takeaways
- •Inlays sit within the cusps of a back tooth, while onlays extend over one or more cusps, covering a larger area like a partial crown.
- •They sit between fillings and crowns, offering stronger, longer-lasting restoration while preserving more natural tooth than a full crown.
- •NHS inlays and onlays fall under Band 2 at £77.70 in England, with private costs ranging from £400 to £1,000 depending on material.
- •Ceramic, zirconia, gold, and composite resin are all options, with gold and ceramic lasting the longest at up to 30 years.
- •Some private practices offer same-day CEREC inlays and onlays, completing the whole process in around an hour with no temporary filling needed.
What Are Dental Inlays and Onlays?
Inlays and onlays are custom-made restorations used to repair teeth that have moderate damage or decay. Unlike a standard filling, which is packed directly into the tooth and hardened on the spot, an inlay or onlay is fabricated outside the mouth (usually in a dental laboratory) and then bonded into place for a precise, long-lasting fit.
- Inlay: Fits within the cusps (the raised points) of a back tooth, restoring the centre of the biting surface
- Onlay: Covers one or more cusps, extending over a larger area of the tooth. Sometimes called a "partial crown"
Both are typically used on premolars and molars where the damage is too extensive for a simple filling but not severe enough to justify removing healthy tooth structure for a full crown.
Inlay vs Onlay vs Crown: When Is Each Used?
Choosing between a filling, inlay, onlay, or crown depends on how much healthy tooth structure remains:
- Direct filling: Best for small to moderate cavities where plenty of healthy tooth remains. Placed and cured in a single visit.
- Inlay: Used when the cavity or damage is too large for a reliable filling but the cusps of the tooth are still intact.
- Onlay: Chosen when one or more cusps are weakened or damaged. Provides structural reinforcement while keeping as much natural tooth as possible.
- Full crown: Necessary when the tooth is extensively damaged, has had root canal treatment, or needs protection on all sides. Requires more tooth preparation than an onlay.
In short, inlays and onlays fill the gap between fillings and crowns. They allow your dentist to take a conservative approach, preserving healthy enamel and dentine wherever possible.
Good to know: If you have an old large amalgam (silver) filling that needs replacing, your dentist may recommend an inlay or onlay rather than another filling, because the remaining tooth walls may be too thin to support a direct restoration reliably.
Materials: What Are Inlays and Onlays Made From?
Several materials are available, each with different strengths:
Material Comparison
- Ceramic / porcelain: Excellent aesthetics that blend with natural teeth. Strong and stain-resistant. The most popular choice at private practices. Includes modern options like E-max (lithium disilicate) for superior translucency and strength.
- Zirconia: Extremely strong and durable. A good option for patients who grind their teeth or need a restoration on a heavily loaded back tooth.
- Composite resin: Tooth-coloured and more affordable than ceramic. Easier to repair if damaged, but not as long-lasting or wear-resistant.
- Gold: The most durable material with a long clinical track record (often 20 to 30+ years). Very gentle on opposing teeth. Less popular today due to appearance and cost, but still considered the gold standard by many clinicians for longevity.
Your dentist will recommend a material based on the location of the tooth, the forces it needs to withstand, your aesthetic preferences, and your budget.
How Much Do Inlays and Onlays Cost in the UK?
Costs depend on whether you are treated on the NHS or privately, and on the material your dentist uses.
UK Pricing Guide (2026)
- NHS (England) Band 2: £77.70 per course of treatment (covers all Band 2 work in that course, including any fillings, inlays, or root canal treatment needed)
- Private composite inlay/onlay: £400 - £600
- Private ceramic/E-max inlay/onlay: £500 - £900
- Private gold inlay/onlay: £600 - £1,000
- Private zirconia inlay/onlay: £500 - £900
- CEREC same-day ceramic: £550 - £900
Prices vary by region, with London and the South East typically at the higher end. Many practices offer payment plans to help spread the cost of private treatment.
NHS note: Material choice on the NHS may be limited. Your dentist will use the material they consider clinically appropriate, which may be amalgam or composite rather than ceramic or gold. If you want a specific material for cosmetic reasons, private treatment may be the better route.
The Procedure: What to Expect
The traditional inlay or onlay procedure takes two appointments, though same-day options are increasingly available.
Appointment 1: Preparation
- Your dentist numbs the area with local anaesthetic
- Decay or the old filling is removed, and the tooth is shaped to receive the inlay or onlay
- A digital scan or impression is taken and sent to the dental laboratory
- A temporary filling is placed to protect the tooth while the restoration is made
Appointment 2: Fitting (usually 1 to 2 weeks later)
- The temporary filling is removed
- Your dentist checks the fit, shape, and colour of the new restoration
- The inlay or onlay is bonded permanently to the tooth using dental cement or adhesive
- Your bite is adjusted if needed, and the surface is polished smooth
Same-Day Option: CEREC and CAD/CAM
Some private practices use CEREC or similar CAD/CAM technology to design and mill your inlay or onlay from a ceramic block in a single appointment. A digital scan of your tooth is taken, the restoration is designed on screen, and a milling machine produces it in around 15 to 20 minutes. The whole process can be completed in about an hour, with no need for a temporary filling or a second visit.
How Long Do Inlays and Onlays Last?
One of the main advantages of inlays and onlays is their longevity. With good oral hygiene and regular dental check-ups:
- Composite resin: 5 to 10 years
- Ceramic / porcelain: 10 to 20 years
- Zirconia: 15 to 25 years
- Gold: 20 to 30+ years
By comparison, large direct fillings typically last 5 to 10 years before they need replacing. The longer lifespan of an inlay or onlay can make them more cost-effective over time, even if the upfront price is higher.
Advantages Over Large Fillings
Why would your dentist recommend an inlay or onlay instead of simply placing a larger filling? There are several clinical benefits:
- Stronger: Laboratory-made restorations are harder and more wear-resistant than fillings placed directly in the mouth
- Better fit: Custom fabrication means a more precise fit with tighter margins, reducing the risk of bacteria getting underneath
- Preserve tooth structure: Less healthy tooth needs to be removed compared to preparing for a full crown
- Last longer: Typically outlast large direct fillings by a significant margin
- Structural support: An onlay in particular reinforces weakened cusps, reducing the risk of the tooth cracking in future
- Stain resistance: Ceramic and gold restorations resist staining better than composite fillings
Aftercare
Looking after an inlay or onlay is straightforward:
- Brush twice daily with fluoride toothpaste and clean between your teeth with floss or interdental brushes
- Avoid biting down on very hard objects (ice, pen caps, hard sweets)
- If you grind your teeth at night, ask your dentist about a night guard to protect the restoration
- Attend regular dental check-ups so your dentist can monitor the restoration and catch any issues early
- Some sensitivity to hot and cold is normal in the first week or two after fitting and should settle on its own
Bottom line: Dental inlays and onlays offer a durable, tooth-preserving solution for moderate damage. If your dentist recommends one, it is usually because they want to give you the strongest, longest-lasting result while keeping as much of your natural tooth as possible.
Frequently Asked Questions
What is the difference between a dental inlay and an onlay?
An inlay fits within the cusps of a tooth, restoring the centre of the biting surface. An onlay extends over one or more cusps, covering a larger area. Both are custom-made in a dental laboratory and bonded into place.
How much do inlays and onlays cost in the UK?
On the NHS in England, they fall under Band 2 at £77.70. Privately, expect to pay between £400 and £1,000 depending on the material and the practice. Costs are comparable to crowns as the clinical workload is similar, with bonding and isolation often taking longer.
How long do inlays and onlays last?
With good care, 10 to 30 years depending on the material. Gold and ceramic tend to last the longest, while composite resin may need replacing sooner.
Are inlays and onlays better than fillings?
For large restorations, yes. They are stronger, more precise, and longer-lasting than large direct fillings. For small cavities, a standard filling is usually the simpler and more cost-effective option.
Is the procedure painful?
The area is numbed with local anaesthetic, so you should not feel pain during treatment. Mild sensitivity afterwards is common and usually resolves within a few days.
Can you get same-day inlays and onlays?
Yes. Practices with CEREC or CAD/CAM technology can design and mill a ceramic inlay or onlay in a single visit, typically within about an hour. Not all practices offer this, so ask when booking.