An inlay is a custom-made restoration that fills the centre of a back tooth, and an onlay is one that also covers one or more of its cusps; both sit between a filling and a crown in how much of the tooth they replace. Composite inlays and onlays are made from tooth-coloured resin in a laboratory, then bonded to the tooth, which makes them a durable and more affordable alternative to porcelain. In Turkey, composite inlays and onlays cost about €150 to €250 per tooth, compared with £300 to £600 privately in the UK, €250 to €500 in Germany and $600 to $1,000 in the US. Review data puts the 5-year survival of indirect composite inlays, onlays and overlays at about 91%, and a prospective study reported an 85% success rate at 9 years. This guide explains what composite inlays and onlays are, what they cost across countries, how they differ from fillings and porcelain, and how to care for them.
The information in this article is for educational purposes only and does not constitute medical advice. Consult a qualified dental professional before making any treatment decisions.
What are composite dental inlays and onlays?
Composite dental inlays and onlays are tooth-coloured resin restorations made outside the mouth to rebuild a tooth damaged by decay or fracture. An inlay fits inside the grooves between the cusps, an onlay extends over one or more cusps, and an overlay covers the whole biting surface; all three are sometimes called partial crowns. They are used when a cavity is too large for a dental filling to hold up under chewing, yet the tooth still has enough healthy structure to avoid a full crown. Inlays and onlays can also be made from porcelain or gold, but composite is chosen when cost and easy repair matter most. That makes the price the first thing most patients compare.
Composite inlays and onlays cost about €150 to €250 per tooth in Turkey, against £300 to £600 privately in the UK, €250 to €500 in Germany and $600 to $1,000 in the US, which is why treatment in Istanbul saves patients up to 75%. They cost more than a direct filling because they are made in a laboratory and fitted over two visits, but less than a porcelain inlay or a crown on the same tooth.
| Country | Typical fee for a composite inlay or onlay | Notes |
|---|---|---|
| Turkey (Istanbul) | €150 – €250 per tooth | Laboratory-made, bonded over two visits |
| United Kingdom (private) | £300 – £600 per tooth | Ceramic inlays usually cost £550 to £700 |
| United Kingdom (NHS, England) | £332.10 per course of treatment | Band 3 charge from 1 April 2026; covers all treatment in the course |
| United States | $600 – $1,000 per tooth | Porcelain sits at the upper end of the $650 to $1,200 inlay range |
| Germany | €250 – €500 per tooth | Statutory insurance pays only the equivalent of a basic filling |
The number of teeth, the size of each restoration, and whether old fillings need removing all change the final figure, and travel and accommodation should be added when comparing countries. What that fee buys becomes clearer once you know what the material is made of.
What are composite inlays and onlays made of?
Composite inlays and onlays are made from a resin matrix filled with fine ceramic or glass particles, the same family of material as a tooth-coloured filling but processed differently. Because the restoration is cured in the laboratory rather than in the mouth, it sets more completely and shrinks less than a filling placed directly in a large cavity. That gives better contact points with the neighbouring teeth, a smoother surface and a more accurate fit at the margins. The result is a restoration that behaves more like a laboratory crown than a filling, which is the key difference patients ask about.
How is a composite inlay different from a composite filling?
A composite filling is shaped and hardened directly in the tooth in one visit, while a composite inlay is made in a laboratory from an impression and bonded in a second visit. The indirect method suits larger cavities, where a direct filling would be hard to contour and more prone to shrinkage gaps at the edges. Inlays and onlays cost more than fillings and take two appointments, but they rebuild lost cusps and contact points more predictably. For small cavities, a direct composite filling is usually the simpler and more conservative choice. How long the laboratory version lasts is the next question.
How long do composite inlays and onlays last?
Indirect composite inlays, onlays and overlays show a 5-year survival rate of about 91% and a success rate of about 84% in a systematic review and meta-analysis (Fan and colleagues, 2021). Over a longer period, a prospective study of 60 composite inlays and onlays reported an 85% success rate at 9 years, with marginal discolouration the most common change (Galiatsatos and colleagues, 2021). Ceramic restorations tend to keep their surface and colour longer, while composite can be repaired chairside if it chips. Lifespan depends on the size of the restoration, bite forces and daily cleaning, so the preparation stage matters as much as the material.
What happens during inlay preparation and fitting?
Inlay preparation and fitting usually take two appointments, a few days apart:
- Numbing: the tooth is numbed with local anaesthetic.
- Preparation: decay and old filling material are removed and the walls of the cavity are shaped slightly outward so the inlay can seat without undercuts.
- Impression or scan: the prepared tooth is recorded to create an exact model.
- Temporary: a temporary restoration seals the tooth.
- Laboratory: the composite inlay or onlay is built up, cured and polished.
- Bonding: the temporary is removed and the restoration is bonded with resin cement.
- Bite check: contacts are adjusted and the margins polished.
At MDC the restoration is made in the in-house laboratory, which lets the dentist and technician adjust shade and fit without shipping work elsewhere. With the restoration in place, the material comparison becomes more practical.
How do composite and porcelain inlays compare?
Composite and porcelain inlays differ mainly in cost, repairability and how long they keep their surface. Composite is less expensive and can be repaired in the chair if it chips, and it is slightly kinder to opposing teeth. Porcelain, such as E-max glass-ceramic, is harder, resists staining and wear better, and shows survival of 91% at 10 years in review data. Both are bonded to the tooth with adhesive cement, so both strengthen the remaining structure. Our guide to porcelain inlays and onlays explains the ceramic option in detail. Whichever material you choose, the aftercare is the same.
How do you care for composite inlays and onlays?
You care for composite inlays and onlays by brushing twice a day with fluoride toothpaste, cleaning between the teeth daily and limiting staining drinks. Plaque at the margin is the main cause of decay around any restoration, so floss or interdental brushes are essential. Coffee, tea and red wine can discolour the resin margin over time, and a professional polish at check-ups keeps the surface smooth. Avoid biting hard objects and ask about a night guard if you grind. The questions below cover the decisions patients face most often.
Is an onlay better than a crown?
An onlay is usually better when the tooth still has sound walls and cusps, because it removes much less healthy structure than a crown. A crown is preferred for root-filled, cracked or badly broken teeth that need full protection. Our comparison of inlays and onlays vs crowns sets out the evidence in detail. The dentist confirms the choice after examining the tooth.
Can amalgam fillings be replaced with inlays or onlays?
Yes, large amalgam fillings are often replaced with composite or porcelain inlays and onlays, especially where the old filling has left thin or cracked cusps. The amalgam is removed, the cavity cleaned and reshaped, and a bonded tooth-coloured restoration rebuilds the tooth. Details of the process are on the amalgam filling change service page. Sound amalgam fillings in good condition do not always need replacing.
Is a composite inlay cheaper than a porcelain inlay?
Yes, a composite inlay usually costs less than a porcelain one. In Turkey, composite inlays and onlays cost about €150 to €250 per tooth, while ceramic versions cost about €250 to €350, because resin is less expensive than E-max ceramic and needs less laboratory time. Porcelain costs more but resists staining and wear for longer, so the cheaper option is not always the better value for a heavily loaded back tooth. Current fees for ceramic inlays are listed on the clinic’s price list, and composite fees are confirmed at consultation.
Sources
- Fan, J., Xu, Y., Si, L., Li, X., Fu, B., & Hannig, M. (2021). Long-term Clinical Performance of Composite Resin or Ceramic Inlays, Onlays, and Overlays: A Systematic Review and Meta-analysis. Operative Dentistry, 46(1), 25–44. https://doi.org/10.2341/19-107-LIT (verified 2026-09-21)
- Galiatsatos, A., Galiatsatos, P., & Bergou, D. (2021). Clinical Longevity of Indirect Composite Resin Inlays and Onlays: An Up to 9-Year Prospective Study. European Journal of Dentistry. https://doi.org/10.1055/s-0041-1735420 (verified 2026-09-21)
- Morimoto, S., Rebello de Sampaio, F.B.W., Braga, M.M., Sesma, N., & Özcan, M. (2016). Survival Rate of Resin and Ceramic Inlays, Onlays, and Overlays: A Systematic Review and Meta-analysis. Journal of Dental Research, 95(9), 985–994. https://doi.org/10.1177/0022034516652848 (verified 2026-09-21)
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