Both restore damaged or decayed teeth — but they differ in strength, longevity and how they are made. A filling is placed directly in the cavity in a single visit. An inlay is custom-made in a laboratory for a stronger, more precise and longer-lasting result. The right choice depends on the size and location of the cavity.
If your dentist has found a cavity or an area of damage on a tooth, you may be offered a choice between a composite filling and an inlay. Both restore the tooth to full function and appearance — but they differ in how they are made, how strong they are and how long they last.
A filling is placed directly into the cavity in a single appointment — quick, affordable and ideal for smaller restorations. An inlay is custom-fabricated in a dental laboratory from porcelain, ceramic or gold, then bonded to the tooth at a second visit — stronger, more precise and significantly longer-lasting. Both are part of our comprehensive restorative dentistry services, and the right choice depends on the size, location and function of the cavity.
Not sure which you need? Book a consultation or call us on 020 7183 0527 — your dentist will examine the tooth and recommend the most appropriate option.
At a Glance
Fillings vs inlays — side by side.
| Feature | Composite Filling · From £185 | Inlay · From £995 |
|---|---|---|
| Coverage of Tooth | Fills the cavity directly — sits within the tooth structure | Custom-made piece fitted precisely within the cusps of the tooth |
| Procedure Type | Direct — placed and cured chairside in a single visit | Indirect — impression taken, lab-fabricated, bonded at second visit |
| Treatment Time | 1 appointment · 30–45 minutes | 2 appointments · 45–60 minutes each, 1–2 weeks apart |
| Structural Support | Good — bonds to tooth and reinforces remaining structure | Very high — lab-made from porcelain or gold, significantly stronger |
| Aesthetics | Good — shade-matched composite resin, virtually invisible | Excellent — porcelain shade-matched with natural translucency |
| Cost at Our Clinic | From £185 (small) · From £325 (large) | From £995 (porcelain, ceramic or gold) |
| Longevity | 7–15 years with good care | 15–25 years (porcelain); 25–30+ years (gold) |
| Suitability | Small to medium cavities on any tooth | Medium to large cavities, especially on back teeth |
Treatment recommendations depend on individual clinical assessment. All prices confirmed before treatment begins.
Direct Restoration
A composite filling is a direct restoration — your dentist removes the decayed or damaged portion of the tooth, then places tooth-coloured composite resin directly into the cavity, sculpts it to match the natural shape and hardens it with a curing light. The entire process is completed in a single 30–45 minute appointment.
At Dental Clinic London, composite fillings start from £185 for a small (single-surface) restoration, from £245 for a medium (two-surface) and from £325 for a large (three or more surfaces). The composite is BPA-free, mercury-free and shade-matched to your natural tooth colour — making it virtually invisible once polished.
With good oral hygiene and regular check-ups, composite fillings typically last 7–15 years. They are ideal for small to medium cavities, chip repairs and replacing old amalgam fillings with a tooth-coloured alternative.
Lab-Made Restoration
An inlay is a custom-made restoration fabricated in a dental laboratory from porcelain, ceramic or gold. Unlike a filling, which is moulded directly in the mouth, an inlay is crafted from a precise impression of your prepared tooth — resulting in a stronger, more accurate and longer-lasting restoration. It fits within the cusps (raised points) of the tooth, restoring the biting surface without covering the cusps.
At Dental Clinic London, inlays start from £995 — the same price regardless of whether you choose porcelain, ceramic or gold. Treatment requires two appointments over 1–2 weeks: the first to prepare the tooth and take an impression, the second to bond the finished inlay permanently in place.
Porcelain and ceramic inlays typically last 15–25 years with good care — significantly longer than composite fillings. Gold inlays can last 25–30 years or more and are exceptionally durable. Inlays preserve more healthy tooth structure than a crown, making them the preferred conservative option for medium to large cavities.
Understanding the Difference
A composite filling is applied directly into the cavity and cured with a light. It bonds well to the tooth and provides good support for small to medium restorations. An inlay is fabricated in a laboratory from porcelain, ceramic or gold — materials that are significantly harder and more wear-resistant than composite resin. This makes inlays considerably stronger, particularly on back teeth that bear heavy chewing forces. For cavities covering more than about one-third of the biting surface, an inlay provides a more reliable, long-term result.
Both fillings and inlays require the removal of decayed or damaged tooth structure. Composite fillings bond directly to the tooth, so the preparation can be minimal and conservative. Inlay preparation requires slightly more defined cavity margins to ensure the lab-made piece fits precisely — but an inlay still preserves significantly more tooth than a crown, which requires reducing the entire outer surface. If the tooth has enough healthy structure remaining, an inlay is always the more conservative option compared to a crown.
This is one of the most significant differences. Composite fillings typically last 7–15 years with good oral hygiene. Porcelain and ceramic inlays last 15–25 years, and gold inlays can last 25–30 years or more. The difference comes down to material strength and precision of fit — lab-fabricated restorations are harder, more wear-resistant and fit more tightly to the tooth, reducing the risk of micro-leakage and secondary decay over time.
Fillings are significantly more affordable. A small composite filling starts from £185, a medium from £245 and a large from £325. Inlays start from £995. The cost difference reflects the laboratory fabrication, stronger materials and two-appointment process. However, because inlays last 2–3 times longer than fillings, the cost per year of service is often comparable. For a tooth that will need a restoration replaced multiple times over your lifetime, an inlay may be the more cost-effective choice long-term.
For small cavities — a single surface or a minor chip — a composite filling is almost always the best option. It is quick, affordable and perfectly adequate. For medium to large cavities, especially on premolars and molars, a filling may not provide enough strength to withstand years of chewing forces without fracturing. An inlay gives the tooth significantly more structural support. If the damage is too extensive even for an inlay, a dental crown (from £995) or root canal treatment may be needed.
Weighing Up
Advantages
Limitations
Advantages
Limitations
Transparent Pricing
Prices at Dental Clinic London. View our complete fee guide for all treatment pricing.
| Treatment | Price | Longevity |
|---|---|---|
| New Patient ExaminationFull assessment, X-rays & treatment plan | £30 | — |
| Composite Filling — Small (1 surface)Single-surface direct restoration | From £185 | 7–15 years |
| Composite Filling — Medium (2 surfaces)Two-surface direct restoration | From £245 | 7–15 years |
| Composite Filling — Large (3+ surfaces)Multi-surface direct restoration | From £325 | 7–15 years |
| Inlay or Onlay (Porcelain / Ceramic)Custom lab-made restoration — precision fit | From £995 | 15–25 years |
| Inlay or Onlay (Gold)Exceptionally durable — ideal for back teeth | From £995 | 25–30+ years |
| Dental CrownFull-coverage restoration — for more extensive damage | From £995 | 10–20 years |
| Amalgam Replacement FillingRemove old silver filling & replace with composite | From £185 | 7–15 years |
All costs confirmed before treatment begins. 0% finance available on selected treatments, subject to status.
Making Your Decision
The right choice depends on the size and location of the cavity, the forces the tooth bears and your priorities. Here is a general guide — your dentist will confirm the best approach following examination.
For small, single-surface cavities — and most chips, cracks or worn edges — a direct composite filling is the ideal restoration. It is completed in one quick appointment (30–45 minutes), is the most affordable option and preserves the maximum amount of healthy tooth. There is no clinical advantage to placing a lab-made inlay on a small cavity — a well-placed composite filling will serve you reliably for 7–15 years.
When a cavity covers more than about one-third of the biting surface — particularly on a premolar or molar — an inlay provides significantly more structural support than a direct filling. The lab-fabricated porcelain or gold is harder, more wear-resistant and fits with greater precision. For patients with a large, failing filling that needs replacing, upgrading to an inlay is often the strongest, most conservative option before a crown would be needed.
If longevity is your priority, an inlay is the clear choice for medium to large restorations. Porcelain inlays typically last 15–25 years — roughly double the lifespan of a composite filling. Gold inlays can last 25–30 years or more. The tighter, more precise fit also reduces the risk of bacteria entering at the margins and causing secondary decay. Over a lifetime, fewer replacements means less drilling and more natural tooth preserved.
If budget is your primary concern, a composite filling is the most affordable way to restore a damaged tooth — starting from just £185 for a small cavity. Even a large, three-surface filling (from £325) is significantly less than an inlay (from £995). For small to medium cavities, a well-placed composite filling is a perfectly effective restoration. 0% finance is also available on selected treatments to help spread the cost.
If the tooth is too damaged for an inlay, a dental crown or root canal treatment may be needed. For missing teeth, dental implants provide a permanent replacement. All options are discussed as part of our general dentistry services.
Common Questions
Have another question? Contact our team and we will be happy to help.
Book a new patient examination at Dental Clinic London for just £30. Your dentist will assess the tooth, explain the options clearly and recommend the most appropriate restoration — whether that is a filling, an inlay, an onlay or something else. No pressure, no obligation.
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).