South Kensington
- 20 Old Brompton Road, London SW7 3DL
- Open seven days a week
- 020 7183 2362
Treatment comparison · Wimpole Street, Marylebone
Filling or inlay: when a cavity is better served by something made in a laboratory
Most cavities are repaired with a filling: decay is cleared and tooth-coloured composite is shaped into the space and hardened on the spot. An inlay does the same job with a different method. The prepared cavity is scanned, a piece is milled or fired in a laboratory to fit it exactly, and that piece is bonded in at a second visit. The two approaches overlap for medium-sized holes in back teeth, which is where the question usually arises.
Decision guide
Which is right for you?
Choose White fillings if…
- The cavity is small or medium-sized and the walls of the tooth are still sturdy.
- You want the tooth repaired in a single visit of roughly 30 to 45 minutes.
- Keeping the fee down matters more to you than maximum longevity.
- The tooth is a front tooth or a premolar where a well-placed composite blends easily.
Choose Dental inlays if…
- The cavity occupies a large part of the chewing surface of a molar but the cusps are intact.
- An older, large filling has cracked or leaked and needs replacing with something more robust.
- You grind or clench and want a restoration that resists wear better than composite.
- You are prepared to attend twice and pay more for a piece expected to last 10 to 20 years.
At a glance
Side by side
| Feature | White fillings | Dental inlays |
|---|---|---|
| How it is made | Shaped directly in the mouth from composite resin | Fabricated in a laboratory from a scan, then bonded in |
| Where it sits | Fills the cavity within the tooth | Fits inside the cusps as a single custom piece |
| Strength | Suits small to medium cavities | Higher; helps brace a tooth that has lost more structure |
| Expected lifespan | Around 7 to 10 years | Around 10 to 20 years depending on material |
| Appearance | Good; composite is colour-matched at the chair | Excellent; shade and surface texture are finished in the laboratory |
| Visits | One, usually 30 to 45 minutes | Two, one to two weeks apart |
| Fee per tooth at Wimpole Street | From £185 | From £995 |
| Tooth preparation | Only the decayed tissue is removed | Cavity is shaped with smooth walls so the piece can be seated |
| Shrinkage on setting | Composite contracts slightly as it cures | The piece is pre-formed, so there is no curing shrinkage inside the tooth |
| Best suited to | Small and moderate cavities anywhere in the mouth | Larger cavities on the biting surfaces of premolars and molars |
In the chair
What the treatment involves
White fillings
After local anaesthetic, the dentist removes decay and any weakened enamel, then isolates the tooth from saliva. The cavity is etched, a bonding agent is applied, and composite is placed in thin layers, each set with a curing light. The final layer is carved to recreate the grooves and cusps of the chewing surface, the bite is checked, and the surface is polished. The whole appointment generally takes 30 to 45 minutes and the tooth can be used as soon as the numbness wears off.
Dental inlays
The first appointment mirrors the start of a filling: numbing, decay removal and shaping. Instead of filling the space, the dentist takes a digital scan or impression and places a temporary filling to protect the tooth. The laboratory then produces the inlay in porcelain or a reinforced composite, matching the shade recorded at the visit. One to two weeks later the temporary is removed, the inlay is tried in, adjusted for a precise fit and bonded with resin cement. A final polish and bite check complete the treatment.
Fees
Cost and longevity at Wimpole Street
White fillings at Wimpole Street will start from £185 per tooth, with the fee rising for larger cavities. A laboratory-made inlay starts from £995. The gap reflects the second appointment, the technician’s time and the material itself.
Longevity shifts the picture somewhat. A composite filling typically serves for seven to ten years, so a large one may be replaced once or twice in the time an inlay of ten to twenty years remains in place. Each replacement also removes a little more tooth. For a big cavity in a molar, the inlay can therefore be the more economical choice across a couple of decades, even though the initial bill is higher.
All prices are indicative and are confirmed in a written treatment plan at your consultation. Fees are the same at every Medical & Dental clinic.
Weighing it up
Strengths and trade-offs
White fillings
Strengths
- Finished in one visit
- Lowest-cost tooth-coloured repair
- Removes only the decayed tissue
- Blends well with surrounding enamel
- Mercury-free alternative to amalgam
Trade-offs
- Shorter lifespan, particularly in large cavities
- Slight shrinkage during curing can leave microscopic gaps at the margin
- A large filling can weaken the surrounding tooth over time
- May pick up stain or wear at the edges
- Not ideal where most of the chewing surface is missing
Dental inlays
Strengths
- Roughly twice the working life of a composite filling
- Laboratory fit reduces gaps and food traps
- Conserves more tooth than a crown would
- Resists wear and staining
- No curing shrinkage inside the cavity
Trade-offs
- Higher fee
- Requires two appointments and a temporary in between
- Unnecessary for small cavities a filling can handle
- Cannot brace a tooth whose cusps have already broken down; an onlay or crown is then needed
FAQ
Common questions
The main measure is how much sound tooth is left to support the repair. When a cavity spans more than roughly a third of the distance between the cusps, or when the remaining walls are thin, composite is more likely to fail under chewing loads. An X-ray and a look at the tooth after the decay is removed usually settle the question.
They are made the same way, but an inlay sits between the cusps whereas an onlay extends over one or more of them. If a cusp is cracked or missing, the dentist will suggest an onlay rather than an inlay.
Usually porcelain or a high-strength laboratory composite. Porcelain is harder and more stain-resistant; composite is slightly kinder to the opposing tooth. Gold is still occasionally used where appearance is not a concern.
Often yes. Repeated fracture or leakage is a sign that the filling is too large for the job. Provided the cusps are intact and enough tooth remains, an inlay is a common next step; if not, an onlay or crown may be advised instead.
A temporary filling protects the prepared tooth in the interval, and mild sensitivity to cold is not unusual for a few days. It is worth avoiding very sticky foods on that side until the inlay is bonded.
Yes. Both are available now at South Kensington and St Paul’s with the same fees, and treatment records transfer to Marylebone when the clinic opens on 1 October 2026.
Marylebone, W1
Wimpole Street opens 1 October 2026
Register your interest and we will contact you when the Marylebone diary opens. If you would rather not wait, the same clinicians can see you at South Kensington or St Paul's now.
Related treatments at Wimpole Street
Opening 1 October 2026
Wimpole Street is not yet seeing patients. Until then, please book or call our South Kensington clinic on 020 7183 2362 or our St Paul's clinic on 020 7183 3709. Questions about the new clinic: wimpolestreet@md.co.uk.
Until we open
Need an appointment before 1 October 2026?
The same clinical team already works from two other Medical & Dental clinics. Book at either one now and, if you prefer, move your ongoing care to Wimpole Street once the doors open.
St Paul's, City of London
- 5 Ave Maria Lane, London EC4M 7AQ
- Open Monday to Friday
- 020 7183 3709
