Added by Anne Beckett on | Reviewed by Katarzyna Gorska

What is a Dental Inlay?

Inlay, onlay and overlay  are cosmetic crown fillings that are used for large cavities, when the tooth structure is very damaged . Sometimes the term ‘pinlay’ is also used when the inlay/onlay/overlay is held in place by a pin or pins.

dental inlay

Inlay pre-prepared filling fitted into the grooves of a tooth

A dental inlay, also known as a tooth inlay, is essentially a filling which sits inside your tooth and is used for restorative work.  It rebuilds the chewing surface of the tooth and unlike a normal filling which is built up inside your tooth by the dentist, an inlay is actually created in a laboratory as a solid piece before being placed inside your tooth by the dentist.  An inlay is only used when the cusps of the tooth are still in tact. These should not be confused with a bone inlay (graft) which is something completely different.

What is a Dental Onlay?

A dental onlay, or tooth onlay, is also used for dental restorative work.  However, unlike the inlay, it sits on the tooth rather than in it.  It rebuilds not only the chewing surface but  also part of the cusps (either one or both). It, too, is constructed in a laboratory as one solid piece and attached to the tooth by the dentist.

What is Dental Overlay?

A dental overlay is more extensive than both an inlay or onlay. Constructed in a laboratory, an overlay is a partial crown which rebuilds the chewing surface and cusps in addition to part of the lateral surfaces of the tooth.  In comparison a crown usually covers the entire lateral surfaces of a tooth down to the gum

What is the difference between Inlay, Onlay and Overlay?

In simple terms, an inlay sits inside the tooth, an onlay sits on the tooth and covers the biting surface of the tooth and at least one cusp and an overlay sits on the tooth and covers both cusps and part of the lateral surface of the tooth .  An onlay or overlay may be required where there is more extensive damage to the cusps or edges of the tooth or sometimes the actual biting surface of a tooth.

dental inlay

The main difference among inlays, onlays and overlays is in the size of damage and the area of the tooth being treated

Inlay/Onlay/Overlay vs Filling

Generally a dentist will consider filling a tooth when a maximum of 40% of the tooth is damaged. A filling is considered a ‘direct’ filling, because it can be applied in one visit directly by your dentist in his surgery.  Inlays and onlays are considered to be ‘indirect’ fillings because, like crowns, they are made in a laboratory. This means that a patient will need at least two visits to the dentist – one visit for cleaning and to either take a mould of the tooth or digitally scan it, and the second visit to have the inlay/onlay/overlay fitted.  Inlays, onlays and overlays are used when a tooth is too badly damaged or decayed to have a simple filling (about 40%-60% of the tooth is damaged) or when a filling would be so big it could weaken the whole structure of the tooth. The goal of a dentist is always to save a tooth where possible, so if they think a dental filling won’t do the job, they may offer an inlay, onlay or overlay.

Dental onlay/inlay/overlay  vs filling



Requires less removal of the tooth

Requires more removal of the tooth

Can actually strengthen the structure of the tooth

Can weaken the structure of the tooth

May last up to 30 years

Composite fillings last up to 7 years (gold and silver amalgam will last longer)

Are custom made and do not shrink or change shape during the curing process

Fillings may shrink over time

Inlay/Onlay/Overlay vs Crown

In fact, inlays/onlays/overlays lie somewhere between a filling and a crown.  Crowns completely cover the tooth and are used for very badly damaged teeth (over 60% damage). Often,  a considerable amount of the tooth may have to be removed so that the crown can fit over it. With an inlay/onlay/overlay much less of the tooth has to be removed – indeed, the outside of the tooth may hardly be touched. So, we can say that when a tooth needs to be repaired through either decay or damage, a dentist will firstly consider a filling.  Only the decay or damaged part of the tooth has to be removed and the procedure is relatively easy and cost-effective. Where a dentist feels that a filling may not solve the problem either because the tooth is too weak or has too much damage, then the answer could be an inlay/onlay or overlay. However, where there is not enough of the tooth remaining and possibly taking away a little more of the tooth will not really make a lot of difference, then probably a dental crown is the best solution.

Dental inlay/onlay/overlay vs crown

Inlays/Onlays/ Overlays


Can only be used for a tooth which is damage up to about 60%

Crowns cover the entire tooth preventing it from further damage, breaking or fracturing

May last up to 30 years

Crowns last on average up to 15 years, but gold crowns up to 30 years

Minimal damage to existing tooth

Quite a lot of tooth may have to be drilled away so that crown can sit over the top

Types of Inlay/Onlay/Overlay

There are three materials available for  inlays/onlays/overlays – gold, porcelain and composite.

The choice mainly depends on cost, expected durability and aesthetics.

Gold inlay/onlay/overlay

gold inlay

There are few types of inlay one of them is the gold hardwearing and extremy strong
can last up to 30 years with proper hygiene

A gold inlay/onlay is actually made of a gold alloy and therefore is extremely strong and hardwearing.  It is made from gold, copper and other metals. This is the most expensive option, but with good oral care a gold inlay/onlay/overlay can last up to 30 years.  There is the problem, of course, that they are much more conspicuous than other materials, however with back teeth this shouldn’t be a problem.

Porcelain inlay/onlay/overlay

A less expensive option is a porcelain inlay/onlay.  This, obviously, blends in with the teeth much better than gold, but it will probably not be so hardwearing and can even sometimes crack.

Composite inlay/onlay

Dental composite is a mixture of plastic and ceramic and is the material used in ‘white’ fillings.  It can be produced with a colour near to the tooth colour, and unlike a normal ‘composite filling’, is less likely to shrink away from the walls of the tooth.


Gold inlay/onlay/overlay

Porcelain inlay/onlay/overlay

Composite inlay/onlay/overlay


The most expensive typ

Middle - price

The lowest priced type


Visible when used on teeth at the front of the mouth

Blend in with the teeth

Blend in with the teeth but may stain more easily


30+ years

25 years +

25+ years


Dental inlay/onlay/overlay procedure

The inlay, onlay and overlay procedure are performed in a similar way and all require at least two visits to the  dentist.

3D imagine

3D image as a modern treatment tool by this kind of treatment which can have in the offer some dental clinics

On the first visit you may be offered a local anaesthetic while the dentist generally prepares and cleans the tooth.  This may require some drilling to remove any decay or damage or even an old filling. Once the tooth is prepared the dentist will take a mould of the damaged tooth, usually by using dental putty inserted into a small tray.  Some dental surgeries may have sophisticated 3D imaging equipment which they can use. The information about the size and shape of the inlay/onlay/overlay is sent away to a dental laboratory. In the meantime, the dentist will cover the tooth with a temporary filling.

On the second visit, the dentist will remove the temporary filling and check that the inlay/onlay/overlay that the laboratory has created is, in fact, a good fit for the tooth.  When the dentist is sure that this is the case, it will be glued or bonded to the tooth. Your treatment is now finished.

As with all dental work, there may be some soreness after the procedure but the level of pain should be very low.  If necessary over-the-counter painkillers can be taken. For the first few days the onlay/overlay may feel strange in the mouth, but this will soon pass.

How much do inlays, onlays abd overlays cost

Private treatment for inlays, onlays and overlays varies greatly between different dentists and different regions.

In London expect to pay upwards of £600 for inlays/onlays.

Outside of London and the bigger cities it may be possible to find dentists charging £400-£450.

The above prices are starting prices, so extra will need to be added for more complex treatments and for gold inlays/onlays.

Is inlay/onlay/overlay covered by NHS?

Yes, both inlays and onlays may be available through the NHS.  However unlike standard fillings which fall into Price Band 2 (£62.10), inlays and onlays fall into Price Band 3 (£269.30).

Some categories of people are entitled to free dental services.  Inlays/onlays/overlays would fall into the category of a free procedure although many NHS dentist may recommend ordinary fillings instead.

Those people who have access to free treatment are:

  • Those under 18, or under 19 if in full-time education
  • Women who are pregnant or who have given birth in the last 12 months
  • Those receiving low-income benefits or under 20 year olds who are dependent on somebody receiving low-income benefits.

Inlay/Onlay/Overlay abroad

Even after factoring in the cost of flights, it can be cheaper to obtain private dental treatment abroad.  Both Poland and Turkey are amongst the most popular countries to travel to for overseas dental treatment, offering modern hi-tech dental clinics and well-trained dentists.  The two visits to the dental clinic are relatively short – 60-120 minutes for the first visit and about 30 minutes for the second visit, so, where possible, the procedure can be performed with two day-trip flights.  Sometimes, where the dental clinic has its own laboratory on site, the waiting time for the production of the inlay/onlay may be reduced so that an extended first visit may be possible rather than two visits.

travel inlay

Being in another country you will gladly visit a dentist to get treatment which doesn`t take much time

Inlay/Onlay/Overlay in Poland

Polish dental clinics offer one of the best standards in dental care and the prices are very competitive  – starting at about £100 depending on the material used. The clinics are modern with the latest equipment and all dental staff are fully trained.  English is widely spoken in Poland so communication is easy. There are many frequent budget flights to the main cities in Poland from most major European airports, so flight availability and costs are not usually a problem.  Flight costs vary hugely depending on the airline, route, advance booking period and time of year and time of day. However, it is not unusual to find flights from UK to Poland for around £50 return, especially if the trip can be booked some way in advance.  You caneasily find inlay/onlay/overlay in Poland. Dental treatment may also be combined with a holiday to Poland. Its cities, like Krakow – which has just been voted the Best City Break destination for the third year running – have many interesting places to visit.

Inlay/Onlay/Overlay in Turkey

Many dental clinics in Turkey also offer good standards of dental care with competitive prices.  Like in Poland, it is possible to find inlays/onlays/overlays in Turkey at reputable dental clinics from about £100.  The more frequent flights to Turkey are either to Istanbul, the capital, or to the tourist beach holiday centres like Izmir or Antalya  One advantage of Turkey is that the dental visit can be combined with a holiday on one of its Mediterranean or Aegean beaches.

Dental Inlay/Onlay/Overlay alternatives

The only real alternatives to dental inlays/onlays and overlays are either normal fillings, crowns or, worst case scenario, tooth extraction.  However, a dentist will always try to save a tooth if at all possible. Both fillings and crowns have advantages and disadvantages compared to inlays/onlays/overlays.  The tables above in the fillings and crown sections give comparisons.

Inlay/Onlay/Overlay pros and cons

 Dental Inlay/Dental onlay/Dental Overlay advantages :

  • Better protection for the tooth compared to fillings
  • A wide choice of different colours, so a better match to the colour of the tooth being filled
  • Usually last longer than ordinary fillings and less likely to cause sensitivity
disadvantages inlay

Be aware of the pros and cons of treatment like inlay /onlay does not protect teeth from further decay, which is why maintaining proper hygiene is very important

 Dental Inlay/Dental Onlay/Dental Overlay disadvantages:

  • Cost a lot more than standard fillings – NHS costs for a filling £62.10 but for an inlay/onlay/overlay £269.30
  • As the inlay/onlay is custom-made in a laboratory the procedure will require two visits to the dentist
  • Sometimes longer  tooth preparation is required

There is the possibility of a dental inlay/onlay/overlay falling out but this seldom happens.  This just means that something has gone wrong with the bonding process. A return visit to the dentist should be able to rectify this.

A dental inlay/onlay/overlay doesn’t make the tooth immune to further damage and decay so it is essential that the tooth is brushed and flossed regularly.


Although more expensive than ordinary fillings, inlays/onlays/overlays  last much longer. Minimal damage is done to the tooth and despite having to make two visits to the dentist the procedure is relatively simple and pain free.  Depending on the material they can blend in perfectly with the tooth colour. Gold inlays/onlays, although more noticeable are a good choice for back teeth which often have to work harder than the front teeth.  One option to reduce the cost, is to consider having the work done abroad – Poland or Turkey are good options and our friendly and knowledgeable consultants can give you more information about our recommended dentists in each country.

Get the insurance for treatment abroad:


NHS Charges:

Inlays, onlays and veneers

David Bartlett, David Ricketts, in Advanced Operative Dentistry, 2011

Clinical Evaluation of Ceramic Inlays Compared to Composite Restorations

RT Lange • P Pfeiffer Operative Dentistry 2009

A Guide to Onlays/Inlays – Dental Guide UK 2017

Anne Beckett

In the UK Anne was a professionally qualified trainer with many years of experience in the training industry. She mainly worked in the travel, tourism and leisure industries (including Thomas Cook and British Airways) as well as in other sectors.

Since moving to Poland  twelve years ago, Anne has become involved in other business sectors – teaching English as a foreign language and translating documents from Polish into English. She specialises particularly,  in  medical translations and  works closely with dentists, cardiologists and neurologists in translating and preparing articles for publication. She has also trained as a practitioner in the field of neuro-linguistic programming and is a qualified hypnotherapist.

Any spare time is spent renovating the house in Poland which Anne bought some years ago.

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