What Is the Difference between Inlays, Onlays and Fillings?

Tooth decay is a common problem and it is important to fill cavities and to protect the tooth against any further infection and loss of structure. Here at Downham Market Dental Care, our dentists are likely to suggest you have a filling or an inlay or onlay. So what is the difference between these options and when are they used?


Fillings are used to fill small to medium sized cavities in teeth where most of the tooth structure is still intact. They can be made from a variety of different materials. An NHS dentist in Downham Market will use silver coloured amalgam fillings to mend back teeth, while front teeth will be mended using strong, tooth coloured composite resins to create a cosmetically pleasing effect. Composite resin fillings are considered to be a cosmetic dental treatment which is why they aren’t generally used to mend back teeth under the NHS. Amalgam is hard wearing and is a very effective way of filling back teeth but it isn’t the prettiest material.

We use the most advanced composite resins to provide hard wearing and long-lasting results and they can look amazing. Often our dentists will use several different colours to ensure you get an exact match and that your new filling will blend in beautifully with the rest of your teeth. You will find our Downham Market dentist can provide you with both options and even if you are receiving NHS treatment then you can still opt to pay the extra to have your back teeth filled with more cosmetically pleasing composite resin.

Inlays and Onlays

An inlay or onlay is used to repair a large cavity in a back tooth. It’s what’s known as an indirect filling which means it has to be made in a dental laboratory to custom fit your tooth. You may require an inlay or onlay if you have a badly decayed back tooth and where a filling wouldn’t be strong enough to restore all its structure but where the damage isn’t enough for you to require a crown that would completely cover up the tooth. An inlay is slightly smaller than an onlay and is only designed to repair the very central part of the chewing surface of your back tooth. An onlay will repair this surface plus one or more of the tooth cusps so it can be quite large and is sometimes called a three-quarter crown as it will cover up a substantial amount of your tooth but some of its natural structure will still be visible.

Your inlay or onlay can be made from either porcelain or gold alloy. We might suggest you have a gold inlay or onlay if our dentist in Downham Market thinks you have a particularly heavy bite. This is because gold is quite soft and it will not damage your opposing teeth when you bite or chew. If your inlay or onlay is to be made from porcelain then you can look forward to having a restoration that is virtually invisible.

If you do have fillings that are coming to the end of their natural life or if you just want to talk to us about perhaps replacing amalgam fillings with something more cosmetically pleasing, then why not give us a call on 01366 382265. You can also find more information about inlays, onlays and fillings on our website at www.Downhammarketdentalcare.co.uk.

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