A Guide to Onlays and Inlays

The earlier your dentist spots your tooth decay, the better. It means that the decay is easier to clear away, the cavity smaller and therefore easier to fill. But what happens when the decay is not spotted earlier? What happens when the tooth has already decayed considerably so that a filling will not be sufficient?

In immediate answer is that, where a filling is insufficient, a crown is required. A crown is needed when the tooth has decayed to such an extent that the tooth itself is not strong enough to hold a filling. Therefore, your dentist clears away the decay, shapes the remaining parts of the tooth and then the crown is quite literally placed over the top.

Therefore, in terms of procedures, it is quite a leap from a filling to a crown. A filling is quite often a relatively quick procedure that can be completed in just one visit. A crown is much more expensive to fit and requires at least two visits, as the mould needs to be taken then sent to a laboratory for the crown to be constructed.

So it is natural to look for a treatment which can sit neatly in between. Something stronger and more durable than a filling. Yet also something which is easier to fit than a crown and which allows you to salvage the remaining healthy parts of your existing tooth. This is exactly where onlays and inlays can be included in your dentist’s repertoire.

Onlays and inlays are deployed when the cavity is too large for a filling but the structure of the tooth is still sound. Therefore, rather than re-shaping a sound tooth to fit under a crown, your dentist can simply use an inlay or onlay. An inlay fills the gap in the tooth while the onlay is applied to the top of the tooth – but apart from positioning they essentially play the same function.

Usually, inlays and onlays are used to restore the back teeth as these are the teeth that do the most work, are the hardest to clean and often suffer the most from decay. Sometimes, they are also used to replace older amalgam fillings. The reason for this is because onlays and inlays can be manufactured from tooth-coloured materials, such as composite resin or porcelain.

The treatment for onlays and inlays is usually a more straightforward process than fitting a crown. However, that does depend on the tooth and the amount of decay. An old amalgam filling may need to be removed, as well as the decay cleaned away. Then the onlay or inlay is prepared in a laboratory and usually fitted at a second appointment. Nowadays, some dental practices have the technology to create onlays and inlays on the same day, which means that they can sometimes be fitted during a single appointment.

Therefore, there are a number of advantages to dental inlays and onlays. The first, and most important advantage, is that they do a fantastic job. They are made from very durable materials which means that they have the potential to last much longer than standard amalgam fillings – up to 30 years in fact.

Of course, you must maintain a good standard of oral hygiene, brushing your teeth and visiting your dentist regularly. However, your newly restored tooth will not require any special treatment when it comes to how you look after it.

Secondly, your inlays and onlays are made from tooth-coloured materials. So they have a much greater aesthetic quality that a standard amalgam fillings. In fact, many people choose to have their existing amalgam fillings replaced with onlays and inlays purely for aesthetic reasons. They help to create an attractive, healthy and natural looking smile.

Finally, the most important advantage to onlays and inlays is that they allow your dentist to salvage as much of your natural tooth as they can. When fitting a crown, your dentist has to file and shape the tooth into a conical shape so that the crown will fit over it. So some of the healthy tooth may need to be chipped away. Onlays and inlays ensure that this process is avoided – and the longer you can keep your natural teeth healthy, the less likely you are to face serious dental work in the future.