A ceramic inlay is a ceramic tooth filling produced in a dental laboratory, used to treat damage caused by cavities.

Here you can see the upper jaw of a patient who has two loose plastic fillings in his side teeth, recognizable due to a black gap (the black arrows point to the teeth). He has already had two fillings replaced by ceramic inlays – which are difficult to differentiate from the rest of the teeth – the 2 white arrows show the corresponding teeth. Now he would like ceramic inlays for the remaining two.

First, the old fillings are removed, using water to cool the teeth so that they do not overheat. A magnifying glass is used when removing fillings and cutting, in order to make sure that as little of the healthy tooth material is removed as possible. The dark discolorations under the fillings were caused in part by the earlier amalgam filling. These discolorations need not be removed.

After the fillings are removed, the cavity detector is applied and then rinsed away to make sure that the cavity was completely removed. Now the cut is performed and the edges roughed up using an Arkansas stone, which ensures a better fit for the ceramic inlays. Before the imprint is taken another sealant is applied, rinsed out after the appropriate exposure time, and the imprint is taken.

A magnifying glass is also used on the imprint to check that the tooth and preparation edges are clearly visible.
One week has passed after the cut was made, and now the ceramic inlays are inserted into the mouth of the patient. You can see the teeth, which are covered by a temporary denture, and protected from saliva and the tongue using a coffer dam. Ceramic inlays need to be glued – a process known as bonding. Bonding is a complicated procedure, since ceramic glues are very sensitive to moisture when hardening.

The temporary dentures are removed and the ceramic inlays tried on – a magnifying glass is used to check whether the fit is good. Then the tooth stump is cleansed using special polishing pastes. Once the stumps have dried, the blue etching gel is applied, first to the enamel – you can find more details on this process under Bonding. After some time has passed, the etching gel is then applied to the dentine, and a short while after that rinsed away thoroughly with water. Now the tooth is treated using various chemicals and allowed to dry between each application. The dentist must work carefully and observe the exposure times specified by the manufacturer, a good dentist usually uses a stop-watch.

Glue is then applied, the best kind being a two-phase glue, which is mixed shortly before glueing and then begins to solidify. A lamp can be used to speed up this process. Using a 2-phase glue may be more complicated, but has the advantage that even if not all areas of the glue solidified under the lamp, they will still continue the process after the lamp is switched off. Glues which only harden under lamplight may never do so completely – and glue which is not completely solid can be toxic for the tooth – resulting in toothaches and the need for root treatment.

Now the ceramic inlay is inserted, allowed to harden partially under the lamp, after which excess glue is removed. Finally a glycerin gel is applied, which makes the glue harden at the edges as well, which it does only in the absence of oxygen – which is what the gel is used for.

After hardening, the teeth are polished, since smooth surfaces provide fewer footholds for ccavity bacteria. Ideally, even a dentist should not be able to recognize the glued edge – ceramic inlays offer an excellent method of repairing teeth – assuming the proper guidelines are observed.

Here you can see a picture of the lower jaw of a patient, the old amalgam fillings have been removed and replaced with ceramic inlays.

Irrespective of the material used, there are three different types of fillings: inlays, onlays and overlays. These differ in terms of size. Inlays do not touch the opposing tooth. If they do, they are known as onlays. If a tooth is „covered“ by a filling, this is known as an overlay. But the term usually used is inlays.