Inlays and onlays are utilised when the amount of tooth to be replaced becomes so large so that a composite filling may not be the ideal solution.

Composite resin is very effective when used to restore small to medium size cavities. When larger restorations are required composite resin has a few disadvantages which may affect the longevity of the filling.

Composite resin shrinks as it sets so it must be placed in small increments. With very large restorations it is difficult to control the amount of shrinkage that may occur hence bond strength to tooth may be compromised.

Composite resin has a differing coefficient of thermal expansion to tooth structure. This means that it changes shape at a different rate to tooth structure when cold and hot fluids pass over your tooth. This can compromise the bond strength of the composite resin.

Very large composite fillings are technically demanding and time consuming to place.

Several attributes have led to the increased use of inlays and onlays.  They are a durable long-term solution, requiring only a small amount natural tooth structure to be removed adding to their strength.  Additionally they are a more conservative option than a full crown, which is utilised when only minimal tooth structure remains.

An inlay is similar to a traditional amalgam filling as it is placed within the cusps (bumps) of the chewing surface of your back teeth, where as an onlay is used to restore a larger surface area and may cover one or more tooth cusps.

Preparation is the key to ensuring the success of your treatment.  Firstly the decay is meticulously removed and your tooth cleaned.  Then a highly accurate impression mould is made of the prepared tooth surface and used to create a model of your tooth.  This is then sent to a dental laboratory where a highly skilled technician will sculpt your inlay or onlay; this will take between one – two weeks.

While your inlay or onlay is being made a temporary restoration can be placed to protect your prepared tooth and allow you to have full mouth function and appearance.

At your subsequent appointment, your temporary inlay or onlay is removed and replaced with your laboratory created permanent restoration.  It is checked for comfort and fit and any minor adjustments made so it aligns perfectly with your surrounding and opposing teeth, prior to being securely bonded with a specially formulated dental cement and polished to a tooth-like finish.

The longevity of your new inlay or onlay will depend greatly on your at home care routine and regular appointments with our dental team for check-ups and cleaning. When cared for correctly your new restorations can last more than ten years.
As with all areas of restorative dentistry preparation and insertion of an ideal inlay/onlay requires meticulous attention to detail and years of experience. Both Dr’s Jon Kerr and Keith Doonan have extensive Post Graduate training and experience in the provision of inlays/onlays and related procedures.