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 of 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.
What are inlays and onlays?
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, whereas an onlay is used to restore a larger surface area and may cover one or more tooth cusps.
Preparation is the key to ensure the success of your treatment. Firstly the decay is removed and your tooth cleaned. Then a highly accurate impression 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. A process than can take between one to 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 then checked for comfort and fit. At this point any minor adjustments are made so it aligns perfectly with your surrounding and opposing teeth. Once this has been done it is 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 having regular appointments with our dental team for check-ups and cleaning.
As with all areas of restorative dentistry preparation and insertion of an ideal inlay or onlay requires meticulous attention to detail and years of experience.