Dental Onlays

The most common reasons include:

• The tooth may have been weakened by having a very large filling, or extensive decay that has extended under one of the cusps (points);
• You may have a root filling that requires an onlay to protect it; or
• You may have a large mercury amalgam filling that you would like to remove to improve the appearance of the tooth.

Originally, onlays were made of gold. Nowadays, they tend to be made of tooth-coloured materials, the strongest and most natural of which include zirconium/porcelain or pressed porcelain. Composite resin-based materials such as Belle-Glass are less expensive, but do not retain their appearance for so long.

All decayed or weakened parts of the tooth are removed. The dentist then takes an impression of the prepared tooth, which, with details of the shade of the tooth, is sent to the dental laboratory. A temporary filling is placed in the tooth for the two weeks required for the dental technician to make the permanent onlay in the lab.

A pressed porcelain or zirconium/porcelain onlay would be virtually unnoticeable.

After the fit and appearance has been checked and approved by you, and the bite checked and perfected by the dentist, the onlay is cemented in place using a special dental cement.

A crown is a more involved procedure than an onlay. A crown is a porcelain cap that the dentist fits over a tooth.

First, they remove the old filling and any decay. Then, they have to remove even more of the tooth (the healthy part) so the crown fits on top.

With porcelain onlays, you have a solution that puts off needing a crown.

If you have a dental onlay installed to replace a broken cusp, you’ll get many years of use out of it. When it has finally been ground down, then a crown is a good way to restore the tooth the second time.