A dental filling is used to restore function to a tooth by filling in missing parts from, for example, a cavity or other external trauma.
Before a filling or restoration can be performed, the tooth needs to be prepared. This involves cutting the tooth with special dental tools (even sandblasting) to make room for the materials that will be used during restoration of the tooth.
This stage is referred to as a “tooth preparation”.
There are several materials that can be used to restore a tooth, including dental composites, resin-reinforced glass ionomers, porcelain, even gold.
How are Tooth Preparations Performed?
There are two types of tooth preparation: internal and external. Internal preparations, or Intracoronal, and external, or extracoronal. Intracoronal preparations hold restorative material, whatever it may be, within the structure of the tooth. That’s the type that we’re more interested in – a cavity filling. Once the hole is prepared to receive the filling, one of two types of restoration takes place: a direct restoration or an indirect restoration.
Direct Restoration: Quick and Painless
A direct restoration involves putting a soft filling into the tooth and then building the tooth up before the material sets. This restoration can be done in one procedure because it sets quickly, and the material must set while it’s in contact with the tooth. This procedure can usually be completed within an hour, depending upon how many teeth need to be treated this way.
Indirect Restoration: One, Two!
An indirect restoration usually requires two visits, as the restoration must be created outside the mouth and then attached with dental cement. The restoration is built using dental impressions of the tooth that would be made after preparing it to receive the filling.
More About Direct Fillings
The most-used material for direct fillings are white fillings, also called dental composites, and they are tooth-colored. The unfortunate part is that they are more prone to wear and discoloration than porcelain and metal restorations – they also are not as strong or durable.
Dental composites are resin-based, often made up of urethane dimethacrylate and silicon dioxide silica, though composition will vary. After the tooth is prepared, a thin glue is applied and then the composite is filled, layer by layer, with each being photo-polymerised via light. When everything is finished the surface is shaped and polished. This filling feels “sticky” against the other teeth when one is biting, but this feeling gradually fades as the restored tooth gets more use.
Fillings are Important!
If you have a cavity, you need to get a filling – it will prevent further damage to the insides of the tooth, re-build what you have lost, and protect exposed nerves by covering them up again.
