There's a dental solution for practically any problem that your teeth and gums may experience. Even when a tooth is conclusively past the point of no return and must be extracted, there is a range of replacement options (such as dental implants, bridges, and dentures). But sometimes a problem requires several solutions to reach the desired outcome. This can be the case when a large cavity needs a large filling.

The Cavity

Filling a cavity is not like simply filling a hole. The decayed portions of the tooth must first be removed with a dental drill. The cavity itself is a carious lesion, and the decayed portions are rich in cariogenic bacteria (which corrode your teeth). Failure to adequately prepare the tooth means that its deterioration will continue, even when the restoration (the composite resin dental filling) has been placed. This basic principle becomes somewhat more complicated when the filling has to cover a significant part of the tooth's surface area.

Dental Matrix

A large filling often requires the use of a dental matrix. This is a small piece of metal that mimics the shape of the tooth. It essentially creates a frame for the filling material—allowing the missing sections of the tooth to be rebuilt. The filling material fills the matrix and the prepared tooth, before drying (or setting). Although the filling material integrates with the tooth's structure, a large filling may not give the tooth sufficient structural stability. This is why large cavities must often be finished with dental crowns.

Two Steps

Think of your restoration as being a two-step process. The filling is necessary to replace the tooth's lost structure—to rebuild it and restore its mass with a synthetic substitute. However, given the bite pressure that the tooth will undergo, this surface restoration may be inadequate. A large filling must be contained, and this containment is provided by a dental crown that fully encompasses the tooth.

Dental Crowns

A filling is often used in conjunction with a crown. For example, this is common when a dentist must make an access cavity to perform a root canal. The filling is essential, but it's the crown that will hold everything together. When removing the tooth's decayed portion, your dentist will similarly prepare the tooth for its crown. A tiny amount of the tooth's surface area (both decayed and healthy portions) will be removed to reduce the tooth's overall size. Once the crown is bonded in place, the tooth will be an exact match for its former self—prior to its deterioration, naturally.

It might feel unfortunate to learn that you will need to receive both a filling and a dental crown, but when the cavity is sufficiently large, a crown can be mandatory to prevent the tooth from losing any more of its structure. And this is far more straightforward than having the tooth extracted and replaced.