Dental fillings

22 February 2015

Tooth decay (also known as caries) is very common but easily preventable. It’s caused when the bacteria acids in your mouth dissolve the outer layers (enamel) of the teeth. This creates a cavity in the tooth which becomes sensitive to hot and cold and eating sweet things. If left, the cavity and caries will increase and can cause toothache and infection known as an abscess.

Early intervention is vital. If the decay is very small your dentist may be able to stop further decay by painting fluoride onto the tooth.

If the decay has worn away the enamel the dentist will remove the soft decay with a drill and the replace the hole with a filling.

Fillings can be all sizes and shapes. The cavity size and the tooth involved will affect the material that’s used to fill the hole. Silver fillings (amalgam) are made from a mixture of mercury, silver, tin, copper and zinc. These are traditionally used on back teeth and would be used for all NHS patients. White fillings (composites) are used for front teeth on all patients, NHS or private. Sometimes your dentist may choose to use a material called a glass ionomer, a strong white material often used in awkward spaces or where the biting forces are quite strong. Your dentist will offer the most appropriate type of filling according to the clinical need.

A medicated lining is sometimes applied direct onto the tooth before putting in the filling to protect the nerve of tooth and stop any reaction between the filling and the nerve.

Your dentist will check your bite is ok at the end of the procedure. A white filling is hard immediately. An amalgam filling is soft for a couple of hours so you’ll be instructed not to eat on it for that time.

Root fillings

If decay is left untreated it will soften the outside layers of the tooth (enamel) and then the inner layers of the tooth (dentine). At this point the patient will have strong reactions to hot and cold and eating with pain lasting for some time.

If left further the decay will spread into the nerve of the tooth. The blood or nerve supply of the tooth becomes infected and sets up an inflammatory response. The body will try to cope with the infection by sending additional blood to the area so the white cells in the blood can counter the infection. This causes swelling, pressure and pain and is commonly known as an abscess.

To treat this it’s necessary to remove the infected nerve. As the nerve tracks into the roots of the tooth this is known as Root Canal Treatment or Endodontics. It’s necessary to remove all the infected nerve tissue. To treat the immediate infection the dentist may prescribe antibiotics.

The dentist will open the tooth with a drill and access the nerve canals in each root with fine files and gradually remove all the nerve tissue. The empty canal will then be flushed out with disinfectant and finally the empty nerve chamber will be filled right to the tip of the root. This can take up to 3 visits with the dentist.

The tooth is then sealed with a filling. The dentist may suggest a crown for this tooth as it will become brittle and already have a large restoration in it.

If the root canal treatment isn’t carried out the infection will spread and the tooth may need to be taken out.

Root canal treatment can be done on the NHS. If the roots of the tooth are curved or twisted your dentist may refer you to a specialist in root fillings known as an endodontist. Endodontists are usually only available privately.