Tooth decay is a disease of the calcified tissues of the teeth caused by the action of microorganisms on fermentable carbohydrates (sugars). 4 factors are necessary to produce dental decay: Dental plaque, a suitable carbohydrate, a susceptible tooth surface and time. These factors work together in the following way.
Some plaque bacteria are capable of fermenting a suitable dietry carbohydrate (such as the sugars sucose and glucose) to produce acid, causing the plaque pH to fall to below 5 or 4.5 within 1-3 minutes.
Unfortunately the plaque pH remains acid for some time, taking 30-60 minutes to return to its normal pH in the region of 7. It is such repeated falls in pH which in time may result in demineralisation of a susceptible tooth surface, thus initiating tooth decay and leading to the formation of a tooth cavity.
The treatment of teeth cavities depends on the extent of decay and the amount of tooth structure remaining.
If the decay is restricted to the outer layer of tooth structure, called enamel then often a filling is not required and this early legion can be managed preventively. This involves measures either to keep the area cleaner, by reducing plaque levels or stengthening the enamel by adding pastes, creams, gels or mousses which help to remineralise the tooth structure. These can be applied at home by the patient or at the surgery by the dentist.
Once the decay has penetrated this outer layer of enamel the decay reaches a point of no return and what ever is done to try and prevent it the decay will get deeper and needs a filling.
If enough tooth structure has been lost then you may need a restoration constructed in the laboratory to strengthen and protect the remaining tooth structure. These can be provided in the form of onlays or crowns.
If the tooth is very badly decayed the tooth may require a root treatment first. Back teeth often require crowns following the root treatment since the tooth is often severely weakened following the root treatment.
Front teeth can often manage without a crown, premolar teeth should be assessed individually.