Several factors affect how long a filling can last.
- The Material used- Resin composites are not as durable as amalgam (silver) fillings. However, the strength of resin composites have improved over time and some studies have shown that the durability of resin composites is similar to amalgam fillings when the right technique is used for placement.
- Size of the filling- the larger a filling is, the higher the likelihood of failure or other complications as a large filling means that there was a large amount of decay in the tooth to start with. With extensive decay, a tooth is more likely to develop further issues such as nerve inflammation. A larger filling is also more likely to chip or fracture.
- The location of the tooth in the mouth affects the likelihood of the filling failing. A filling in a back tooth that does most of the chewing can wear down or chip more easily than a filling in a front tooth.
- Oral hygiene level will affect the lifetime of a filling. With poor oral hygiene, there is a higher likelihood of decay developing again under or around an existing filling, causing failure.
- A diet high in sugary and acidic foods can also lead to increased rates of decay under and around existing fillings.
The higher the number of fillings a person has, the more important it is to have good oral hygiene, avoid frequent sugary foods, have regular checks and cleans at the dentist in order to maximise the lifetime of the fillings.