When enamel and dentine becomes softened by acid attack by the presence of sugar, dental decay occurs and a cavity is formed. If the cavity isn’t too large a regular filling will suffice once the decay has been removed.
Fillings are restorations of the tooth. There are two main materials that can be used, amalgam (a silver, mercury containing material) or composite (a white cosmetic material).
Although amalgam contains mercury, there is no strong evidence to suggest that this causes any medical issues.
The advantages of a composite, white filling material are that it doesn’t contain mercury and that it can be matched to the colour of the tooth. It also allows less removal of the tooth due to its adhesive nature.