When a tooth has a cavity, or the tooth is broken or the current filling is leaking (meaning there is bacterial contamination and decay underneath) often a new filling is required.
One option in restoring a tooth is to have a tooth-coloured (or “white”) filling — commonly known as a ‘Composite Filling’.
After removal of decay or a previous filling, and bonding, tooth-coloured material is applied to a tooth’s surface, hardened, and then contoured and polished for natural appearance.
Composite is not ideal for all restorations (fillings) on back teeth especially if you require a large filling. As the cavity gets larger there is less tooth structure available for bonding and the longevity of the filling will be reduced.
Also, when the cavity extends onto the root surface (often this is in between the teeth), the bonding and seal become less predictable and failure occurs more quickly. When the bite is heavy, choosing an alternative to a composite filling is usually a wise decision. It should be noted that research has indicated that a well-placed composite filling on a back tooth usually takes longer to place (than a “silver amalgam” filling), will cost more and has a significantly higher failure rate (shorter longevity).
Silver fillings (amalgam):
Another option in restoring a tooth is to have an “Amalgam Filling”. However, with the high quality tooth-coloured materials and techniques now available, for many people the use of amalgam is now restricted to larger fillings on back teeth (if those are required).
There are also many patients for whom tooth coloured appearance on back teeth is not a priority and who choose to have the amalgam filling because it offers greater longevity and durability (and less cost).
When protection of cusps of teeth is required (for example after “root canal treatment”), amalgam fillings are also a satisfactory long-term option to protect the remaining tooth structure before the much more expensive porcelain (ceramic) crown or onlay can be placed.
Although there is no documentation available (acknowledged by the medical/scientific community) to require this, we usually choose to seek alternative options (to amalgam fillings) for children, for those who are pregnant, for those who are immune-compromised and for those with proven allergy (very rare).