Tooth decay is not dissimilar in appearance to bad spots in a potato. It is soft and yellow/brown but unless there is a lot of decay there may not be an actual cavity. A tooth is a bit like a pumpkin too, really hard on the outside and softer the further in you get. If tooth decay is only in the hard enamel it can heal out and we don’t fill those teeth. However as it burrows deeper into the softer parts of the tooth fillings become necessary. It is important to realise though that fillings don’t strengthen teeth – Nothing is ever as good as the original! If a tooth is filled too much it can be like a shopping bag being stuffed until it bursts. This is when crowns become necessary to save teeth.
Amalgam – is the old, black metal material that almost all of us have in our back teeth. It is strong and lasted well but because turns black and contain mercury, we don’t use it any more. In fact we don’t even have it.
Composite – is plastic and works nicely in small cavities. It is routinely used for front teeth, it is bonded to the tooth and sets hard in the presence of blue light. If composite fillings are big and there is hard chewing done on them, they fail after a few years; new decay easily forms under them.
Glass Ionomer and RM Glass Ionomer – is a white fillings material that can be used in back teeth. The advantage is that new decay doesn’t form too easily under it but on the other hand glass ionomer is brittle and hard chewing fractures the material. Suitable for fillings that are either temporary (root canal temporary fillings, fillings in baby teeth), permanent fillings in areas of minimal load (away from the biting surface such as on the root of the tooth) or fillings that cannot be kept dry. It has a chemical bond with the tooth.