A cavity or tooth decay occurs when the enamel or dentin de-mineralised and infected with bacteria. The infected and de-mineralised part of the tooth/teeth is removed and the space is restored with filling material.

Types of Restoration

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• Amalgam Restorations

• Composite Restorations

• Glass Ionomer Restorations

• Indirect Restorations

Disadvantages of Amalgam Restorations :

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• There could be some short-term sensitivity to heat or cold after the filling is done.

• It is silver coloured and does not look natural.

• The dentist may need to remove more tooth structure to accommodate an amalgam filling
  when compared to other types.

Composite Restorations

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• Composite fillings are durable and are fracture-resistant.

• Recommended in small and mid-size restorations in teeth that handle moderate chewing pressure.

• Less tooth structure is removed during preparation, resulting in a smaller filling than that of an amalgam.

• Composites can also be "bonded" or adhesively held in a cavity, which allows the dentist to
  make a more conservative repair to the tooth.

Glass Ionomer Restorations

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• Glass ionomers are translucent, tooth-coloured material which are primarily used in teeth
  that are not subject to heavy chewing pressure, as they have a low resistance to fracture.

• They are mainly used in small non-load bearing fillings or on the roots of teeth.

• Glass ionomers release a small amount of fluoride, which is beneficial to patients at risk of decay.

Indirect Restorations

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• Sometimes the best dental treatment for a tooth is a restoration made in a lab from a mould.

• These custom-made restorations require two or more visits.

• Materials used to fabricate these restorations are metal and ceramic.

• The strength of this type of restoration depends on an adequate thickness of ceramic
  and the ability to be bonded to the underlying tooth.

• They are highly resistant to wear and tear.