Dental fillings are done to repair broken or cracked teeth and teeth
that have been worn down from misuse, such as by nail-biting
or tooth grinding. No doubt, dental material used to rebuild teeth
has their pros and cons too.

Types of Filling Materials Available
Nowadays, there is a choice of several dental filling materials:
teeth can be filled with gold; porcelain; silver amalgam (which
consists of mercury mixed with silver, tin, zinc, and copper);
or tooth-colored, plastic and glass materials called composite
resin fillings. The location, the extent of the decay, cost of filling material, patients' insurance coverage and dentist's recommendation assist in determining the type of filling that will best take care of your needs.

Cast gold

Advantages:

1. Lasts at least 10 to 15 years, usually longer; doesn't corrode
2. Can withstand chewing forces
3. Some patients find gold more pleasing to the eye than silver, amalgam fillings

Disadvantages:

1. Up to 10 times higher than cost of amalgam filings
2. Requires at least two clinic visits to place
3. A gold filling placed immediately next to a silver, amalgam filling can cause a sharp pain (galvanic shock). The interaction between the metals and saliva causes a flow of electric current, though rare.

Silver-fillings (Amalgams) --  [ NOT DONE AS IT IS HIGHLY TOXIC ]

Disadvantages:

1. Fillings don't match the colour of your natural teeth
2. Healthy parts of a tooth must often be removed to make place for the amalgam filling
3. Amalgam fillings can create a greyish hue to the surrounding tooth structure
4. An amalgam, in comparison with other filling materials, may experience a wider degree of expansion and contraction and lead to a higher incidence of cracks and fractures
5. A small percentage of people, approximately 1 per cent, are allergic to the mercury present in amalgam restorations

Tooth-coloured composite fillings

Advantages:

1. The shade/colour of the composites can be closely matched to the colour of existing teeth; is particularly well suited for use in front teeth or visible parts of teeth
2. Composite fillings actually chemically bond to tooth structure, providing further support to the tooth
3. In addition to use as a filling material for decay, composite fillings can also be used to repair chipped, broken or worn teeth
4. Sometimes less tooth structure needs to be removed compared with amalgams when removing decay and preparing for the filling

Disadvantages:

1. Composite fillings wear out sooner than amalgams (lasting at least 5 years compared with at least 10 to 15 for amalgams); in addition, they may not last as long as amalgams under the pressure of chewing and particularly if used as the filling material for large cavities
2. Because of the process to apply the composite material, these fillings can take up to 20 minutes longer than amalgams to place
3. If composites are used for inlays or onlays, more than one clinic visit may be required
4. Depending on location, composite materials can chip off the tooth
5. Composite fillings can cost up to twice the cost of amalgams

There are two other tooth-coloured fillings available: ceramics and glass ionomer.

1. Ceramics, which are most often made of porcelain, are more resistant to staining than composite resin material but are also more abrasive. This material generally lasts more than 15 years and can cost as much as gold.
2. Glass ionomer is made of acrylic and a specific type of glass material. This material is most commonly used for fillings below the gum line and for fillings in young children (drilling is still required). Glass ionomers release fluoride, which can help protect the tooth from further decay. However, this material is weaker than composite resin and is more susceptible to wear and prone to fracture. Glass ionomer generally lasts 5 years or less with costs comparable to composite resin.