Amalgam:

Made of : Mercury mixed with silver, tin, zinc and copper. Mercury is nearly 50 percent of the mixture. Types : Traditional (non-bonded), bonded Use for : Fillings in teeth Advantages : 1. Amalgam fillings are strong and can withstand the forces of chewing. 2. They are inexpensive and convenient. 3. The filling can be completed during one dental visit.

Disadvantages :

1.	Amalgam doesn't match the color of your teeth.
2.	Healthy parts of your tooth must often be removed to make a space large enough to hold an amalgam filling.
3.	Amalgam fillings can corrode over time, causing discoloration where the filling meets the tooth.
4.	A traditional (non-bonded) amalgam filling does not bond to the tooth. It just sits in a pocket created by your dentist.
5.	Some people may be allergic to mercury or be concerned about its effects, although research shows the amount of mercury  exposure from fillings is comparable to what people get from other sources in the environment.

Composite Resin:

Made of : A mixture of plastic and fine glass particles. Types : Direct or indirect Use for : Small and large fillings, especially in front teeth or the visible parts of teeth; inlays

Advantages :

1.	Your fillings or inlay will be invisible. Your dentist chooses a resin that matches the color of your teeth.
2.	A filling can be completed during one dental visit. An inlay may require two visits.
3.	Composite fillings can bond directly to the tooth, making the tooth stronger than it would be with an amalgam filling.
4.	Less drilling is involved than with amalgam fillings because your dentist does not have to shape the space as much to hold the filling securely. The bonding process holds the composite resin in the tooth.
5.	Indirect composite fillings and inlays are heat-cured, increasing their strength.
6.	Composite resin can be combined with glass ionomer to provide the benefits of both materials.

Disadvantages :

1.	Although composite resins have become stronger and more resistant to wear, it's not clear whether they are strong enough to last as long as amalgam fillings under the pressure of chewing.
2.	These fillings take 10 to 20 minutes longer, or sometimes more, to place than amalgam fillings because each thin layer of the filling must be cured, or hardened, using a visible blue light.
3.	Indirect fillings and inlays take at least two visits to complete. Your dentist takes impressions at the first visit and places the filling or inlay at the second visit.
4.	In large cavities, composites may not last as long as amalgam fillings.

Glass Ionomer

Made of :	Acrylic and a component of glass called fluoroaluminosilicate
Types :	Traditional, resin-modified or hybrid composite, metal-reinforced
Use for :	Most commonly used as cementation for gold inlays, but is also used for fillings in front teeth. As filling material, glass ionomer is typically used in people with a lot of decay in the part of the tooth that extends below the gum (root caries). It is also used for filling baby teeth and as a liner for other types of fillings.

Advantages :

1.	Glass ionomer matches the color of the teeth, although it does not always match as precisely as composite resin. Resin-modified glass ionomer is usually a better match than traditional glass ionomer.
2.	In some cases, no drilling is required to place a glass ionomer filling. This makes this type of filling useful for small children.
3.	Glass ionomers release fluoride, which can help protect the tooth from further decay.
4.	Glass ionomer restorations bond to the tooth, helping prevent leakage around the filling and further decay.

Disadvantages :

1.	Traditional glass ionomer is significantly weaker than composite resin. It is much more susceptible to wear and prone to fracture.
2.	Traditional glass ionomer does not match your tooth color as precisely as composite resin.
3.	If you are receiving a resin-modified glass ionomer filling, each thin layer needs to be cured, or hardened, with an ultraviolet light before the next layer can be added. This makes the tooth stronger, but can lengthen the time of the dental appointment.