If a single spot on one of your teeth is not cleaned daily, the remaining bacteria will transform themselves into a sticky film substance called plaque. The plaque will produce acids which eat away at the enamel of the tooth and will eventually cause cavities. When the cavity gets through the enamel, into the underlying tooth structure (the dentin), repair or restoration is necessary. If there is sufficient tooth structure remaining after removal of all the caries, a filling is placed. There are three types of fillings commonly used:
Amalgam (silver) fillings have been used for decades and they remain one of the most commonly used filling materials. They are often referred to as metal fillings. Amalgam is a mixture of silver and other metals, such as copper, tin and zinc, grounded into powdered form. The silver powder is mixed with mercury and placed into the cavity preparation where it is shaped before hardening. In recent years, the safety of amalgam fillings has come under scrutiny because of the mercury it contains. The absorption of elemental mercury is known to be a contributing factor to several diseases, including Alzheimer's, multiple sclerosis, dementia and arthritis. However, recent studies have proved amalgam fillings to be perfectly safe.
Gold fillings are widely viewed of restorations. From a bio-mechanical perspective, they are the ideal material as they will not tarnish or corrode and they wear at the same rate as tooth enamel. The placement of a gold filling requires two separate appointments with your dentist. At the first visit, the cavity is removed and the tooth is prepared. An impression is taken of the tooth preparation and a temporary restoration is placed. A custom made filling is made from the impression. At the second visit the temporary restoration is removed and the gold filling is placed.
Composite fillings are the newest type of filling in common usage. They are commonly known as white fillings. They are a porcelain/plastic hybrid that is bonded directly to the cavity preparation. Composite fillings were created as an alternative to traditional metal dental fillings. They are coloured to look like natural teeth and are more aesthetically pleasing than amalgam or gold fillings. They are also strong, durable, and make for a very natural looking smile. Your dentist will give you a local anaesthetic to numb the area before preparing an access to the decayed area of the tooth and removing the decayed portions. Traditional drills, micro air abrasion or even with a dental laser can be used to accomplish this. A special dental material is then used to open up the pores of your tooth's dentin and roughens up the surface of the exposed enamel. This creates a stronger bond between the tooth and the filling. The bond resin is applied to stick the composite to your tooth. This material is made of the same dental resin as the composite however it is much more fluid. With a composite filling, your dentist will be able to preserve more of the natural tooth as the composite resin can be bonded to the tooth in thin layers and slowly built up to form a complete filling. A bright dental light will harden each layer before the next is applied.