White or tooth-coloured fillings are either composite or glass ionomer. Composite fillings are strong and are now more hard wearing than they used to be. The composite material is made up of powdered glass quartz, silica and other ceramic particles in a resin to give a material that is made in different shades to blend with your natural tooth colour. They are bonded to the tooth with a bonding agent, and the material is set with a light. Tooth preparation can be conservative and so this can be the filling material of choice where this is particularly important. Conversely where a tooth is quite broken down this material can be used to rebuild it due to the ability to bond it to the remaining tooth structure, although better shape and overall results can be gained in this instance with inlays and onlays. We use a very high quality type of composite with good wear resistance and colour maintenance. Composites need replacing when they have worn or stained over time to maintain their excellent appearance. Glass ionomer fillings form a chemical link between the filling and the tooth. They may also release fluoride, which helps to prevent further tooth decay. This type of filling is fairly weak and so is used when this is not a problem, for example if the filling is only temporary so does not need to last a long time, or in baby teeth, or on the sides of teeth where pressure is less. Again preparation can be minimal.