Patients in this day and age have a number of choices when it comes to choosing a material to fill cavities, thanks to advances in the dental industry. The most common choices are between the metal-based amalgam – classically the ‘silver’ filling – or a natural tooth coloured composite – also known as a ‘white’ filling. These newer tooth coloured materials have a huge aesthetic advantage and can be placed to create as natural a filling as possible. However, they have not totally eliminated the need for stronger and more durable metal materials which is why they are both applicable to day and are case dependant.
What is amalgam?
Dental amalgam is commonly called a silver filling. In addition to containing silver, it also contains a number of other metals held together with mercury. Historically, there have been concerns over the safety of the use of mercury but research has showed that when mixed with these other metals it is rendered harmless.
Many dentists consider amalgam to be stronger than composite fillings and many patients may prefer it as it is often quicker and cheaper. But it does carry the aesthetic disadvantage and many people are becoming more conscious of dark fillings in their teeth. Amalgam does not bond to tooth so it often requires removal of more tooth to make it retentive.
What are composites?
Composite material is resin based and is relatively new to the field of dentistry, though it has still racked up decades of use and research. It does not have the same research as the 150 years to back up dental amalgam, but over the years it has improved greatly as technology has improved to create stronger composite materials. When they first became available, their use was preferable in the front areas of the mouth where its lack of strength was not an issue. Its use in the back areas of the mouth was questionable as many dentists feared composite lacked the strength to withstand the forces when chewing. However, new composite materials on the market how improved strength properties to facilitate use of this material in the back of the mouth as well as the front.
In the back areas of the mouth, composites are not available on the NHS service so they often carry a higher associated cost when compared with amalgam. But they bond to tooth unlike metal fillings and therefore have the added advantage of being more preservative of the tooth.
What are the differences?
Both materials are still available and used today due to the fact that they are both applicable in different scenarios. In that sense they cannot be compared in order to state which is better than the other.
Amalgam is less technique sensitive so can often be a lot quicker to place and is better for cavities that extend below the gum line. But they do not bind to tooth so gaps can form between the filling and the tooth and usually requires greater removal of tooth structure.
Composites can take longer to place and cost more but are much more appealing aesthetically. Despite concerns about their strength compared to amalgam, they have proven that they can withstand forces at the back of the mouth. They also bond to the tooth reducing chances of a gap forming and can help strengthen the tooth. Some larger cavities can be filled with lab-made composites that minimise the risks of failure and increase the strength even more