On average our routine dental visits are centred around cavities on the teeth and removal of them. These cavities are caused by bacteria which use sugar in the mouth, digest it, and release slightly acidic chemicals which cause disintegration of teeth. The black areas on the white of the tooth indicate presence of bacteria and development of caries (as dental surgeons call it) or cavities.
After initial examination and some investigations, the dentist may tell you that you need to have a filling done. The filling is merely a replacement of the defective tooth structure containing bacteria with another material. It does not cure the tooth. In this process, the dental surgeon may ask you what kind of filling would you like, white or silver. Below is what he means by these statements.
Silver fillings are also known are amalgam fillings. Amalgam fillings are made up of a mixture of metals which uses liquid mercury as a medium to create a semi formed mass. This mass is mixed and then placed in the cavity prepared in the tooth. The mass is then condensed and shaped to match the contours of the tooth structure. These fillings have been used for quite some time and are considered strong and robust enough to handle strong jaw chewing pressures. These are also somewhat cheaper due to the contents in the material.
The white fillings are of many types. But let us focus on the two types that are commonly used when doing a final filling. The composite filling material is a combination of small rounded glass beads with porcelain and other similar materials, which are given particular shades to match the tooth structure. These are present in semiliquid or liquid forms. The tooth is specially prepared for this; the filling is placed and then cured with a special blue light to set it in place.
The composite fillings have highly aesthetic appearance which makes them ideal for use in front teeth. Now due to improved compositions these fillings are also used in the posterior teeth. There is less cutting involved, and the results and function are adequate according to the needs of the mouth.
The second type is glass ionomer cements or GIC fillings. These have a special capability to release fluoride, making the surrounding tooth structure stronger. These fillings are also highly aesthetic with a natural appearance. However due to lesser ability to tolerate eating and pressure sources, the filling is generally applied in children and in adult cases where less pressure forces would be exerted on the tooth.
The silver fillings have raised concerns due to an essential component in it called mercury. Mercury in low doses can impact the nervous system. The dosage of mercury in the dental filling is not a cause of concern. However, when multiple amalgam fillings take place or repeated fillings are done, then the risk of mercury goes higher.
It is for this reason that many dentists have started to avoid the use of mercury based fillings or amalgams. The patients are less satisfied since these fillings are not aesthetic in appearance. These fillings also require a lot of preparation of the tooth structure, which means loss and cutting of the tooth structure.
You can discuss these options with your dentist about the kind of filling and which would be the best filling for that particular tooth.