When you go for a dental exam, your dentist checks your fillings and may suggest that you replace any loose or broken ones. Your dentist also looks for signs of decay, such as brown or black spots and may want to use X-rays to take a closer look at problem spots.
If you have a cavity, your dentist may keep an eye on it (if it's small) or fill it right away. If a large cavity is not filled, it can get bigger and cause pain. The tooth may even have to be removed and replaced with a false (or artificial) tooth.
Overview - If you have a cavity and it needs a filling, there are different kinds of fillings to do the job.
If you have a cavity and it needs a filling, there are different kinds of fillings to do the job.
Your dentist cares about you and your oral health. If you have any questions or concerns about fillings, talk to your dentist. He or she will advise you on the type of filling that works best in your particular case, and inform you about the aesthetic and cost implications for each type.
There are several different types of fillings that can be used to fill a cavity, but the final decision on which type of filling is placed in your mouth is yours alone.
How Fillings Are Done
To fill a cavity, your dentist may first give you "freezing" (or local anesthetic), so you do not feel any pain. Your dentist then takes out all traces of decay, shapes the hole and fills it.
Most fillings are done in two ways:
Direct Filling - These fillings go right into the cavity, after your dentist has cleaned out the decay. Amalgam (or silver) fillings and plastic (or white) fillings are examples of direct fillings. They harden quickly. Most of the time, you will be able to have a direct filling put in place in one appointment.
Indirect Filling - Examples of this type of filling are crowns (or caps) and inlays. They are custom made in a lab to fit your tooth. Your dentist cements the filling in place. Most indirect fillings take two or more appointments to complete.
Taken from the Canadian Dental Association: http://www.cda-adc.ca/en/oral_health/talk/procedures/fillings/overview.asp