Imagine that you need a cavity restored, and you are offered a choice of materials. It can be quite confusing, but the decision is important and a little complicated. The choices can be simplified by breaking them down into categories. First consider direct versus indirect materials. Direct materials are the traditional silver-amalgam filling which is gray and composite which is essentially acrylic plastic with porcelain powders for color and durability. These two materials are placed directly into a tooth and hardened in a single visit. Because they are so quick and easy to place, they are relatively inexpensive. The drawback is that they only last nine years on an average, and then you have an even bigger problem. With people living beyone a hundred, drilling a tooth every nine years wittles it down until it either breaks or hurts. So these materials are cheap in the short term but expensive in the long term in terms of dollars and health. The indirect materials on the other hand last indefinitely, but they are more difficult to create. Regardless of whether a gold alloy or a tooth colored ceramic is selected, both require two visits with a laboratory expense in between. This makes these restorations more costly in the short term, but because they can last a lifetime, in the long term they become inexpensive and the best thing for your health. Some dentists offer indirect restorations that are milled right there in their offices, but to date the precision is not equal to a technician making it by hand which compromises the longevity. If you need a filling, I hope that this explanation helps understand your various choices.