If your tooth develops a hole due to decay, you have the option of getting it filled. There are a number of fillings available depending on your critera.
It can vary, but fillings are generally made of glass particles, synthetic resin and a setting ingredient. Your local dentist should be able to provide you with more detail.
Composite fillings are the same colour as your teeth, and so are more aesthetically appealing. However, they are more difficult to place than silver fillings so may take your dentist 15-20 minutes longer to complete and because they are considered to be a cosmetic treatment, they are not available on the NHS and must be paid for. They do not last as long as silver fillings, although recent advances in technology are changing that.
Are resistant to wear and are inexpensive. They last longer than composite fillings, but due to their colour, are very noticeable, and so often used at the back of the mouth.