1. The size that the new filling will be.

Fillings of a relatively small size can be restored with composite filling material- this is a special type of plastic material that is set hard by a blue light. These can match the surrounding tooth colour extremely well.

Fillings that will be medium to large generally should be restored with a stronger material than composite. Examples of this type of material would be porcelain or laboratory made composite fillings. These are bonded in to the tooth with a cement and can be extremely durable. The down side is that you usually need to have a temporary filling for a couple of weeks whilst they are been made and a second visit to have them cemented. In my practice we use Cad Cam technology ( Cerec) to make the porcelain fillings at the same visit. This produces a long lasting restoration all in one visit rather than two visits.

2. The amount of forces on the tooth to be filled. A composite filling that will have a very light biting force on it will have a greater chance of lasting than if it is exposed to very heavy forces – such as if you grind your teeth when you are asleep. When these larger forces are present a laboratory made porcelain , a laboratory made composite or a Cerec restoration is usually required. If the forces are very high even these types of techniques are not strong enough and a gold filling may be required.

At the end of the day your dentist needs to guide you on the beat alternative to the silver fillings you have in your mouth.

Hope this helps.

Regards,