Traditionally, metal fillings using silver amalgam have been used to replace
decayed or fractured tooth structure. Silver amalgam fillings are held in place
in a tooth by locking into undercuts placed by the dentist during tooth preparation.
This is necessary because silver amalgam does not adhere to tooth structure.
These undercuts have been shown to actually compromise the strength of a tooth,
leading to tooth fracture.

In the past few years, resin bonded materials have proven to be much more
advantageous than silver amalgam restorations. By chemically bonding to the tooth
structure, resin fillings require less healthy tooth to be removed in order to make the
restoration stay in place. On the other hand, this chemical bond seals the tooth from
saliva and bacteria, which in turn makes the tooth itself stronger. Resin fillings come
in different colors and match teeth so perfectly that they cannot be detected. The
procedure of restoring a tooth with a resin filling is similar to the traditional silver filling:
the decay is removed and the tooth is prepared to receive the composite, the material
is layered into the cavity and hardened with a curing light. The filling is then polished
and the bite is checked.