Many dentists still fill teeth with
Amalgam (silver + mercury fillings). To hold these
amalgam fillings in place, they prepare a hole, that is undercut (larger at the base of the tooth than at the top). After all, you cannot take a quarter out of a hole the size of a dime. This principle has remained the standard of care for most dentist. The main problem with this principle is that excess tooth needs to be removed in order to achieve proper retention (so the filling will not fall out).
By using the latest generation of bonding techniques, tooth structure is preserved. The procedure requires far less tooth removal to achieve superior retention. It is the most conservative way to treat broken, chipped, or decayed teeth. The procedure has certain limitations when too much tooth structure has been lost, but is ideally suited for many teeth in need of restoration.
To get an idea of what happens when bonding is performed, think of cheese melting into a slice of bread. Bonded restorations integrate or mesh with the dentin and enamel of teeth and become as one, just like the way the cheese worked its way into the bread. The tooth is often stronger than a tooth without a filling. Teeth can be restored to their original beauty with the advances in tooth-shade matched materials. Bonding can allow chipped, fractured, and unsightly teeth to be restored to their original form or enhanced to appear better than they ever did before?
