Dental onlays repair damage on the cusp — the elevated part of the tooth surface. These are made from a porcelain or gold material, and they cover only the damaged part of the tooth.

At NYC Smile Design, porcelain inlays or onlays are offered to patients when they have large cavities or desire to replace their existing metal filling. The porcelain inlays or onlays are fitted ...

Teeth can be filled with gold; porcelain; silver amalgam (which consists of mercury mixed with silver, tin, zinc, and copper); or tooth-colored, plastic, and materials called composite resin fillings.

But one study shows that the second lower molar — possibly because it takes a fair amount of pressure when chewing — and teeth with fillings are most prone to chipping.