Tooth-colored fillings, also called white fillings, are dental fillings that restore and mimic the natural appearance of tooth structure. In addition to restoring teeth that have fractured or decayed, tooth-colored fillings may also be used cosmetically to change the size, color, and shape of teeth. This quality is particularly useful in closing gaps between teeth; repairing chipped teeth and making teeth appear to be more straight or even.
Tooth-colored fillings were first introduced to the American public in the mid-1960s. Since that time tooth-colored filling materials have undergone continual improvements in durability, aesthetics, and material handling. The most versatile and widely used tooth-colored filling today is composite resin filling. A composite is a material in which filler particles are encased in and bound together by a hard matrix material. For composite resin fillings a fluid matrix of an acrylic, called BIS-GMA, is hardened around glass filler particles to form composite resin. Trace metals (e.g. cobalt, gold, and copper) give color to the glass while zirconium and titanium oxides add opacity.