Bonding

Dental bonding is a procedure where a composite resin (type of plastic) is bonded to the surface of a damaged tooth and then sculpted to a natural looking and feeling result. Bonding is used to handle problems from minor cosmetic imperfections to repairing damage due to decay and is a preferred  alternative to traditional silver fillings.

Bonding is excellent for cosmetic problems which are unsuitable for veneers since the color of the resin can be closely matched to the natural tooth color (note that resin is porous, so smoking will cause it to yellow). Bonding can be used to fix problems such as small gaps between the front teeth, uneven teeth, discolored teeth, and small chips.

Bonding is also excellent for structural problems such as cracks since the crack is not only repaired but the entire tooth is strengthened. In the case of repairing damage due to decay, bonding has advantages over silver fillings not only aesthetically but structurally. Since silver does not adhere to tooth material, a lot of tooth material needs to be drilled out to insert a silver filling regardless of the amount of decay. Also, composite resin expands and contracts like natural tooth material and is much less likely to cause cracks in the tooth. Silver's only advantage over bonding is that it costs less. 

The bonding procedure involves first applying an etching solution to the area of the tooth to be treated (when decay is involved the decayed material is drilled out first). The etching solution creates tiny pores that allow for proper adhesion of the resin. The resin is then applied to the teeth in layers and each layer is hardened with a curing light. Once enough layers have been applied and hardened the resin can be sculpted.