Bonding involves the application of composite resin to the existing tooth. The bonding technique is used as a conservative method of closing small gaps and covering stain. The tooth is prepared using a mild etching solution, and then the material is bonded to the tooth and cured using a special light. The composite resin material is shaped and polished as a final step. Bonding may have to be replaced due to wear or discoloration of the material over time.