When teeth are chipped or slightly decayed, bonded plastic resins called composites may be the materials of choice. Bonding is hardened on the tooth using a light gun. First the tooth structure is cleaned and etched with a mild acid solution (exactly the same type and strength of acid for in sodas). Microscopically, the tooth surface resembles an English muffin with nooks and crannies. Then a clear adhesive liquid is painted onto the tooth and flows into the indentations. A putty-like tooth colored plastic filling material is applied to the tooth and shaped. It is permanently hardened and fused to the tooth with a handheld very bright blue light. This process is called photo curing. Bonding makes a great tooth colored filling for small cavities, chipped or broken surfaces, and for filling in small gaps. When the restoration reaches too large a size, the bonded material becomes too weak to withstand the forces placed upon it. If problems with bonding occur, the next choice for restorations would be porcelain laminate veneers or simply "veneers".