An Orthodontist uses a Curing Light to harden the special adhesive that bonds the braces brackets to your teeth. The adhesive requires a chemical reaction to convert it from a liquid or thermoplastic to a solid. The reaction is provided by a light that falls under the visible blue light spectrum. Because the Curing Light might harm your eyes if you look at it directly, the Dentist or Orthodontist has you wear special glasses for protection, and may additionally ask you to close your eyes when it is being used.