A pre-packaged dental treatment system including a dental treatment device having a barrier layer configured for placement over at least a portion of a person's teeth, a dental treatment composition (e.g., a bleaching composition) disposed adjacent to the barrier layer, and a sealed packaging container within which the dental treatment device is disposed. At least a portion of the packaging container includes a laminated polymer material that is substantially impervious to water molecules, which prevents the dental treatment composition from drying out. The laminated polymer material is optionally also a barrier to oxygen molecules.