Dental bleaching compositions are in the shape of a dental tray or tray-like configuration, optionally in combination with a protective barrier layer. Shaped bleaching compositions comprise a substantially solid dental bleaching composition that has increased adhesiveness to teeth when moistened with saliva or water. The shape of the dental bleaching composition facilitates placement of the composition over a person's teeth with substantially less manipulation compared to the use of initially flat bleaching strips. The substantially solid dental bleaching composition becomes more adhesive when moistened with saliva or water, yet remains intact and coherent after the dental bleaching composition is placed over a person's teeth during bleaching, particularly when used in combination with a moisture-resistant barrier. The result is that the moistened dental bleaching composition is able to reliably adhere against a user's teeth during a bleaching procedure.