Kits for bleaching and desensitizing a person's teeth include 1) at least one dental bleaching composition or device in the shape of a dental tray or having a tray-like configuration and 2) at least one dental desensitizing composition or device in the shape of a dental tray or having a tray-like configuration. The shaped treatment compositions comprising the kit have increased adhesiveness to teeth when moistened with saliva or water. The shape of the treatment composition or device facilitates placement of the composition or device over a person's teeth with substantially less manipulation compared to the use of initially flat strips. The substantially solid treatment compositions become more adhesive when moistened with saliva or water, yet remain intact and coherent when protected by a moisture-resistant barrier layer. The substantially solid treatment compositions adhere and remain in place more reliably than treatment strips that include a treatment composition initially in a gel-like condition.