Methods for manufacturing dental bleaching devices

Method of manufacturing a dental bleaching device including a dental bleaching composition and a barrier layer. The bleaching composition includes a dental bleaching agent, a generally linear high molecular weight polyvinyl pyrrolidone (PVP) and/or polyethylene oxide (PEO) tissue adhesion agent that imparts adhesiveness, a rheology-modifying agent such as fumed silica or fumed alumina that reduces or eliminates stringiness otherwise caused by the high molecular weight PVP and/or PEO, and a carrier. The barrier layer may comprise a dental tray or strip. Dental treatment devices including a barrier layer and a quantity of the dental bleaching composition positioned adjacent to the barrier layer.