Dental bleaching compositions include a dental bleaching agent, a generally linear high molecular weight (i.e., greater than about 500,000) polyvinyl pyrrolidone (PVP) and/or polyethylene oxide (PEO) tissue adhesion agent included in amount that imparts a high level of 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 solvent or carrier. Dental bleaching compositions may include carboxypolymethylene instead of or in addition to PVP and/or PEO, wherein the fumed silica or fumed alumina increases long-term rheological stability even in the presence of a high concentration of dental bleaching agent. Dental treatment devices including a barrier layer and a quantity of the dental bleaching composition positioned adjacent to the barrier layer.
