A dental bleaching composition comprises a dental bleaching agent and a
polyvinylpyrrolidone thickening agent. The bleaching composition may
include water, flavoring agents, a basic substance and desensitizing
agents, as desired. Polyvinylpyrrolidone avoids acid etching and
chelation of teeth that were problematic in bleaches using carbomer as a
thickener. A delivery system for delivering the bleaching composition
comprises the aforementioned dental bleaching composition in combination
with a moisture-resistant barrier layer such as a dental tray or a
flexible strip of material.