Abstract: A composition for the rapid desensitization of dentin and a system for its application, comprising a subsaturated aqueous solution of monopotassium monohydrogen oxalate and a disposable single-use applicator/dispenser apparatus. The apparatus includes a crushable ampule containing the desensitizing solution housed in a flexible body, with a filter which retains ample fragments but allow the solution to flow to and saturate an applicator tip or swab. The applicator may be used to treat the teeth directly, or the swab may be removed from the applicator after saturation and placed on hard-to-reach dentinal surfaces. In one embodiment, the apparatus further includes a dispensing package containing a plurality of the single-use applicators and provided with a magnetic means affixed thereto for securing the package to convenient metallic surfaces. Another embodiment includes a blister dispensing package comprising a plurality of detachable sheets which stores the applictors.