As an adjunct to infection control in dental impression procedures, several manufacturers have incorporated disinfectants into irreversible hydrocolloid impression materials. However, these compounds have been shown to be tissue irritants and capable of producing allergic reactions. An anonymous, self-administered questionnaire was distributed to 56 second-year dental students who had used an irreversible hydrocolloid containing a quaternary ammonium compound as an antimicrobial (Jeltrate Plus) to make impressions during a summer preclinical occlusion course. Within the limitations of this report, the incorporation of a quaternary ammonium compound into an irreversible hydrocolloid impression material resulted in a greater incidence of dermal and mucosal irritation.