Anaphylactic shock during endodontic treatment due to allergy to formaldehyde in a root canal sealant

A 41-yr-old patient experienced an anaphylactic shock reaction caused by fo rmaldehyde in a root canal sealant during endodontic treatment. The clinica l events, positive skin tests, and a high level of immunoglobin E to formal in RAST (class 4) suggest the involvement of immunoglobin E-dependent mecha nisms toward formaldehyde. This very infrequent observation in endodontic t herapy focuses attention on the different pathological manifestations relat ed to formalin, their mechanisms, and the prevention possibilities in denti stry.