Periodontal implications of formocresol medication.

Intracanal medications have historically played an important role in root canal therapy. Their purpose is to establish an antimicrobial environment within the pulp chamber (1). The root canal system may contain significant types and numbers of organisms that cause acute exacerbations, delay treatment procedures, and retard or prevent healing. Although mechanical instrumentation and frequent irrigation eliminate the majority of microorganisms, an intracanal medication is often used to reduce the bacterial population retained within dentin (2). Formocresol is an effective and frequently used medicament. The combined action of cresol, a proteincoagulating phenolic compound, and formaldehyde, an alkylating agent, is highly antimicrobial; but it may cause significant destruction of vital tissues (2). Several studies (3-6) have confirmed the tissue-irritating and cytotoxic effects of formocresol which result in inflammation and tissue fixation Morse (7), in his review of immunological aspects of pulpal-periapical diseases, states that formocresol can act as a hapten, interact with the host protein, and result in an immunological reaction. He suggests that immunological responses caused by this mechanism can result in endodontic "flare-ups" in the form of pain, swelling, and bone resorption. Others (8, 9) also described the immune response. Because formocresol has the potential to produce severe adverse effects on vital tissue, application of the medication in the canal system must be carefully controlled. Wesley et al. (1) recommend that formocresol be applied to a sterile cotton pellet and squeezed dry in a sterile gauze before being placed into the pulp chamber. Vaporization results in permeation of the medication throughout the