Antibacterial properties of dilute formocresol and eugenol and propylene glycol

Formocresol and eugenol are the two nonspecific intracanal medicaments commonly used in endodontic practice. Both have high tissue irritation potential when used in conventional strength. Propylene glycol is an alcohol that is injectable and itself possesses significant antibacterial action. It is a popular vehicle and hence was used to modify the two drugs. Standard bacteriologic methods were employed to test the antibacterial action of these lower concentrations of the two drugs against four test organisms. The investigations indicate that formocresol at as low as 10 to 20% and eugenol at 75% are bactericidal in action and hence may be useful at these concentrations for clinical use. Evaluation of these lower concentrations is warranted for possible clinical use. Propylene glycol, which possesses antibacterial action and is remarkably innocuous to tissues, appears to be a suitable vehicle for dilution of formocresol and eugenol.