Evaluation of methods for sterilizing root canal instruments

Abstract

1. 1. Molten metal at 425° F. for ten seconds will destroy all forms of organisms which are commonly found in root canals. 2. 2. Glass beads, extrafine, at 425° F. for ten seconds will destroy all forms of organisms which are commonly found in root canals. 3. 3. Hot air, at its present maximum temperature of 394° F., is effective against vegetative forms but not against spore forms within ten seconds. 4. 4. Mechanical cleansing of endodontic instruments prior to their sterilization was found to be as important as the method of sterilization itself. 5. 5. Chemical sterilization was found to be uncertain in its effect upon the various types of microorganisms found in root canals. Some of the chemical solutions were found to be caustic or had an objectionable odor. 6. 6. Clinically, glass bead sterilization has several advantages over molten metal sterilization, namely: there is no dross formation; no antiflux is needed; no blockage of canals occurs; and there is less danger of serious burns through spillage, as the beads do not cling to skin or clothing. The disadvantages of glass bead sterilization are that glass beads require as much time as molten metal to attain initial sterilizing temperature and a close check with a thermometer is required to be certain that the proper sterilizing temperature has been reached when the sterilizer is not thermostatically controlled.