An evaluation by scanning electron microscopy of small dental cutting instruments through use and cleaning

The progressive status of some selected small dental cutting instruments was examined from the time of their unpackaging through routine institutionalized cleaning and sterilizing procedures both before and after first and subsequent use. The cleaning protocol in place at the time involved a phosphoric acid based detergent and ultrasonic cleaning. All assessments were made by scanning electron microscopy. It was found that new burs as unpackaged are unacceptable for use without first being subjected to a cleaning process and that the cleaning procedure utilized was ineffective and unsuitable. Also observed was the potential for gross contamination; the need for subsequent ultrasonic cleaning; and the different rate and nature of deterioration, with use, of the three bur types studied. This study has led to the introduction of modified procedures for the physical cleaning of small cutting instruments in our institution and confirms the usefulness of the scanning electron microscope in the ongoing practice of quality assurance.