Surface analysis of ProFile instruments by scanning electron microscopy and X-ray energy-dispersive spectroscopy: a preliminary study.

Abstract

The purpose of this preliminary study was to analyze surface irregularities on ProFile nickel-titanium (NiTi) rotary instruments before use, after sterilization by two different methods and after instrumentation of molar root canals. Five new ProFile NiTi rotary instruments with 0.04 taper, size 20, five instruments with 0.04 taper, size 25 and five with 0.06 taper, size 20 were analyzed by scanning electron microscopy (SEM) and X-ray energy-dispersive spectroscopy (EDS). The instruments were then divided into two groups: three of each taper and size were sterilized in a dry heat sterilizer, whilst two of each taper and size were sterilized in an autoclave. After inspection by the same techniques, the files were used to instrument six molar root canals, and again analyzed by SEM/EDS. Together with the usual machining defects, a variable amount of material containing mainly carbon and sulphur was found on the surface of new instruments. This material was not removed by standard cleaning and sterilization procedures. The use of the files for instrumentation of root canals eliminated a considerable amount of the adhered substance, but deposits rich in calcium and phosphorus accumulated on the remaining impurities. The adherence of dentine on surface deposits found on new ProFile instruments requires special cleaning, prior to sterilization.