Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Scanning electron microscope micrographs showing changes on instrument surface after use. (a) Micrograph showing pitting on the tip of the instrument (magnification × 1,000). (b) Used file have metal strips near the cutting edge. (magnification × 520). (c) Microfractures on the blade. (magnification × 520). (d) Disruption of cutting edge with morphological alterations. (magnification × 520)
