A scanning electron microscopic evaluation of four root canal irrigation regimens

A scanning electron microscope was used to evaluatethe debridement capabilities of four irrigation regimens on both instrumented and uninstrumented root canal surfaces. A typical smear layer was seen on the instrumented surfaces of specimens irrigated with saline and NaOCl. EDTA demineralized much of the smear layer from the instrumented surfaces and exposed the orifices of some of the underlying dentinal tubules. NaOCl removed all pulpal remnants and predentin from the uninstrumented surfaces of the root canal while EDTA and saline left pulpal remnants and predentin on the uninstrumented surfaces. The combination of NaOCl and EDTA used alternately completely removed the smear layer from the instrumented root canal surfaces as well as the pulpal remnants and predentin from the uninstrumented surfaces. In addition, the combination of NaOCl and EDTA caused the exposed calcospherites on the uninstrumented surfaces to have an eroded appearance.