The synergistic relationship between ultrasound and sodium hypochlorite: A scanning electron microscope evaluation

Abstract

Twenty-eight freshly extracted human teeth were hand instrumented to clinical standards. Distilled water was used as the irrigant during instrumentation of all specimens in order to produce a uniform smear layer. The canals were given a final irrigation with either 4% sodium hypochlorite, ultrasonic irrigation with different concentrations of sodium hypochlorite, or ultrasonic irrigation with distilled water. The results indicated that 4% sodium hypochlorite, or ultrasound with water, did not remove the smear layer. Four percent or 2% sodium hypochlorivate activated by ultrasound did remove the smear layer from instrumented areas of the canal wall. It was concluded that a synergistic relationship existed between sodium hypochlorite and ultrasound, and that the relationship was clinically significant in the presence of 2% available chlorine. Twenty-eight freshly extracted human teeth were hand instrumented to clinical standards. Distilled water was used as the irrigant during instrumentation of all specimens in order to produce a uniform smear layer. The canals were given a final irrigation with either 4% sodium hypochlorite, ultrasonic irrigation with different concentrations of sodium hypochlorite, or ultrasonic irrigation with distilled water. The results indicated that 4% sodium hypochlorite, or ultrasound with water, did not remove the smear layer. Four percent or 2% sodium hypochlorivate activated by ultrasound did remove the smear layer from instrumented areas of the canal wall. It was concluded that a synergistic relationship existed between sodium hypochlorite and ultrasound, and that the relationship was clinically significant in the presence of 2% available chlorine.