Effect of nonsterile versus sterile water irrigation with ultrasonic scaling on postoperative bacteremias.

The contribution of nonsterile water irrigation during ultrasonic scaling to postoperative blood stream contamination was evaluated. Thirty human volunteers were subjected to a random split-mouth technique comparing sterile and municipal tap water irrigation with ultrasonic root preparation on contralateral mandibular quadrants. Scaling was performed by a single operator using a premeasured quantity of irrigant. Postoperative blood samples were obtained immediately and cultured aerobically and anaerobically in tryptic soy broth and on BHI agar plates for enumeration of colony forming units. Positive blood cultures were inoculated onto selective media for presumptive identification. The difference in the bacteremia incidence after scaling with sterile water (50%) versus scaling with tap water (53.3%) was not significant. The degree of the bacteremias (less than 1 colony forming unit/ml) was similar between groups. Therefore tap water irrigation used in ultrasonic scaling did not appear to be a significant causative agent in postoperative bacteremias.