Comparative In Vitro study of apically extruded material after four different root canal instrumention techniques / Estudo comparativo in vitro do material marginal extraido depois de quatro diferentes técnicas de instrumentos de canais radiculares

ABSTRACT

Forty newly extracted human upper central incisors were submitted to root canal instrumentation 1 mm from the apex using four different techniques standard, step-preparation, crown-down, and ultrasound, with distilled and deionized water as the irrigative solution. The extrusion product was colleted into a collecting device constructed for this purpose. Extrusion was calculated by the determination of the mass of extruded material. The step-preparation technique caused a larger amount of extrusion than the standard technique, which in turn caused greater extrusion than the crown-down and ultrasound techniques. All techniques used caused extrusion of material beyond the apical foramen