In vivo study of apical cleaning.

This study sought to evaluate the efficiency with which debris is removed in the clinical environment by evaluating 53 teeth that had undergone in vivo root canal therapy and were extracted for various reasons, including fractures, pain, caries, and financial considerations. The teeth were cross-sectioned 1.0 mm from the apical constriction and 120 canals were evaluated for residual debris based on photographs taken at a magnification of 50x. Of the canals evaluated, 82% had residual debris. Canals treated with the crown down (with apical gauging) technique and/or the step-back technique were free of debris 1.0 mm from the apical constriction only 18% of the time. These techniques prematurely gauged the correct apical canal size because the gauging file bound either in the tangent of the curves or in the narrower dimension of the typical oval canal. All of the canals instrumented to a round shape were free of debris 1.0 mm from the apical constriction. Of the canals treated with tapered instruments, 48% were transported. Of the canals cleaned with the LightSpeed technique (that is, engaging the canal), 100% were free of debris 1.0 mm from the apical constriction.