An in vivo comparison of the step-back technique versus a step-back/ultrasonic technique in human mandibular molars

By Haidet J, Reader A, Beck M, Meyers W

Date: 01/1989
Journal: JOE


Purpose: To compare histologically the in vivo debridement efficacy of a step-back preparation (SB) vs a step-back/ultrasound preparation in the mesial root canals of human mandibular molars with vital pulps.


n: 60 patients were included

 2 experimental Gps (Gp.1; n: 15 MR prepared with SB tech without ultrasonic; Gp.2: n: 23 MR prepared with SB tech and 3 minutes of ultrasonic); Gp.3 (Control) n:21 MR were not instrumented only access cavity

-Teeth were prepared using SB tech with K files with 2 ml of 5.25% NaOCL.

-Cavi-Endo ultrasonic instrument was used and was set at high power level  with 30 ml/minute in GP.2.

-Teeth were then extracted and fixed with 10% formalin, decalcified, dehydrated, infiltrated, cleared using methyl salicylate as a clearing agent, sectioned at level 1 and 3 mm from the foramen, and stained with Gomori’s One-Step Trichrome Stain. One evaluator outline each canal, isthmuses, and remaining pulp tissue and the area was quantified using compensating polar planimeter



– At the l-mm apical level, the ultrasound technique was superior to the step-back technique in both canals (99.6% versus 88%) and isthmus (86% versus 10%) cleanliness Fig 1,2.

– At the 3-mm apical level, there were no statistical differences in canal or isthmus cleanliness between the step-back and ultrasound preparations Fig 1,2.

– Both instrumented groups demonstrated significantly cleaner canals and isthmuses than those in the control



Step-back/ultrasonic technique was superior to the step-back technique in canal cleanliness.