Evaluation of cleaning efficacy of a nickeltitanium rotary system, with or without 17% EDTA passive ultrasonic activation: a scanning electron microscopic study

Resumo

The goal of endodontic instrumentation is to promote
root canal cleaning and shaping to prepare it for the subsequent
three-dimensional filling. Objective: The aim of this study was to
evaluate, ex vivo, root canal cleaning ability executed by nickeltitanium rotary system instrumentation and this same system plus
ultrasound passive activation of 17% EDTA, through SEM. Material
and methods: Seventy upper second single-rooted human bicuspids
were used. All teeth presented a single root canal, flattened towards
buccal-palatal direction. The teeth were randomly separated into 3
groups. Group 1 (n = 30), had the canals instrumented by using
the original operative sequence of ProTaper Universal System, up to
instrument #F3. In this group, 5 ml of 5.25% sodium hypochlorite
was employed as irrigant, every each instrument change. After
group 1 instrumentation, root canals were irrigated with 5 ml of
17% EDTA, which was kept inside the canal for 3 minutes. Next, a
final irrigation with 5 ml of 5.25% NaOCl was performed to remove
the smear layer in suspension. Group 2 (n = 30) had the canals
instrumented by the same system and up to the same instrument
size. It was used 5.0 ml of 5.25% NaOCl as irrigant substance
every each instrument change. In group 2, however, 17% EDTA (5
ml) was applied through ultrasonic passive activation for 1 minute,
and then leaving the substance for 2 minutes within root canal.