Influence of Hero Apical instruments on cleaning ovoid-shaped root canals

Renato Interliche,Jesus Djalma Pécora,Melissa Andréia Marchesan,Silvio Rocha Correa Da Silva,Yara Teresinha Corrêa Silva-Sousa,Manoel Damião De Sousa-Neto

doi:10.1590/s1806-83242011000400006

Renato Interliche, Jesus Djalma Pécora + Show 4 more

Open Access

https://doi.org/10.1590/s1806-83242011000400006

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Abstract

The cleaning capacity of Hero 642 nickel-titanium files, complemented by the Hero Apical instruments in flattened roots, was determined by histological analysis, considering the area of action of the instruments on the coronal walls and the presence of remaining debris. Twenty-four single-canal, human mandibular incisors were divided into three groups and prepared as follows: GI, instrumented with Hero 642 NiTi files 30/.06, 25/.06, 20/.06, 25/.06, and 30/.06; GII, instrumented as GI followed by Hero Apical size 30/.06; GIII, instrumented as GI followed by Hero Apical sizes 30/.06 and 30/.08, then returning to 30/.06 with pendulum movements. The apical thirds were prepared for histological processing, analyzed at 40× magnification and the images were examined morphometrically. Statistical analysis showed that GIII presented the best results for removing debris (5.22% ± 4.13), with more contact between the instruments and the root canal walls (19.31% ± 0.15). This differed statistically from GI (14.04% ± 4.96 debris removal, with 42.96% ± 7.11 instrument contact) and GII (12.62% ± 5.76 debris removal, with 35.01% ± 0.15 instrument contact). Root canal preparation with Hero 642, complemented by Hero Apical instruments (30/.06 and 30/.08, then re-instrumented with Hero Apical 30/.06 using pendulum movements), was more efficient for debris removal and allowed more contact of the instruments with the root canal walls. GII presented the worst results.

Highlights

The use of rotary nickel-titanium instruments in endodontics has brought significant contributions to clinical practice in terms of safety, speed, cleanliness and the shaping of root canals.[1,2,3] These instruments do not follow the ANSI/ADA or ISO/FDI standards, and they present different cross-section designs when compared to conventional manual files.[4]
Provides correct initial instrument determination. It is well established in the literature that the use of NiTi rotary instruments during preparation of the middle and coronal cross-sections of ovoid-shaped root canals frequently shows circular bulges; yet, the buccal and lingual extensions of the ovoid root canals often remained unprepared.[8,9,10,11,12]
GIII followed the protocol established for GI, complemented with the Hero Apical instruments 30/.06, 30/.08 and again 30/

Summary

Introduction

The use of rotary nickel-titanium instruments in endodontics has brought significant contributions to clinical practice in terms of safety, speed, cleanliness and the shaping of root canals.[1,2,3] These instruments do not follow the ANSI/ADA or ISO/FDI standards, and they present different cross-section designs when compared to conventional manual files.[4]. Rotary nickel-titanium instruments should be used preferably with the crown-down technique, in which the cervical and middle thirds of the canal are prepared with more tapered instruments, with the taper size decreasing as it reaches the working length.[5,6,7] This technique reduces the occurrence of aberrations, ledges, zips and instrument fracture; it . Interliche R, Marchesan MA, Silva SRC, Pécora JD, Silva-Sousa YTC, Sousa-Neto MD provides correct initial instrument determination It is well established in the literature that the use of NiTi rotary instruments during preparation of the middle and coronal cross-sections of ovoid-shaped root canals frequently shows circular bulges; yet, the buccal and lingual extensions of the ovoid root canals often remained unprepared.[8,9,10,11,12]

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