Critical instrumentation area: influence of root canal anatomy on the endodontic preparation.

Maria Antonieta Veloso Carvalho De Oliveira,Luís Henrique Araújo Raposo,Jessyca Figueira Venâncio,João Carlos Gabrielli Biffi,Analice Giovani Pereira

doi:10.1590/0103-6440201300013

Maria Antonieta Veloso Carvalho De Oliveira, Luís Henrique Araújo Raposo + Show 3 more

Open Access

https://doi.org/10.1590/0103-6440201300013

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Abstract

The aim of this study was to evaluate the root canal anatomy of mandibular incisors before and after endodontic instrumentation, identifying regions inaccessible to the action of files (Critical instrumentation Area - CA) in a three-dimensional perspective. Thirty human mandibular central incisors were selected, assigned to two groups (n=15) and instrumented using ProTaper Universal rotary files. In the RX group, longitudinal digital radiographic images were obtained in the buccolingual (BL) and mesiodistal (MD) views. In the CT group, cross-sectional micro-computed tomography (µCT) images were obtained at 3, 9 and 15 mm from the apex. The canal area of the specimens was evaluated before and after instrumentation using digital images from each group. Data were analyzed using t-test, one-way ANOVA with subdivided parcels and Tukey's test (α=0.05). The canal area found in the MD radiographs was larger than in the BL radiographs, which was also confirmed in the transversal images (p<0.01). The CA was only detected in the MD radiographs and µCT scans. On the root canal configuration, a continuous reduction in the canal conicity was observed in BL radiographs, while in MD view there was a constriction at the cervical third and subsequent increase at the middle third (p<0.01). The conical shape of the root canal was observed only in the BL view. The canal enlargement in BL radiographs was not indicative of homogeneous instrumentation, since unprepared areas (CA) were also verified on the buccal and lingual walls in different images.

Highlights

Anatomical complexities may characterize physical barriers that prevent adequate disinfection of root canals [1]
The root canal configuration and curvature angle before and after endodontic instrumentation differ when compared in BL and MD views [5]
Larger root canal areas were observed in the MD radiographs, before and after the instrumentation

Summary

Introduction

Anatomical complexities may characterize physical barriers that prevent adequate disinfection of root canals [1]. This is one of the main reasons why it is not possible to assure adequate endodontic treatment for teeth without a thorough knowledge of the internal details of root anatomy [2]. Root canals should be analyzed in a three-dimensional perspective; the conventional radiographic images usually available in clinical practice, allow only two-dimensional visualization of teeth. The root canal configuration and curvature angle before and after endodontic instrumentation differ when compared in BL and MD views [5]

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