A Cone Beam Computed Tomographic Analysis of Root Canal Preparations in Deciduous Teeth Using Self Adjusting Files- An In Vitro Study

Research Article

Austin J Dent. 2017; 4(4): 1078.

A Cone Beam Computed Tomographic Analysis of Root Canal Preparations in Deciduous Teeth Using Self Adjusting Files- An In Vitro Study

Prabhakar AR, Renuka GN*, Saraswathi VN and Chandrashekar MY/p>

Department of Pedodontics and Preventive Dentistry, Bapuji Dental College and Hospital, India

*Corresponding author: Renuka GN, Department of Pedodontics and Preventive Dentistry, Bapuji Dental College and Hospital, Davangere-577004, India

Received: March 20, 2017; Accepted: April 28, 2017; Published: May 18, 2017

Abstract

Background: The complex root canal anatomy of primary root canals is considered to be most challenging. Most of the root canal instruments available till date are ineffective in cleaning the root canal in three dimensions. Self Adjusting Files (SAF) was recently introduced. The aim of this study was to evaluate and compare remaining root thickness, centering ability, canal transportation and instrumentation time of Hand files and Self adjusting files in primary root canals using a Cone Beam Computed Tomographic (CBCT) analysis.

Study Design: This is an experimental, in vitro, intergroup study.

Material and Methods: Twenty eight extracted human primary teeth with minimum 7 mm root length were randomly divided into two groups (Group 1-Hand K-files, Group 2-SAF) were included in the study. CBCT images were taken before and after the instrumentation for each group. Remaining Dentin thickness, centering ability, canal transportation and instrumentation times were evaluated for each group.

Results: A significant difference was found in instrumentation time and canal transportation between Hand K-Files and SAF. Self adjusting files showed less canal transportation as compared to Hand K-Files and the mean instrumentation time of ‘Self Adjusting Files’ was significantly less than ‘Hand K-Files’.

Conclusion: Self adjusting files system was found to be faster with much less errors in shaping the root canals of primary teeth and can hence be recommended for shaping the root canals of primary teeth.

Keywords: Self adjusting files; Cone beam computed tomography; Pulpectomy

Introduction

Biomechanical preparation of root canals is one of the main steps in achieving endodontic success due to enabling bacterial elimination, removal of debris and facilitating obturation. Endodontic mishaps such as Perforations, canal transportation, ledge and zip formation and separation of instruments are some of the complications encountered during root canal preparation of permanent teeth [1,2]. whereas in primary teeth ,especially in primary molars due to fear of damage on the developing permanent tooth buds, as also due to difficulty in negotiating, cleaning, shaping, and filling the bizarre and tortuous canal anatomy of these teeth with resorbing and open apices. Many time’s extraction of deciduous teeth having necrotic pulps with or without periapical infection is preferred following placement of the space maintainers. However, there is no better space maintainer than primary tooth itself, and the success rate of pulpectomy in primary teeth has been reported to be fairly high i.e., 80% and 100%. So it becomes very important to save every primary molar [3].

Effective cleaning and shaping of root canal system is essential for achieving the biological and mechanical objectives of root canal treatment. Till date wide variety of instruments are available for

the root canal instrumentation. But traditionally, the shaping of the root canals was achieved by the use of stainless steel hand files. However, over the last decades, technological advancements in rotary nickel-titanium instruments have led to new design concepts and easier, faster, and better root canal shaping [4]. These instruments performed better when the canals were straight, narrow and round, but were ineffective for cleaning long oval, flat and curved canals [5].

This, yet unmet challenge resulted in a new branching point in the “evolution tree” of endodontics. One branch consists of attempts to meet this three-dimensional (3D) challenge by advanced irrigation methods [5]. The other new branch is represented by the Self- Adjusting File (SAF) system, which was recently introduced [5].

The self-adjusting files have shown to have better cleaning and shaping efficacy and better adaptation of the root canal filling than the traditional rotary files in permanent teeth [7-11]. In contrast to the permanent teeth, the primary teeth show more of flat root canals and even more curved canals, and as these self-adjusting files like other rotary systems available till date do not impose any shape on the canals but rather they adapt to the canal architecture because of its and also self-adjusting files have never been used on primary teeth.

So we decided to conduct a study that aimed to evaluate whether the use of self-adjusting files in the primary root canals provides a better three dimensional cleaning and shaping.

Materials and Methods

Twenty eight freshly extracted human primary teeth (4 molars, 6 incisors, 4 canines) collected from the Department of Pedodontics and Preventive Dentistry, Bapuji Dental College and Hospital, Davangere, Karnataka, were included in the study. Institutional ethical board approval was obtained prior to the study. Groups that were used in the study:

Group 1: Hand K Files.

Group 2: Self adjusting files.

Sample preparation

The primary teeth with minimum two third root length were included and Teeth with resorbed roots were excluded from the study. The specimens were embedded in auto polymerizing acrylic resin using a plastic mold. In order to prevent the resin from entering and polymerizing into the apical foramen, the apices of the roots were sealed with wax. Acrylic resin was mixed according to the manufacturer’s instructions and poured into the mold. Each sample was inserted into the unset acrylic resin so that its long axis was parallel to the long axis of the mold to ensure standardization of the specimens for the tomography images before and after root canal instrumentation [12].

Root canal preparation

Access cavity preparation was done using endo access bur to obtain straight line access, unroofing of the chamber was done and the pulp extripation was done for both the groups [13]. In Group 1, the root canals were instrumented manually with K-files with the step-back technique up to file ISO size 30 [14], and in Group 2 initially a glide path was prepared to allow free insertion of a #20 K-file to its working length, which allowed free insertion of the SAF to the full length of prepared canal [13].

CBCT

Teeth were scanned (Dental digital imaging CBCT Centre, Davangere) before and after mechanical preparation with CBCT scanner with the following parameters: 60 kVp, 12. 5 mA, field of view 8x8, and the sections were taken at coronal, middle and apical level of the root (Figure 1) [13]. The measurements of the canal before and after root canal preparation was done voxel by voxel wherein, M1 is the measurement of the quantity of voxels from the external surface of the mesial portion of the root to the mesial wall of the noninstrumented canal, M2 is the measurement of the quantity of voxels from the external root surface of the mesial portion of the root to the wall of the canal after instrumentation, D1 is the measurement of the quantity of voxels of the external surface of the distal portion of the root to the distal wall of the non-instrumented canal, D2 is the measurement of the quantity of voxels from the external surface of the distal portion of the root to the distal surface of the canal after instrumentation [13]. Canal transportation (CT) was calculated from the following equation [12].