International Journal of Preventive and Clinical Dental Research

ORIGINAL ARTICLE
Year
: 2020  |  Volume : 7  |  Issue : 2  |  Page : 22--25

A cone-beam computed tomographic analysis to evaluate and compare the root thickness of prepared teeth, centering ability, canal transportation, and instrumentation time in the deciduous teeth using Hyflex controlled memory and ProTaper next file systems – An in vitro study


AR Prabhakar1, Bibi Zohra Sunti2, Basappa Nadig3, Ummey Salma4,  
1 Vice Principal, Department of Pedodontics and Preventive Dentistry, Bapuji Dental College and Hospital, Davangere, Karnataka, India
2 Post Graduate Student, Bapuji Dental College and Hospital, Davangere, Karnataka, India
3 Professor, Bapuji Dental College and Hospital, Davangere, Karnataka, India
4 Research Scholar (PhD), Department of Pedodontics and Preventive Dentistry, M. S. Ramaiah University of Applied Sciences, Bengaluru, Karnataka, India

Correspondence Address:
Dr. Ummey Salma
Department of Pedodontics and Preventive Dentistry, M. S. Ramaiah University of Applied Sciences, Bengaluru, Karnataka
India

Abstract

Objectives: The aim of this study was to evaluate and compare remaining root thickness, centering ability, canal transportation, and instrumentation time of Hyflex controlled memory (CM) and ProTaper (PTN) files in the primary root canals using a cone-beam computed tomographic (CBCT) analysis. Materials and Methods: Fifty freshly extracted human primary teeth with minimum of 7 mm root length were randomly divided into two groups (Group 1 – Hyflex CM files, Group 2 – PTN files) were included in the study. Teeth were scanned using CBCT before and after the instrumentation for both the groups. Remaining dentin thickness, centering ability, canal transportation, and instrumentation time were evaluated for each group. Results: A significant difference was found in remaining root thickness and instrumentation time between Hyflex CM and PTN file system. PTN files showed better remaining root thickness as compared to Hyflex CM files, and the mean instrumentation time of “PTN” was significantly less than “Hyflex CM files.” Conclusions: PTN file system was found to be faster with more remaining root thickness of the primary teeth and hence can be recommended for shaping the root canals of the primary teeth.



How to cite this article:
Prabhakar A R, Sunti BZ, Nadig B, Salma U. A cone-beam computed tomographic analysis to evaluate and compare the root thickness of prepared teeth, centering ability, canal transportation, and instrumentation time in the deciduous teeth using Hyflex controlled memory and ProTaper next file systems – An in vitro study.Int J Prev Clin Dent Res 2020;7:22-25


How to cite this URL:
Prabhakar A R, Sunti BZ, Nadig B, Salma U. A cone-beam computed tomographic analysis to evaluate and compare the root thickness of prepared teeth, centering ability, canal transportation, and instrumentation time in the deciduous teeth using Hyflex controlled memory and ProTaper next file systems – An in vitro study. Int J Prev Clin Dent Res [serial online] 2020 [cited 2021 Jul 29 ];7:22-25
Available from: https://www.ijpcdr.org/text.asp?2020/7/2/22/288185


Full Text



 Introduction



Pulpectomy of the primary teeth is a difficult procedure to perform due to the morphology of the root canals in the primary teeth.[1] The thin, tortuous, branching path of the pulp filaments in the primary molar precludes the possibility of complete removal of all radicular pulp. The use of rotary instrumentation for pulpectomy is an emerging practice in the pediatric dentistry. The canals of the permanent teeth are prepared rapidly and uniformly with nickel-titanium (NiTi) files, resulting in superior obturation. On the other hand, the main purpose for the utilization of rotary instrumentation in the primary teeth is for its ability to provide conical-shaped canals and reduce the instrumentation time.[2] It was concluded that with the use of NiTi rotary files for root canal preparation in the primary teeth was the treatment rendered was more cost-effective, faster, and resulted in consistently uniform and predictable fillings in comparison to hand instrumentation. More importantly, rotary files shorten the preparation time considerably and therefore suit the shorter attention spans of children, thus increasing their cooperation for the endodontic procedure.[3] Newly introduced, Hyflex rotary instruments are fabricated from NiTi wire that is subjected to a proprietary process. They are made from a controlled memory (CM) NiTi wire, which is manufactured by a unique process that controls the material's memory.[4] Hyflex CM NiTi files respond to increased resistance by the straightening of spirals, which avoids instrument binding to the walls, thereby increasing its fracture resistance. The manufacturers claim that these instruments are up to 300% more fatigue resistant. Another file system, the ProTaper Next (PTN) (Dentsply, Maillefer), was introduced with a completely new design comprising unique snake-like swaggering movement, greater flexibility, the M-wire technology, and its offset design. PTN is a new set of rotary instruments designed with progressive and regressive percentage tapers. Having various percentage tapers decreases the effect of the screw and dangerous taper lock by minimizing the contact between the file and the dentin.[5] The off-centered rectangular cross-section of PTN generates an enlarged space for debris removal. Recent studies have demonstrated excellent shaping and centering ability of the above two file systems in the permanent teeth. However, these file systems have not been evaluated or compared for their efficacy in the primary teeth. Hence, there is a need to assess this as primary teeth are anatomically more challenging than the permanent teeth. Therefore, the aim of the present study is to evaluate and compare centering ability, canal transportation, dentin thickness, and instrumentation time in Hyflex CM and PTN file systems.

 Materials and Methods



Study design: Experimental, in vitro, comparative study

Procedure

Fifty freshly extracted human primary teeth having a minimum two-third of its root length intact were collected and included in the study. The extraction procedure was done for therapeutic purposes at the Department of Pedodontics and Preventive Dentistry, Bapuji Dental College and Hospital, Davangere, Karnataka. Institutional ethical board approval was obtained before the study (Ref. No. BDC/Exam/283/2016-17).

Sample preparation

Each tooth was embedded in modeling wax-shaped-like an arch and oriented in a way that its long axis was parallel to the long axis of the wax [Figure 1], to ensure standardization of the specimens for the tomography images before and after root canal instrumentation. The teeth were then divided into two groups by simple randomization: Group 1: Hyflex CM files and Group 2: PTN files [Figure 2]a and b]. The measurement of teeth before and after root canal preparation [Figure 3] was done voxel by voxel.{Figure 1}{Figure 2}{Figure 3}

Statistical tests used

The data obtained were tabulated and subjected to appropriate statistical analysis; unpaired t-test was used for pair-wise comparison of remaining root thickness, canal transportation, and centering ability between two groups. MannWhitney U-test was used to compare the instrumentation time between two groups. The statistical analysis was done using Statistical Package for the Social Sciences (SPSS) Version 20 (IBM Corp., Armonk, N.Y., U.S.A).

 Results



Hyflex CM and PTN file systems did not show any difference in canal transportation and centering ability (P > 1). They showed a difference in the remaining root thickness [Table 1] and instrumentation time [Table 2]. PTN file system showed a greater amount of remaining root thickness and lesser instrumentation time than Hyflex CM file system. The difference in the remaining root thickness was observed at:{Table 1}{Table 2}

The middle (P = 0.092) and apical third (P = 0.056) of the mesial sideThe apical third on the distal side of the prepared roots (P = 0.099).

 Discussion



In this study, fifty freshly extracted human primary teeth having a root angulation of 15-30 degrees using the Schneider method were prepared using K-files, Hyflex CM, and PTN files. Mesial root of the mandibular first molar and palatal root of the maxillary first molar were used. This was done because the distal root of mandibular teeth showed maximal variation in the occurrence of the number of canals.[6] The palatal root of the maxillary first molar rarely reported two canals and two distinct palatal roots. Both the file systems were used in the crown-down approach, as flaring the coronal portion of the root canal before instrumenting the apical region is beneficial as it increases the mechanical efficiency of the instrument and provides better access to the apical portion. Evaluation of the root thickness is important because excess removal of tooth structure could predispose teeth to root fracture.[7] In this study, the root thickness of the teeth prepared with Hyflex CM and PTN files did not show much statistical significant difference, except at the middle (P = 0.092) and apical third (P = 0.056) of the mesial side and apical third (P = 0.099) on the distal side, where the significance value was more than 0.05 but <0.1. This result is in agreement with that of Jason Gagliardi et al. The difference in canal transportation and centering ability between the two groups at the coronal (P = 0.353 at CTc and P = 0.530 at CAc), middle (P = 0.762 at CTm and P = 0.257 at CAm), and apical (0.875 at CTa and P = 0.639 at CAa) section was not statistically significant. This result is in agreement with that of Troiano et al.[8] and Mital P et al.[9] The primary purpose for which rotary instruments are being utilized in primary dentition is due to its reduced instrumentation time.[10] In this study, instrumentation time required by PTN files was significantly less when compared to Hyflex CM files, which could be explained by the fact that PTN does not over engage the dentin because of its design features such as off-centered mass of rotation and rectangular cross-section, thus reaching the working length faster when compared with Hyflex CM files. Moreover, the number of files used in PTN was less compared to Hyflex CM file system, which could be another reason for decreased instrumentation time. Hence, both PTN and Hyflex CM file system can be used in pulpectomy procedures in the primary teeth because of its greater ease in technique and lesser procedural error. However, due to an increased remaining root thickness and a decreased instrumentation time, when using PTN, it can be better recommended for its use in pediatric dentistry as it lessens the chairside time enabling better patient cooperation.

 Conclusions



Under the conditions of the present study, the following conclusions can be drawn:

Hyflex CM and PTN files maintained good amount of remaining root thicknessHyflex CM and PTN files produced less canal transportation and good centering abilityInstrumentation time required with PTN files is significantly less when compared to hyflex CM files.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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