Smear Layer removal efficacy of different types of Irrigation Solutions with single file system: An in vitro SEM Study
Madhu Varma K1, Manishaa B2*, Kalyan Satish R1, Sita Rama Kumar M3,
Panithini D B2, Madhavi K2
1Professor, Department of Conservative Dentistry and Endodontics,
Vishnu Dental College and Hospital, Bhimavaram 534201, Andhra Pradesh, India.
3Senior Lecturer, Department of Conservative Dentistry and Endodontics,
Vishnu Dental College and Hospital, Bhimavaram 534201, Andhra Pradesh, India.
2Postgraduate Student, Department of Conservative Dentistry and Endodontics,
Vishnu Dental College and Hospital, Bhimavaram 534201, Andhra Pradesh, India.
*Corresponding Author E-mail: madhuvarma.k@vdc.edu.in, manishaabondada97@gmail.com, rkalyansatish@vdc.edu.in, sitaramkumar.m@vdc.edu.in, durgabhavanipanitini@gmail.com, kumpatlamadhavi@gmail.com
ABSTRACT:
Aim: To compare the effectiveness of three different irrigating solutions (NaOCl+ EDTA, REMIX 2 IN 1, TWIN KLEEN) on the removal of smear layer with the single file system (XP-Endo Shaper) in mandibular premolars using a scanning electron microscope. Materials and Methods: Thirty-three human single-rooted mandibular premolar teeth were selected and decoronated to a standardized length. Biomechanical preparation was done with a single file system (XP-Endo Shaper) using 3% NaOCl as an irrigant during instrumentation. Three experimental groups were formed by randomly dividing teeth, with eleven teeth in each Group (n=11), and final irrigation was carried out using the following solutions; Group I - (control group) 5.25% Sodium Hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic (EDTA), Group II - REMIX 2 IN 1 solution (Neelkanth healthcare, India), Group III - freshly prepared TWIN KLEEN (Maarc dental, India) solution. The teeth were separated into two halves and observed under a scanning electron microscope at 3mm, 6mm, and 9mm from the apex to analyze the amount smear layer in 1000X and were evaluated using a 5-grade scoring system. Kruskal–Wallis test and Mann–Whitney U test were used to analyze the data. Results: On comparing the three different irrigating solutions, no statistically significant difference was found in the ability to remove the smear layer from the coronal and middle third's (P>0.05). Group I (1.14±0.68) and Group II (1.18±0.40) showed significantly higher removal of smear layer when compared to Group III (1.81±0.60) in the apical third. Conclusion: Sequential use of 5.25% NaOCl + 17% EDTA and REMIX 2 IN 1 solution were found to be the most efficient than TWIN KLEEN solution in removing the smear layer in the apical third of root canals instrumented with the single file system (XP-Endo Shaper).
KEYWORDS: Etidronic acid, SEM, Smear layer, Surfactant, XP-Endo Shaper.
INTRODUCTION:
The awareness about root canal treatment among patients has been increased significantly in recent times1.
The steps in the root canal treatment include removal of the damaged and diseased dental pulp, shaping of the canal walls and obturating the canal with sterile material.
Cleaning and shaping of the root canal using rotary instruments result in the smear layer formation that covers the dentinal tubules and fills canal irregularities2. The smear layer is composed of dentin particles, inorganic debris, organic materials including necrotic or viable pulp tissue remnants, blood cells, bacteria, and their byproducts3. Various studies have shown the effectiveness of different chemicals4, antibiotics5,6 and Herbal extracts7,8,9,10 as effective antimicrobial agents. The smear layer prevents the penetration of Irrigants, intracanal medicaments, and sealants into the dentinal tubules. There is a high risk of endodontic treatment failure if the pathogens survive and remain at the time of obturation11. As a result, removing the smear layer is critical for improving the fluid-tight seal during root canal obturation12.
The single instrument is potentially time-saving and cost-effective as compared to multiple rotary instrument systems13. XP-endo Shaper (XPS) is a snake-shaped instrument with thermomechanically treated Ni-Ti alloy termed as Max-Wire (Martensite-Austenite-electropolish-fileX). This instrument exhibits shape memory and possesses super elasticity during preparation14.
Successful root canal therapy relies on thorough disinfection of the root canal system10. Mechanical instrumentation must be supplemented by irrigation to keep the canal wall lubricated, eliminate bacteria and their byproducts, dissolve pulpal remnants and remove the smear layer12.
Sodium hypochlorite (NaOCl) is the most widely used irrigation solution10 for root canal disinfection because of its efficacy against biofilms and capacity to break down organic debris15. This reaction with only the organic part is termed as 'soap effect'16. NaOCl solutions, on the other hand, are incapable of removing the inorganic components of the smear layer and accumulated hard tissue debris generated during mechanical instrumentation. Therefore, alternating application of the chelating agent ethylene diamine tetra acetic acid (EDTA) is commonly advocated15.
For the dual effect on the removal of smear layer and disinfection of the root canals, an alternative final irrigation solution REMIX 2 IN 1 solution (Neelkanth healthcare, India) containing a mixture of 17% EDTA, 2% chlorhexidine (EDTA+CHX), and a surfactant was introduced.
Etidronic acid or Etidronate (1hydroxyethylidene1, 1bisphosphonate; HEBP) has been proposed as an alternative to EDTA or citric acid17. Etidronic acid is a calcium-complexing agent that has good short-term compatibility with sodium hypochlorite (NaOCl)18. HEBP when used in combination with a NaOCl solution, a concept that has been termed ‘continuous chelation’. Recently a new formulation of Etidronic acid has been commercially available as TWIN KLEEN (HEBP + NaOCl) (Maarc dental, India)
As there is limited literature available comparing the efficacy of different root canal irrigants with the single file system (XP-endo shaper – FKG Dentaire SA, La Chaux-de-Fonds, Switzerland). The purpose of this study is to compare the smear layer removal efficacy of three different irrigation solutions with the single file system (XP-Endo Shaper).
MATERIALS AND METHODS:
Thirty-three human mandibular single-rooted premolars that were extracted for orthodontic or periodontal reasons were selected for the study. Teeth with caries, calcified canals, open apices, any developmental anomalies, previously root canal treated teeth were excluded from the study. Teeth were cleaned by removing the hard deposits and soft tissues and then stored in daily changed normal saline until use. To get the flat reference point, all the teeth were decoronated and standardized to the root canal length of 14mm12. The root canal patency was determined by passing a stainless steel 15 K-hand file through it till it just appeared at the apex. Working length was obtained by instrumenting the root canal 1mm short of the apical foramen. The root canal was prepared with XPS (FKG Dentaire SA, La Chaux‑de‑Fonds, Switzerland) at a speed of 800rpm and 1-Ncm torque in gentle 3–5 strokes until the canal was prepared to the full working length19. About 2ml solution of 3% NaOCl was used as an irrigant during instrumentation in all experimental groups using a 2ml syringe and 30-gauge side vented needle12. For effective irrigation in the apical third of the root, the needle was inserted till 1 mm short of the apex. Following irrigation with NaOCl, the canals were irrigated with 3mL of distilled water2. All the specimens were divided randomly into three groups (n=11) to perform the final irrigation protocol with a 30-Gauge side vented needle.
Group I control:
Canals were irrigated using 2.5ml of 5.25% NaOCl followed by 2.5ml of 17% EDTA
Group II:
Canals were irrigated using 5ml of REMIX 2 IN 1 solution (Neelkanth healthcare, India)
Group III:
Canals were irrigated using Freshly prepared TWIN KLEEN (Maarc dental, India)
Preparation of specimens for scanning electron microscope study:
To facilitate study under the scanning electron microscope (SEM), two parallel longitudinal grooves were prepared on the lingual and buccal surfaces of each root using diamond disc. Longitudinal grooves were made without penetrating the root canal. The teeth were longitudinally split into two halves using a chisel. The half containing the greater part of the apex was selected and coded. After that, the coded specimens were mounted on metallic stubs, gold-sputtered, and scanning electron microscope images were obtained at 1000X20. Each root canal was evaluated at 3, 6, and 9mm from the apex representing apical, middle, and coronal thirds19.
Scanning Electron Microscopic evaluation:
Two investigators were blinded and scored the presence or absence of smear layer on the root canal surface or in the dentinal tubules at each canal's coronal, middle, and apical portion according to the criteria given by Hulsmann et al21.
Scoring criteria:
· Score 1: No smear layer, dentinal tubuli open.
· Score 2: Small amount of smear layer, some dentinal tubuli open.
· Score 3: Homogenous smear layer covering the root canal wall, only few dentinal tubuli open.
· Score 4: Complete root canal wall covered by a homogenous smear layer, no open dentinal tubuli.
· Score 5: Heavy, non-homogenous smear layer covering the complete root canal wall
These are the scanning electron microscopic images at apical third at 1000X
Group I
Group II
Group III
Statistical analysis:
Results were tabulated and statistically analyzed. Kruskal-Wallis test was carried out, in order to find out any significant difference between groups, that is, Group A, Group B, and Group C. Mann-Whitney test was carried out, In order to find out significant difference among pair of groups, using software version SPSS 26.0 version. (Table 1 and Table 2)
RESULTS:
On comparing the smear layer removal scores of three different irrigating solutions,
There was no statistically significant difference found in terms of the ability to remove the smear layer from the coronal and middle third’s (P>0.05). (Table 1)
Group I (1.14±0.68) and Group II (1.18±0.40) showed significantly (P<0.05) higher smear layer removal in the apical third when compared to Group III (1.81±0.60). (Table 1)
Table 1: Comparison of mean scores of smear layer removal from apical third using Kruskal-Wallis test
|
Position |
Groups |
Mean |
Std. Deviation |
X2 value |
P-value |
|
9mm |
Group I |
1.2727 |
0.46710 |
0.127
|
0.881
|
|
Group II |
1.4545 |
1.21356 |
|||
|
Group III |
1.3636 |
0.67420 |
|||
|
6mm |
Group I |
1.8182 |
0.75076 |
2.414 |
0.107 |
|
Group II |
2.1818 |
1.40130 |
|||
|
Group III |
2.9091 |
1.30035 |
|||
|
3mm |
Group I |
1.1455 |
0.68755 |
3.364
|
0.048*
|
|
Group II |
1.1818 |
0.40452 |
|||
|
Group III |
1.8182 |
0.60302 |
Table 2: Pairwise comparison of mean scores of smear layer removal using Mann Whitney U test
|
Dependent Variable |
(I) GROUP |
(J) GROUP |
Mean Difference (I-J) |
Std. Error |
Sig. |
|
9mm |
Group I |
Group II |
-0.18182 |
0.36059 |
0.870 |
|
Group I |
Group III |
-0.09091 |
0.36059 |
0.966 |
|
|
Group II |
Group III |
0.09091 |
0.36059 |
0.966 |
|
|
6mm |
Group I |
Group II |
-0.36364 |
0.50562 |
0.754 |
|
Group I |
Group III |
-1.09091 |
0.50562 |
0.095 |
|
|
Group II |
Group III |
-0.72727 |
0.50562 |
0.335 |
|
|
3mm |
Group I |
Group II |
0.0363 |
0.24618 |
0.316 |
|
Group I |
Group III |
-0.67273* |
0.24618 |
0.031* |
|
|
Group II |
Group III |
-0.63649* |
0.24618 |
0.038* |
DISCUSSION:
The internal anatomy of mandibular premolars consists of oval-shaped canals. They were selected in this study as they offered a challenge to any instrumentation technique by having a higher percentage of unprepared surface and leaving debris on the root canal walls22,23,24.
To adapt to the root canal morphology, XPS can expand beyond its core size. The file has an initial taper of 0.01 in its M-phase but, upon exposure to body temperature (35°C), the taper changes to 0.04. In oval-shaped canals, the XPS can prepare and touch more canal walls25. Root canal preparation with XPS in oval-shaped canals also resulted in significantly less smear layer and remaining debris when compared to the other instrument systems19.
Scanning electron microscopic evaluation was selected for this study. It provides for high resolution and magnification of canal walls, which is utilized to determine the cleanliness of canal walls26.
In Group I, 5.25% NaOCl followed by 17% EDTA was used. NaOCl dissolves organic matter of the smear layer (pulpal remnants, bacteria, and infected predentin), while EDTA dissolves the inorganic portion of the smear layer.5.25% NaOCl followed by 17% EDTA group showed better results because of the synergistic effect of the combination of 5.25% NaOCl and 17% EDTA15.
Group II (2% CHX and 17% EDTA) had shown comparable results with that of Group I, which might be due to the presence of surfactant, which enhances the effectiveness of REMIX by decreasing the surface tension of solution and facilitating the contact of irrigant with the dentinal walls, enabling better smear layer removal27.
Group III, TWINKLEEN, which contain NaOCl and 9% (wt/vol) etidronic acid (HEBP) comparatively, showed the least smear layer removal from the apical third of the root canal. Hypochlorite-compatible chelator (HEBP) can reduce but not completely prevent smear layer during root canal instrumentation, as 9% (wt/vol) etidronic acid (HEBP) is a weak chelating agent than 17% EDTA. This was in accordance with the previous study conducted by Paqué F et al28.
CONCLUSION:
Within the limitations of this in vitro study, Sequential use of 5.25% NaOCl + 17% EDTA and EDTA+CHX (REMIX 2 IN 1) solution were found to be the most efficient than HEBP (TWIN KLEEN) solution in the removal of smear layer in the apical third of root canals instrumented with the single file system (XP-Endo Shaper). From a clinical perspective, EDTA+CHX solution offers a reasonable and efficacious alternative to NaOCl + EDTA.
CONFLICTS OF INTEREST:
The authors have no conflicts of interest regarding this investigation.
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Received on 10.11.2021 Modified on 02.05.2022
Accepted on 12.09.2022 © RJPT All right reserved
Research J. Pharm. and Tech 2023; 16(4):1875-1879.
DOI: 10.52711/0974-360X.2023.00307