ORIGINAL RESEARCH |
https://doi.org/10.5005/jp-journals-10024-3142 |
In Vitro Assessment of Intracanal Calcium Hydroxide Removal Using Various Irrigation Systems: An SEM Study
1Department of Conservative Dentistry and Endodontics, Buddha Institute of Dental Sciences and Hospital, Patna, Bihar, India
2Department of Prosthodontics, Crown and Bridge and Implantology, Vydehi Institute of Dental Sciences and Research Hospital, Bengaluru, Karnataka, India
3Department of Public Health Dentistry, AB Shetty Memorial Institute of Dental Sciences (ABSMIDS), NITTE (Deemed to be University), Mangaluru, Karnataka, India
4Department of Public Health Dentistry, Kusum Devi Sunderlal Dugar Jain Dental College and Hospital, Kolkata, West Bengal, India
5Department of Conservative Dentistry and Endodontics, Faculty of Dental Science, DDU, Nadiad, Gujarat, India
6Department of Public Health Dentistry, Vaidik Dental College and Research Centre, Daman, Daman and Diu, India
Corresponding Author: Abhinav K Singh, Department of Conservative Dentistry and Endodontics, Buddha Institute of Dental Sciences and Hospital, Patna, Bihar, India, Phone: +919576969374, e-mail: akspat01@gmail.com
How to cite this article: Singh AK, Ramanna PK, Kumari D, et al. In Vitro Assessment of Intracanal Calcium Hydroxide Removal Using Various Irrigation Systems: An SEM Study. J Contemp Dent Pract 2021;22(9):1003–1007.
Source of support: Nil
Conflict of interest: None
ABSTRACT
Aim: The aim of this research was to assess the effectiveness of three different irrigation systems in elimination of calcium hydroxide [Ca(OH)2]from root canals.
Materials and methods: This in vitro research included ninety recently extracted mandibular premolar teeth with a solitary root. The sample teeth were subjected to disinfection employing sodium hypochlorite at 5.25%. The root canal preparation was performed followed by placement of premixed Ca(OH)2 within every canal. The sample teeth were then randomly allocated into one of the three experimental groups (each comprising 30 samples) as follows: Group 1, NaviTip FX irrigation system; group 2, Vibringe sonic irrigation system; and group 3, EndoVac apical negative pressure irrigation system. Following the preparation, each of the sample teeth was examined beneath a scanning electron microscope (SEM) at a magnification of 1000×.
Results: An intragroup comparative analysis revealed that the highest Ca(OH)2 elimination was seen at middle third (0.82 ± 0.09, 0.30 ± 0.11) in NaviTip FX irrigation system and Vibringe sonic irrigation system, respectively. Higher Ca(OH)2 was eliminated at the apical third (0.26 ± 0.02) by the EndoVac irrigation system. At coronal third, maximum Ca(OH)2 removal was seen in EndoVac irrigation system (0.49 ± 0.03). A statistically significant difference was noted amid Vibringe sonic irrigation and EndoVac irrigation systems. The intergroup evaluation of Ca(OH)2 elimination at coronal, middle, and apical third showed a statistically significant difference between NaviTip FX irrigation and Vibringe sonic irrigation as well as between NaviTip FX irrigation and EndoVac irrigation at a p value of 0.001. The difference between EndoVac irrigation and Vibringe sonic irrigation was not statistically significant.
Conclusion: Amid the limitations of this research, this research concludes that none among the irrigation methods employed could totally eliminate the Ca(OH)2 off the root canals. Nevertheless, EndoVac apical negative pressure irrigation has slightly superior potential in eliminating Ca(OH)2 from the root canals in comparison with Vibringe sonic irrigation as well as the NaviTip FX irrigation system.
Clinical significance: Even though the Ca(OH)2 is largely suggested as medicament, its elimination at the point of canal obturation is likewise significant and complex as any remaining portion may avoid sealer diffusion inside the dentinal tubules, consequently substantially escalating the apical leakage of endodontically treated teeth.
Keywords: Calcium hydroxide, Irrigation systems, Root canal, Scanning electron microscope.
INTRODUCTION
The triumph of an endodontic treatment depends on a precise diagnosis and planning a suitable therapeutic plan. Unfortunately, the abolition of microorganisms coupled with total elimination of tiny organic debris remnants, necrosed tissue, remaining pulp tissue, and dentin chips from the root canals is amid the ignored phases of root canal treatment.1
Herman in the year 1920, pioneered calcium hydroxide [Ca(OH)2] that has a very alkaline pH along with the ability to breakdown to release calcium and hydroxyl ions that exhibit antibacterial action. Ca(OH)2 paste is often used in the field of endodontics as an medication within the root canal owing to its antimicrobial effectiveness against a vast number of root canal pathogenic organisms as well as its biocompatibility.2
Prior to endodontic obturation, the Ca(OH)2 medicament that had been coated on to the root canals must be taken off. The presence of Ca(OH)2 remainders on the walls of the root canal has detrimental consequences on the quality of the obturation. In vitro research has noted that Ca(OH)2 residues can deter sealant penetration into tubular dentin and hamper the bond between resin sealer and dentin surface. Additionally, significant apical leakage of endodontically treated teeth and interaction with zinc oxide eugenol sealers that make them granular and fragile have also been noted in the presence of remnants of Ca(OH)2. This thus mandates the total elimination of any Ca(OH)2 residues from the root canal prior to root canal filling. Removal of the Ca(OH)2remainders in irregular canals can nevertheless be challenging.3
Various techniques have been previously recommended to eliminate Ca(OH)2 off the canal walls, including the use of hand and rotary files, passive ultrasonic irrigation, sonic activation, and the canal brush. Clinical practice employs use of hand instruments frequently, utilizing a master apical file under abundant irrigation by sodium hypochlorite.4
A NaviTip FX brush covered needle introduced for the irrigation during canal preparation. It eliminates the root canal wall debris chemically and mechanically simultaneously during irrigation.5 Vibringe is a sonic washing system, a system in which sonic activation and manual are combined. Along with that, the needle attached to the syringe, the irrigation solution can also be activated sonically. The EndoVac system acts as a apical negative pressure irrigation system, which is designed to deliver irrigation solutions to the apical end portion of the root canal systems and to suction out debris from the root canals.6 This research was thus performed to evaluate the effectiveness of different irrigation systems thatpossess differing techniques to eliminate Ca(OH)2 from root canals.
MATERIALS AND METHODS
The present study was performed in the Department of Conservative Dentistry and Endodontics, Buddha Institute of Dental Sciences and Hospital, Patna. This in vitro research included ninety recently extracted mandibular premolar teeth with a solitary root, which were removed for periodontal or orthodontic treatment procedures. After the extraction, these sample premolars were subjected to a complete washing beneath running water followed by cleaning by ultrasonic equipment. The sample teeth were then subjected to disinfection employing sodium hypochlorite at 5.25%. Those teeth thathad a solitary root canal, no evidence of radicular dental caries, fractures/cracks, lack of internal/external resorption or calcification, and a fully formed apex were included in the study. The radicular canal morphology was confirmed with pretreatment mesiodistal as well as buccolingual radiographs.
Root Canal Preparation
A diamond disk (KG Sorensen, Barueri, Sao Paulo, Brazil) under water coolant at a slow speed was used to remove the crowns at the cementoenamel junction to procure a standard radicular length of 10 mm. A K-file of size 10 was then introduced into the canal till it could be seen at the apical foramen. One millimeter subtracted from the aforementioned measurement helped determine the working length. The ProTaper rotary arrangement (Dentsply Maillefer, Ballaigues, Switzerland) was used to instrument the root canals up to a size 30 with 9% taper (size F3) serving as the master apical file. The root canal was subjected to irrigation with 2 mL of 2.5% sodium hypochlorite solution following every instrument throughout the preparation. Irrigation was done using a 27-gauge root canal irrigation syringe that was placed in the canal up to the working length. A final burst was then applied after completion of the instrumentation employing 5 mL of 17% ethylenediaminetetraacetic acid (EDTA) and 5 mL of 2.5% sodium hypochlorite.
Subsequently, the root canals were subjected to drying using paper points. After this, a premixed Ca(OH)2(Calcicur, Voco, Cuxhaven, Germany) was introduced in the canal with a lentulo spiral adjusted till the working length until the medication was evident at the apical foramen. Following this, the cavities thus created by access opening were closed with a small cotton ball and temporary restoration (Cavit, ESPE, Seefeld, Germany). For the next 7 days, these samples were stored at a temperature of 37°C as well as 100% humidity.
Three different systems were then employed to eliminate Ca(OH)2 present in the root canals. These sample teeth were then randomly allocated to one of the three study groups (30 each) as follows:
Group 1: NaviTip FX Irrigation System
A 30-gauge NaviTip FX tip (Ultradent Products Inc, South Jordan, Utah, United States) was employed for irrigating the canals, which was fit into the body of a disposable syringe of 2.5 mL volume. Robust irrigation of the root canal systems was performed via the needle utilizing 2.5 mL of 2.5% sodium hypochlorite as well as 2.5 mL of 17% EDTA for 60 seconds with up and forth motion of the needle.
Group 2: Vibringe Sonic Irrigation System
A 27-gauge close-end and side vented irrigating needle (Kerr Hawe SA, Bioggio, Switzerland) coupled with Vibringe sonic irrigating apparatus was employed to eliminate Ca(OH)2 from the surface of the root canals. In accordance with the manufacturer’s recommendations, the needle was inserted about an mm or 2 short of the working length. Active irrigation of the radicular canals with help of the needle was done utilizing 2.5 mL of 2.5% sodium hypochlorite as well as 2.5 mL of 17% EDTA for 60 seconds with up and forth motion of the needle. Following each active irrigating step, the canal was left untouched for a minute to attain passive irrigation. The finishing irrigating step was performed employing 2.5 mL of 2.5% sodium hypochlorite for 60 seconds and then again leaving the canal untouched for a minute.
Group 3: EndoVac Apical Negative Pressure Irrigation System
In this group, the system employed for irrigation was the apical negative pressure irrigation (EndoVac, Discus Dental, Culver City, California, United States). A macrocannula tip was used to carry the irrigant an mm down the canal after which three phases of microcannula irrigation wereperformed. At every microcannula irrigation phase, the tip was introduced for 6 seconds to the entire working length and then removed by about 2 mm off the entire working length for around 6 seconds. These steps were repeated across a period spanning 30 seconds. A total of 10 mL of 2.5% sodium hypochlorite was used.
Evaluation of Samples under Scanning Electron Microscope
Following the preparation of the canal as mentioned above, all the sample premolars were subjected to sectioning in the buccolingual direction employing a carborundum disk, prior to which a groove was made buccolingually using a diamond bur. Subsequent to this, each tooth was examined beneath a scanning electron microscope (SEM) (LEO 440i, Carl Zeiss, Tokyo, Japan) at 1000× magnification. Prior to the examination, dehydration of the specimens followed by fixation on stubs of aluminum and sputter coating with gold was accomplished. A four-grade system was used to score the remnants of Ca(OH)2 in each sample along with three portions of the radicular canal (coronal, middle, as well as apical):7
Score 0 = Absence of Ca(OH)2 on the root canal surface.
Score 1 = One-third of the root canal surface is covered by Ca(OH)2.
Score 2 = Two-thirds of the root canal surface is covered by Ca(OH)2.
Score 3 = Ca(OH)2 has completely covered the root canal surface.
As a means to avoid bias, two independent skilled observers verified the scores. The mean thus derived from the two observers’ scores was statistically analyzed.
Statistical Analysis
Kruskal Wallis tests and Mann Whitney U-test were used to perform the statistical analysis via Statistical Packages for Social Sciences (SPSS) software, version 20.0 for Windows (SPSS Inc., Chicago, Illinois, United States). Statistical significance was set at p value less than 0.05.
RESULTS
Table 1 depicts the assessment of mean Ca(OH)2 elimination of the three different irrigation systems at the coronal, middle, and apical third of the root canal surface. An intragroup comparative analysis revealed that the highest Ca(OH)2elimination was seen at middle third (0.82 ± 0.09, 0.30 ± 0.11) in NaviTip FX irrigation system and Vibringe sonic irrigation system, respectively. Higher Ca(OH)2 was eliminated at the apical third (0.26 ± 0.02) by the EndoVac irrigation system. And at coronal third, the maximum Ca(OH)2removal was seen in EndoVac irrigation system (0.49 ± 0.03) followed by Vibringe sonic irrigation system (0.52 ± 0.07) and NaviTip FX irrigation system (0.89 ± 0.13). A statistically significant difference was noted between Vibringe sonic irrigation and EndoVac irrigation.
| Irrigation systems | Coronal (Mean ± SD) | Middle (Mean ± SD) | Apical (Mean ± SD) | K ANOVA value | p value |
|---|---|---|---|---|---|
| Group1: NaviTip FX irrigation | 0.89 ± 0.13 | 0.82 ± 0.09 | 1.09 ± 0.06 | 23.10 | 0.06 |
| Group2: Vibringe sonic irrigation | 0.52 ± 0.07 | 0.30 ± 0.11 | 0.37 ± 0.10 | 24.82 | 0.001* |
| Group3: EndoVac apical negative pressure irrigation | 0.49 ± 0.03 | 0.32 ± 0.16 | 0.26 ± 0.02 | 24.68 | 0.001* |
Mann Whitney U-test was employed to estimate the intergroup evaluation of Ca(OH)2elimination at coronal, middle, and apical third. A statistically significant difference was noted between NaviTip FX irrigation and Vibringe sonic irrigation as well as between NaviTip FX irrigation and EndoVac irrigationat a p value of 0.001. The difference between EndoVac irrigation and Vibringe sonic irrigation was not statistically significant (Tables 2 to 4).
| Intergroup comparison | Mean rank | Mann-Whitney U-test | p value |
|---|---|---|---|
| NaviTip FX irrigation vs Vibringe sonic irrigation | 24.25-5.06 | 29.31 | 0.001* |
| NaviTip FX irrigation vs EndoVac irrigation | 22.84-7.42 | 30.26 | 0.001* |
| EndoVac irrigation vs Vibringe sonic irrigation | 23.16-8.04 | 32.20 | 0.782 |
| Intergroup comparison | Mean rank | Mann-Whitney U-test | p value |
|---|---|---|---|
| NaviTip FX irrigation vs Vibringe sonic irrigation | 24.50-7.16 | 31.66 | 0.001* |
| NaviTip FX irrigation vs EndoVac irrigation | 23.28-6.12 | 29.40 | 0.001* |
| EndoVac irrigation vs Vibringe sonic irrigation | 22.08-6.05 | 28.13 | 0.972 |
| Intergroup comparison | Mean rank | Mann-Whitney U-test | p value |
|---|---|---|---|
| NaviTip FX irrigation vs Vibringe sonic irrigation | 26.22-8.84 | 35.06 | 0.001* |
| NaviTip FX irrigation vs EndoVac irrigation | 25.39-7.82 | 33.21 | 0.001* |
| EndoVac irrigation vs Vibringe sonic irrigation | 24.48-9.14 | 33.62 | 1.210 |
This research thus implies that EndoVac irrigation systems exhibit probableen couraging results in their capability to eliminate Ca(OH)2 from the root canals at the apical third meticulously pursued by the Vibringe sonic irrigation and NaviTip FX irrigation system in that order.
DISCUSSION
Ca(OH)2 paste has an extremely alkaline pH and is an inorganic intracanal medicament. It is highly popular because of its antibacterial effectiveness as well as compatible biologic characteristics. Nevertheless, inability to completely eliminate Ca(OH)2 from the root canals causes buildup of its residues on the walls of the canals that can lead to enhanced canal permeability. This can further impede the sealing efficiency of root canal sealers, finally resulting in endodontic treatment failure. It has additionally been documented that residual Ca(OH)2 within the canals may chemically interact with ZOE sealers with resultant formation of weak calcium eugenolate avoiding sealer penetrability, finally leading to improper bonding of resin sealer to the dentinal surface.8 Therefore, every interappointment medication placed within the canal must be meticulously eliminated prior to obturation.
Various techniques to determine the quantity of residual Ca(OH)2 in the root canal walls have been used like stereomicroscope, computed tomography (CT), digital photographs, SEM, micro and spiral CT.9 For the purpose of this research, SEM assessment was done with the sample teeth being examined under 1000× magnification employing a scoring system. Lambrianidis et al.4 and Kuga et al.10 have employed a comparable method previously, inferring that the scoring structure is rather dependable in comparison with area calculation techniques owing to the challenges in differentiating Ca(OH)2 in certain portions of the dentinal walls because of color likeness.
Irrigation with sodium hypochlorite in the absence of activation has been documented to be insufficient for the elimination of Ca(OH)2 from radicular canals due to restricted capability to liquefy inorganic substances.11 Margelos et al.12 have shown that the use of 15% EDTA solution or sodium hypochlorite only for irrigation does not eliminate Ca(OH)2 competently from the root canals, though a blend of two irrigating solutions along with hand equipment enhances the elimination capacity. Thus, in this study, it was proposed to assess the efficiency of dissimilarirrigation systems along with NaOCl/EDTA use for the elimination of Ca(OH)2 off the root canals.
In this research, the EndoVac irrigation method exhibited higher capability to take off Ca(OH)2 from root canals in the apical third region, pursued by Vibringe sonic irrigation and NaviTip FX irrigation techniques in that order. Likewise, Turker et al.13 found that EndoVac irrigation demonstrated significantly superior capability in eliminating Ca(OH)2 from the apical third region of the canals. This efficiency is due to an enhanced mechanical flush effect and vacuum aspiration phenomenon exhibited by EndoVac. Additionally, the microcannula openings aid as an exit pathway for Ca(OH)2 leading to its efficient elimination from the apical portion of the radicular canal. Ahmetoglu et al.14 inferred that the EndoVac irrigation proposes secure and valuable cleansing of Ca(OH)2 in the apical third of the radicular canal.
Yücel et al.15 came to a conclusion later that EndoVac irrigation method enhanced elimination of Ca(OH)2 from the coronal, middle, and apical portions leading to better cleaning of the radicular canal walls.
The highest Ca(OH)2 elimination capacity was exhibited by the EndoVac system of irrigation in contrast to the Vibringe sonic irrigation. Schoeffel16 have cited that in the process of sonic action, the acoustic process and cavitation consequence are absent in situations where the active tips release the irrigant and makes contact with apical gas bubble, leading to incomplete cleaning effect. Also in sonic method, less dislodgement amplitude (1.2 ± 0.1 mm) of the tip employed leads to insufficient fluid motion and results in reduced cavitation referred to as the vapor lock effect, and the less energy present is not enough in the overcurrent.17 In this research, though the tip of the sonic irrigation device was positioned near the apex, low effectiveness could have resulted from the vapor lock effect that arises in the radicular canals and hampers the motion of the irrigant. Even so, the Vibringe sonic system does not have an ergonomic design and possesses a big integrated syringe organization, making it challenging for the clinician to use with shortened activation.
In this research, despite using dissimilar irrigant activation methods, total elimination of Ca(OH)2could not be achieved at the apical portion of the root canal. This can be attributed to the dentinal tubular nature that is inherently few in number and irregular.
The limitations of this research are due to its design of being an in vitro study. Such in vitro studies are pioneer researches to assess the efficiency in an appropriately controlled lab atmosphere employing test replicas and in the absence of human participants. This research was performed with less sample size. Thus, further research with higher sample size is recommended.
CONCLUSION
Amid the limitations of this research, this research concludes that none among the irrigation methods employed could totally eliminate the Ca(OH)2off the root canals. Nevertheless, EndoVac apical negative pressure irrigation has slightly superior potential in eliminating Ca(OH)2 from the root canals in comparison with Vibringe sonic irrigation as well as the NaviTip FX irrigation system.
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