|Year : 2019 | Volume
| Issue : 1 | Page : 63-67
Effect of continuous soft chelating irrigation protocol on removal of smear layer
Vibha Hegde, Pranav Thakkar
Department of Endodontics and Conservative Dentistry, Y. M. T Dental College, M. D. S Endodontics and Conservative Dentistry, Mumbai, Maharashtra, India
|Date of Web Publication||19-Jun-2019|
Prof. Vibha Hegde
401 Shobha Suman, M. M. Malviya Road, Mulund (West), Mumbai - 400 080, Maharashtra
Source of Support: None, Conflict of Interest: None
Aim: The purpose of this study was to compare the efficacy of continuous soft chelating irrigation protocol with conventional irrigation protocol.
Methodology: sixty extracted single-rooted human teeth were randomly divided into 5 groups (n =12) and instrumented using Protaper Universal nickel-titanium rotary instruments. In conventional irrigation group each canal was subsequently irrigated with 5.25% NaOCl followed with 17%EDTA (Group A), SmearClear (Group B) or SmearOFF (Group C). After that, all the specimens were subjected to irrigation with 5.25% NaOCl. In continous soft chelating irrigation group The irrigation while instrumentation and after instrumention was done with Chloroquick Low (9% hebp + 3% NaOCl) (Group D) and Chloroquick High (18% hebp + 5.25% NaOCl) (Group E). teeth were then processed for scanning electron microscopy (SEM), and the removal of the smear layer was examined in the coronal, middle, and apical thirds.
Result: The efficacy of various agents for smear layer removal was assessed by comparison of groups using Kruskal Wallis ANOVA and Mann- Whitney U test. The results showed that there were no significant differences in Conventional irrigation protocol groups and continuous irrigation protocol group at coronal and middle thirds of root canals but at apical third Chloroquick High was able to remove more smear layer statistically when compared to all the groups (p_0.029).
Conclusion: this in-vitro study both the protocols conventional as well as continuous soft chelating irrigation protocols were able to remove smear layer at coronal and middle third of the root canals but at apical third only continues soft chelating irrigation protocol performed with Chloroquick High shows better removal of smear layer.
Keywords: Ethylenediaminetetraacetic acid, etridonic acid, smear layer, smearclear, smearoff
|How to cite this article:|
Hegde V, Thakkar P. Effect of continuous soft chelating irrigation protocol on removal of smear layer. Endodontology 2019;31:63-7
| Introduction|| |
Literature is suggestive that the dentin wall gets covered with smear layer after shaping of the root canals with instruments., Disregarding the controversy over its retention, it has been recognized that the smear layer itself may be infected and may protect the bacteria within the dentinal tubules. Smear layer not only contains organic components but also has an inorganic component in the form of dentin chips and the debris which prevents the penetration of intracanal disinfectants and sealers into dentinal tubules, which in turn affects the final seal of the root canal filling.,,
Irrigants are of paramount importance of complete debridement of the root canals with mechanical instrumentation. Studies have shown there is no single potent solution appropriate for removing both organic and inorganic parts of the smear layer. To eliminate this smear layer, a mix of sodium hypochlorite (NaOCl) and a strong chelating agent such as ethylenediaminetetraacetic acid (EDTA) is recommended. Crumpton et al. proposed that complete removal of smear layer can be achieved by 17% EDTA for 1 min followed by 5.25% NaOCl., On the other hand, the application of a strong chelating agent like EDTA for more than a min and 1 ml of volume has been reported to be associated with dentinal erosion.,
Smearclear (Sybron Endo, Orange, CA, USA) is a product introduced for eliminating the smear layer. It contains 17% EDTA solution in conjunction with a cationic (cetrimide) and an anionic surfactant to improve its action. SmearOFF (Vista Dental Products) is proprietary EDTA and chlorhexidine mix. It is prepared with a combination of wetting agents and surface modifiers for the best outcomes. These solutions are used only as a final rinse.
Etridonic acid (HEBP) which is a soft chelating agent that appears to have a nominal effect on dentine walls and still acts on the smear layer. Lottanti et al. showed that HEBP could be used in combination with NaOCl without affecting its proteolytic or antimicrobial properties., In contrast to EDTA, HEBP is a weak decalcifying agent and hence cannot be used as a mere final rinse; therefore, it is suggested that HEBP has to be mixed with NaOCl to be used as a complete root canal irrigation solution. Chloroquick (innovationsendo, India) is a combination of NaOCl and HEBP. Chloroquick high contains 18% HEBP and 5.25% NaOCl, whereas chloroquick low contains 9% HEBP and 3% NaOCl both need to be premixed with surfactant tween 80 for a complete root canal irrigation solution.
Therefore, this study aims to compare the efficacy of continuous soft chelating irrigation protocol with the chloroquick solutions to conventional irrigation protocol on smear layer removal in coronal, middle, and apical thirds of the instrumented root canals.
| Materials and Methods|| |
Sixty freshly extracted human premolar teeth with single and straight root canal were preferred and stored in distilled water. Average root length of 12 mm was retained by decoronating the teeth and then divided into five groups (n = 12) randomly. Working length was determined with #10 K-files and deduction of 1 mm was done from recorded root length as a safety factor.
- Group A EDTA (control) – 1 ml of 17% EDTA for 1 min followed by 3 ml of 5.25% NaOCl
- Group B smear clear (EDTA + surfactants) – 1 ml of smear clear (Sybron Endo, Orange, CA) for 1 min followed by 3 ml of 5.25% NaOCl
- Group C smear off (EDTA + Chlorhexidine + surfactant) – 1 ml of smear off (Vista dental,) for 1 min followed by 3 ml of 5.25% NaOCl
- Group D chloroquick low (HEBP + NaOCl) – 1 ml of chloroquick low solution (9%HEBP + 3%NaOCl) for 1 min and final rinse with 3 ml same solution
- Group E chloroquick high (HEBP + NaOCl) – 1 ml of chloroquick high solution (18%HEBP + 5.25%NaOCl) for 1 min and a final rinse with 3 ml of the same solution.
Conventional irrigation protocol was pursued for the first three groups. After using each file and before proceeding to the next canals were irrigated with 2 ml of 5.25% NaOCl. After instrumentation, all teeth underwent final irrigation as mentioned in GROUP A, B, and C.
Continuous soft chelating irrigation protocol was followed for two groups Group D and Group E. After the use of each file, canal was irrigated with 2 ml of respective chloroquick solution. After instrumentation, all teeth underwent final irrigation as mentioned above.
In-between two solutions, 5 ml of distilled water was used for rinsing canal walls and solutions were introduced with the help of a 30G side vented needle (innovationsendo), which penetrated within 1–2 mm from the working length. At the end, 5 ml of distilled water were used to rinse root canal walls which were dried with paper points.
At the end of the entire procedure, two longitudinal grooves were prepared with the help of diamond disc without cutting into the canal. Grooves were prepared on the buccal and lingual surfaces of each root. A Chisel was used for splitting the teeth. Then, the specimens were mounted on the metallic stubs and investigated under a scanning electron microscope (FEI Quanta 200 FE-SEM MK2, Netherlands). Images were obtained at ×2000 at coronal (9 mm to apex), middle (6 mm to apex), and apical (3 mm to apex) third of each specimen.
Scoring criteria used was given by Torabinejad, Khademi et al. where scores were given as follow score 1 = no smear layer; all tubules were clean and open and smear layer was absent on the surface of the canals; score 2 = moderate smear layer; smear layer was not present on the surface of the canal, but debris were present in tubules; score 3 = heavy smear layer; the debris were observed in tubules and smear layer enclosed the dentin wall surfaces.
An endodontist who was unaware of groups and coding evaluated and scored all the images to exclude observer bias. The repeated evaluation was done to ensure intra-examiner consistency.
| Results|| |
Descriptive statistics were expressed as numbers for each group. The efficacy of various agents for smear layer removal was assessed by comparison of groups using Kruskal–Wallis ANOVA and Mann–Whitney U-test. In the above tests, P ≤ 0.05 was taken to be statistically significant. All analyses were performed using SPSS software (ver. 20; SPSS Inc., Chicago, IL, USA).
The results for smear layer scores in each group at the coronal, middle, and apical are conferred in [Table 1], [Table 2], [Table 3]. The examination of the surface of the root canal walls at coronal third groups showed less or no smear layer [Figure 1], and there was no statistically significant difference (P = 0.643). Most samples at middle thirds showed no smear layer or minimal smear layer present [Figure 2], and there was no statistically significant difference at the middle layer of root canals (P = 0.615). Chloroquick high group showed better smear layer removal at the apical thirds [Figure 3]. Chloroquick high showed statistically significantly better results (P = 0.029) as compared to the other groups. Mann–Whitney U-test displayed that chloroquick high can remove better smear layer compared to chloroquick low (P = 0.028). Choloroquick low has related chelating ability as compared to other solutions with no statically significant difference at apical third.
|Table 1: Efficacy of various agents in smear layer removal in the coronal third of the canal|
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|Table 2: Efficacy of various agents in smear layer removal in the middle third of the canal|
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|Table 3: Efficacy of various agents in smear layer removal in the apical third of the canal|
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|Figure 1: Scanning electron microscope images of coronal third treated with all the irrigating agent groups|
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|Figure 2: Scanning electron microscope images of middle third treated with all the irrigating agent groups|
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|Figure 3: Scanning electron microscope images of apical third treated with all the irrigating agent groups|
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| Discussion|| |
This examination provides an insightful understanding of the smear layer removal capability of conventional irrigation protocol and continuous soft chelating irrigation protocol. Satisfactory irrigation, disinfection, and obturation are the main principles of root canal treatment. Accumulation of smear layer is observed while shaping of canals which need tobe eliminated with the help of irrigating solutions. The objective of using an irrigant to reduce the smear layer from the canal wall cannot be obtained by the use of a sole irrigating solution. Therefore, the combined application of multiple irrigating solutions is mandatory for optimal removal of smear layer. The novel chloroquick solution is a mix of HEBP (a soft chelating agent) and NaOCl which can disinfect root canals as well as reduce smear layer. The highlight of such combination of NaOCl and HEBP is that the NaOCl does not surrender its biological, antibacterial, and tissue dissolving properties,, whereas the reduction and elimination of the inorganic element are done with the help of HEBP.,
The outcome of this current research reveals eradication of smear layer was more decisive in middle and coronal third in comparison to the apical third. These results are in accordance with the study done by Abbott, et al. and numerous studies, which have proven to have an effective cleaning action in the middle and coronal third of the root canals regardless of the nature of irrigation solutions, volume, and time.,, In coronal and middle third areas where a large canal diameter allows better flow of irrigants, efficient fluid dynamics and greater time of contact with dentine surface facilitates the irrigant to act on the smear layer comprehensively.,,
Role of surfactant has been discussed and reviewed by numerous authors, in the current study smearclear, smearoff and chloroquick contains surfactant. Abou-Rass and Patonai confirmed that reduction of surface tension of endodontic solutions improved their flow into slender and narrow root canals. Thus, an improved penetration into apical complexities of canals can be seen with the addition of surfactants to irrigation solution. In the present study, smearclear and smear off despite having additional surfactant do not show the significant removal of smear layer in the apical third when compared to the control group of 17% EDTA, which does not have any additional surfactant. This result is in accordance with the observations of Lui et al. and also, other studies which have shown that calcium chelating ability of the solution is not improved by reducing the surface tension of the solution.
Results of the present study display that, the continuous soft chelating irrigation shows the significantly better removal of smear layer than conventional irrigation protocol at the apical third level when 18% HEBP was used in combination with 5.25% NaOCl (chloroquick high). Whereas 9% HEBP in combination with 3% NaOCl (chloroquick low) did not show any significant difference when compared to conventional irrigation protocol groups. These results can be attributed not only to the chelating agent being in the canal for a longer time but also to the chelating procedure occurring while instrumentation, unlike conventional irrigation protocol where removal of smear layer is done only once instrumentation is completed. Paqué et al. revealed that the accumulation of hard tissue debris in root canals when irrigated with an amalgamation of NaOCl and etradonic acid was significantly less than when irrigation was performed with 2.5% NaOCl alone. Another advantage of this combination is that it has better tissue dissolution capacity by keeping the hypochlorite-hypochlorous acid equilibrium toward hypochlorite., This combination is effective on the inorganic as well as organic part of smear layer at the same time.
A study performed by De-Deus et al. on the impact of strong (MTAD) or soft HEBP chelating solution on the bond strength of resilon epiphany root canal sealers. It was demonstrated that a soft chelating irrigation protocol optimizes bonding quality of the sealers because of the better opening of dentin tubules which were covered with the smear layer.
The result of this study is in contrast to the recently published research by Kuruvilla et al. where 7%malic acid was significantly efficient in eliminating the smear layer as compared to 17% EDTA and 18% etidronic acid. This observation may be attributed to the fact that 18% etidronic acid which is a soft chelating agent was merely used as a final rinse irrigation protocol and not combined with sodium hypochlorite.
There is limited literature available on the use of the continuous soft chelating agent for smear layer removal. Future research should be aimed toward the effect of both these protocols on the dentinal walls of the root canal. In the present study, continuous soft chelating irrigation protocol has shown promising results to eliminate the smear layer.
| Conclusion|| |
Within the constraint of this present in-vitro study, both conventional, as well as continuous soft chelating irrigation protocols, were able to remove the smear layer at coronal and middle third of the root canals. At apical third, continuous soft chelating irrigation protocol accomplished with chloroquick high (18%HEBP) showed the better removal of smear layer.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]