|Year : 2021 | Volume
| Issue : 4 | Page : 267-271
Effect of root canal irrigants on calcium silicate cements: An In vitro study
Astha Agrawal, Anika Mittal, Shifali Dadu, Aditi Dhaundiyal, Nikita Tyagi
Department of Conservative Dentistry and Endodontics, Inderprastha Dental College and Hospital, Ghaziabad, Uttar Pradesh, India
|Date of Submission||21-Oct-2020|
|Date of Decision||17-Dec-2020|
|Date of Acceptance||20-Jan-2021|
|Date of Web Publication||08-Oct-2021|
Department of Conservative Dentistry and Endodontics, Inderprastha Dental College and Hospital, Sahibabad, Ghaziabad, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Aim: The objective of the study was to compare the effect of different irrigation regimes on push out bond strength of calcium silicate cements – Biodentine and mineral trioxide aggregate (MTA). Materials and Methods: Forty-eight human teeth with single root canals were divided into three groups according to irrigation regimes. Each canal was irrigated with 5 ml of each irrigant during and after biomechanical preparation as follows: 3% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid; 3% NaOCl during and Q mix 2 in 1 after instrumentation and distil water as the control group. Canals were filled with biodentine and MTA accordingly. A horizontal middle root section of 1.5-mm thickness was taken, and analysis was done under the universal testing machine. Statistical Analysis Used: The statistical analysis was done by the one-way analysis of variance and post hoc Tukey test. The comparative analysis was done by using the independent t-test. Results: The push-out bond strength of 3% NaOCl + Q mix 2 in 1 was highest. The least was of the control group. Conclusion: The irrigation regimes have a differential effect on root canal sealers.
Keywords: Biodentine, mineral trioxide aggregate, push-out bond strength, Q mix 2 in 1, smear layer, sodium hypochlorite
|How to cite this article:|
Agrawal A, Mittal A, Dadu S, Dhaundiyal A, Tyagi N. Effect of root canal irrigants on calcium silicate cements: An In vitro study. Indian J Dent Sci 2021;13:267-71
|How to cite this URL:|
Agrawal A, Mittal A, Dadu S, Dhaundiyal A, Tyagi N. Effect of root canal irrigants on calcium silicate cements: An In vitro study. Indian J Dent Sci [serial online] 2021 [cited 2021 Oct 19];13:267-71. Available from: http://www.ijds.in/text.asp?2021/13/4/267/327811
| Introduction|| |
Chemomechanical preparation plays a vital role in endodontic therapy. The irrigants are able to render a microbe-free environment, stimulating healing procedure. Root canal conditioning affects the characteristics of dentin, affecting the adhesion of dentin and root canal filling materials.
Smear layer produced during root canal shaping impedes the infiltration of sealer into the dentinal tubules compromising the adhesion of obturating materials. Specific irrigation protocols should be followed for its removal.,
Sodium hypochlorite (NaOCl) is commonly used for irrigation due to its antibacterial and disinfecting property. Apart from NaOCl, several others irrigants are also used, ethylenediaminetetraacetic acid (EDTA) and its various formulations, tetracycline, organic acids such as maleic acid, citric acid, and tannic acid.
EDTA due to its chelating property forms soluble complexes with calcium ions, dissolving the smear layer. The effect of EDTA is negligible in the apical portion of the root canal. Furthermore, EDTA also affects the adhesive strength of resin cements.,
A new novel irrigating solution has been developed-Q mix 2 in 1 for final irrigation. The composition is EDTA, chlorhexidine, and surfactant. The working time is 60–90 s. It is less aggressive and completely eliminates the smear layer and smear plugs. It kills >99.99% of Enterococcus faecalis. The storage life of solution is 2 years at the room temperature.
Tricalcium silicate-based cements such as mineral trioxide aggregate (MTA) are biocompatible and can be used for vital pulp therapy, as root end filling material, perforation repair, and as root canal sealers.
MTA came into market in 1998. The composition is tricalcium silicate, dicalcium silicate, tricalcium aluminate, tetracalcium aluminoferrite, calcium sulfate, and traces of bismuth oxide. It is biocompatible with tissues, have excellent sealing and antibacterial properties. However, it has major drawbacks like difficulty in handling, can cause potential tooth discoloration, and has long-setting time.
To overcome the drawbacks of MTA, biodentine was developed by Septodont in 2009. It is composed of tricalcium silicate, calcium carbonate, zirconium oxide, and a water-based liquid-containing calcium chloride as an accelerator. Calcium chloride in liquid acts as an accelerator reducing the setting time to 9–12 min.,
Bond strength and dislodgment resistance of the root canal sealers are the two crucial factors determining the success of endodontic therapy. The push-out bond strength assesses the bond strength of a restorative material to radicular dentin.
The influence of Q mix on the adhesive strength of tricalcium silicate cements to radicular dentin has not been investigated. Hence, the objective of this in vitro study was to the evaluate the effect of 17% EDTA, 3% NaOCl, and Q mix 2 in 1 when used with different irrigation protocols on the push-out bond strength of biodentin and MTA to root dentin.
Null hypothesis states that no significant difference was found in the dislodgment resistance of biodentin and MTA.
| Materials and Methods|| |
Forty-eight extracted single rooted teeth were selected as the sample size and divided into two groups according to material used. Radiographs were taken from the two aspects: The buccal and mesial to check for calcifications.
- Single rooted teeth with straight canal
- Mature and fully formed apices.
- Curved canals
- Calcified canals/fused roots
- Root canal treated teeth
- Root caries.
The debris was removed, and the extracted teeth were stored in normal saline till further use. The teeth were decoronated using a diamond disc. The working length was calculated using a K file. A 10 K file was inserted in the root canal up to the apical foramen, such that it was slightly visible at the apex. To calculate the final working length, 1 mm was subtracted from the recorded length as “safety allowance.” Sticky wax was used to seal the apices forming a closed end system, simulating the intraoral environment and allowing the reverse flow of irrigants.
The samples were divided into two groups: 1 and 2 according to the material being used, using the randomization method.
- BIODENTINE (n = 24)
- MTA (n = 24)
These groups were subdivided into three groups (n = 08) according to the irrigation regimen
- The distilled water group: 5 mL distilled water for 1 min between instrumentation/final rinse of 5 mL distilled water for 1 min
- The NaOCl/EDTA group: 5 mL 3% NaOCl for 1 min and 5 mL 17% EDTA (Smear Clear, Kerr) for 1 min during instrumentation with a final rinse of 5 mL distilled water for 1 min
- The NaOCl/Q mix group: 5 ml 3% NaOCl for 1 min after every instrument/final rinse with 5 ml Q mix 2 in 1 for 1 min.
The biomechanical preparation was done with ProTaper rotary system (DENTSPLY Sirona) up to a size of F3 using the crown down technique. Irrigation was performed using a 27G side-vented needle inserted 1 mm short of the working length. The canals were dried with paper points.
MTA (MTA Angelus, Brazil) was mixed in the ratio of 3:1 (Powder: liquid ratio) using distill water. Biodentine (Septodont) was mixed with a powder: liquid ratio of 1 capsule of powder to 5 drops of liquid. The materials were condensed in increments using an amalgam carrier and pluggers, obturating the canals. The cut surface of decoronated sections was cleaned using a sterile cotton swab. Radiographs of obturated roots were taken to ensure that the canals were densely obturated, free of voids.
Pushout bond strength
A horizontal section of 1.5 ± 0.1 mm thickness was obtained from the middle root region of each using a hard-tissue microtome. The diameter and height of each slice was recorded. Universal testing machine was used for push out bond strength. The force was applied in apico-coronal direction at a crosshead speed of 1 mm/min using a stainless-steel plunger of 0.6 mm so that they contacted the filling material only. The maximum force (F) applied at bond failure was recorded in Newtons. The push-out bond strength was calculated in mega-Pascal using the following formula:
The adhesion surface area is calculated as 2¶rh
Where ¶ is a constant value, i.e., 3.14
r is radius of the slice
H is height of the slice
All collected data were entered in MS excel and analyzed. The statistical software SPSS version 16.0 for Windows (SPSS Inc., Chicago, IL, USA, 2001) was used for the analysis of data. Push-out bond strength data were analyzed using the one-way analysis of variance and post hoc Tukey test for intragroup comparison. The intergroup comparative analysis was done by the independent test. The 95% confidence interval and 5% level of significance was used for the analysis of data.
| Results|| |
The irrigants and irrigation regime do have a differential effect of the calcium silicate cements used. The difference in push-out bond strength of both irrigants and filling materials were highly significant (P < 0.01). Multiple intragroup comparisons were done by the one-way analysis of variance and post hoc Tukey resulted in Group 1C and 2C, the Q mix group with highest push-out bond strength. The mean value observed was 15.666 and 14.815 in Groups 1 and 2, respectively. The least was shown by the control group, i.e., the distilled water group (Group 1A and 2A) with a mean value of 8.536 and 7.406 [Figure 1] and [Figure 2]. On intergroup comparison, Biodentine (Group 1) showed significantly higher push-out bond strength when compared with MTA (Group 2) with respect to all irrigants used in the study [Figure 3]. The mean values of all the irrigants used on the study are summarized in [Table 1].
|Figure 1: Bar diagram with intragroup comparison of Group 1 (Biodentine). Group 1C (3% sodium hypochlorite + Q mix 2 in 1) showed maximum resistance to dislodgment|
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|Figure 2: Bar diagram with intragroup comparison of Group 2 (Mineral trioxide aggregate). Group 2C (3% NaOCl + Q mix 2 in 1) showed maximum resistance to dislodgment|
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|Figure 3: Bar diagram with intergroup comparison between Groups 1 and 2. Group 1 (Biodentine) has higher push out bond strength than Group 2 (mineral trioxide aggregate)|
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|Table 1: Distribution of mean in both the groups showing biodentine is better than mineral trioxide aggregate|
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| Discussion|| |
In the present study, the effect of various irrigants on tricalcium-based cements was compared and evaluated. It was concluded that the irrigants have a variable effect on the bond strength of sealers. Hence, the null hypothesis was invalid.
Among the irrigants used, Q mix 2 in 1 (Group C) showed the maximum push-out bond strength (P < 0.01) followed by EDTA/NaOCl (Group B) and least was in Group A (control group).
The improved performance of Q mix was due to the chelating property of EDTA resulting in increased demineralization of radicular dentin. The surfactant in Q mix lowers the surface tension, increasing its wettability, thus enhancing the flow of irrigant, removing the smear layer and disinfecting dentin., This allows the penetration of sealers in the dentinal tubules. 2% chlorhexidine is responsible for the antimicrobial activity of Q mix. Chlorhexidine adsorbs onto dentin, thus preventing microbial colonization on the dentinal surface, enhancing the anti-microbial property.
The neutral pH of Q mix makes it less corrosive to calcium silicate hydrate crystals. Thus, increasing the cohesiveness of the crystalline structure, improving the dislocation resistance and microhardness of the set cement.
EDTA due to its acidic nature affects the setting of calcium silicate cements. It forms complexes with calcium ions released from the tricalcium silicate. It reduces the micro-hardness and flexural strength of the silicate cement. It combines with calcium ions from the surrounding radicular dentin causing dentinal erosion reducing the hardness of dentin. It dissolves the cements thus affecting the bonding of root canal filling materials to dentin. Hence, poor adhesion due to EDTA.
The dentinal erosion is accelerated with NaOCl used in combination with EDTA. The organic matrix of radicular dentin acts as a limiting factor preventing further dissolution of EDTA. The NaOCl used in combination with EDTA causes dissolution of organic portion, thus accelerating dentinal erosion.,
EDTA has a detrimental effect on hydration of calcium silicate cements. The set cement has a less crystalline and more porous surface due to dissolution of crystalline components. This reduces the strength of tricalcium silicate cements. EDTA dissolves the smear layer and infiltrate into the interfacial layer, interfering with chemical adhesion between the calcium silicate cements and radicular dentin.
Gade et al. concluded similar results stating that Q mix showed a least negative effect on bonding of tricalcium silicate cements to radicular dentin when compared with 17% EDTA.
Elnaghy A also concluded that Q mix 2 in 1 does not have any effect on bond strength of Biodentine and MTA to root dentin. However, Biodentine showed higher dislodgment resistance than MTA.
NaOCl has a proteolytic action; hypochlorous acid so formed is responsible for its tissue-dissolving property. The chlorine and hydroxyl ions released are strong oxidant with broad-spectrum antimicrobial activity. The high pH due to the presence of hydroxyl ions interferes with cell membrane integrity of the bacterial cell, disrupting the cellular metabolism, causing cell lysis.
The reason for low strength is that NaOCl interferes with crystallization of calcium silicate cements resulting in poor adhesion to dentin. It also has low smear removal property. The color stability of MTA is also affected by NaOCl. Bismuth oxide, a component of MTA on exposure to NaOCl reacts and reduces to Bismuth metal, resulting in dark-brown black precipitate and NaOCl is reduced to sodium chloride.
In the present study, Biodentine showed increased dislodgment resistance than MTA (P < 0.05) as it forms tag-like structures, resulting in increased bond strength. According to Han and Okiji, calcium and silicon ions are released into dentin, forming micro-tags increasing the resistance of Biodentine.
The calcium silicate-based materials form apatite-like crystals at the dentine-cement interface and within the dentinal tubules. This results in the formation of tag-like structures and a hybrid layer responsible for chemical adhesion. The bond strength of these cements is directly proportional to the calcium content of the material.
The higher calcium ion release of biodentine is responsible for higher bind strength. The leaching of calcium ions of biodentine is higher because of higher proportion of tricalcium silicate than MTA.
These findings coincide with the study done by Guneser et al. comparing the outcome of root canal irrigants on the adhesive strength of biodentine with other root repair materials. Biodentine showed higher resistance to dislodgment forces when compared to GIC and MTA. Exposure to NaOCl, chlorhexidine, and saline solutions had no effect on Biodentine.
According to Yahya, Biodentine showed better results when compared with MTA and glass ionomer cement when exposed to Q mix, MTAD, and saline. All the irrigants reduced the bond strength of MTA.
The results were contrary to the study done by Alsubait. They evaluated the effect of 2.5% NaOCl on push out bond strength of ProRoot MTA, Biodentine, EndoSequence repair material and NeoMTA plus. NaOCl used in the study accelerated the hydration of MTA and increased its strength. NaOCl used in this study decreased the setting time of MTA increasing its push out bond strength. The irrigant also results in hydration of remaining unreacted particles increasing the strength of the set cement.
However, biodentine is good alternative to MTA with improved properties. The small particle size and less water content result in better interlocking of Biodentine within dentinal tubules. The low water content makes it denser and more homogeneous than MTA.
- The sample size is limited which might have affected the results.
| Conclusion|| |
The force needed to dislodge biodentine was higher when compared to MTA. The irrigation protocol followed during endodontic therapy influences the bonding of cements to radicular dentin. In this study, also the push-out bond strength of calcium silicate sealers was differentially influenced by various irrigation regimes. The use of 3% NaOCl and Q mix 2 in 1 enhanced the bond strength of calcium silicate sealers to root dentin when compared with other groups.
Taken from ethical committee of Inderprastha Dental College & Hospital, Sahibabad.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]