Hydration Characterization of Two Generations of MTA-Based Root Canal Sealers
Round 1
Reviewer 1 Report
The manuscript entitled ‘Hydration Characterization of Two Generations of MTA-based 2 Root Canal Sealers’ submitted to Applied Science journal is related to important materials used in dental practice. After reading the manuscript, I have the following (the most important) critical comments:
- The introduction does not really introduce the reader to the subject of the work to an appropriate degree. It is too general and very simple.
2. Setting a time test in this work based on the very old ASTM standard (30 years) recommended to completely different materials. It is hard to explain why the authors used this method (they did not try to explain it), when we have ISO 6876:2012(en) Dentistry - Root canal sealing materials, where the setting time test was described. Why are the experiments not based on this method, even with modification? Why was the experiment (setting time) conducted at room temperature not at body temperature as it is recommended in ISO standard? This is a significant difference because the temperature affects the setting time, and therefore testing in this way causes the results to deviate from the reality. This is important considering the journal to which you submitted the article. Such results are of limited cognitive value and, from a practical point of view, mislead clinicians.
3. The rest of the methods are too weakly described; no references are given. Very long time intervals of the control points at which the measurements were performed.
4. The setting time in the results sections looks strange to me. For example, for is marked NA* - in other studies, also based on similar method, similar results were not rot registered, e.g. Vitti et al. - working time – 0,5h, initial setting time 2,3 h, final setting time 4.55 h - these results are similar than declared by manufacturer, unlike yours. It seems to know that this experiment was poorly made. The authors did not try to explain it.
5. ‘Regarding the setting time, both MTA-Bioseal and Adseal complied with ISO standards however MTA-Fillapex failed to fulfil the ideal requirement described by Grossman’ - you didn’t use method by ISO... Please also note (again) that ISO required 37 ° C and no less than 95% RH – you didn’t use that conditions.
6. The discussion is in some parts interesting, but the problem is that the experiments were conducted under different conditions than they should have been, which significantly reduces the value of the results and discussions obtained. These problems have not been mentioned/discussed at all.
7. As a result, after reading all of it, I cannot say that I feel enriched and, moreover, I have serious doubts about the method of conducting the research, and thus the results themselves.
Other: There are many too general statements in the paper, e.g. " (...) there was no obvious indentation on sealer", they are too numerous to list them all.
Author Response
The manuscript entitled ‘Hydration Characterization of Two Generations of MTA-based 2 Root Canal Sealers’ submitted to Applied Science journal is related to important materials used in dental practice. After reading the manuscript, I have the following (the most important) critical comments:
- The introduction does not really introduce the reader to the subject of the work to an appropriate degree. It is too general and very simple.
It was modified.
- Setting a time test in this work based on the very old ASTM standard (30 years) recommended to completely different materials. It is hard to explain why the authors used this method (they did not try to explain it), when we have ISO 6876:2012(en) Dentistry - Root canal sealing materials, where the setting time test was described. Why are the experiments not based on this method, even with modification? Why was the experiment (setting time) conducted at room temperature not at body temperature as it is recommended in ISO standard? This is a significant difference because the temperature affects the setting time, and therefore testing in this way causes the results to deviate from the reality. This is important considering the journal to which you submitted the article. Such results are of limited cognitive value and, from a practical point of view, mislead clinicians.
I agree with the reviewer, it is already performed according to ISO 6876 and ADA specification # 57 as readjusted within the manuscript. According to the recommendation of reviewer, reference of ASTM was deleted. The room temperature (23 ± 1oC) was applied only during the application of Vicat needle at the surface of mixed sealer. The missed statement was added; “The mixed sealer was inserted inside the mold that packed between two glass plates then inserted into the incubator at 37oC and 95% humidity. After 30 minutes the molds get out the incubator to apply the Vicat needle at room temperature (23 ± 1oC). Then they reinserted inside the incubator. The periodic reading was repeated every 15 minutes to determine the initial and final setting time.”
- The rest of the methods are too weakly described; no references are given. Very long time intervals of the control points at which the measurements were performed.
The methods were modified. Plz check section 2.1
- The setting time in the results sections looks strange to me. For example, for is marked NA* - in other studies, also based on similar method, similar results were not rot registered, e.g. Vitti et al. - working time – 0,5h, initial setting time 2,3 h, final setting time 4.55 h - these results are similar than declared by manufacturer, unlike yours. It seems to know that this experiment was poorly made. The authors did not try to explain it.
Although final set of MTA-Fillapex was determined by Vitti etal (≈4.55 hr) that nearly simiar to that described by manufacturer, other previous studies (Lee et al 2017 and Benezra et al 2017) revealed that it did not set indefinitely.
- ‘Regarding the setting time, both MTA-Bioseal and Adseal complied with ISO standards however MTA-Fillapex failed to fulfil the ideal requirement described by Grossman’ - you didn’t use method by ISO... Please also note (again) that ISO required 37 ° C and no less than 95% RH – you didn’t use that conditions.
The procedure was already followed the ISO 6876 and ADA specification # 57 as described in section 2.1.
- The discussion is in some parts interesting, but the problem is that the experiments were conducted under different conditions than they should have been, which significantly reduces the value of the results and discussions obtained. These problems have not been mentioned/discussed at all.
The experiments were conducted under the same conditions as described by ISO 6876 and ADA specification # 57 as described in details
- As a result, after reading all of it, I cannot say that I feel enriched and, moreover, I have serious doubts about the method of conducting the research, and thus the results themselves.
Plz read the methods after adding the missing issue of the procedures. The mixed materials were inserted in incubator (at 37 oC/ humidity) except when the Vicat needle was applied. Then reinsert again in the incubator
Other: There are many too general statements in the paper, e.g. " (...) there was no obvious indentation on sealer", they are too numerous to list them all.
Corrections and English editing done.
every time the needle was applied to the smooth surface.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Thank you for your submission. I have several questions.
1.- You described the use of 10 mm polyhetylene molds and the Vicat needle of the same diameter, how was you able to check the needle penetration?
2.- Page 2 Line 60: fix the word manufacturer.
3.- How was you able to measured using FTIR & XRD on Meta fillapex at 4 and 24 hours, if it wasn't set?
4.- please don't use hrs, use hours.
5.- You mentioned ISO 6875, it is 6876 for endodontic sealers. Please explained and make reference on how silicate based sealers were added to this standardization.
6.- Please do a detailed explanation on how you provided the humitity to allow sealers to set.
Author Response
Comments and Suggestions for Authors
Thank you for your submission. I have several questions.
1.- You described the use of 10 mm polyhetylene molds and the Vicat needle of the same diameter, how was you able to check the needle penetration?
There is a millimeter scale on the device representing its penetration.
2.- Page 2 Line 60: fix the word manufacturer.
It was done
3.- How was you able to measured using FTIR & XRD on Meta fillapex at 4 and 24 hours, if it wasn't set?
The FTIR was applied on the same mix at different intervals, immediate, 4 hours and 24 hours for the three tested sealers. The spectra of final set of Adseal and MTA-Bioseal was recorded according to the result of Vicat final setting time. Regarding MTA-Fillapex, it was subjected to initial set, but failed to final set. So, the specta of final set was recorded after 3 months where it can be milled. While XRD was applied to all the material after 3 months.
4.- please don't use hrs, use hours
It was done.
5.- You mentioned ISO 6875, it is 6876 for endodontic sealers. Please explained and make reference on how silicate based sealers were added to this standardization.
Thank you for your mention, it was corrected.
The standardization was described in section 2.1
6.- Please do a detailed explanation on how you provided the humidity to allow sealers to set.
It was described in detail in the methodology; “The mixed sealer was inserted inside the mold, the mold packed between two glass plates then inserted into the incubator at 37oC and 100% humidity. After 30 minutes the molds get out the incubator to apply the Vicat needle at room temperature (23 ± 1oC). Then reinserted inside the incubator. The periodic reading was repeated every 15 minutes to determine the initial and final setting time.”
Author Response File: Author Response.pdf
Reviewer 3 Report
Dear authors,
I appreciate your effort to conduct this study. I am little bit embarrassed whether this manuscript support or to refuse. What I am the most missing in the manuscript is something new, the novelty. That you measured some values corresponds to a technical report rather than a scientific article.
The discussion of the results is more of a description of the measured values, nothing scientific.
The typos and English must be corrected. Please also check abbreviations (ARD..) and keep uniform layout for units (cm-1 vs. cm-1). Keywords are missing..
The text in paragraph 3.1 or the Table 1 - one of them can be omitted as one duplicates the other more or less.
Can you explain how you measured the hardness (on line 89)?
What you wanted to express by asterixes in Table 1 (on both rows)?
Have you documented indentation marks from indentation by Vicant needle? It would be maybe beneficial for reader to show it.
Figure one: please add label on x-axis.
The sentence "There were no further changes after 24 hrs (Figure 1C)" is not right. I see difference between FTIR spectra after 24 hrs and as final set roughly at 900 cm-1.
You have written in discussion that humidity is affecting the setting time of resins, but no mention in experimental part.
I hope that you can improve your manuscript to achieve higher quality level to be published in impacted journal.
Author Response
Dear authors,
I appreciate your effort to conduct this study. I am little bit embarrassed whether this manuscript support or to refuse. What I am the most missing in the manuscript is something new, the novelty. That you measured some values corresponds to a technical report rather than a scientific article.
I appreciate your concern, but what we were interested in is its efficacy.
The technical data that was discussed in this article are important deciding factors as the by-product of setting reaction initiat all biological behaviour (such as antimicrobial activity, biological compatibility, osteogenic potentiality and bioactivity that initiate hydroxyapatite formation) that are essential for success of the outcome of clinical treatment using such materials in root canal treatment.
The discussion of the results is more of a description of the measured values, nothing scientific.
Within the discussion section, the result of setting time was described and compared with the result of other previous studies and explained by the finding of FTIR and XRD that described the byproduct of setting reaction that initiate the biological activity of such sealer during endodontic treatment.
The typos and English must be corrected. Please also check abbreviations (ARD..) and keep uniform layout for units (cm-1 vs. cm-1). Keywords are missing..
It was done, plz check line ----- and keywords
The text in paragraph 3.1 or the Table 1 - one of them can be omitted as one duplicates the other more or less.
It was done, plz check line----- and table 1
Can you explain how you measured the hardness (on line 89)?
The hardening means complete setting that determined by Vicat needle as no indentation was observed. So the word “hardening” was replace by “setting”
What you wanted to express by asterixes in Table 1 (on both rows)?
It was added
Have you documented indentation marks from indentation by Vicant needle? It would be maybe beneficial for reader to show it.
The device of Vicat needle contain millimetre scale, it was described within the manuscript
Figure one: please add label on x-axis.
It was done, plz check figure 1
The sentence "There were no further changes after 24 hrs (Figure 1C)" is not right. I see difference between FTIR spectra after 24 hrs and as final set roughly at 900 cm-1.
It was corrected
You have written in discussion that humidity is affecting the setting time of resins, but no mention in experimental part.
The missing issue in methodology was described in details as described in manuscript
I hope that you can improve your manuscript to achieve higher quality level to be published in impacted journal.
The correction was done
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have introduced some explanations, but I am still not satisfied with some explanations.
"Although final set of MTA-Fillapex was determined by Vitti etal (≈4.55 hr) that nearly simiar to that described by manufacturer, other previous studies (Lee et al 2017 and Benezra et al 2017) revealed that it did not set indefinitely."
So what are you suggesting? The manufacturer provides incorrect and false data, misleading customers? Or maybe something went wrong in your experiment that you got these results? This matter needs to be clarified. After all, this cannot be left like that and the problem must be identified.
You write "it was suggested that MTA-Fillapex could not set when stored dry", but your storing work was not under dry conditions, so this explanation is not true.
The question also arises: if your experimental conditions interfered with the proper seting of the material, is the experiment plausible?
Where are the problems and what is the truth?
It's hard for me to believe that this material has been on the market for so many years ... and can't setting completely as you suggest. .
How will readers benefit from this work?
Author Response
Comments and Suggestions for Authors
The authors have introduced some explanations, but I am still not satisfied with some explanations.
"Although final set of MTA-Fillapex was determined by Vitti etal (≈4.55 hr) that nearly simiar to that described by manufacturer, other previous studies (Lee et al 2017 and Benezra et al 2017) revealed that it did not set indefinitely."
So what are you suggesting? The manufacturer provides incorrect and false data, misleading customers? Or maybe something went wrong in your experiment that you got these results? This matter needs to be clarified. After all, this cannot be left like that and the problem must be identified.
We did not conflict with the manufacturer information. Our result is not the only finding such this data, it was supported by others (Lee et al 2017 and Benezra et al 2017) [Lee JK, Kwak SW, Ha J-H, Lee W, Kim H-C. Physicochemical properties of epoxy resin-based and bioceramic-based root canal sealers. Bioinorg Chem Appl. 2017, 2017. + Benezra MK, Wismayer PS, Camilleri J. Influence of environment on testing of hydraulic sealers. Sci Rep. 2017, 7(1):1-11.] who determined that MTA-Fillapex did not set indefinitely.) If the suggestion of reviewer is true as our result went wrong in the experiment, what out of the experiment of these two studies (lee et al 2017 & Benezra et al 2017).
The next paragraph was added in discussion section:
“Both the setting times of the sealer are proposed to depend on their compositions, temperature and humidity[45]; it was suggested that the calcium silicate sealers MTA-Fillapex could not set when stored dry [46]. The MTA-Fillapex is a premixed injectable paste of hydraulic calcium silicate sealer, containing water-free thickening vehicle[12]. For its hydration reaction, it needs water to permit final set and maximum hardness. According to Lee et al 2017[13], the humid incubator condition was not sufficient for a complete setting of such hydraulic sealers (MTA-Fillapex). However, in a clinical situation, when such sealer inserted in the root canal, the dentinal tubules are filled with fluid that enhances its hydration reaction and complete setting. This fact can explain the failure of MTA-Fillapex setting during the environment of the current study.”
You write "it was suggested that MTA-Fillapex could not set when stored dry", but your storing work was not under dry conditions, so this explanation is not true.
The question also arises: if your experimental conditions interfered with the proper seting of the material, is the experiment plausible?
Where are the problems and what is the truth?
Yes, I agree with the reviewer as the condition of the current study was not dry, but at humidity of incubator. However, according to Loushine et al 2011 and Lee et al 2017, the humid incubator condition does not sufficient as a moisture environments to enhance the final setting reaction. The explanation was added as shown in line 190
It's hard for me to believe that this material has been on the market for so many years ... and can't setting completely as you suggest. .
How will readers benefit from this work?
The same results were obtained by several studies Lee et al 2017, Benezra et al 2017.
As described in conclusion section; the benefit is that “Since the premixed MTA-Fillapex root canal sealer contains water-free vehicle, during clinical situation, a sufficient moisture environment is essential for complete set of such sealer”.
Author Response File: Author Response.pdf
Reviewer 3 Report
"all biological behaviour (such as antimicrobial activity, biological compatibility, osteogenic potentiality and bioactivity that initiate hydroxyapatite formation) that are essential for success of the outcome of clinical treatment using such materials in root canal treatment."
None of the mentioned above study solves, only the description that some sealers were set and another was not. The explanation why is missing.
Photos from the curing process and indentation places after using the Vicat needle are missing. The scientific contribution is zero. Only reporting on measured values, which is completely insufficient for a scientific article in an impact journal.
Author Response
Comments and Suggestions for Authors
The English was rechecked
"all biological behaviour (such as antimicrobial activity, biological compatibility, osteogenic potentiality and bioactivity that initiate hydroxyapatite formation) that are essential for success of the outcome of clinical treatment using such materials in root canal treatment."
None of the mentioned above study solves, only the description that some sealers were set and another was not. The explanation why is missing.
The explanation was added in discussion section line 190:
Photos from the curing process and indentation places after using the Vicat needle are missing. The scientific contribution is zero. Only reporting on measured values, which is completely insufficient for a scientific article in an impact journal.
I am not sure I understand what the reviewer means, do we need to add an image of the discs after application of vicat needle? Unfortunately, It is not available because the discs were milled for XRD analysis. The data of FTIR support the results of Vicat test.
Moreover, I think it is not nessessary to add as there is no previous study published in impact journal (e.g Vitti et al 2013) added such images.
Author Response File: Author Response.pdf
Round 3
Reviewer 1 Report
After improving the discussion, it looks much better. I accept your corrections.
Author Response
Thank you for your effort to revise our manuscript
Reviewer 3 Report
No more comments from my side.
Author Response
Thank you for your effort to revise our manuscrpit
