Enamel Erosion Reduction through Coupled Sodium Fluoride and Laser Treatments before Exposition in an Acid Environment: An In Vitro Randomized Control SEM Morphometric Analysis

Round 1

Reviewer 1 Report

Good day,

Dear Authors,

Thank You for a pleasure to read Your work.

 

I have several comments to improve Your article.

 

Abstract

Background. It is the aim of your study, as I understood

Please, add at least one sentence about the work actuality.

 

Results. Please, add results of our comparisons between groups and explain the nature of a described amorphous substance because it is not clear.

 

Materials and methods

 

Why did you use exactly spring water for samples preparations? Line 137

 

Lines 173-185. Please, write besides companies also country and city of manufacture.

 

Line 191. Please, check it

 

Legend for figures. Please, create from this description exactly legend. In this form it is more appropriate for Results text. You have all legends in Appendix A.

 

Please, remove in this section ‘Statistics analysis’, also, with explanation of sample size counting.

 

Results

 

There are not all possible comparisons between groups, please, add them.

 

Also, please, think about use of ANOVA for all for groups besides paired tests.

 

Discussion

 

Do you mean in case of amorphous material exactly the amorphous layer which appears before laser use?

 

Please, add the explanation of the amorphous substance in the article beginning for better understanding of the work results.

 

Sincerely, Reviewer

 

Author Response

Dear Reviewer,

Thank you for reading our manuscript and sending your advice to us

 I tried to reply to comments and advices 

You wrote: Abstract

Background. It is the aim of your study, as I understood

Please, add at least one sentence about the work actuality.  Thanks for your advice.

                                                    We added a sentence about what currently prompted our research.

 

You wrote:  Results. Please, add results of our comparisons between groups and explain the nature of a described amorphous substance because it is not clear.

                          We added the comparison between groups and we have tried to describe amorphous substance. In addition We have changed Amorphous substance in amorphous layer

 

You wrote: Materials and methods

 Why did you use exactly spring water for samples preparations? Line 137.

                            We apologize for the mistake, We used distilled water to rinse our samples and not spring water

 

You wrote:  Lines 173-185. Please, write besides companies also country and city of manufacture.

                         Thanks , we added companies, country e city of manufacture for materials and equipment used

 You wrote: Line 191. Please, check it.  We cheeked this line

 You wrote: Legend for figures. Please, create from this description exactly legend. In this form it is more appropriate for Results text. You have all legends in Appendix A.

                                                                              We added “Legend for figures”

 

You wrote:  Please, remove in this section ‘Statistics analysis’, also, with explanation of sample size counting.

                                                                            Thanks we corrected this section

 You wrote: Results

 There are not all possible comparisons between groups, please, add them.

                                                          it was not possible to compare the results with group X, because the prisms of enamel were not highlighted because masked by an amorphous layer.

 

Also, please, think about use of ANOVA for all for groups besides paired tests.                                 We preferred the T test with paired comparison in two groups because our software does not have the ANOVA test. However I added the test results.

 

Discussion

 

Do you mean in case of amorphous material exactly the amorphous layer which appears before laser use?

                                                     We mean by amorphous layer, the formation of a amorphous material on the surface of the enamel that did not allow a distinct identification of the prisms of the enamel after it was preliminary treated with the fluoride gel in association with laser irradiation.

Please, add the explanation of the amorphous substance in the article beginning for better understanding of the work results.

                                                      Thanks, We have added an possible explanation  for amorphous layer.

                                                    Thanks again for you collaboration and to have spent your time for me

Sincerely, Felice Femiano

 

Reviewer 2 Report

The aim of this study was to evaluate the erosion-inhibiting potential of a diode laser irradiation and topical fluoride used alone or in combination on the enamel surface of extracted teeth before being exposed to an acidic environment 

English should be revised in order to improve quality of the overall manuscript.

When strong statement are declared please provide references at the end (Ex. line 48-49) 

Please be a little more specific in the material & methods regarding the explanation of the procedures and the technical details of the materials/instrument (Ex. Model of the SEM?)

The number of 40 molars seems to be aleatory since there are no details about the sample-size calculation. Was sample-size calculation performed before the start of the study?

Some parts regarding the explanation of the randomization and the procedures are a bit repetitive and might sound convoluted.

It is always recommended to synthesize the data into graphics or tables.

Author Response

Dear Reviewer,

Thank you for reading our manuscript and sending your advice to us

 

The aim of this study was to evaluate the erosion-inhibiting potential of a diode laser irradiation and topical fluoride used alone or in combination on the enamel surface of extracted teeth before being exposed to an acidic environment 

You wrote: English should be revised in order to improve quality of the overall manuscript.

                                                                        Thanks, We have tried improve English

You wrote:  When strong statement are declared please provide references at the end (Ex. line 48-49):

                                                                     We added more references

You wrote: Please be a little more specific in the material & methods regarding the explanation of the procedures and the technical details of the materials/instrument (Ex. Model of the SEM?).

                                                                    Thanks, We added these requests

You wrote: The number of 40 molars seems to be aleatory since there are no details about the sample-size calculation. Was sample-size calculation performed before the start of the study?

                                                                   Thanks for this question: We performed the sample size calcolation: a sample consisting of 90 samples of NCCLs  with DH will have a power of 80% to be able to demonstrate an effect size of 30% with a Wilcoxcon test for paired samples and with a first type error of 0, 05.

You wrote: Some parts regarding the explanation of the randomization and the procedures are a bit repetitive and might sound convoluted.

                                                      We have tried to clarify this section by eliminating of repetitive and convoluted parts.

You wrote: It is always recommended to synthesize the data into graphics or tables.

                                                         We have tried to synthesize the data in figures

Thanks and regards

Felice Femiano

Reviewer 3 Report

Dear Authors, The work presented for evaluation undoubtedly refers to the important, from the cognitive and clinical point of view, issue of improving the resistance of tooth enamel to the erosive influence of an acidic environment. Unfortunately, the work contains a number of errors that prevent it from being submitted for publication. Here they are: 1. Contrary to the thesis contained in the title, the text does not contain any results confirming the effectiveness of the applied treatments modifying the composition and properties of the enamel. Relying on similar works by other authors is far from sufficient. 2. The assumption made in the study that the density of enamel prisms differs under the influence of fluoridation and / or laser beams is untrue from the beginning. The spatial arrangement and dimensions of the prisms are an inherent feature of the enamel and cannot, for example, change their packing density. Various chemical or physical interactions only help to "reveal" the internal architecture of the enamel, without changing the geometry of the prisms. 3. SEM images of the enamel taken with a slight magnification do not add any additional value. The shown striae of Retzius can be easily found in the extensive literature on the subject. 4. It is not clear how the authors counted the enamel prisms. Pits appear in the SEM images, which, according to the authors, are formed in the central part of the prisms, seem insufficient. However, effective counting of prisms is only possible when their boundaries are revealed. According to the reviewer's experience, it is possible at higher magnifications, i.e. above 1500, because then the inter-prismatic substance is also revealed, showing the boundaries between the prisms. 5. The results of the statistical evaluation do show differences between the groups, but this is probably due to individual variability, certainly not due to the effect of the treatments used on the enamel. Resolving this dilemma would require the use of a paired test (4 test variants on the same tooth). Moreover, the small sample size (10 teeth for each group) raises some concerns. It would be worthwhile 6. The calculated number of prisms per 1000 micrometers is also questionable. Assuming the size of 3-5 micron prisms, which is dominant in the literature, these values should be significantly greater than those given in the work of several items. 7. The unpaired Student's t-test is not an appropriate test in the described case. The multiple comparison test, i.e. ANOVA or non-parametric equivalent, should be used in the absence of homogeneity of variance.

Author Response

Dear Reviewer,

Thank you for reading our manuscript and sending your advice to us

 

You wrote: 1. Contrary to the thesis contained in the title, the text does not contain any results confirming the effectiveness of the applied treatments modifying the composition and properties of the enamel. Relying on similar works by other authors is far from sufficient.  I cannot reply if this is your belief

 

2. The assumption made in the study that the density of enamel prisms differs under the influence of fluoridation and/or laser beams is untrue from the beginning. The spatial arrangement and dimensions of the prisms are an inherent feature of the enamel and cannot, for example, change their packing density. Various chemical or physical interactions only help to "reveal" the internal architecture of the enamel, without changing the geometry of the prisms.

                                          We intended to highlight that due to preliminary procedures such as the use of topical fluoride in gels and lasers used individually or in combined modalities on the enamel, there is a change in the chemical and structural properties of the enamel on the surface. This is responsible for the increased mechanical resistance of enamel in opposition to the erosive action in an acid environment. We changed this in the test

 

3. SEM images of the enamel taken with a slight magnification do not add any additional value. The shown striae of Retzius can be easily found in the extensive literature on the subject. I cannot reply if this is your belief

 

4. . It is not clear how the authors counted the enamel prisms. Pits appear in the SEM images, which, according to the authors, are formed in the central part of the prisms, seem insufficient. However, effective counting of prisms is only possible when their boundaries are revealed. According to the reviewer's experience, it is possible at higher magnifications, i.e. above 1500, because then the inter-prismatic substance is also revealed, showing the boundaries between the prisms.. I cannot reply if this is your belief

 

5. The results of the statistical evaluation do show differences between the groups, but this is probably due to individual variability, certainly not due to the effect of the treatments used on the enamel. Resolving this dilemma would require the use of a paired test (4 test variants on the same tooth). Moreover, the small sample size (10 teeth for each group) raises some concerns. It would be worthwhile

                                    Our study was conducted in the same way  that you recommended. In fact, to avoid individual variability, each face of the dental crown was used for the construction of a study group, in this way it was possible to apply 4 different pre-treatments on each dental crown. For this way, our study sample consisted of 40 teeth with 4 study groups each of 40 samples

 

6. The calculated number of prisms per 1000 micrometers is also questionable. Assuming the size of 3-5 micron prisms, which is dominant in the literature, these values should be significantly greater than those given in the work of several items.

                                         We would like to clarify that the text was reporting a type error. The prisms number was reported per 1000 µm². An area of 1000 µm² corresponds to a rectangle of approximately 33 µm x 33 µm. Accordingly, the number of exposed prisms in a square of 33 µm x 33 µm are likely to be a number around 4 to 10

 

7. The unpaired Student's t-test is not an appropriate test in the described case. The multiple comparison test, i.e. ANOVA or non-parametric equivalent, should be used in the absence of homogeneity of variance. Dear Reviewer, we added the ANOVA test too even if our groups presented homogeneity

 

Thanks and regards

Felice Femiano

Reviewer 4 Report

I have reviewed the manuscript “Enamel erosion reduction through coupled sodium fluoride and laser treatments before exposition an acid environment: an in-vitro randomized control SEM morphometric analysis.” submitted to “Applied Sciences” for publication. In this study, the authors have evaluated the effect on enamel of a combined fluoride gel and diode laser compared to single procedure before of immersion in an acid solution.  This is a well-designed and well conducted study and the manuscript fits well within the scope of the journal; it needs some major improvements; there are a few suggestions that authors may consider to improve it further:

The use of English language is reasonable, however, there are a number of punctuation and grammatical errors; that should be corrected and rephrased using academic English for a better flow of text for reader.

Abstract: is structured and to the point: the aim of the study should be rephrased for further clarity. early, more information about methodology and results (key findings) can be included to further improve. The authors should be consistent in using p-values  with the 4 or 5 digit points.

Introduction is very comprehensive and detailing all the background information and rationale of the study.

Authors should make sure that all the figures are cited in the text.

Figure 5 should be completely edited on Page 7.

All results figures should be moved to results section instead of methods sections.

Line 201: “The results were expressed as percentages in numeric data” however, I could not find any, could you please cite, which data is referred here?

Further studies should be included in the discussion section as only a limited number of studies are incorporated at present. Some related studies can be found from the literature.

The effects of acid etching time on surface mechanical properties of dental hard tissues." Dental Materials Journal (2015): 2014-083.

Applications of light amplification by stimulated emission of radiation (lasers) for restorative dentistry." Medical Principles and Practice 25.3 (2016): 201-211.

There is no mention of the limitation of the study. Authors should add limitations of the study and describe future directions of this research.

Conclusion section should be precise and to the point; authors may consider adding a separate section for the conclusions.  

Author Response

I have reviewed the manuscript “Enamel erosion reduction through coupled sodium fluoride and laser treatments before exposition an acid environment: an in-vitro randomized control SEM morphometric analysis.” submitted to “Applied Sciences” for publication. In this study, the authors have evaluated the effect on the enamel of a combined fluoride gel and diode laser compared to the single procedure before immersion in an acid solution.  This is a well-designed and well-conducted study and the manuscript fits well within the scope of the journal; it needs some major improvements; there are a few suggestions that authors may consider to improve it further:

Dear Reviewer, We are delighted that you enjoyed our research work. We thank you for your valuable suggestions that will help us improve our manuscript.

The use of the English language is reasonable, however, there are a number of punctuation and grammatical errors; that should be corrected and rephrased using academic English for a better flow of text for the reader.

Thanks for your comment, the article has been reviewed by a native English speaker to remove any lacks present

Abstract: is structured and to the point: the aim of the study should be rephrased for further clarity. early, more information about methodology and results (key findings) can be included to further improve. The authors should be consistent in using p-values with the 4 or 5 digit points.

Thanks for the comment. We rephrased the aim of the paper in the abstract and considered all p-values with 4 points

The introduction is very comprehensive and details all the background information and rationale of the study.

Thank you for your positive review

Authors should make sure that all the figures are cited in the text.

Thank you for your suggestion. Yes, they are.

Figure 5 should be completely edited on Page 7.

Thank you for your suggestion. We move it.

All results figures should be moved to the results section instead of the methods section.

Thanks for your comment. We believe that Figures 1 to 4 help us to clarify and explain the materials and methods of the study, so we think we can leave them in the same position. Let's move to figure 5, instead, following your advice.

Line 201: “The results were expressed as percentages in numeric data” however, I could not find any, could you please cite, which data is referred to here?

Thanks for your comment. We have removed the sentence because we believe it is redundant in the text

Further studies should be included in the discussion section as only a limited number of studies are incorporated at present. Some related studies can be found in the literature.

The effects of acid etching time on surface mechanical properties of dental hard tissues." Dental Materials Journal (2015): 2014-083.

Applications of light amplification by stimulated emission of radiation (lasers) for restorative dentistry." Medical Principles and Practice 25.3 (2016): 201-211.

Thanks for your suggestions, the references have been inserted into the text

There is no mention of the limitation of the study. Authors should add limitations of the study and describe future directions of this research.

Thanks for your comment we have inserted the following sentence: “Certainly, the limitations of our study are the in vitro protocol and that the data obtained from our research require studies with a larger number of samples, but we believe that we can advance the possibility of recommending a standardized protocol that can be used for the prevention of enamel demineralization to be used in patients who have a structural alteration of the enamel, who are taking drugs for therapeutic purposes that cause a costant decrease in salivary pH or who have limited oral hygiene options”

The conclusion section should be precise and to the point; authors may consider adding a separate section for the conclusions.  

Thank you very much for your comment, we have proceeded to insert a section dedicated to the Conclusions as you suggested.

Round 2

Reviewer 3 Report

Dear Authors,

The errors indicated by me in the review, and especially the assumption about the existence of a relationship between the packing density of the prisms and the use of erosive interaction, are irremovable. In fact, this is also apparent from the replies to the comments submitted in the review.
I stand by my decision to reject the submitted article.

Author Response

Dear reviewer thank you for your answer.

I am sorry that you remain in your position but I want to clarify.

In our article, the following sentence is reported: “The mean number of prisms x 1000µm² was 7.2 units”. The units of prisms were reported per area and not for linear measurement. An area of 1000 µm² corresponds to a rectangle of approximately 33 µm x 33 µm. Considering that a prism could have a diameter of 7- 8 µm and an area of about 30-100 µm², in our section we can find a mean of 7-9 units of prisms.

Reviewer 4 Report

Dear authors,

Many thanks for the revision; just one more minor point:
Please delete "In studies conducted by Mostafa Abdallah B et al. in 2019" from the line 337 and cite references [21,23-24] after the statement.