Comparative Evaluation of Microhardness, Water Sorption and Solubility of Biodentin and Nano-Zirconia-Modified Biodentin and FTIR Analysis

Round 1

Reviewer 1 Report

The main question addressed in the research “Comparative evaluation of microhardness, water sorption, solubility of biodentin, nanozirconia modified biodentin and FTIR analysis” is how the addition of zirconia in different wt% affects microhardness, water sorption, and solubility of Biodentin.

Biodentin contains zirconium oxide, and its addition to the material has been studied in the context of increasing radiopacity, but according to the available literature the modification with additional zirconia and its influence on solubility, water sorption and microhardness has not been studied so this study brings some new findings.

There are a number of issues that need to be addressed:

ABSTRACT

Results in the abstract- it is not clear which group(s) exhibited significantly different properties compared to the control group. For example. ‘’ Group 3 had the highest mean microhardness measurement compared to Biodentin (Control group), followed by Groups 2 and 4 (P = 0.008).'' Does this mean that microhardness was significantly higher in all experimental groups compared to the control group? Since you gave just one p value, this implies that the microhardness differed significantly between groups in general. Consider summarizing microhardness results like this: Microhardness was significalntly higher in group 3 than in Biodentin (control) group (p=0.043), while the difference between control group and other two experimental groups was not significant (p>0.05).

Similarlly, for other two properties.

Absorbance peaks fell between 474.63 and 3438.33 what does that mean which species are between the peaks?

conclusions in the abstract are not in accordance with the results.

It is stated that Biodentin lacks hardness and solubility. Solubility is not a desirable property. This statement is not supported by the results of this study.

INTRODUCTION

Generally, the first paragraph of the Introduction section should rewritten. There are many problematic statements which are not justified with relevant references. For example “pulp vitality” is not a property of a material, there are no materials that could be classified as the “materials that replace dentin layer” Calcium silicate-based cements do not have excellent mechanical properties, and are not replaced with natural tissues, etc.

 

I suggest you start with describing hydraulic calcium silicates (HCS) as materials and listing the procedures in dentistry where they are indicated. Note that bioactivity (forming bond with living tissues and precipitating apatite like crystals in phosphate containing solution in vitro) is the most important comparative advantage of HCSs.

Biodentin was well described, but include its other properties besides hardness, and avoid formulations like “extraordinary properties”.

The paragraph explaining the properties could better be moved up. Explain why these properties are important and how they could improve clinical performance of Biodentin as a “dentin substitute”, and in its other clinical indications (as pulp capping agent, dentin tissue replacement, furcation repair material, retrograde filling)

Zirconia was well described, but these two sentences “Nanotechnology has revolutionized dentistry by enhancing material proper[1]ties and has put forward many improvements to study, visualize and develop new mate[1]rials or revise the existing ones at an extremely small level. Currently, many nanomaterials are accessible in dentistry, like nano GIC, Nano zirconia, Chitosan, Endo sequence BC sealer, nanocarbon, and nano silver [7]“ are out of place and should better be deleted.

The end of the introduction is well written but add references when you state that there are studies where zirconia was added to different materials. Also, state your null hypotheses.

 

MATERIALS

Section 2.1.

As I understand, you had weight percentages wt%, and not volume percentages  

 

Section 2.4

Hydration is enabling HCSs to set. Leaving the samples dry for 24 h might be a problem. Maybe the initial measurement should have been performed after the initial setting after 12-15 minutes after which the samples should have been placed in 100% moisture.

RESULTS

In Results there is some duplicity. For example, no need for Figure 2. All the information is in Table 4. Also, Figure 3. Is more informative than table 6 where some information is duplicated. Similarly, Table 8 and Figure 4.

 

CONCLUSIONS are not supported by the results. Solubility is increased in experimental groups, water sorption was reduced in some experimental groups, microhardness was increased in only one experimental group so the conclusion that the addition of nano-zirconia to Biodentin increases microhardness does not stand.  

Author Response

We would like to thank the academic editor and reviewers for taking their precious time to review this manuscript and give us comments. We would like to explicitly state that we agree with all the comments as these helped us improve the quality of our paper. We have made a conscious effort to answer all the remarks in the paper as advised by the reviewers and highlighted changes with red colour in the revised manuscript for their convenience. Changes have been carried out in the revised manuscript.

 

Author Response File: Author Response.docx

Reviewer 2 Report

This manuscript is conducted to determine the microhardness, water sorption, and solubility of nano zirconia reinforced groups in different percentages to biodentine, which concludes that a 20% addition of nano zirconia to biodentine is considered the ideal ratio for enhancing microhardness. Furthermore, with the addition of nano zirconia the water sorption was reduced but the solubility of nano zirconia added to biodentine was almost equal to biodentine.

However, there are some concerns.

1. The conclusion and discussion are not accurate and overall. For example, the conclusion part mentioned that adding nano zirconia has improved the microhardness and less water sorption properties. However, there are upper limits to the addition of nano zirconia followed by the authors' experiments.

2. In the discussion of FTIR results, the authors pointed out that there are some free molecules in group 2 and group 4, as the absorption band shows 3643.26 cm^-1. Why do only 2 and 4 have free molecules? Please analyze and discuss the reasons, and the conclusions that the FTIR can provide, such as the difference between Group 1 and other groups, or whether the absorption peak of the group changes, etc.

3. Why are both microhardness and solubility compared with group 4 instead of group 1 with pure biodentine?

4. I am confused that why 30% zirconia reduces its microhardness so much. It is suggested to discuss and analyze other factors to affect the microhardness of the addition of nano zirconia except for the uneven distribution in the materials. Besides, if there has been a study of the addition of nano-zirconia between 20% and 30%, such as 25%?

5. The aspects of characterization are not comprehensive enough, and it is suggested to add more characterizations, for example, radiation permeability, acid resistance, mechanical strength or impact resistance, etc.

6. The abstract is a bit verbosity and unclear; it needs to be revised.

7. Please pay attention to the writing of the units, especially in the note in Figure 1.

Author Response

We would like to thank the academic editor and reviewers for taking their precious time to review this manuscript and give us comments. We would like to explicitly state that we agree with all the comments as these helped us improve the quality of our paper. We have made a conscious effort to answer all the remarks in the paper as advised by the reviewers and highlighted changes with red colour in the revised manuscript for their convenience. Changes have been carried out in the revised manuscript.

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Dear authors,

 

thank You for considering the suggestions. Introduction is much improved and results are better presented with conclusions being supported by the results. However, the manuscript would benefit if a native English speaker would edit the text. 

Best regards

Reviewer 2 Report

The authors have improved the manuscript and solved my previous concerns. In this case, I would like to recommend the acceptance of this revised version.