Silver Nanoparticles–Chitosan Nanocomposites as Protective Coatings for Dental Remineralization Treatment: An In Vitro Study

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Please compare the literature analysis results of the last 5 years in the introduction section and explain in detail the superior contribution of this research to the literature

 

-Please do not forget to write the unit in the citation section of the manuscript below

The lowest value was achieved using the FV + AgNPs + CG treatment with a reduction from 72.5 to 4.75. The means v..................

 

-Comment the letter symbols for the statistical analysis results in Table 1 together with the results

 

-Please improve the image resolution of the x-ray analysis results in Figure 2

 

-Take care that all images are at the same magnification scale in the SEM analysis results

 

-The conclusion section should be rewritten as it is quite insufficient

 

-Also, add a table in the discussion section comparing the findings with the literature results

 

-Please make suggestions that can guide future research in the conclusion section

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

Please compare the literature analysis results of the last 5 years in the introduction section and explain in detail the superior contribution of this research to the literature

Introduction section was expanded to provide an analysis of the literature in the las 5 years (resalted text in the introduction section lines 48-78). The contribution of this study was detailed in conclusion section lines 397-401.

Please do not forget to write the unit in the citation section of the manuscript below

The lowest value was achieved using the FV + AgNPs + CG treatment with a reduction from 72.5 to 4.75. The means v..................

The reason why this values have no units is that values obtained using Diagnodent pen are unitless. For clarity, the following lines were modified in section 2.5 (lines 127-129).

The DIAGNOdent pen 2190 (DIAGNOdent pen, Kavo, Biberach, Germany) was used according to the manufacturer's recommendations, this is a device which measures the depth of the caries lesion and gives a unitless numerical value

Comment the letter symbols for the statistical analysis results in Table 1 together with the results

Letter symbols in Table 1 are commented in lines 210-218

Please improve the image resolution of the x-ray analysis results in Figure 2

The resolution of Figure 2 was improved.

Take care that all images are at the same magnification scale in the SEM analysis results

SEM images are now in the same magnification for a better understanding of the SEM analysis results. 

The conclusion section should be rewritten as it is quite insufficient

The conclusion section has been rewritten.

Also, add a table in the discussion section comparing the findings with the literature results

Table 3 was added in discussion section with 8 extra references.

Please make suggestions that can guide future research in the conclusion section

The conclusion section has been rewritten and now it contains some perspectives for future research.

Reviewer 2 Report

Comments and Suggestions for Authors

See the attachment

Comments for author File: Comments.pdf

Author Response

1. In the introduction, the discussion of prior studies on fluoride varnishes and alternative materials (e.g., chitosan, silver nanoparticles) could be expanded to provide a broader context.

The introduction section has been expanded to provide a broader context of the prior studies using fluoride, chitosan and nanoparticles.

This expansion is resalted in lines 48 – 78.

2. Authors provide insufficient explanation of why this combination (FV + AgNPs + CG) is unique or better compared to existing methods.

The explanation is now detailed in conclusion section.

3. The use of verbal consent instead of written consent may raise ethical concerns, as verbal consent is less documented.

The protocol of this study was approved by the Research Ethics Committee of the Faculty of Dentistry of the University of El Salvador with the Document Number:

CEI- FOUES/2022/003.

The 61 healthy teeth used in this work were extracted for orthodontic reasons without any relation to this protocol. The patients were informed and they donated with a verbal consent their pieces for this study.

This last paragraph was added at line 91 for a better comprehension.

4. The EDX results are described but not shown, which limits the evaluation of elemental changes in detail.

EDX results are now included as supplementary file and the evaluation of elemental changes can be done with detail.

5. The impact of using AgNPs and chitosan on potential cytotoxicity or long-term effects is not considered.

Our research group have explored the cytotoxicity of this sort of nanoparticles, that is, gallic acid stabilized 9 nm silver nanoparticles and we have found a low impact both in vitro and in vivo studies.

A paragraph mentioning these studies has been added in line 375.

6. The results of FV combined with AgNPs and CG are promising but lack a detailed mechanistic explanation of how these materials interact at the enamel surface.

The following paragraph (line 296) has been added in the discussion section dealing with the mechanistic aspects of remineralization of this study:

The mechanism of remineralization under in vitro conditions has been studied elsewhere but there is still not an agreement among researchers.  According to Enax et al. (2024), “…It has been conclusively shown by such in vitro crystallization studies under well-defined conditions that additives can influence nucleation and crystal growth of calcium phosphate even at low concentrations…” [50]. In our research we found that the presence of silver nanoparticles promotes a different sort of compounds in the crystallization products (see DRX results) due to a heterogeneous precipitation process and also, it is well known the great affinity of silver to fluoride and the presence of silver fluoride in low concentrations not detectable by XRD can influence the remineralization process, a research in this area is also needed

7. Figure 2 resolution is very low.

The resolution of Figure 2 was improved.