Effect of Glazing Protocol on the Surface Roughness and Optical Properties of Lithia-Based Glass-Ceramics

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Abstract:

1.        Please add quantitative results to emphasis your study

2.        Please add a "take-home" message in the abstract that can introduce the novelty and motivate readers.

Introduction:

1.      Please The limitations of similar prior studies must be explained in the introduction section to highlight the research gaps that the current study aims to fill.

2.      The authors need to elaborate on previous literature, including their previous work, recruiting similar conceptualization and/or methodology to address this research

3.        The authors mentioned that “Thus, the objective of this study was to evaluate the effect of different firing protocols on the surface roughness and optical properties of two lithium disilicates. The null hypotheses state that different firing protocols would promote [1] different surface roughness and would negatively affect [2] color stability and [3] translucency parameters when submitted to different pigment solutions.” . It would be better to add the expected surface roughness in the commercial products

4.        Describe the novelty of the article made by the author.

Materials and methods:

1.        Please indicate the number of samples used to investigate in each experiment

Results:

1.        Please highlight the important results of your study

2.        Please concise and point out the key interesting points from each experiment.

3.        Please indicate A B C in Ra (mean ± sd) (Table 3)

4.        No SD represented in Figure 1, Figure 2, and Figure 3

5.        The number in Y Axis should be . not ,

Discussion

The outcomes must be compared to similar past research. The authors already added the previous research. However, the discussion in the present article needs to improve to become more comprehensive.

Conclusion

Please indicate the limitations of this study

 

References are not in the order. Please check 

Author Response

Abstract:

1. Please add quantitative results to emphasis your study
2. Please add a "take-home" message in the abstract that can introduce the novelty and motivate readers.

R: The abstract has been updated as requested. However, no values for color and translucency were included since they are many, and because they were reported based on a threshold.

 

Introduction:

1. Please The limitations of similar prior studies must be explained in the introduction section to highlight the research gaps that the current study aims to fill.

R: The research gap was identified in the introduction by “However, there is no previous literature concerning the optical properties and how this important aesthetic feature can be affected by different firing protocols”.

2. The authors need to elaborate on previous literature, including their previous work, recruiting similar conceptualization and/or methodology to address this research

R: We believe that this topic is already presented at the end of the introduction section.

3. The authors mentioned that “Thus, the objective of this study was to evaluate the effect of different firing protocols on the surface roughness and optical properties of two lithium disilicates. The null hypotheses state that different firing protocols would promote [1] different surface roughness and would negatively affect [2] color stability and [3] translucency parameters when submitted to different pigment solutions.” . It would be better to add the expected surface roughness in the commercial products

R: The hypothesis has been updated as requested.

4. Describe the novelty of the article made by the author.

R: The novelty it to evaluate if optical properties can be affected by different firing protocols that are currently available to crystallize lithium disilicate glass-ceramics.

 

Materials and methods:

1. Please indicate the number of samples used to investigate in each experiment

R: This information is present in the beginning of Materials and Methods section, as follows: “Six (6) blocks of CAD/CAM lithium disilicates (IPS e.max CAD - LD and Cerec Tessera blocks - ALD)  were sliced into sixty (60) discs that were divided into three subgroups (n=10) according to the firing and glazing protocols”.

Results:

1. Please highlight the important results of your study

R: The most interesting trend of results are highlighted in figures 1-3 through the graphs and can be identified with the Tukey letters.

2. Please concise and point out the key interesting points from each experiment.

R: The main points consisted on that the evaluated firing protocols affected the ceramic’s surface roughness, and that the firing protocol c-g promoted rougher surfaces. In addition, in all evaluated conditions, LD and ALD showed clinical acceptable color changes and translucency. Those points are presented in the results and conclusion sections.

3. Please indicate A B C in Ra (mean ± sd) (Table 3)

R: Thank you for this observation. The table footnote has been updated.

4. No SD represented in Figure 1, Figure 2, and Figure 3

R: We opted to keep the SD only on tables. The figures readability is easier without vertical lines.

5. The number in Y Axis should be . not ,

R: The figures have been corrected.

Discussion

The outcomes must be compared to similar past research. The authors already added the previous research. However, the discussion in the present article needs to improve to become more comprehensive.

R: The discussion has been updated as requested.

Conclusion

Please indicate the limitations of this study

R: Limitations have been indicated in the end of conclusion section. 

References are not in the order. Please check 

R: References have been checked.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presented by the authors presents many textural properties, and they are good according to the experiments proposed, but the authors do not present any comparison with similar materials used for the same purpose. On the other hand, in order to use the material under study, the mechanical properties must also be reported and known, such as hardness, Young's modulus, density, so the authors can present a novel material and its publication would be well received by readers. Therefore, I follow that the authors report the mechanical properties of the material studied and make a comparison of their material with the literature.

Comments on the Quality of English Language

The manuscript presented by the authors presents many textural properties, and they are good according to the experiments proposed, but the authors do not present any comparison with similar materials used for the same purpose. On the other hand, in order to use the material under study, the mechanical properties must also be reported and known, such as hardness, Young's modulus, density, so the authors can present a novel material and its publication would be well received by readers. Therefore, I follow that the authors report the mechanical properties of the material studied and make a comparison of their material with the literature.

Author Response

The manuscript presented by the authors presents many textural properties, and they are good according to the experiments proposed, but the authors do not present any comparison with similar materials used for the same purpose. On the other hand, in order to use the material under study, the mechanical properties must also be reported and known, such as hardness, Young's modulus, density, so the authors can present a novel material and its publication would be well received by readers. Therefore, I follow that the authors report the mechanical properties of the material studied and make a comparison of their material with the literature.

R: Thank you for your feedback. We've added a table comparing the mechanical properties of our material with similar ones in the literature, addressing your suggestion. We believe this strengthens the manuscript's value.

Reviewer 3 Report

Comments and Suggestions for Authors

The present study evaluated the impact of glazing protocols and immersion media on the surface and optical properties of two materials; lithium disilicate and Advanced Lithium Disilicate.

The article is well written and well presented. The assessment methods used were adequately chosen, sufficiently explained and detailed in a scientific manner. The quality of English is good, and the references used to acknowledge different points were adequately chosen.

However, from the reviewer point of view, the article has some issues that need to be addressed before being published:

Results

The justification given for why the results for the two materials were not compared is not convincing from the point of view of the reviewer. The role played by each of these materials’ nature and composition on how their corresponding surface and optical properties are impacted is important to demonstrate.

Discussion

The discussion section should be rewritten, or at least modified.

It is not enough just to compare the study results with what was obtained in previous studies.

In fact, no actual explanation for the results was presented, the authors should put forward even a hypothetical justification for their results. Why wine for example had such impact on such material and vice versa.

Conclusions

should be more definite, showing which material resisted better the change in surface roughness and translucency change, even if those were not statistically significant.

Some minor observations:

§  The abstract is a little vague. results better be more specific, which material was more impacted and in what way. This important information should be revealed briefly to the reader on reading the abstract.

§  Page 2, line 64, as bacteria in the oral cavity easily adhere to ceramic restorations within the oral cavity [7, 8]. Should be rephrased. The statement as such gives a false impression, glazed ceramic restoration surfaces are the least attractive to bacterial adhesion. The statement could be true only in case of inadequately polished or glazed ceramic surfaces.

§  materials and methods section: Demonstrative figures would be useful and would add to the quality of the article.

Author Response

The present study evaluated the impact of glazing protocols and immersion media on the surface and optical properties of two materials; lithium disilicate and Advanced Lithium Disilicate.

The article is well written and well presented. The assessment methods used were adequately chosen, sufficiently explained and detailed in a scientific manner. The quality of English is good, and the references used to acknowledge different points were adequately chosen.

R: Thank you for your positive feedback on our study. We are pleased that you found the article well-written.

However, from the reviewer point of view, the article has some issues that need to be addressed before being published:

Results

The justification given for why the results for the two materials were not compared is not convincing from the point of view of the reviewer. The role played by each of these materials’ nature and composition on how their corresponding surface and optical properties are impacted is important to demonstrate.

R: We understand, but this was made to improve the results presentation. The properties were not compared between each because there is a threshold that can be used for both of them as clinically acceptable values. In addition, considering the firing protocol (x6) and period of evaluation (x4) we already ended up with 24 groups. Using material (x2) as another factor would only complicate even more the presentation of the results. We believe that in the end, with the adopted approach the conclusion can be supported and the most suitable group can be selected based on the threshold presented.

Discussion

The discussion section should be rewritten, or at least modified.

It is not enough just to compare the study results with what was obtained in previous studies.

In fact, no actual explanation for the results was presented, the authors should put forward even a hypothetical justification for their results. Why wine for example had such impact on such material and vice versa.

R: The discussion has been checked and modified.

 

Conclusions

should be more definite, showing which material resisted better the change in surface roughness and translucency change, even if those were not statistically significant.

R: This study did not aim to compare both materials that can be used in the same indications. Instead, we evaluated them in many different conditions that represents possible clinical/real situations. However, both of them behaved sufficiently, with acceptable clinical outcomes.

Some minor observations:

• The abstract is a little vague. results better be more specific, which material was more impacted and in what way. This important information should be revealed briefly to the reader on reading the abstract.

R: Compare the ceramics was not our purpose. Instead, we used a threshold to determine the ceramics performances. However, the abstract has been improved.

• Page 2, line 64, as bacteria in the oral cavity easily adhere to ceramic restorations within the oral cavity [7, 8]. Should be rephrased. The statement as such gives a false impression, glazed ceramic restoration surfaces are the least attractive to bacterial adhesion. The statement could be true only in case of inadequately polished or glazed ceramic surfaces.

R: Thank you for this observation. This sentence has been corrected.

• materials and methods section: Demonstrative figures would be useful and would add to the quality of the article.

R: Thank you for your suggestion. We opted to not use images since the used methods are well know and described in the literature, and because the manuscript is already long.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

No additional comments

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have followed the recommendations therefore it is ready to be published