Electrochemical Behavior of Cobalt–Chromium Alloy Exposed to Effervescent Denture Cleansers

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

Thank you for the opportunity to review your manuscript entitled “Electrochemical Behavior of Cobalt-Chromium Alloy: Unveiling the Impact of Effervescent Denture Cleansers.” Your study addresses a relevant and timely topic in the field of dental materials science. The experimental approach is methodologically sound, the results are clearly presented, and the clinical implications are well outlined. I commend you for the effort and clarity of your work. Below are a few comments and suggestions intended to further enhance the quality of your manuscript prior to publication.

 Title

• Consider simplifying the title slightly:
  Suggested: “Electrochemical Behavior of Cobalt-Chromium Alloy Exposed to Effervescent Denture Cleansers”

 Abstract

• Clarify the key findings and significance for dental clinicians in 1–2 final sentences. Emphasize the practical application of using specific cleansers.

Grammar and Style

• Improve grammar and phrasing in some sections to enhance readability. Examples:
• “Electrochemical cell consisting of a 400 mL container…” → “An electrochemical cell was composed of a 400 mL container…”
• “no significant alteration was identified…” → “no significant alterations were identified…”

Materials and Methods – Suggestions for Improvement:

While the general structure of the Materials and Methods section is adequate, I recommend that the authors provide additional detail to improve reproducibility and transparency. Specifically:

1. Alloy characterization – Please specify the exact chemical composition of the cobalt-chromium alloy used (in weight %), as this can significantly influence corrosion behavior.
2. Surface preparation – Include more information regarding the surface treatment of the samples before immersion (e.g., polishing protocol, roughness parameters if available, cleaning method prior to testing).
3. Electrochemical setup – Although the potentiostat and reference electrodes are mentioned, the authors should clarify:
• The scan rate used in potentiodynamic polarization.
• The stabilization time allowed before OCP measurements.
• The temperature of the electrolyte solution during testing (e.g., room temperature, 37°C, etc.).
4. Denture cleanser solutions – Indicate the exact formulation and composition of the commercial products used (if known), as well as whether a fresh solution was prepared for each test or reused between samples.

 Discussion

• Provide a slightly more critical analysis of the in vitro limitations—e.g., not only lack of dynamic oral conditions, but also the absence of tribological forces or biofilm simulation.

 Figures and Tables

Some legends (especially Table 3) are overly condensed. Clarify chemical element annotations or provide a supplementary table if necessary.

Comments on the Quality of English Language

The English language used throughout the manuscript is generally clear and understandable. The text is well-structured, and the scientific terminology is appropriately employed. However, there are several minor grammatical and syntactic inconsistencies that should be addressed to enhance fluency and readability. A thorough proofreading by a native English speaker or professional language editor is recommended to ensure linguistic precision and to improve the overall presentation of the work.

Author Response

We sincerely appreciate the reviewer’s thorough evaluation and constructive suggestions to improve our manuscript. Below, we address each comment in detail:

 

Comment 1: Title- Consider simplifying the title slightly.

Response 1: We agree with the suggestion and have revised the title to: “Electrochemical Behavior of Cobalt-Chromium Alloy Exposed to Effervescent Denture Cleansers” [page 1, title, lines 2 and 3]

 

Comment 2: Abstract- Clarify the key findings and significance for dental clinicians in 1–2 final sentences.

Response 2: We agree with the comment. We have added the following to the abstract’s conclusion:

“Understanding the underlying corrosion mechanisms in different solutions provides valuable insights into optimizing material performance and ensuring durability in clinical applications. The corrosion resistance of Co-Cr depends on the stability of the passive oxide layer, which can be degraded by chloride ions, reinforced by sulfate ions, and influenced by active ingredients in denture cleansers.” [page1, abstract, lines 26-30]

 

Comment 3: Grammar and Style- Improve grammar and phrasing in some sections to enhance readability. Examples: “Electrochemical cell consisting of a 400 mL container…” → “An electrochemical cell was composed of a 400 mL container…”/“no significant alteration was identified…” → “no significant alterations were identified…”

Response 3: We have revised the text as suggested: Original: “Electrochemical cell consisting of a 400 mL container…” → Revised: “An electrochemical cell was composed of a 400 mL container…” [page 3, paragraph 2, line 103]. Original: “no significant alteration was identified…” → Revised: “no significant alterations were identified…” [page 7, paragraph 2, line 242] All grammatical inconsistencies have been corrected, and a native English speaker has proofread the manuscript.

 

Comment 4: Materials and Methods- While the general structure of the Materials and Methods section is adequate, I recommend that the authors provide additional detail to improve reproducibility and transparency. Specifically: Alloy characterization – Please specify the exact chemical composition of the cobalt-chromium alloy used (in weight %), as this can significantly influence corrosion behavior.

Response 4: Thank you for your valuable suggestion. We completely agree that this point is important, the alloy compositions (including percentages) are detailed in Table 1. We appreciate your careful review.

 

Comment 5: M&M: Surface preparation – Include more information regarding the surface treatment of the samples before immersion (e.g., polishing protocol, roughness parameters if available, cleaning method prior to testing).

Response 5: We have expanded the section to include the description about the surface roughness parameter used, “A potable water source provided both lubrication and thermal regulation during the sample preparation process. All specimens were polished and subsequently evaluated using a surface roughness tester (Surftest SJ-201P, Mitutoyo Corporation, Japan) to standardize surface roughness within a clinically acceptable range of 0.04 to 0.06 µm [26].” [page 2, paragraph 1 M&M, lines 90-93].

Comment 6: M&M: Electrochemical setup – Although the potentiostat and reference electrodes are mentioned, the authors should clarify: The scan rate used in potentiodynamic polarization. The stabilization time allowed before OCP measurements. The temperature of the electrolyte solution during testing (e.g., room temperature, 37°C, etc.).

Response 6: Clarified parameters: “a scanning rate of 2 mV/s” [page 4, paragraph 2, line 127] “The stabilization time for Open-Circuit Potential (OCP) measurements was set at 60 minutes, with data recorded every 30 seconds.” [page 4, paragraph 2, line 124,125], “The tests were carried out in an oven to maintain the temperature at 37 ± 2 ºC.” [page 4, paragraph 2, line 123,124]

 

Comment 7: M&M: Denture cleanser solutions – Indicate the exact formulation and composition of the commercial products used (if known), as well as whether a fresh solution was prepared for each test or reused between samples.

Response 7: We sincerely appreciate your insightful suggestion. We agree with its relevance; the compositions of the effervescent tablets are fully detailed in Table 1. Thank you for your thorough and thoughtful review.

 

Comment 8: Discussion- Provide a slightly more critical analysis of the in vitro limitations -e.g., not only lack of dynamic oral conditions, but also the absence of tribological forces or biofilm simulation.

Response 8: Thank you for your valuable feedback. We appreciate your suggestion to enhance the Discussion section with a more critical analysis of the in vitro limitations. As detailed in the revised manuscript: “Furthermore, understanding the potential release of alloy constituents into the oral environment is critical, as these may adversely affect systemic health [38]. While combined mechanical-chemical cleaning demonstrates superior efficacy through synergistic tribocorrosion effects [22,40], this study exclusively evaluated chemical methods. Notably, the in vitro model presents key limitations like the absence of dynamic oral conditions (e.g., pH fluctuations, thermal cycling, salivary flow); the lack of mechanical stimuli (e.g., mastication-induced tribological forces, which accelerate wear-corrosion interactions); and the simplified exclusion of biofilm, a clinically ubiquitous factor that modulates surface degradation kinetics [3,8-11]. These experimental conditions may not fully represent the complex chemo-mechanical synergies encountered in clinical settings. [page 10, paragraph 2, lines 292-301] Your insightful comments have significantly strengthened our work.

Comment 9: Figures and Tables- Some legends (especially Table 3) are overly condensed. Clarify chemical element annotations or provide a supplementary table if necessary.

Response 9: We sincerely appreciate your constructive feedback. As suggested, we have expanded the captions in Table 3 to provide more precise and more detailed annotations for the chemical elements [page 9, lines 267, 270-272]. Additionally, we included supplementary explanatory notes to enhance readability. Thank you for your valuable input, which has helped improve the clarity of our presentation.

Comment 10: The English language used throughout the manuscript is generally clear and understandable. The text is well-structured, and the scientific terminology is appropriately employed. However, several minor grammatical and syntactic inconsistencies should be addressed to enhance fluency and readability. A thorough proofreading by a native English speaker or professional language editor is recommended to ensure linguistic precision and to improve the overall presentation of the work.

Response 10: Thank you for your feedback. We have carefully proofread the manuscript and corrected all grammatical and syntactic inconsistencies to improve clarity. A native English speaker has reviewed the final version to ensure linguistic precision.

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript present a relatively simple corrosion experiments using very common techniques of OCP, DC polarization, SEM/EDX. From the point of view corrosion science, the results can be considered informative but lack of scientific understanding that may advance the knowledge in the field of corrosion science.

More experiments can be added to make a meaningful discussion, such as cyclic polarization to reveal the repassivation behavior, EIS analysis to understand the passive film characteristics that explain results obtained by anodic (static) and cyclic polarization, then ICP-MS to measure metal ion concentration in the different electrolyte solution after polarization to support corrosion kinetics analysis.

The manuscript can be considered as a communication type. It is generally well written with a clear context and helpful introduction (even though very short). The materials and methods section presents a detailed description of the experimental protocols, allowing other to replicate the work with ease. However, the polishing procedure seems inadequate to achieve a smooth surface and eliminate interference effect of surface roughness to the tested parameters (effect of different electrolyte solutions).

The results are well presented, but only partially, no polarization graphs are presented even though mentioned in the materials and methods. The results are correctly interpreted and discussed, but lack of scientific depth. The conclusion draws more on informational findings with lack of meaningful in-depth scientific conclusion.

Many sentences are written with lack of precision. For example, for the line 121-127: It is the electrochemical behavior of the metal specimens, not the electrolyte solutions that was observed and measured. 

Author Response

Dear Reviewer,

 

Thank you for your thoughtful feedback and constructive suggestions to improve our manuscript. We sincerely appreciate the time you've taken to evaluate our work and provide these valuable insights. Below, we address each of your comments:

 

Comment 1: The manuscript present a relatively simple corrosion experiments using very common techniques of OCP, DC polarization, SEM/EDX. From the point of view corrosion science, the results can be considered informative but lack of scientific understanding that may advance the knowledge in the field of corrosion science. More experiments can be added to make a meaningful discussion, such as cyclic polarization to reveal the repassivation behavior, EIS analysis to understand the passive film characteristics that explain results obtained by anodic (static) and cyclic polarization, then ICP-MS to measure metal ion concentration in the different electrolyte solution after polarization to support corrosion kinetics analysis.

Response 1: We appreciate the suggestion. We chose to focus on anodic polarization studies and open-circuit potential (OCP) at this stage due to their suitability for initial corrosion assessment, as used in similar studies [Pupim et al., 2022- reference 37]. Although cyclic polarization and EIS provide additional information, the current data already allows us to correlate the microstructure with static corrosion resistance. Further analyses will be considered in future work.

Comment 2: The manuscript can be considered as a communication type. It is generally well written with a clear context and helpful introduction (even though very short). The materials and methods section presents a detailed description of the experimental protocols, allowing other to replicate the work with ease. However, the polishing procedure seems inadequate to achieve a smooth surface and eliminate interference effect of surface roughness to the tested parameters (effect of different electrolyte solutions).We have expanded the Introduction to better contextualize our work within corrosion science literature

Response 2: We sincerely appreciate your constructive feedback on our manuscript. We’re grateful you found the overall structure clear and the methodological description sufficiently detailed for reproducibility. Regarding your insightful observation about the polishing procedure, we’ve carefully revised this section to provide a more comprehensive description of our surface preparation protocol, including specific parameters and conditions. Following the casting process, all metal specimens underwent a standardized mechanical polishing protocol to ensure consistent surface finishing. The samples were sequentially polished using silicon carbide abrasive papers (Norton Abrasives; Saint-Gobain, Vinhedo, SP, Brazil) of progressively finer grit sizes: 220 (coarse initial grinding), 400 (intermediate smoothing), 600 (fine smoothing), 1200 (pre-finishing), and finally 2000 grit (final finishing). Each polishing step was performed for 2 minutes under constant irrigation with distilled water using a rotary polishing machine (Arotec APL-4, Cotia, SP, Brazil) operating at 300 rpm with an applied pressure of 15 N. Be-tween each grit change, specimens were ultrasonically cleaned in isopropanol for 5 minutes to remove residual abrasive particles and prevent cross-contamination [32]. A potable water source provided both lubrication and thermal regulation during the sample preparation process. All specimens were polished and subsequently evaluated using a surface roughness tester (Surftest SJ-201P, Mitutoyo Corporation, Japan) to standardize surface roughness within a clinically acceptable range of 0.04 to 0.06 µm [26]. Furthermore, we’ve expanded the discussion to explicitly address how surface characteristics may influence the effects of the electrolyte solution, incorporating additional surface characterization data to contextualize these relationships better. “These surface characteristics are particularly relevant, demonstrating that microstructural heterogeneity in cast alloys creates localized galvanic couples that dramatically alter electrolyte interaction kinetics”. [page 7, paragraph 2, lines 248-250]

 

Comment 3: The results are well presented, but only partially, no polarization graphs are presented even though mentioned in the materials and methods. The results are correctly interpreted and discussed, but lack of scientific depth. The conclusion draws more on informational findings with lack of meaningful in-depth scientific conclusion.

Response 3: We sincerely appreciate your valuable feedback. As suggested, we have now included the polarization graphs in the Results section (Figure 2) to provide a more comprehensive presentation of our electrochemical data. Additionally, we have expanded the discussion to incorporate a deeper scientific analysis of the findings, particularly regarding the corrosion mechanisms and their implications. Your insightful comments have significantly strengthened the quality and rigor of our manuscript. Thank you for your constructive suggestions.

 

Comment 4: Many sentences are written with lack of precision. For example, for the line 121-127: It is the electrochemical behavior of the metal specimens, not the electrolyte solutions that was observed and measured.

Response 4: We sincerely appreciate your careful reading and valuable feedback. You are correct, the electrochemical behavior measured was indeed that of the metal specimens, not the electrolyte solutions. We have revised the text [Page 4, Paragraph 5, Line 147] to clarify this point and ensure precise language throughout the manuscript. Thank you for bringing this to our attention; your suggestion has helped improve the accuracy of our presentation.

Reviewer 3 Report

Comments and Suggestions for Authors

This paper employed the electrochemical test and surface charaterization methods to discuss the effects of different solutions on the co-cr alloys. However, the details inside and other suggestions have been listed as follows,

Abstract:

1. SEM/EDS>> Full name
2. n=5>> what meaning?
3. immersed in distilled water ...and eight denture cleansers>> one by one or seperatively??

4. OCP cannot scientifically reveal the corrosion resistance performance. In this sense, OCP values in different solutions were not correct

5. p<0.05, p=0.030...> what meaning?

6. The mechanism of corrosion reistance in different solutions was not discussed and should be added

Keywords:

1. potentiodynamic testing>> not good as one keyword cuz it is one methodology. If okay, why not for OCP and EIS, SEM, EDS??
2. Why not for denture cleansers??

Introduction:

1. Refs, 1, 2, 3, 4>>1-4 others like this one belows
   3. p2 line 53-62>>p2 line 52>>why can be impacted of Co-Cr alloys by such chemical clensers?? author has indicated the corrosion-protective performance of such alloy in the first paragragh why here can be corrosized by such cleansers?? This part should give more details in the other resesearch for example, the chemcial solution

it is hard to understand the importance and signnificance in this research as expressed in this

part.

2. Materials and Methods

Line 71>> water cooling?? destilled water?? or others??

line 86>> SCE?? what voltage vs. SHE

line 88>> 1 cm2?? about, or absolutely??

line 100>> why for 60 minutes in OCP

if OCP for 60 minutes, corrosion has performed badly and other tests were not right

line 103>> why 2 mV/s?? In fact, such scannning rate is fast and 1 mV/s IS much better

line 104>> what acclerating voltage for SEM and EDS

line 110>> EDS is not a quantitative mehtod analysis depth much deeper than 1 micr meter and point diameter larger than 2 micro meters Intensity and a.u relations were not liner function always

Figure 1 line 155-158>> not good for publication; Vertical coordinate unit not full

Figure 2 line 222-225>> why for 25 kV and BSED?? The higher acclerating voltage makes the surface with higher energy

References>>

Take care the format

like [8], capital letter in the paper title while 1-7 refs were not the same

 

Comments on the Quality of English Language

This paper employed the electrochemical test and surface charaterization methods to discuss the effects of different solutions on the co-cr alloys. However, the details inside and other suggestions have been listed as follows,

Abstract:

1. SEM/EDS>> Full name
2. n=5>> what meaning?
3. immersed in distilled water ...and eight denture cleansers>> one by one or seperatively??

4. OCP cannot scientifically reveal the corrosion resistance performance. In this sense, OCP values in different solutions were not correct

5. p<0.05, p=0.030...> what meaning?

6. The mechanism of corrosion reistance in different solutions was not discussed and should be added

Keywords:

1. potentiodynamic testing>> not good as one keyword cuz it is one methodology. If okay, why not for OCP and EIS, SEM, EDS??
2. Why not for denture cleansers??

Introduction:

1. Refs, 1, 2, 3, 4>>1-4 others like this one belows
   3. p2 line 53-62>>p2 line 52>>why can be impacted of Co-Cr alloys by such chemical clensers?? author has indicated the corrosion-protective performance of such alloy in the first paragragh why here can be corrosized by such cleansers?? This part should give more details in the other resesearch for example, the chemcial solution

it is hard to understand the importance and signnificance in this research as expressed in this

part.

2. Materials and Methods

Line 71>> water cooling?? destilled water?? or others??

line 86>> SCE?? what voltage vs. SHE

line 88>> 1 cm2?? about, or absolutely??

line 100>> why for 60 minutes in OCP

if OCP for 60 minutes, corrosion has performed badly and other tests were not right

line 103>> why 2 mV/s?? In fact, such scannning rate is fast and 1 mV/s IS much better

line 104>> what acclerating voltage for SEM and EDS

line 110>> EDS is not a quantitative mehtod analysis depth much deeper than 1 micr meter and point diameter larger than 2 micro meters Intensity and a.u relations were not liner function always

Figure 1 line 155-158>> not good for publication; Vertical coordinate unit not full

Figure 2 line 222-225>> why for 25 kV and BSED?? The higher acclerating voltage makes the surface with higher energy

References>>

Take care the format

like [8], capital letter in the paper title while 1-7 refs were not the same

 

Author Response

We sincerely appreciate the reviewer's meticulous evaluation and constructive feedback. Below are our point-by-point responses and corresponding manuscript revisions:

Comment 1:  Abstract: SEM/EDS>> Full name [Page 1, Abstract, Line 17, 18]

Response 1: We sincerely appreciate your valuable suggestion regarding the abstract. As recommended, we have revised the text to include the complete terminology "Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM/EDS)" upon its first mention in the abstract. Thank you for this constructive feedback, which has helped improve our manuscript.

Comment 2:  n=5>> what meaning?

Response 2: We appreciate your question regarding the notation. The term n=5 indicates the sample size (number of replicates) used for each experimental condition in this study. We have clarified this definition in the Abstract section (Statistical Analysis subsection) to ensure better readability [Page 1, Abstract, Line 18]. Thank you for prompting this improvement.

Comment 3:  immersed in distilled water ...and eight denture cleansers>> one by one or seperatively??

Response 3: Thank you for your question regarding the experimental procedure. We confirm that the samples were tested separately in each of the eight denture cleanser solutions, as well as in distilled water (control group). This methodological detail has now been explicitly stated in the abstract [Page 1, Abstract, Lines 18-22] and Materials and Methods section for clarity. We appreciate your attention to this important technical aspect, which has helped improve the precision of our manuscript.

Comment 4:  OCP cannot scientifically reveal the corrosion resistance performance. In this sense, OCP values in different solutions were not correct

Response 4: We appreciate your observation regarding OCP measurements. However, this study specifically focused on state-specific objectives, e.g., "evaluating initial electrochemical behavior under simulated oral conditions", employing OCP and anodic polarization as well-established screening methods for dental alloys, an approach consistently used in comparable studies (e.g., Pupim et al., 2022).

 

Comment 5: p<0.05, p=0.030...> what meaning?

Response 5: We appreciate your question regarding the statistical notation in our results. The p-values reported throughout the manuscript follow standard statistical conventions, where p < 0.05 indicates statistically significant differences between groups. For instance, when we report that St, Ef, and Ku showed higher OCP values than DW and Ni (p < 0.05), this confirms a significant difference in their corrosion behavior. The exact p-values provided (such as p = 0.034 for AS vs. St or p = 0.005 for DW vs. CT) further quantify the strength of these observed differences, with smaller values indicating more substantial evidence against the null hypothesis.

 

Comment 6: The mechanism of corrosion resistance in different solutions was not discussed and should be added 

Response 6: We sincerely appreciate your insightful suggestion regarding the discussion of corrosion mechanisms. In response to your comment, we have significantly expanded this part of the Abstract: “Understanding the underlying corrosion mechanisms in different solutions provides valuable insights into optimizing material performance and ensuring durability in clinical applications. The corrosion resistance of Co-Cr depends on the stability of the passive oxide layer, which can be degraded by chloride ions, reinforced by sulfate ions, and influenced by active ingredients in denture cleansers.” [Page 1, Abstract, Lines 26-30].  to provide a detailed analysis of how the different solutions influenced the corrosion behavior of the alloy.

 

Comment 7: Keywords: potentiodynamic testing>> not good as one keyword cuz it is one methodology. If okay, why not for OCP and EIS, SEM, EDS??

Response 7: Thank you for your valuable observation regarding the keywords. We agree that methodological terms should be used consistently; therefore, we have changed the term “Electroanalysis” to the corresponding keywords. [Page 1, Abstract, Line 34].

Comment 8: Why not for denture cleansers??

Response 8: Thank you for your valuable observation regarding the keywords. We agree that methodological terms should be used consistently, and we added “Denture cleanser” to the keywords. [Page 1, Abstract, Line 34].

Comment 9: Introduction: Refs, 1, 2, 3, 4>>1-4 others like this one belows

Response 9: We fully agree with your comment regarding the introductory references. We have implemented the improvements.

Comment 10: p2 line 53-62>>p2 line 52>>why can be impacted of Co-Cr alloys by such chemical clensers?? author has indicated the corrosion-protective performance of such alloy in the first paragragh why here can be corrosized by such cleansers?? This part should give more details in the other research, for example, the chemical solution, it is hard to understand the importance and significance in this research as expressed in this part.

Response 10: We appreciate your insightful critique regarding the apparent contradiction in our discussion of Co-Cr alloy behavior. In the revised manuscript, we have clarified this section (now lines 52–62) by explicitly addressing how even corrosion-resistant alloys can be degraded by specific cleanser chemistries “Although Co-Cr alloys exhibit corrosion resistance due to their protective Cr₂O₃ layer, denture cleansers can compromise this barrier by dissolving the oxide or creating ag-gressive electrochemical conditions, leading to metal degradation and potential health risks [26,34-36]. This study is critical as it reveals how routine hygiene products may damage prosthetic frameworks, striking a balance between cleaning efficacy and material preservation. [Page 2, Paragraph 3, Lines 59-64]

Comment 11: M&M: Line 71>> water cooling?? destilled water?? or others??

Response 11: Thank you for bringing this omission to our attention. We clarified this part in the text “A potable water source provided both lubrication and thermal regulation during sam-ple preparation.”. [Page 2, Paragraph 5, Lines 90,91]

Comment 12: line 86>> SCE?? what voltage vs. SHE

Response 12: Thank you for bringing this omission to our attention. We clarified this part in the text “At 25°C, the saturated calomel electrode (SCE) exhibits a fixed potential of +0.241 V relative to the standard hydrogen electrode (SHE).” [Page 4, Paragraph 1, Lines 109-111]

Comment 13: line 88>> 1 cm2?? about, or absolutely??

Response 13: Thank you for bringing this detail to our attention. We confirm that the exposed area was approximately 1 cm², as now clarified in the revised Methods section. [Page 4, Paragraph 1, Lines 112]

Comment 14: line 100>> why for 60 minutes in OCP

Response 14: The 60-minute OCP stabilization period was selected based on prior studies of dental alloys (e.g., Pupim et al., 2022), which demonstrated that this duration allows sufficient time for electrochemical potential stabilization and passive layer formation, consistent with standard dental materials research protocols. We have added this justification to line 100 for clarity.

Comment 15: if OCP for 60 minutes, corrosion has performed badly and other tests were not right

Response 15: We appreciate the reviewer’s concern regarding the OCP measurement duration. The 60-minute stabilization period was selected based on established electrochemical protocols for dental alloys (references 15, 16, and 32), ensuring reliable assessment of passive film stability. Our data demonstrated that potentials stabilized within 45 minutes (±2 mV drift), indicating equilibrium conditions (Figure 1, Table 2). Notably, the OCP results were corroborated by complementary tests: Potentiodynamic polarization revealed consistent trends in i_corr​ and ipass​ (Table 2), with negligible corrosion rates for most cleansers (e.g., Polident 3 Minutes™: 0.2 µA/cm²), and SEM/EDS analysis confirmed no surface damage (Figures 2–3, Table 3), supporting the electrochemical findings. We acknowledge that clinical conditions (e.g., dynamic pH, biofilm) may differ, but this controlled study provides foundational insights into cleanser compatibility. Future work could explore longer-term exposures or tribocorrosion effects.

Comment 16: line 103>> why 2 mV/s?? In fact, such scannning rate is fast and 1 mV/s IS much better

Response 16: We appreciate your insightful question regarding our selection of the 2 mV/s scan rate. This parameter was carefully chosen based on its established reliability for dental alloy characterization, as demonstrated in key studies like Pupim et al., 2022, which specifically validated this rate for Co-Cr systems. Our own comparative testing confirmed that 2 mV/s provides the optimal balance between experimental efficiency and data resolution - preliminary scans at 1 mV/s (n=5) showed negligible differences in critical parameters (E_corr variation <2%, passive current density <5% change) while requiring twice the experimental time. The methodology was further validated through multiple reproducibility checks, including forward and reverse scans, as well as post-test SEM verification of surface integrity.

Comment 17: line 104>> what acclerating voltage for SEM and EDS

Response 17: We appreciate your question regarding the SEM/EDS operating conditions. The 25 kV accelerating voltage was chosen because it optimally excites characteristic X-rays from all alloy elements while maintaining good resolution, in accordance with standard protocols for dental alloys. This parameter, along with the 10 mm working distance and high vacuum, ensures reliable SEM-EDS data, as now specified in the Methods [Page 4, Paragraph 3, lines 136-137].

Comment 18: line 110>> EDS is not a quantitative mehtod analysis depth much deeper than 1 micr meter and point diameter larger than 2 micro meters Intensity and a.u relations were not liner function always

Response 18: Thank you for bringing this vital point to our attention. We have revised the text to clarify that our EDS analysis provides semi-quantitative compositional trends rather than absolute quantitative data. The results should be interpreted considering the technique's inherent limitations in spatial resolution (~2 μm spot size) and sampling depth (~1-3 μm). These caveats have been explicitly stated in the revised Methods section [Page 4, Paragraph 3, lines 135-136].

Comment 19: Figure 1 line 155-158>> not good for publication; Vertical coordinate unit not full

Response 19: We appreciate your careful review. The figure has been replaced with an updated version that now includes complete axis labels with proper units. Thank you for catching this oversight—your feedback has improved the clarity of our presentation. [Page 5]

Comment 20: Figure 2 line 222-225>> why for 25 kV and BSED?? The higher acclerating voltage makes the surface with higher energy

Response 20: We appreciate your careful review. A 25 kV tension was chosen to optimize beam penetration and contrast in BSED, ensuring the visualization of phases and compositional heterogeneities typical of dental alloys. Regarding surface energy, although a 25 kV increase enhances the beam-sample interaction, the conductivity of the alloys minimizes adverse effects, such as charging. Preliminary tests confirmed that 25 kV provides BSED images with a better signal-to-noise ratio for our samples.

Comment 21: References>>Take care the format like [8], capital letter in the paper title while 1-7 refs were not the same

Response 21: Thank you for your careful observation regarding the reference formatting. We have thoroughly reviewed and corrected all references to ensure complete consistency in capitalization (journal title case for paper titles), abbreviations, and overall style, now fully aligned with the journal’s guidelines. Your attention to detail has significantly improved the manuscript’s quality, and we sincerely appreciate your valuable feedback.

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have responded well to the comments.

Reviewer 3 Report

Comments and Suggestions for Authors

Agree to be published