-->PONE-D-25-59612-->-->Bond Strength of Recycled Orthodontic Brackets After Different Reconditioning and Priming Protocols-->-->PLOS One

Dear Dr. Nguyen,

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Reviewers' comments:

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-->Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. -->

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Partly

Reviewer #4: No

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-->2. Has the statistical analysis been performed appropriately and rigorously? -->

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: No

**********

-->3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.-->

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: No

Reviewer #4: No

**********

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Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

-->5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)-->

Reviewer #1: Comments for the Authors

Comment 1 – Suggest adding some definitions and importance of performance indicator parameters (i.e - SBS, ARI, bonding reliability etc), this could make the manuscript more coherent and user-friendly for broader audience.

Comment 2 – Discussion of Potential Enamel Risk with High SBS Groups

Location: Section 4, Page 20, Lines 337–340

While mentioned briefly in the Discussion, please expand on the clinical implications regarding enamel crack risk during debonding, and the balance between strong adhesion and safe removal procedures.

Comment 3 – Weibull Analysis Explanation

Location: Section 3.2 – Weibull Analysis, Page 12–13, Lines 224–235

The Weibull analysis is appropriate and informative. To improve clarity for readers, please add a brief explanation on how modulus m relates to clinical reliability

Comment 4 – Minor Formatting Improvements

A light editorial pass is recommended to ensure consistency in:

• Figure numbering and caption style (Figures 1–3)

• Table formatting

These edits will improve readability and professional presentation.

Reviewer #2: Dear Author,

The manuscript entitled, Bond Strength of Recycled Orthodontic Brackets After Different Reconditioning and Priming Protocols and the objective was to assess these interactions to develop evidence-based protocols for safe and effective bracket recycling, with the ultimate goal of improving clinical reliability while promoting cost efficiency and sustainability in orthodontic practice.

I have no any comments.

Reviewer #3: Short summary

===========

Bond Strength of Recycled Orthodontic Brackets After Different Reconditioning and Priming Protocols reports an in‑vitro comparison of three bracket reconditioning methods (OneGloss polishing, flaming, sandblasting) combined with three primer protocols (Mani Bond, Denu Bond, none) on shear bond strength (SBS), ARI and SEM appearance. Sandblasting + primer (especially Mani Bond) produced the highest mean SBS and favorable ARI patterns; the authors conclude sandblasting is the best reconditioning method. (Manuscript PONE‑D‑25‑59612, Abstract: “Sandblasting was the most effective reconditioning method…” and “Sandblasting with Mani Bond achieved the highest SBS (9.33 ± 3.02 MPa).”)

Major points

========

(1) Statistical reporting and methods need correction. A two‑way Welch ANOVA was used but post‑hoc testing used Tukey HSD (which assumes equal variances); replace with appropriate post‑hoc (e.g., Games‑Howell) or justify the current choice and show robustness.

(2) Inconsistencies in factor degrees of freedom and labels. Table 4 lists Primer with df = 1 despite three primer levels; interaction df and other ANOVA entries appear inconsistent—these must be corrected and rechecked in the analysis code and tables.

(3) Experimental design ambiguity about primer/bonding agent. Methods state Denu Bond was applied as the bonding agent during initial bonding for all teeth, yet Denu Bond is also a primer level; clarify whether the primer factor duplicates the initial bonding agent and, if so, how this was controlled.

(4) Clinical relevance and thresholds not fully addressed. Many groups show mean SBS below commonly cited clinical thresholds (6–8 MPa). Discuss clinical acceptability explicitly and temper claims that sandblasting “restores or enhances” adhesion when most groups remain below the threshold.

(5) SEM and reliability limitations. SEM sampling (two brackets per group) and Weibull moduli interpretation require caution; expand justification for SEM sample size or add more images/quantitative surface metrics (e.g., roughness, EDS) to support mechanistic claims.

(6) Manuscript clarity and typographical errors. Multiple typos and inconsistent labels (e.g., “60” or “00” for characteristic strength, missing values in Table rows, p = 0.00) reduce credibility—correct numeric formatting, report exact p‑values or p < 0.001, and ensure all table cells are complete.

Minor points

========

(1) Power calculation detail: Provide the exact effect size, test family, and input parameters used in G*Power; report achieved power for the observed effects.

(2) Thermocycling rationale: State why 1,500 cycles were chosen and cite standards or precedent; discuss how this relates to clinical aging.

(3) Bonding protocol clarity: Report light‑curing irradiance in mW/cm² (1000 W/cm² is implausible unit) and confirm curing times and distances.

(4) ARI scoring presentation: Provide a small table with counts per ARI score per group (not only figure) and include exact p‑values for the exact tests.

(5) Weibull analysis reporting: Give confidence intervals for characteristic strength and explain the method used to estimate m and characteristic strength (software, fitting method).

(6) Ethics and consent: State whether written consent was obtained for use of extracted teeth and include a short sentence on donor anonymity and storage.

(6) ChatGPT use disclosure: The Acknowledgments note ChatGPT‑4o for language editing; ensure this complies with journal policy and add a short statement in Methods/Acknowledgments per journal guidance.

Concrete revision requests

=================

(1) Re-run statistics correcting df errors; use Welch ANOVA → Games‑Howell post‑hoc (or robust alternatives) and report effect sizes (e.g., partial 2) and exact p‑values.

(2) Clarify bonding/primer workflow: explicitly state which material(s) were used as initial bonding agent and which as primer at rebonding; if the same product appears in both roles, explain controls to avoid confounding. Add a short flowchart or table of the bonding sequence for each group.

(3) Correct units and typos (e.g., LED irradiance, Table 3/4 labels, Weibull headings). Replace “p = 0.00” with exact values or “p < 0.001.”

(4) Expand SEM and surface analysis (or temper claims): either increase SEM sample size and add quantitative roughness/EDS data or rephrase mechanistic statements as hypotheses.

(5) Add clinical interpretation: compare group means to the 6–8 MPa clinical threshold and discuss implications for reuse in practice.

(6) Provide raw data and code (SBS values, scripts for ANOVA/Weibull) as supplementary files and include a short README so reviewers can reproduce analyses.

Recommended short text insertions and exact manuscript locations

=========================================

(1) Introduction, where sandblasting benefits are discussed (end of paragraph mentioning sandblasting):

Insert: “Recent in‑vitro work comparing enamel reconditioning methods supports sandblasting as an effective approach to restore bond strength in rebonding scenarios.”

Place after sentence: “By contrast, sandblasting has been shown in multiple studies to efficiently remove residual adhesive…”

Reference to add: Al‑Daher et al., 2024. DOI: 10.7759/cureus.66210.

(2) Methods, when describing sandblasting parameters (after the current parameter sentence):

Insert: “Comparable studies have evaluated sandblasting combined with acid etching for rebonding and provide methodological precedent for particle size and pressure selection.”

Place after: “Sandblasting was applied at a 90° angle to the base, 1 cm distance, 0.3 MPa pressure, for 10 s.”

Reference to add: Dirie et al., 2021. DOI: 10.1016/j.ejwf.2020.12.001.

(3) Introduction or Discussion, when discussing primer/adhesive systems (after paragraph on adhesive role):

Insert: “Comparative in‑vitro and in‑vivo evaluations of self‑etch and conventional primers show variable effects on bracket bond strength and should be considered when interpreting primer interactions.”

Place after: “The attachment of brackets to enamel relies not only on the mechanical retention…”

Reference to add: Alomar et al., 2024. DOI: 10.7759/cureus.72226.

(4) Methods (curing description): if LED irradiance is corrected, add a short citation about LED curing modes and bond outcomes where curing mode is discussed.

Place after curing description.

Reference to add: Najjar et al., 2023. DOI: 10.1016/j.ortho.2023.100787.

Reviewer #4: Title

- "Bond Strength of Recycled Orthodontic Brackets After DifferentReconditioning and Priming Protocols" - first, please revise for typos.

- Second, please note that you refer to bond strengths to enamel with your submitted draft. Whether you have used new or recycled brackets does not matter.

- Third, please provide type of study with your Title.

- Finally, do not capitalize your letters. Please consult some recently published Plos One papers.

Abstract

- Please stick to sound subheadings according to Journal style.

- With your current 200 words, you do not provide maximum information. Stick to the maximum word count allowed for with this section, and revise thoroughly.

- Provide sound aims and objectives.

- A sound rational would seem missing.

- You have compared enamel bond strengths of "ninety recycled brackets", and you have compared those bond strengths to "ten new brackets", right? At the end of the day you have done a laboratory in vitro study on enamel bond strengths, no matter whether you have tested recycled or new brackets.

- You have studied (1) bracket bases with scanning electron microscopy (SEM), (2) enamel shear bond strength (SBS), and (3) (enamel) adhesive remnant index (ARI), right? Why don't you provide all results here?

- What does "m = 5.27 vs. 3.52" mean?

- With your Conclusions, please stick exclusively to your revised/adapted aims, and do not overstate. Do not simply repeat your results here. Do not speculate. Do not provide well-accepted (but unambiguous or even meaningless) phrases. Instead, provide a reasonable and generalizable extension of your outcome.

Intro

- No numbers with your headlines, please. Revise thoroughly.

- Revise thoroughly for sound spacebar use. Compare "23.4% [4]" and "90%[10]".

- Please provide a sound and valid null hypothesis at the end of this section. The latter must be deducible from the forgoing thoughts.

Methods

- Again, revise for sound headlines sticking to Journal style. Must read "Materials and methods".

- Sample size calculation must be explained in detail.

- With ALL materials (including chemicals) and methodologies (including statistical software), please use general/non-proprietary names with your text, followed by (brand name; manufacturer, city, ST[ate - abbreviated, if US], country) in parentheses. Stick to semicolon. Please ensure reproducibility, and revise thoroughly.

- Please add missing details to Table 1, which is not considered complete.

- Please avoid legal terms with your draft. Delete "™" or "GmbH & Co. KG" (and do not use "Ltd.", "®", "Inc", "CO.", "LTD.", "Corp.", "Co.", "Ltd", and so on).

- Details missing with "universal primer (Mani Bond (Mani, Japan)" and "5th generation primer (Denu Bond, HDI, Seoul, South Korea)". Please provide composition, and stick to main aspects like pH, viscosity, and so on.

- You have tested SBS "at the bracket–tooth interface by applying shear force". Again, this would mean that you have tested enamel bond strengths. See comments given above.

Results

- You state that "bond strengtsh ranging from 6–8 MPa are considered below the clinically acceptable range" (see Intro section). However, with the exception of Group 7, all test groups revealed lower bond strengths. These low values would seem astonishing, since you did not mention this aspect with your Abstract section.

- Same with "In most groups, ARI = 3 was the predominant score (ranging from 60–90% of samples)." Again, this would mean that enamel bond strengths have been tested.

- Same with "Groups 7-9 showing ARI scores of 0–2 accounting for 50–90% of samples".

- With all Tables and Figures, please provide sound and exhausting legends. Each Table/Fig must be self-explanatory.

- Provide 3-digit p values.

- "p = 0.00" is not considered probable. Must read "p < 0.0001".

Disc

- What about H0?

- Avoid mentioning Authors' names with your full text. Instead, stick to your main thoughts.

- Please carefully discuss aspects of enamel bonding, and the latter's influence on your outcome.

- What does "highest bond strength" mean when reflecting the various ARI outcomes?

- Same with thoughts on "to help maintain SBS values within the optimal 6–8 MPa range". See comments given above.

- What about the strengths of your study?

- What about the responses to your teaching objectives?

Concl

- Again, with your Conclusions, please stick exclusively to your revised/adapted aims, and do not overstate. Do not simply repeat your results here. Do not speculate. Do not provide well-accepted (but unambiguous or even meaningless) phrases. Instead, provide a reasonable and generalizable extension of your outcome.

- Remember that "Conclusion" does neither mean Repetition of Results" nor "Summary".

Refs

- References have not been adapted to sound and uniform Journal style.

In total, several shortcomings do not allow for any proceeding with this submitted draft. Many aspects would call for a sound and thorough clarification.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

Reviewer #4: No

**********

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Attachments

Attachment

Submitted filename: Reviewer_Report_PONE-D-25-59612_Bond_Strength.docx

<p>Bond strength of debonded orthodontic brackets after different reconditioning and priming protocols: An in vitro study

PONE-D-25-59612R1

Dear Dr. Nguyen,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Kind regards,

Andrej M Kielbassa

Academic Editor

PLOS One

Additional Editor Comments (optional):

Please note that I have double checked (R #4) your revised and re-submitted draft after both external Reviewers have recommended 'acceptance'.

Reviewers' comments:

Reviewer's Responses to Questions

-->Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.-->

Reviewer #1: All comments have been addressed

Reviewer #3: All comments have been addressed

Reviewer #4: All comments have been addressed

**********

-->2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. -->

Reviewer #1: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

-->3. Has the statistical analysis been performed appropriately and rigorously? -->

Reviewer #1: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

-->4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.-->

Reviewer #1: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

-->5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.-->

Reviewer #1: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

-->6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)-->

Reviewer #1: All Review comments are addressed. These were the comments from initial review:

Comment 1 – Suggest adding some definitions and importance of performance indicator parameters (i.e - SBS, ARI, bonding reliability etc), this could make the manuscript more coherent and user-friendly for broader audience.

Comment 2 – Discussion of Potential Enamel Risk with High SBS Groups

Location: Section 4, Page 20, Lines 337–340

While mentioned briefly in the Discussion, please expand on the clinical implications regarding enamel crack risk during debonding, and the balance between strong adhesion and safe removal procedures.

Comment 3 – Weibull Analysis Explanation

Location: Section 3.2 – Weibull Analysis, Page 12–13, Lines 224–235

The Weibull analysis is appropriate and informative. To improve clarity for readers, please add a brief explanation on how modulus m relates to clinical reliability

Comment 4 – Minor Formatting Improvements

A light editorial pass is recommended to ensure consistency in:

• Figure numbering and caption style (Figures 1–3)

• Table formatting

These edits will improve readability and professional presentation.

Reviewer #3: Thanks for addressing all my comments.

No further amendments are required.

The paper now looks suitable for publication.

Reviewer #4: - This revised and re-submitted draft would seem ready to proceed.

- Congratulations, and stay healthy!

**********

-->7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review?  For information about this choice, including consent withdrawal, please see our Privacy Policy.-->

Reviewer #1: Yes: Chinmay Potdar

Reviewer #3: No

Reviewer #4: No

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