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The revisions have sufficiently improved the clarity and quality of the work.
Based on my assessment, I find this manuscript ready for publication.
Dear authors,
Please reply to the comment of reviewer 3 about the 3-way ANOVA. Justification should be provided also in the manuscript, before the results presentation.
Kind regards,
Dr. Tribst JPM
The authors addressed all raised criticism.
The authors addressed all raised criticism.
The authors addressed all raised criticism.
The authors addressed all raised criticism.
no comment
no comment
no comment
no comment
The authors improved the English writing and grammar as requested previously.
The authors have made the modifications as suggested.
It is still unclear why the authors chose to perform a 3-way ANOVA test despite the Levene's test indicating unequal variances across groups (heterogeneity of variances;
None.
Dear Authors,
Thank you for your submission. To improve the manuscript, please clarify the sample size per group and simplify or clearly differentiate fit measurement zones. Use consistent units (micrometers) and reanalyze the data using a 3-way ANOVA. Rename groups to reflect the specific variables studied and provide a stronger rationale for the chosen crown designs. Improve grammar and clarify the "advanced" superimposition method. Ensure the title accurately reflects that ceramic crowns were fabricated using heat pressing, not 3D printing.
Best regards,
Dr. Tribst JPM
First of all thank you for considering PeerJ to publish your work. The manuscript, entitled ‘Evaluation of Marginal and Internal Fit of Ceramic Crowns Fabricated by Two Different 3D Printing Techniques Using Advanced Superimposition Method’ is generally well-written, thoughtfully designed, and addresses a relevant topic within the field of dental prosthetics. However, there some aspects require clarification and improvement:
- The current naming convention for the groups (Group A, Group B, etc.) is too generic and does not clearly reflect the factors under study. I recommend renaming the groups to directly represent the specific variables being analyzed. For example, instead of "Group A-1," consider "SLA-i700" and for "Group B-2," use "DLP-Trios3." This will help readers more easily understand the study design and reduce potential confusion.
- The differentiation of fit measurement zones could be simplified. Zones that are technically similar (e.g., opposite sides of the same surface) do not need separate labels. I suggest merging the data from zones that are symmetrical or similar, such as Z1-9, Z2-8, Z3-7, and Z4-6. If the authors wish to keep the current separation, they should clearly differentiate them by adding terms like "buccal" and "lingual/palatal" and provide a detailed explanation of why these differences are relevant to the study.
- The reasoning behind the sample size selection needs more detailed explanation. It appears that the sample size (n=30) was calculated based on one factor alone, potentially overlooking the interaction between both factors under study (scanning method and printing technique). The authors should clarify the assumptions and data used for the sample size calculation, explain how the final number was determined, and whether it was adequate to meet the study’s objectives.
- The measurements for marginal and internal gaps should be presented consistently in micrometers (µm), not millimeters (mm), which is standard practice in the field. The article should also ensure consistent use of decimal places and scale throughout the manuscript (e.g., 0.20 vs. 0.200). In some instances, graphs show varying scales (e.g., 0.25 and 0.1), which can be unprecise for readers. Standardizing these formats would improve clarity.
- Another limitation not mentioned in the study is the lack of a control group using a validated conventional method such as milling or pressing conventional wax. Including such a group would have allowed for a more robust comparison of the new 3D printing techniques with established methods. Nonetheless, I commend the authors for exploring two advanced manufacturing technologies and demonstrating promising results.
In summary, the study is well-conceived and addresses an important topic with two cutting-edge 3D printing technologies. With some modifications to the nomenclature, methodology explanation, and results presentation, this manuscript can make a valuable contribution to the field of dental prosthetics.
All comments were expressed in summary at the subsection 1 of this report. The theme is within aims and scope of the journal. The research question is well defined, relevant and meaningful. Some aspects of the sample size need to be clarified, to assure the validity of the data.
All comments were expressed in summary at the subsection 1 of this report. The theme is novel, and seems sound. However, some aspects need to be clarified, and authors were questioned in such sense.
In summary, the study is well-conceived and addresses an important topic with two cutting-edge 3D printing technologies. With some modifications to the nomenclature, methodology explanation, and results presentation, this manuscript can make a valuable contribution to the field of dental prosthetics.
General Comments: The study investigates the effects of two intraoral scanning methods, three crown margin designs, and two 3D printing techniques for wax fabrication on the internal and marginal fit of lithium disilicate crowns produced by heat pressing. Overall, the writing is clear and professional; however, a few areas could be improved for greater clarity and consistency, and to provide better context for readers.
Introduction: The statement “typically 5 to 20 per millimeter of material in a layer” in the introduction is unclear and may confuse the reader. Please revise.
Background and References: The selection of the three crown margin designs should be better justified in the manuscript. Please provide a clear rationale for why these specific designs were chosen, supported by relevant literature references.
Terminology Consistency: Please ensure consistency in the use of terms throughout the manuscript. For example, standardize the spelling of "3D printing" and avoid variations such as "3-D printing" to maintain clarity and professionalism.
Reducing the use of unnecessary abbreviations: The abbreviation "PC" appears unnecessary in this context and could be removed to improve the flow of the manuscript.
In statistics, 1-way ANOVA was used to evaluate the effect of all the 3 factors, which have interactions. A 3-way ANOVA is recommended to assess both the main effects and interaction effects of these factors.
Additionally, please use a standard format for product and manufacturer information.
The figures currently lack labels on the y-axis, and units are missing.
The first conclusion is suggested to be corrected as ‘compared to other evaluated crowns’; the second conclusion is not clearly written.
The title should be revised for clarity and accuracy. Since the crowns were fabricated using the lost-wax casting method and the 3D printing was utilized solely for wax fabrication, the phrase "fabricated based on 3D printing techniques" would be more appropriate. Additionally, the term "advanced superimposition method" is used in the manuscript but is not sufficiently explained. Please clarify what makes the superimposition method "advanced."
- The introduction section is missing references for several statements. Citations should be distributed throughout the section, rather than grouped together to justify multiple preceding sentences.
- In formal writing, clarity and precision are key, so try to avoid relying on abbreviations like "etc." when possible.
- The introduction lacks depth and does not adequately define the problem considering all the study’s factors. Notably, the authors fail to address the cervical preparation factor in the study's aim considering previous research.
- The manuscript states that intraoral scanning “eliminates” operator errors. In reality, it only reduces these errors, as the equipment handles much of the process. However, impression errors and inaccurate judgments due to improper techniques—such as insufficient gingival retraction, poor scanning processes, or a too-moist environment – can still occur.
- The title is misleading because the ceramic crowns were not fabricated through 3D printing. Instead, resin crowns were 3D-printed and then used to create ceramic crowns via heat pressing.
- The manuscript requires a thorough grammar review to improve readability and coherence.
- The sample size is also misleading. The authors do not account for the three types of cervical preparation, which means the sample size per group is actually five, not 30. This needs to be reviewed.
- Instead of using zones and numbers to label measurement sites, I suggest using abbreviations that represent the site itself. For instance, if Z1 and Z9 represent marginal fit sites, they could be labeled as "marginal fit", or MF, for clarity.
- The method used to measure marginal and internal fit is not well explained. Were the crowns placed on the metal dies before scanning? This process needs to be clarified.
- The unit of measurement is not indicated in the figures. Additionally, I recommend including tables to present the marginal and internal fit results, with appropriate means, standard deviations, and statistical analyses. Supplementary Table S1 should be incorporated into the manuscript, redesigned for greater clarity.
- Supplementary Figure 1 is visually unappealing and unnecessary for the manuscript. Consider removing it.
- The first conclusion could benefit from clarification, especially regarding the phrase 'compared to any other crowns.' It would be helpful for the authors to specify whether they considered all possible methods for preparing, designing, and manufacturing dental ceramic crowns. Revisiting this point could enhance the clarity of the conclusion
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