Effect of Manual and Electronic Toothbrushes on Color Stability and Contact Profilometry of Different CAD/CAM Ceramic Materials After Immersion in Coffee for Varying Time Intervals

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for the article titled: “Effect of Manual and Electronic Toothbrushes on Color Stability and Contact Profilometry of Different CAD/CAM Ceramic Materials After Immersion in Coffee for Varying Time Intervals”. This paper is very interesting and tackles the intriguing and practical topic of how different types of toothbrushes affect the color stability and surface roughness of ceramic materials used in CAD/CAM technology. However, the article requires both substantive and editorial refinement.

 

The introduction section is somewhat lengthy and contains repetitions that can make it difficult to read, ultimately weakening the overall message. I recommend that the authors consider condensing this section and providing a more succinct summary of the existing knowledge, particularly in regard to current findings and research gaps. The content could be organized more logically by addressing the following points: What is known (state of knowledge), what is unknown (research gap), why it’s important (practical significance) and what the authors did (study's purpose and hypothesis).

Moreover please check:

Lines 70–73: While the authors mention that data regarding the effect of different toothbrush types on CAD/CAM materials is limited, they do not expand on this statement. I believe this argument should be strengthened by emphasizing the practical significance of the study.

 

Material and methods section: The authors could enhance the methodology by providing an explanation for the selection of the four specific CAD/CAM materials: Vitablocs Mark II, Ceramill Zolid zirconia, Vita Triluxe Forte, and IPS e.max CAD. The rationale for choosing these materials is not articulated—are they the most commonly used materials in clinical practice? Do they have distinct microstructures that could influence the study's outcomes? Justifying the selection of materials is critical, particularly given the comparative analysis of their optical and surface properties.

Additionally, the number of samples for each material and brush type is not clearly delineated. It is only later mentioned that the total sample count is 140. Although the authors provide details on subgroup division by brush type, it would be beneficial to specify the exact number of samples allocated to each group and the overall total (e.g., 4 materials × 4 brush types × 10 samples = 160?). To enhance clarity, a summary table detailing the experimental groups (material × brushing type × number of samples) is recommended.

Line 179: The authors wrote the name of the toothpaste used (Signal®), but do not include its abrasive properties, such as the RDA value of this paste. This could significantly affect the results regarding material surfaces. It is advisable to include this information or at least acknowledge it as a limitation of the study.

Line 180: The brushing force value (2 ± 0.2 kg) is provided, but information on how this parameter was controlled and calibrated is missing. It is unclear whether a brushing device (e.g., a machine) was used or whether manual brushing was otherwise standardized. The authors should clarify how the reproducibility of this element of the procedure was ensured.

Furthermore, it is not specified whether brushing was performed "dry" or in the presence of a liquid (e.g., immersion in water or a solution), which could influence the abrasion process and contact of the toothpaste with the material surface. It is suggested that these conditions be further specified in the method description.

 

Results section: The results are comprehensive, but their presentation is challenging to follow. The numerous tables make it difficult to analyze the data and focus on key findings. Consider reducing the number of tables by combining some or moving less important data to supplementary materials. Additionally, some results are repeated in both the text and the tables; a concise summary is recommended to avoid duplicating detailed numerical values.

 

Discussion section: The discussion is quite lengthy and often reiterates points made in the results section. I suggest concentrating on interpreting the most significant differences between groups and exploring the potential mechanisms behind the observed phenomena. Although many sources are cited, the discussion remains superficial. It would be beneficial to include in-depth comparisons with other studies, especially where results diverge. A critical analysis of possible reasons for discrepancies with the literature, such as the impact of pH or the abrasiveness of the paste, is also lacking. Moreover, the limitations of the study, including its in vitro nature, simplified conditions, and short observation period, should be more prominently highlighted.

 

The conclusions are somewhat vague. It would be helpful for the authors to specify the clinical implications of their findings, such as how the results might influence a clinician’s or patient’s choice of CAD/CAM materials or toothbrush types.

Author Response

Comment 1.1: Thank you for the article titled: “Effect of Manual and Electronic Toothbrushes on Color Stability and Contact Profilometry of Different CAD/CAM Ceramic Materials After Immersion in Coffee for Varying Time Intervals”. This paper is very interesting and tackles the intriguing and practical topic of how different types of toothbrushes affect the color stability and surface roughness of ceramic materials used in CAD/CAM technology. However, the article requires both substantive and editorial refinement.

Response: thanks

Comment 1.2: The introduction section is somewhat lengthy and contains repetitions that can make it difficult to read, ultimately weakening the overall message. I recommend that the authors consider condensing this section and providing a more succinct summary of the existing knowledge, particularly in regard to current findings and research gaps. The content could be organized more logically by addressing the following points: What is known (state of knowledge), what is unknown (research gap), why it’s important (practical significance) and what the authors did (study's purpose and hypothesis).

Response: We sincerely thank the reviewer for this valuable observation. We agree that conciseness enhances clarity, and have comprehensively revised the Introduction to address these concerns: Removed redundant discussions of background concepts particularly in paragraphs 5and 6 of the original version.

Comment 1.3: Lines 70–73: While the authors mention that data regarding the effect of different toothbrush types on CAD/CAM materials is limited, they do not expand on this statement. I believe this argument should be strengthened by emphasizing the practical significance of the study.

Response: We thank the reviewer for this insightful suggestion. We agree that highlighting the clinical relevance of this research gap strengthens our contribution. The following revisions have been made in the Introduction ( lines 73–75)

Comment 1.4: Material and methods section: The authors could enhance the methodology by providing an explanation for the selection of the four specific CAD/CAM materials: Vitablocs Mark II, Ceramill Zolid zirconia, Vita Triluxe Forte, and IPS e.max CAD. The rationale for choosing these materials is not articulated—are they the most commonly used materials in clinical practice? Do they have distinct microstructures that could influence the study's outcomes? Justifying the selection of materials is critical, particularly given the comparative analysis of their optical and surface properties.

Response: We appreciate this constructive suggestion. A paragraph about Sample Selection Rationale has been added to (lines 110-118) to justify material selection

Comment 1.5:  Additionally, the number of samples for each material and brush type is not clearly delineated. It is only later mentioned that the total sample count is 140. Although the authors provide details on subgroup division by brush type, it would be beneficial to specify the exact number of samples allocated to each group and the overall total (e.g., 4 materials × 4 brush types × 10 samples = 160?). To enhance clarity, a summary table detailing the experimental groups (material × brushing type × number of samples) is recommended.

Response: We thank the reviewer for identifying this important clarification need and sincerely apologize for the numerical discrepancy. The "140" was an inadvertent typographical error We have corrected to 160 samples with no summary table needed as it is clear now. corrections made in lines 15/120           

Comment 1.6: Line 179: The authors wrote the name of the toothpaste used (Signal®), but do not include its abrasive properties, such as the RDA value of this paste. This could significantly affect the results regarding material surfaces. It is advisable to include this information or at least acknowledge it as a limitation of the study.

Response:  We sincerely thank the reviewer for this essential methodological insight. We have added the following details about Signal® toothpaste in  (lines 184) to address this concern: All devices were utilized twice every 24 hours for 60 s with dentifrice (Signal® toothpaste) with a Relative Dentin Abrasivity (RDA) value of 70

Comment 1.7: Line 180: The brushing force value (2 ± 0.2 kg) is provided, but information on how this parameter was controlled and calibrated is missing. It is unclear whether a brushing device (e.g., a machine) was used or whether manual brushing was otherwise standardized. The authors should clarify how the reproducibility of this element of the procedure was ensured.

Response:  We thank the reviewer for highlighting this essential methodological detail. The following clarifications have been added to Section 2.3 (lines 186-189): Brushing was performed using a V8 brushing simulator (JWE GmbH, Germany) The simulator arm was fitted with an inline load cell and force was recorded continuously; the load cell was calibrated with standard masses prior to each session and the brushing force was set to 2.0 ± 0.2 kg

Comment 1.8: Furthermore, it is not specified whether brushing was performed "dry" or in the presence of a liquid (e.g., immersion in water or a solution), which could influence the abrasion process and contact of the toothpaste with the material surface. It is suggested that these conditions be further specified in the method description.

Response: We thank the reviewer for this essential methodological observation. We have clarified the environmental conditions in  (lines 184-185) as follows: Each 30-second brushing segment utilized performed using a toothpaste slurry prepared prepared by mixing 0.25 g of toothpaste with deionized water at a 1:3 ratio for 20 s

Comment 1.9: Results section: The results are comprehensive, but their presentation is challenging to follow. The numerous tables make it difficult to analyze the data and focus on key findings. Consider reducing the number of tables by combining some or moving less important data to supplementary materials. Additionally, some results are repeated in both the text and the tables; a concise summary is recommended to avoid duplicating detailed numerical values.

Response: We thank the reviewer for this insightful suggestion. We removed unnecessary table and counted on figure 1 for easier understanding of the main results. Additionally, we provide a concise summary to avoid duplicating detailed numerical values (page 7, lines241-250)

Comment 1.10:  Discussion section: The discussion is quite lengthy and often reiterates points made in the results section. I suggest concentrating on interpreting the most significant differences between groups and exploring the potential mechanisms behind the observed phenomena. Although many sources are cited, the discussion remains superficial. It would be beneficial to include in-depth comparisons with other studies, especially where results diverge. A critical analysis of possible reasons for discrepancies with the literature, such as the impact of pH or the abrasiveness of the paste, is also lacking. Moreover, the limitations of the study, including its in vitro nature, simplified conditions, and short observation period, should be more prominently highlighted. 

Response:

Thank you for your insightful feedback regarding the Discussion section of our manuscript. We appreciate your suggestions and will make several revisions to enhance the clarity and depth of our analysis.

• We streamlined the discussion by concentrating on the most significant differences between groups, ensuring that we focus on interpreting these findings rather than reiterating points from the Results section. Line333-337 and line 361 we removed the repeated results and replaced them by mentioning table and figure number.
• In line 341-344 we demonstrated the potential mechanisms behind the observed phenomena.
• In line 363-370 we incorporated more detailed comparisons and include a critical analysis of potential reasons for discrepancies with other studies, specifically addressing factors such as pH and the abrasiveness of the paste
• We would like to clarify that these points have already been explicitly addressed in the Limitations section of our manuscript.

Comment 1.11: The conclusions are somewhat vague. It would be helpful for the authors to specify the clinical implications of their findings, such as how the results might influence a clinician’s or patient’s choice of CAD/CAM materials or toothbrush types.

Response: We thank the reviewer for this valuable suggestion. We have revised the conclusion section to explicitly address the clinical implications of our findings. In the revised manuscript (page 14, line 421-428)

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Comments and Suggestions for Authors

This is an outstanding study that offers valuable and clinically relevant insights into how
different types of toothbrushes affect the color stability and surface integrity of CAD/CAM
ceramics. The authors have addressed a practical aspect of restorative dentistry with rigorous
methodology and comprehensive data analysis.
Suggestions for authors:
 The study could benefit from a clinical perspective on how toothbrushing technique
and toothbrush type may influence not only the stability of ceramic restorations but
also periodontal health, particularly in areas adjacent to the restoration margins.
 Differentiate Stain Origins
Consider discussing not only dietary stains (e.g., coffee) but also discoloration caused
by bacterial biofilms. These bacteria can contribute to extrinsic staining on ceramic
margins and influence long-term esthetics.
 Highlight Surface Roughness and Bacterial Adhesion
Since increased surface roughness (Ra) facilitates bacterial colonization, it's relevant
to correlate roughness findings with potential plaque retention
 Propose Microbial Assessment in Future Work
Future studies should assess microbial adhesion (e.g., via PCR or culturing) alongside
color change and surface roughness, to better understand the interplay between
mechanical cleaning, ceramic degradation, and periodontal health.

To further enhance the clinical applicability of the findings, recommend incorporating a brief
discussion on periodontal implications, particularly the impact of surface roughness on
bacterial adhesion and plaque accumulation.
In addition, aligning the discussion with the European Federation of Periodontology (EFP)
guidelines would enhance the clinical relevance, particularly regarding the effective
management of plaque control.
Overall, this article makes a significant contribution to prosthodontic and preventive dentistry
and opens the door for future interdisciplinary studies involving restorative materials.

Author Response

This is an outstanding study that offers valuable and clinically relevant insights into how different types of toothbrushes affect the color stability and surface integrity of CAD/CAM ceramics. The authors have addressed a practical aspect of restorative dentistry with rigorous
methodology and comprehensive data analysis.

Thank you for your positive feedback. 

Comment 2.1: 
Suggestions for authors:
· The study could benefit from a clinical perspective on how toothbrushing technique and toothbrush type may influence not only the stability of ceramic restorations but also periodontal health, particularly in areas adjacent to the restoration margins.

Response: We added a brief discussion in the discussion section about how toothbrush type and technique might affect periodontal health, especially near restoration margins. [Page 13, lines 403].

Comment 2.2: 

• Differentiate Stain Origins
  Consider discussing not only dietary stains (e.g., coffee) but also discoloration caused by bacterial biofilms. These bacteria can contribute to extrinsic staining on ceramic margins and influence long-term esthetics.
  Response: We appreciate this constructive suggestion we expanded the Discussion to include bacterial biofilm as a cause of extrinsic staining. [Page 13, lines 375].

Comment 2.3: 

• Highlight Surface Roughness and Bacterial Adhesion
  Since increased surface roughness (Ra) facilitates bacterial colonization, it's relevant
  to correlate roughness findings with potential plaque retention

Response: We sincerely thank the reviewer for this valuable observation. we added a point in the Discussion linking the observed surface roughness to potential plaque retention in Discussion [Page 13, lines 373-376].

Comment 2.4: 

• Propose Microbial Assessment in Future Work
  Future studies should assess microbial adhesion (e.g., via PCR or culturing) alongside
  color change and surface roughness, to better understand the interplay between
  mechanical cleaning, ceramic degradation, and periodontal health.
  Response: We thank the reviewer for this essential comment we proposed at the end of the limitations [Page 14, lines 416-419].

Comment 2.5: 

To further enhance the clinical applicability of the findings, recommend incorporating a brief
discussion on periodontal implications, particularly the impact of surface roughness on
bacterial adhesion and plaque accumulation.
Response: Incorporated in Discussion [Page 13, lines 373-376].

Comment 2.6: 

In addition, aligning the discussion with the European Federation of Periodontology (EFP)
guidelines would enhance the clinical relevance, particularly regarding the effective
management of plaque control.

Response: We thank the reviewer for this valuable suggestion. We add to the a paragraph to discuss the effective management of plaque control to enhance the clinical relevance of the study in [Page 13, lines 394-403].

 

Comment 2.7: 
Overall, this article makes a significant contribution to prosthodontic and preventive dentistry
and opens the door for future interdisciplinary studies involving restorative materials.

Response: Thank you

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The Vitablocs Mark II and Vita Suprinity circular specimens were glazed and sin-124 tered for 2 h at 1550 °C (this is wrong) in a dental ceramic furnace (Programat P310; Ivoclar Vivadent 125 AG), whereas the lithium disilicate glass ceramic and feldspathic ceramic blocks (Vita 126 Triluxe Forte) were crystallized according to the manufacturer's recommendations (which temperature?). All 127 specimens were constructed by using a CAD/CAM system (Amann Girrbach, GmbH, 128 Durrenweg 40 75,177 Pforzheim, Germany).

Sorry, but not these terrible errors. 1550 °C sintering temperature is for zirconia not for these materials.

The dimensions of round specimens were standardized to a uniform size of 118 10±0.25 mm in diameter and a thickness of 2.0±0.25 mm (very thick). The samples were finished and 119 polished using 300–800-grit silicon carbide paper ( very rough). 

The color parameters depend not only on the sintering temperature but also from surface roughness.

Author Response

Comment 3.1: The Vitablocs Mark II and Vita Suprinity circular specimens were glazed and sin-124 tered for 2 h at 1550 °C (this is wrong) in a dental ceramic furnace (Programat P310; Ivoclar Vivadent 125 AG), whereas the lithium disilicate glass ceramic and feldspathic ceramic blocks (Vita 126 Triluxe Forte) were crystallized according to the manufacturer's recommendations (which temperature?). All 127 specimens were constructed by using a CAD/CAM system (Amann Girrbach, GmbH, 128 Durrenweg 40 75,177 Pforzheim, Germany).

Sorry, but not these terrible errors. 1550 °C sintering temperature is for zirconia not for these materials.

Response:  We thank the reviewer for this valuable observation. We confirm that we have followed the manufacturers’ instructions during preparation of all samples and revised the manuscript accordingly  (page 3, lines 128–136)

Comment 3.2: The dimensions of round specimens were standardized to a uniform size of 118 10±0.25 mm in diameter and a thickness of 2.0±0.25 mm (very thick). The samples were finished and 119 polished using 300–800-grit silicon carbide paper (very rough). 

The color parameters depend not only on the sintering temperature but also from surface roughness.

Response: the sample dimensions and surface finishing were prepared in accordance with previous studies such as: 

1. Al-Ahmari MM, Alzahrani AH, Al-Qatarneh FA, Al Moaleem MM, Shariff M, Alqahtani SM, Porwal A, Al-Sanabani FA, AlDhelai TA. Effect of Miswak Derivatives on Color Changes and Mechanical Properties of Polymer-Based Computer-Aided Design and Computer-Aided Manufactured (CAD/CAM) Dental Ceramic Materials. Med Sci Monit. 2022 Jun 17;28:e936892. doi: 10.12659/MSM.936892.
2. Al Ahmari NM, Alahmari MA, Al Moaleem MM, Alshahrani RSA, Alqahtani FF, Mohammed WS, Al-Makramani BMA, Mehta V, Meto A, Meto A. Physical, Optical, and Mechanical Properties of Ceramic Materials after Coffee Immersion and Evaluation of Cleaning Impact with Different Oral Hygiene Tools. Int J Environ Res Public Health. 2022 Nov 15;19(22):15047. doi: 10.3390/ijerph192215047.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for the revised version of the manuscript. I appreciate the authors' efforts in addressing the previous comments and suggestions.  In my opinion, the manuscript is acceptable in its current form.

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors

you have improved your manuscript. Perhaps the conclusion could be better.