Universal Adhesives: Evaluation of the Relationship between Bond Strength and Application Strategies—A Systematic Review and Meta-Analyses

Round 1

Reviewer 1 Report (New Reviewer)

The review from Triani et al. explores an interesting topic i.e., the one of bond strength and application strategies of Universal Adhesives. It examines the immediate and long- term bond strength of universal adhesives, applied by direct restorative techniques, to the tooth substrate – enamel and dentin tissues.  However, the paper needs a minor revision before being considered suitable for publication.

1-      Please clarify the significance of this review in the section “Introduction’

2-      L101-102 “The inclusion and exclusion criteria…three examiners (F.T., L.P.S. and B.L.).” How do you select the inclusion and exclusion criteria? And please explain why these criteria?

3-      L142-144 “After excluding duplicates, the remaining articles were screened and 1069 were excluded by reading the title and/or abstract.”

What did you based on to exclude such quantity of references after screening?

4-      Phrasing issues (These are only examples of a wider problem)

L161-165 “Description of methodology … a control group (items 5–9).”

L140-244 “Nonetheless, for … of the smear layer.”

L250-251 “Jacker-Guhr, Sander and Luehrs (2019) agree … a long-term assessment in their study [22].”

L285-288 “Recently, the 2-year follow up…rather than by ER adhesion mode [38].”

5-      L279-280 “The use of ER adhesion strategy can improve bond strength results of UAs with medium and soft pH values”.

Explain How the pH can improve the bond strength. What is the range of pH value suitable for stronger bond using only SE adhesive mode or ER adhesive mode or both modes?

6-      L285-288 “Recently, the 2-year follow up…rather than by ER adhesion mode [38].”

Please clearly state the differences in the clinical performance, functional success and retention rates for enamel and dental tissue.

7-      L295-296 “The selective enamel etching…the UA bond strength to the enamel tissue.” can you explain the process of the selective enamel etching?

8-      The section “conclusions” is weak. It is necessary to strengthen this section.

9-      Please add references in Table 2 and Table 3.

Author Response

Point 1: Please clarify the significance of this review in the section “Introduction’.

Response 1: Please see the attachment (L79-L82).

Point 2: L101-102 “The inclusion and exclusion criteria…three examiners (F.T., L.P.S. and B.L.).” How do you select the inclusion and exclusion criteria? And please explain why these criteria?

Response 2: Initially, in our first approach, we tried to only include studies regarding human permanent teeth but, considering how limited the results would be and not wanting to come up with an even smaller sample of articles to review, we had to choose to also include other species’ teeth as samples (such as bovine). In order to undergo an adequate and more complete evaluation of bond strength of this type of adhesives, we chose to include both the shear and microtensile bond strength tests (but only including those articles that referred the specific mean values obtained with each of these tests) and we also had to contemplate both adhesion application strategies by which UAs can be clinically applied – ER or SE mode. In addition, we chose to only perform a search for publications from 2007 onward, since this year portrays the introduction of UAs on the dental market. Finally, we decided to only include articles with a sample size of 20 teeth minimum in order to better get statistically significant results.

Point 3: L142-144 “After excluding duplicates, the remaining articles were screened and 1069 were excluded by reading the title and/or abstract.” What did you based on to exclude such quantity of references after screening?

Response 3: Of 1109, 1069 articles were excluded solely by reading the title or abstract because these studies did not comply with the established inclusion criteria (for example: some of the resulting articles compared other adhesive properties other than bond strength (such as wettability); with that in mind we had to eliminate articles that did not refer directly to shear or microtensile bond strength tests as the main objective to be analyzed.

Point 4: Phrasing issues (These are only examples of a wider problem)

L161-165 “Description of methodology … a control group (items 5–9).”

L140-244 “Nonetheless, for … of the smear layer.”

L250-251 “Jacker-Guhr, Sander and Luehrs (2019) agree … a long-term assessment in their study [22].”

L285-288 “Recently, the 2-year follow up…rather than by ER adhesion mode [38].”

Response 4: Please see the attachment (an attempt was made to correct some of the phrasing issues).

Point 5: L279-280 “The use of ER adhesion strategy can improve bond strength results of UAs with medium and soft pH values”. Explain How the pH can improve the bond strength. What is the range of pH value suitable for stronger bond using only SE adhesive mode or ER adhesive mode or both modes?

Response 5: Please see the attachment (L296-L305).

Point 6: L285-288 “Recently, the 2-year follow up…rather than by ER adhesion mode [38].” Please clearly state the differences in the clinical performance, functional success and retention rates for enamel and dental tissue.

Response 6: Please see the attachment (L-313-L316). We cannot state the differences between enamel and dentin, because that was not the scope of the study (the authors analyzed the clinical performance of different UAs comparing them to a control group comprised of an adhesive applied in an ER mode).

Point 7: L295-296 “The selective enamel etching…the UA bond strength to the enamel tissue.” can you explain the process of the selective enamel etching?

Response 7: Please see the attachment (L-326-L329).

Point 8: The section “conclusions” is weak. It is necessary to strengthen this section.

Response 8: Please see the attachment (L-326-L329).

Point 9: Please add references in Table 2 and Table 3.

Response 9: Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

The systematic review is very structured and with scientific merit. I suggest proofreading in English to correct some errors in writing.

Author Response

Point 1: The systematic review is very structured and with scientific merit. I suggest proofreading in English to correct some errors in writing.

Response 1: A native speaker has read the manuscript and corrected some phrasing issues.

Reviewer 3 Report (New Reviewer)

The presented work concerns a clinically significant issue in the field of dental materials science. I have a few comments to the text that should be noted by the authors:

- Please describe the results presented in table 2 in the results section in a syncretic way. In its current form, the description of the results is of little use as it only concerns differences in research protocols.

- The importance of individual research methods and their relationship to the expected clinical properties should be described in more detail, e.g. in a discussion. Please also describe the differences in both tests and their limitations.

All the work is well written and interesting. The discussion is substantive. The conclusions are adequate to the presented results of the literature analysis.

Author Response

Point 1: Please describe the results presented in table 2 in the results section in a syncretic way. In its current form, the description of the results is of little use as it only concerns differences in research protocols.

Response 1: We've tried to do it but it came across as a repetition of the mean values and standard deviations that are already displayed in table 2.

Point 2: The importance of individual research methods and their relationship to the expected clinical properties should be described in more detail, e.g. in a discussion. Please also describe the differences in both tests and their limitations.

Response 2: Please see the attachment (L228-L239).

Author Response File: Author Response.pdf

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Dear Editors/Authors

I am pleased that I was chosen for reviewer of this work.

The following modifications should be done in the paper before publication. My opinion is that the paper needs a minor revision to be published in the present form. I hope that given comments would be useful for avoiding faults and improving the quality of the paper.

Review:

Title: Universal Adhesives: Evaluation of the Relationship between Bond Strength and Application Strategies—A Systematic Review and Meta-Analyses

·         In the text, reference numbers should be placed in square brackets  for example [1–3]

·         The paper should be organized according to the instructions for authors.

Reviewer 2 Report

Overall: To my point, this research is much more suitable for Journals concerned about dental research, for example Dentistry Jounral, Operative Dentistry, et al. 

Method:  There were only 12 papers were chosen and studied, I think the amount of paper was too small for a review. Moreover, study like Burrer et al. 2020, only provided results obtained from ER, no results from SE were provided. Thus it is not suitable for the paper title.

Conclusion: The results concludede that bond strength of UA to enamel showed better results with the ER adhesion mode. However, in Cruz et al,. 2019, the results showed that ER and SE had the comparable bond strength, so did the research Jacker-Guhr, Sander and Luehrs, 2019 and Frattes et al., 2017.

Therefore, more researches should be reviewed and the results of reviewed papers should be analysed carefully further.