The Cyclic Fatigue Resistance of Different Lengths of CM Gold Wire and CM Blue Wire NiTi Alloy Endodontic Rotary Files: An In Vitro Study
, Vicente Faus-Llácer 1, Celia Ruiz-Sánchez 1,*, Sofía Prats Gallego 1, Álvaro Zubizarreta-Macho 2,3,*, Beatriz Solano-Mendoza 4, Benjamín Martín Biedma 5 and Ignacio Faus-Matoses 1Round 1
Reviewer 1 Report
Dear Authors,
Interesting topic and good methodology!
- It is better to change the topic to "The resistance of different lengths of NiTi endodontic rotary files to cyclic fatigue: An in vitro study"
- Please check the references in the main manuscript. Some are written numerically, some others are [xi], or superscript! Please write all of them according to the author's guidelines of the journal.
- why did you choose only 6% taper and why in teeth with 60°curvature? please add the reason to the discussion section.
- In the following paragraph please add the kind of teeth (with or without curvature) they did their study.
Manufacturers have therefore focused their efforts to reduce failure rates on the NiTi alloy and the geometrical design of NiTi alloy endodontic rotary files. Pruett et al. found that increased apical diameter reduced the resistance of NiTi alloy endodontic rotary files to cyclic fatigue [xviii]. Furthermore, Gambarini et al. reported that increased taper measurements also led to reduced cyclic fatigue resistance of the files [xix]. Kwak et al. found that the helix angle and pitch also reduced the resistance of NiTi alloy endodontic rotary files to cyclic fatigue [xx].
- please remove "(40)" from this part:
2.1. Study Design
Forty (40) sterile,
- 2.4. subtitle in the method and materials section: please write "rotating" normal and not bold. (In order to reduce friction between the rotating files and the)
- for time to failure (seconds): You probably mean time in seconds and not minutes? please clarify and write it better.
- Please increase the resolution of Figure 4&5.
- Discussion needs to be improved and discussed more!
Author Response
Dear Reviewer 1:
I’m pleased to resubmit the manuscript of the work entitled, “Effect of NiTi Alloy Endodontic Rotary File Length on Resistance to Cyclic Fatigue. An In Vitro Study”
Reviewer 1: English language and style are fine/minor spell check required.
Response: In order to adapt to the reviewer's 1 comments, we have sent the manuscript to an English Editing Service.
Reviewer 1: It is better to change the topic to "The resistance of different lengths of NiTi endodontic rotary files to cyclic fatigue: An in vitro study"
Response: In order to adapt to the reviewer's 1 comments, we have changed the title.
Reviewer 1: Please check the references in the main manuscript. Some are written numerically, some others are [xi], or superscript! Please write all of them according to the author's guidelines of the journal.
Response: In order to adapt to the reviewer's 1 comments, we have revised the full manuscript, but we did not find different formats.
Reviewer 1: why did you choose only 6% taper and why in teeth with 60°curvature? please add the reason to the discussion section.
Response: In order to adapt to the reviewer's 1 comments, we have added a sentence in the Discussion section: “It was selected CM Gold Wire and CM Blue Wire NiTi alloy endodontic rotary files with 6% taper, according to previous studies [22,23,25]; moreover, all CM Gold Wire and CM Blue Wire NiTi alloy endodontic rotary files presented the same taper to avoid including another variable. In addition, a 60° curvature angle was selected for the custom artificial root canals, according to previous studies [22,23,25].”
Reviewer 1: In the following paragraph please add the kind of teeth (with or without curvature) they did their study.
Manufacturers have therefore focused their efforts to reduce failure rates on the NiTi alloy and the geometrical design of NiTi alloy endodontic rotary files. Pruett et al. found that increased apical diameter reduced the resistance of NiTi alloy endodontic rotary files to cyclic fatigue [xviii]. Furthermore, Gambarini et al. reported that increased taper measurements also led to reduced cyclic fatigue resistance of the files [xix]. Kwak et al. found that the helix angle and pitch also reduced the resistance of NiTi alloy endodontic rotary files to cyclic fatigue [xx].
Response: In order to adapt to the reviewer's 1 comments, we have added the information required in the Introduction section.
Reviewer 1: please remove "(40)" from this part:
2.1. Study Design
Forty (40) sterile,
Response: In order to adapt to the reviewer's 1 comments, we have removed “(40)”.
Reviewer 1: 2.4. subtitle in the method and materials section: please write "rotating" normal and not bold. (In order to reduce friction between the rotating files and the)
Response: In order to adapt to the reviewer's 1 comments, we have written “rotating” normal, not bold.
Reviewer 1: for time to failure (seconds): You probably mean time in seconds and not minutes? please clarify and write it better.
Response: In order to adapt to the reviewer's 1 comments, we have clarified and write better in the results section: “Table 1 and Figure 4 show the mean and SD values for time to failure expressed in seconds for each of the study groups”.
Reviewer 1: Please increase the resolution of Figure 4&5.
Response: In order to adapt to the reviewer's 1 comments, we clarify that Figure 4 and 5 were removed, according to the Reviewer 2 comments.
Reviewer 1: Discussion needs to be improved and discussed more
Response: In order to adapt to the reviewer's 1 comments, we have added some sentences in the Discussion section.
Reviewer 2 Report
Dear Authors
I have read your manuscript. "Effect of NiTi Alloy Endodontic Rotary File Length on Resistance to Cyclic Fatigue. An In Vitro Study." It is an interesting manuscript that can give an idea of the influence of the length of rotary instruments on their resistance to fatigue. What could help the clinician to make a decision when choosing the instrument that he should use in the clinic. However, the manuscript has some details and critical points that must be clarified.
I will make a few comments below:
The title reflects one of the biggest problems with the manuscript since it is a very general title, and just as the title is very general, many of the statements in the manuscript are too. Only the influence of the length in the CM GOLD-WIRE and CM BLUE WIRE instruments on fatigue resistance was examined in this investigation. These results cannot be generalized to all NiTi rotary files (different commercial brands) since, as you say in the introduction ...different geometrical designs, manufacturing process as heat treatments, electro-polishing, or ion implantation impact the mechanical behavior... Then, the title and the manuscript must be reported only and specifically to the studied instruments and not to all in general.
The second line of the materials and methods section is unclear: …”All files were first examined under magnification (OPMI pico, Zeiss, Oberkochen, Germany), with none being discarded….” What was examined, and why should they have been discarded?
Line 6-10 of the materials and methods section is unclear: …The selected NiTi endodontic rotary files were divided among the following study groups, in keeping with the proportions determined by the researcher, and with a power of 80%. Additionally, an effect size of 0.606 can be observed when testing the null hypothesis H₀. The mean values of the four groups were equal by the means of a 1-factor ANOVA test for independent samples, factoring in a significance level of 5%... In addition to not being clear, it should be written in the statistical analysis section.
Please reduce the last paragraph before 2.2. Section. It is not necessary to repeat …“25.06 CM Gold-Wire NiTi alloy endodontic rotary files, Endogal, Galician Endodontics Company, Lugo, Spain)….” four times.
Please do not show results in the materials and methods section. The images obtained with the SEM and the analyzes obtained with EDX should not go in this section. In addition, it needs to be clarified why both analyzes were carried out; they are not discussed later, neither in the results nor in the discussion. What do they have to do with length and fatigue resistance?
In the results section, please choose one form of presentation to the results, a table or a graph, because one repeats the results of the other. On the other hand, if you present an unusual analysis in fatigue resistance studies, you must interpret it in the discussion. Not all readers know how to interpret the Weibull probability analysis. What are these results translated into, and what information other than the first results (table 1, fig 4) does it provide?
Please limit your conclusion to the brand of instruments you used in this investigation, or at least those made in the same way, with the same alloy and geometry, and not to all NiTi instruments.
Please revise the citation style that you are using. It is incorrect. Also, revise all your references' style and unify them, some do not follow the required style.
Author Response
Dear Reviewer 2:
I’m pleased to resubmit the manuscript of the work entitled, “Effect of NiTi Alloy Endodontic Rotary File Length on Resistance to Cyclic Fatigue. An In Vitro Study”
Reviewer 2: Moderate English changes required.
Response: In order to adapt to the reviewer's 2 comments, we have sent the manuscript to an English Editing Service.
Reviewer 2: The title reflects one of the biggest problems with the manuscript since it is a very general title, and just as the title is very general, many of the statements in the manuscript are too. Only the influence of the length in the CM GOLD-WIRE and CM BLUE WIRE instruments on fatigue resistance was examined in this investigation. These results cannot be generalized to all NiTi rotary files (different commercial brands) since, as you say in the introduction ...different geometrical designs, manufacturing process as heat treatments, electro-polishing, or ion implantation impact the mechanical behavior... Then, the title and the manuscript must be reported only and specifically to the studied instruments and not to all in general.
Response: In order to adapt to the reviewer's 2 comments, we have changed the title.
Reviewer 2: The second line of the materials and methods section is unclear: …”All files were first examined under magnification (OPMI pico, Zeiss, Oberkochen, Germany), with none being discarded….” What was examined, and why should they have been discarded?
Response: In order to adapt to the reviewer's 2 comments, we have decided to remove the sentence from the Material and Methods section.
Reviewer 2: Line 6-10 of the materials and methods section is unclear: …The selected NiTi endodontic rotary files were divided among the following study groups, in keeping with the proportions determined by the researcher, and with a power of 80%. Additionally, an effect size of 0.606 can be observed when testing the null hypothesis H₀. The mean values of the four groups were equal by the means of a 1-factor ANOVA test for independent samples, factoring in a significance level of 5%... In addition to not being clear, it should be written in the statistical analysis section.
Response: In order to adapt to the reviewer's 2 comments, we have clarified the sentence and moved to the statistical analysis section.
Reviewer 2: Please reduce the last paragraph before 2.2. Section. It is not necessary to repeat …“25.06 CM Gold-Wire NiTi alloy endodontic rotary files, Endogal, Galician Endodontics Company, Lugo, Spain)….” four times.
Response: In order to adapt to the reviewer's 2 comments, we have removed the manufacturer information.
Reviewer 2: Please do not show results in the materials and methods section. The images obtained with the SEM and the analyzes obtained with EDX should not go in this section.
Response: In order to adapt to the reviewer's 2 comments, we clarify that SEM analysis were performed to discard manufacturing surface defects which could affect on the cyclic fatigue resistance of the NiTi alloy endodontic rotary files. Additionally, EDX analysis were performed to confirm the NiTi alloy chemical composition of each endodontic rotary file to avoid different NiTi alloy chemical composition which could affect on the cyclic fatigue resistance of the NiTi alloy endodontic rotary files. Briefly, SEM and EDX analysis are not results of the study, but methodological techniques to ensure that the sample is homogeneous; therefore, we consider that both should be in the Material and Methods section. Additionally, we have also place this information in the Material and Methods section of previous studies: Faus-Matoses V, Faus-Llácer V, Ruiz-Sánchez C, Jaramillo-Vásconez S, Faus-Matoses I, Martín-Biedma B, Zubizarreta-Macho Á. Effect of Rotational Speed on the Resistance of NiTi Alloy Endodontic Rotary Files to Cyclic Fatigue-An In Vitro Study. J Clin Med. 2022 May 31;11(11):3143. doi: 10.3390/jcm11113143. Faus-Matoses V, Pérez García R, Faus-Llácer V, Faus-Matoses I, Alonso Ezpeleta Ó, Albaladejo Martínez A, Zubizarreta-Macho Á. Comparative Study of the SEM Evaluation, EDX Assessment, Morphometric Analysis, and Cyclic Fatigue Resistance of Three Novel Brands of NiTi Alloy Endodontic Files. Int J Environ Res Public Health. 2022 Apr 6;19(7):4414. doi: 10.3390/ijerph19074414. Faus-Llácer V, Hamoud-Kharrat N, Marhuenda Ramos MT, Faus-Matoses I, Zubizarreta-Macho Á, Ruiz Sánchez C, Faus-Matoses V. Influence of the Geometrical Cross-Section Design on the Dynamic Cyclic Fatigue Resistance of NiTi Endodontic Rotary Files-An In Vitro Study. J Clin Med. 2021 Oct 14;10(20):4713. doi: 10.3390/jcm10204713. We have added two sentences and references in the Materials and Methods section.
Reviewer 2: In addition, it needs to be clarified why both analyzes were carried out; they are not discussed later, neither in the results nor in the discussion. What do they have to do with length and fatigue resistance?
Response: In order to adapt to the reviewer's 2 comments, we clarify that manufacturing surface defects could affect on the cyclic fatigue resistance of the NiTi alloy endodontic rotary files, and also different NiTi alloy chemical composition which could affect on the cyclic fatigue resistance of the NiTi alloy endodontic rotary files. These are the reasons why the authors performed both SEM and EDX analysis. In addition, these methodological procedures have been also used in previous studies: Faus-Matoses V, Faus-Llácer V, Ruiz-Sánchez C, Jaramillo-Vásconez S, Faus-Matoses I, Martín-Biedma B, Zubizarreta-Macho Á. Effect of Rotational Speed on the Resistance of NiTi Alloy Endodontic Rotary Files to Cyclic Fatigue-An In Vitro Study. J Clin Med. 2022 May 31;11(11):3143. doi: 10.3390/jcm11113143. Faus-Matoses V, Pérez García R, Faus-Llácer V, Faus-Matoses I, Alonso Ezpeleta Ó, Albaladejo Martínez A, Zubizarreta-Macho Á. Comparative Study of the SEM Evaluation, EDX Assessment, Morphometric Analysis, and Cyclic Fatigue Resistance of Three Novel Brands of NiTi Alloy Endodontic Files. Int J Environ Res Public Health. 2022 Apr 6;19(7):4414. doi: 10.3390/ijerph19074414. Faus-Llácer V, Hamoud-Kharrat N, Marhuenda Ramos MT, Faus-Matoses I, Zubizarreta-Macho Á, Ruiz Sánchez C, Faus-Matoses V. Influence of the Geometrical Cross-Section Design on the Dynamic Cyclic Fatigue Resistance of NiTi Endodontic Rotary Files-An In Vitro Study. J Clin Med. 2021 Oct 14;10(20):4713. doi: 10.3390/jcm10204713. We have added two sentences and references in the Materials and Methods section.
Reviewer 2: In the results section, please choose one form of presentation to the results, a table or a graph, because one repeats the results of the other.
Response: In order to adapt to the reviewer's 2 comments, we have removed Figures 4 and 5.
Reviewer 2: On the other hand, if you present an unusual analysis in fatigue resistance studies, you must interpret it in the discussion. Not all readers know how to interpret the Weibull probability analysis. What are these results translated into, and what information other than the first results (table 1, fig 4) does it provide?
Response: In order to adapt to the reviewer's 2 comments, we have added a sentence in the Discussion section to explain the Weibull analysis: “The Weibull analysis allows estimating the probability that a material presents to fracture over time. The more vertical the curve is, the more predictable the mechanical behavior of the material is, since it would indicate that all the samples fracture at the same moment. However, the more horizontal the curve, the less predictable the behavior of the material, as it could fracture at any time. These are expressed with the shape and scale parameters. The larger the scale, the broader the distribution, and when the shape parameter is greater than 1 it indicates that the failure rate increases with time.”.
Reviewer 2: Please limit your conclusion to the brand of instruments you used in this investigation, or at least those made in the same way, with the same alloy and geometry, and not to all NiTi instruments.
Response: In order to adapt to the reviewer's 2 comments, we have rewritten the Conclusion section: “The length of the rotary file is inversely proportional to the cyclic fatigue resistance of the 25.06 CM Gold Wire NiTi alloy, 31-mm, 25-mm and 21-mm length and 25.06 CM Blue Wire NiTi alloy 17-mm length of the endodontic rotary file; the greater the length, the lower the resistance of the 25.06 CM Gold Wire NiTi alloy, 31-mm, 25-mm and 21-mm length and 25.06 CM Blue Wire NiTi alloy 17-mm length of the endodontic rotary to cyclic fatigue”.
Reviewer 2: Please revise the citation style that you are using. It is incorrect. Also, revise all your references' style and unify them, some do not follow the required style.
Response: In order to adapt to the reviewer's 2 comments, we have revised the full references.
Round 2
Reviewer 2 Report
Thank you very much for your corrections.
