In Vivo Bone Progression in and around Lattice Implants Additively Manufactured with a New Titanium Alloy

Round 1

Reviewer 1 Report

Journal: Applied Sciences (ISSN 2076-3417)

Manuscript ID: applsci-2419940

Type: Article

Title: In vivo bone progression in and around lattice implants additively manufactured with a new titanium alloy.

Authors: Anne-Françoise Obaton*, Jacques Fain, Dietmar Meinel, Athanasios Tsamos, Fabien Léonard, Benoît Lecuelle, Madjid Djemaï.

 

a)           Write the objective of the present work carefully.

b)          Do you consider the topic original or relevant in the field? Does it address a specific gap in the field?

c)           Why the author didn’t measure the mechanical properties of the alloy such as roughness, hardness, Impact, Tensile …. etc?  

d)          Why the author didn’t measure the thermal conductivity of the samples?

e)           Please; Refer to the recent refs

DOI: https://doi.org/10.1088/1742-6596/1795/1/012059

DOI: https://doi.org/10.1515/jmbm-2022-0280

Best Regards

Author Response

Referee 1

(x) Moderate editing of English language

 

The paper has been nicely written but needs significant improvement. Please follow my comments.

1. What is the application of this study?

> The speed and quality, through high stability, of the osseointegration of an implant into a patient body is crucial for the rapid recovery of the patient as well as the durability of prosthesis implantation for a better quality of life. The new titanium alloy (Ti–19Nb–14Zr), proposed in this paper, increases the quality of osseointegration with a BIC of 95% and speeds the ossification compared to conventional used titanium alloys. In addition, the lattice structure of the implant increases it stability. Whereas, the laterally closing up of the lattice structures opens the possibility of bone spline key of prostheses allowing the implant to be removed more easily if required (end of life of the implant, material incompatibility into the body, bad positioning). Thus, this new titanium alloy, whose flexibility is close to that of the cortical bone, reducing stress at the bone/implant junction, and hence the risk of loosening, as well as such laterally closed lattice structures, are appropriate candidates to be implemented in a new generation of implants. This new generation of implants is made necessary to face the medical complications that can arise with certain components in alloys presently used, such as Al and V, as well as the prohibition of cobalt in 2025, decreed by the European Chemicals Agency (ECHA) in 2017, and included and enshrined in the European regulation.

 

2. What is the main issue that will be solved by this investigation? Please clarify it in the text.

> This has been clarified in the conclusion as highlighted in the document named “Manuscript with track changes”.

 

3. Is there any differences between this work and other works in the literature?

> Yes, we proposed a new titanium alloy and the lattice structures are laterally closed to design a new solution for bone spline keys.

 

4. Please add a brief statement on your methodology.

> This has been done in the introduction as highlighted in the document named “Manuscript with track changes”.

 

5. What is the future direction of this work?

> The next step of this study, consisting of establishing a partnership with the medical sector to implement a comparative study of the available implants on the market and our proposal (material and geometrical configuration), is ongoing to demonstrate its value. This sentence has been added in the conclusion as highlighted in the document named “Manuscript with track changes”.

 

6. Please proofread the paper.

> It has been done.

 

7. If possible add better quality for Figure 11.

> The image has been changed.

 

8. AM has many usages in different industries. To highlight your work, add a short note in the introduction by using the following papers and mention the privilege of lasers in manufacturing. “Benchmark models for conduction and keyhole modes in laser-based powder bed fusion of Inconel 718”. “Compressive response of selective laser-melted lattice structures with different strut sizes based on theoretical, numerical and experimental approaches”. “Modeling SEBM process of tantalum lattices”.

> It has been done in the introduction as highlighted in the document named “Manuscript with track changes”.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript entitled “applsci-2419940  ” dealing with lattice implants has been reviewed. The paper has been nicely written but needs significant improvement. Please follow my comments.

 

 

1.     What is the application of this study?

2.     What is the main issue that will be solved by this investigation? Please clarify it in the text.

3.     Is there any differences between this work and other works in the literature?

4.     Please add a brief statement on your methodology.

5.     What is the future direction of this work?

6.     Please proofread the paper.

7.     If possible add better quality for Figure 11.

8.     AM has many usages in different industries. To highlight your work, add a short note in the introduction by using the following papers and mention the privilege of lasers in manufacturing. “Benchmark models for conduction and keyhole modes in laser-based powder bed fusion of Inconel 718”. “Compressive response of selective laser-melted lattice structures with different strut sizes based on theoretical, numerical and experimental approaches”. “Modeling SEBM process of tantalum lattices”.

 

 

Proofread the paper.

Author Response

Referee 2

(x) English language fine. No issues detected

 

Does the introduction provide sufficient background and include all relevant references?

Must be improved

> The introduction was improved as highlighted in the document named “Manuscript with track changes”.

 

Are all the cited references relevant to the research?

Must be improved

> More references have been added as highlighted in the document named “Manuscript with track changes”.

 

Is the research design appropriate?

Yes

 

Are the methods adequately described?

Yes

 

Are the results clearly presented?

Yes

 

Are the conclusions supported by the results?

Can be improved

> The conclusions were improved as highlighted in the document named “Manuscript with track changes”.

 

The authors aimed to evaluate ''In vivo bone progression in and around lattice implants additively manufactured with a new titanium alloy''. The subject is an important in its area.

However, there are some comments:

Please improve the conclusion section of the abstract.

> The conclusion of the abstract was improved as highlighted in the document named “Manuscript with track changes”.

 

The introduction does not provide sufficient background and is not include all relevant references. It is also so short. Please improve it using more recent and relevant references. And also please mention the gaps in the study and the solutions you suggested for these gaps.

> The introduction was improved as highlighted in the document named “Manuscript with track changes”.

 

Methods: the research design is appropriate.

The methods are adequately described.

The results clearly presented.

 

Please add statistical section with details. It is so important.

> We agree with the referee. It was also our aim to conduct a statistical analysis. Thus, 3 sheep underwent surgery however the third sheep fought with other sheep during recovery and died. Therefore, the statistical study could not be performed.

 

Please improve the discussion section using potent references comparing the previous studies

> We have not found any recent work carried out "in vivo" on structures similar to those we have studied. An initial study, that we have carried out, on the same structures but with Ti6Al4V showed the inadequacy of the progressions and led to the present study.

Author Response File: Author Response.docx

Reviewer 3 Report

The authors aimed to evaluate ''In vivo bone progression in and around lattice implants additively manufactured with a new titanium alloy''. The subject is an important in its area.

However, there are some comments:

Please improve the conclusion section of the abstract.

The introduction does not provide sufficient background and is not include all relevant references. It is also so short. Please improve it using more recent and relevant references. And also please mention the gaps in the study and the solutions you suggested for these gaps.

Methods: the research design is appropriate.

The methods are adequately described.

The results clearly presented.

Please add statistical section with details. It is so important.

Please improve the discussion section using potent references comparing the previous studies.

Author Response

Referee 3

Quality of English Language

(x) I am not qualified to assess the quality of English in this paper

 

Does the introduction provide sufficient background and include all relevant references?

Must be improved

> The introduction was improved as highlighted in the document named “Manuscript with track changes”.

 

Are all the cited references relevant to the research?

Must be improved

> More references have been added as highlighted in the document named “Manuscript with track changes”.

 

Is the research design appropriate?

Can be improved

 

Are the methods adequately described?

Yes

 

Are the results clearly presented?

Can be improved

 

Are the conclusions supported by the results?

Must be improved

> The conclusions of the abstract were improved as highlighted in the document named “Manuscript with track changes”.

 

Why authors have employed sheeps instead of dogs, for example?

> Sheep have been employed instead of dogs for three reasons:

1. There is less space in a dog to place 6 mm diameter implants than in a sheep;
2. The life time of the sheep is around 5-6 years whereas the life time of a dog is around 12-15 years, thus it was less cruel to kill a sheep around 5 years old than a dog around 5 years old;
3. It's frowned upon in France to use dogs.

 

Can authors compared the results achieved by the implants with the new material with conventional implants in the market? 

> This will be done in a second step. A sentence has been added at the end of the conclusion as highlighted in the document named “Manuscript with track changes”.

 

Advantages and limitations of the study? Is the implant geometry appropiate?

> The geometry is not appropriate as we did not want to study the shape of the implant but the new proposed alloy and the bone progression as a function of the laterally closing of the lattice structures for the possibility of bone spline key.

Author Response File: Author Response.docx

Reviewer 4 Report

Why authors have employed sheeps instead of dogs, for example? Can authors compared the results achieved by the implants with the new material with conventional implants in the market? 

Advantages and limitations of the study? Is the implant geometry appropiate?

Author Response

Referee 4

1. Write the objective of the present work carefully.

> The objective was clearly state in the introduction as highlighted in the document named “Manuscript with track changes”.

 

1. Do you consider the topic original or relevant in the field? Does it address a specific gap in the field?

> Yes as it proposed a new alloy, with better mechanical properties, and a new solution for bone spline key to the medical sector. Thus, this new titanium alloy, whose flexibility is close to that of the cortical bone, reducing stress at the bone/implant junction, and hence the risk of loosening, as well as such laterally closed lattice structures, are appropriate candidates to be implemented in a new generation of implants. This new generation of implants is made necessary to face the medical complications that can arise with certain components in alloys presently used, such as Al and V, as well as the prohibition of cobalt in 2025, decreed by the European Chemicals Agency (ECHA) in 2017, and included and enshrined in the European regulation.

 

1. Why the author didn’t measure the mechanical properties of the alloy such as roughness, hardness, Impact, Tensile …. etc?

> ZTM14N has been studied from a mechanical point of view by the French National Center for Scientific Research (CNRS) according to ASTM standard. The results are newly given in Appendix A. A sentence, in the introduction, was added to address this point as highlighted in the document named “Manuscript with track changes”.

 

1. Why the author didn’t measure the thermal conductivity of the samples?

> This was not necessary. The surface of the implants is smooth, thus this did not required force to place it into the bone. In addition, wetting was carried out to cool the bone when the implant placement hole was drilled, a hole that was slightly wider than the implant itself. Therefore, this minimised friction and heating.

 

1. Please; Refer to the recent refs

DOI: https://doi.org/10.1088/1742-6596/1795/1/012059

DOI: https://doi.org/10.1515/jmbm-2022-0280

> Done in the introduction.

Author Response File: Author Response.docx

Round 2

Reviewer 4 Report

All my comments have been answered and I recommend to publish the paper