Optimization of Image Capture Distance for Facial Thermograms in Dentistry

Round 1

Reviewer 1 Report

Dear Authors,

 

This manuscript aims to evaluate the influence of shooting distances on temperature asymmetries detection on the face for the purpose of dental thermography. This study is interesting and well-written; however, I have some remarks:

 

- Abstract

--> “The mean temperature at the ROI for all different shooting distances within in each profile view were statistically significant”. – please rephrase this, as the differences between temperature values are statistically significant, not the temperatures themselves.

 

- Materials and methods:

--> Why 5 photos of each person? What is the variation between these photos? Is this variation important? How do you manage this information? Otherwise, you just duplicate your study lot…

 

- Results:

--> How did you assess the impact of cosmetic products, knowing that this may influence skin temperature? 23 persons out of 30 is more than 75%. Why did you not perform a test on a person with and without cosmetic products?

--> This is just a question: according to your experience, do wrinkles or age spots influence skin temperature?

--> It was only 1 participant with physiotherapy, yet it is statistically taken into account.

--> “The mean temperature at the ROI for all different shooting distances within in each profile view were statistically significant”. – please rephrase this, same as for the abstract, as the differences between temperature values are statistically significant, not the temperatures themselves (lines 261-262)

--> For Kruskal-Wallis statistical tests -- each group sample should have at least 5 observations for a sufficient sample size… yet you use it for groups of 1 or 2 participants.

 

- Discussion:

-->  There is a discrepancy between the Introduction and the Discussion sections. The Introduction mainly talks about elderly potential patients, while the Discussion is more oriented towards “technical details” regarding the shooting process. I would advise you to update the Introduction, in order to link it more to your discussions.

 

Also, more than 50% of your citations are more than 10 years old. You should cite more recent studies.

 

 

Best regards!

Comments for author File: Comments.pdf

Moderate changes must be made.

Author Response

Dear Authors,

This manuscript aims to evaluate the influence of shooting distances on temperature asymmetries detection on the face for the purpose of dental thermography. This study is interesting and well- written; however, I have some remarks.

1. Authors response: Thank you very much for the kind words, we are happy that you find this interesting and we will be glad to make any modifications/corrections as suggested to facilitate its publication.
2. Abstract
   --> “The mean temperature at the ROI for all different shooting distances within in each profile view were statistically significant”. – please rephrase this, as the differences between temperature values are statistically significant, not the temperatures themselves.
   Authors response: Thank you very much for this comment. We have now rephrased the sentence as, “The differences between the mean temperature values at the ROI for all different shooting distances within in each profile view were statistically significant…”. We hope that this is now acceptable for the kind reviewer.
3. Materials and methods:
   --> Why 5 photos of each person? What is the variation between these photos? Is this variation important? How do you manage this information? Otherwise, you just duplicate your study lot…
   Authors response: Thank you very much for this comment. In order to avoid and eliminate errors that could happen with a single photo that could have been faulty, each view at each distance was repeated five times for each participant. The images were made during the same session. This ensured that the images were in the same conditions and further avoid any discrepancies in the temperature readings if one of the photos were faulty.
4. Results:
   --> How did you assess the impact of cosmetic products, knowing that this may influence skin temperature? 23 persons out of 30 is more than 75%. Why did you not perform a test on a person with and without cosmetic products?
   Authors response: Thank you very much for this valuable comment. Unfortunately, the specific effect of cosmetic products on skin temperature was not assessed in the current study. We understand that this might have had an impact, but in the current study we wanted to assess if this application could be used in a realistic situation without much preparation of the participant. We thank the reviewer for this kind suggestion and hope to implement it in a future study.
5. --> This is just a question: according to your experience, do wrinkles or age spots influence skin temperature?
   Authors response: Thank you very much for this comment. This is our first attempt at using thermography in the application for screening oral health. We are in a learning phase and would like to eventually use this application in screening oral disorders or dental problems in elders who are non-communicative or care resistant. To answer your question, unfortunately we do not know if wrinkles and age spots positively/negatively influence the skin temperature. We hope to find answers to these situations with our future studies.
6. --> It was only 1 participant with physiotherapy, yet it is statistically taken into account.
   Authors response: Thank you very much for this comment. We understand the reviewer’s concern, we had collected the data on this and did not want to exclude the findings and therefore reported on this. We would be happy to exclude this if the reviewer feels that it is not necessary to report based on just one participant.
7. --> “The mean temperature at the ROI for all different shooting distances within in each profile view were statistically significant”. – please rephrase this, same as for the abstract, as the differences between temperature values are statistically significant, not the temperatures themselves (lines 261-262).
   Authors response: Thank you very much for this comment. We have made the changes accordingly.
8. --> For Kruskal-Wallis statistical tests -- each group sample should have at least 5 observations for a sufficient sample size... yet you use it for groups of 1 or 2 participants.
   Authors response: Thank you very much for this comment. Each participant had 5 photos made for each view and for each distance. There were three groups of shooting distances and three different profile views. Therefore, we had used the Kruskal-Wallis tests. The pairwise comparisons were made using the post-hoc tests. Ewe hope that this is fine.

- Discussion:
--> There is a discrepancy between the Introduction and the Discussion sections. The Introduction mainly talks about elderly potential patients, while the Discussion is more oriented towards “technical details” regarding the shooting process. I would advise you to update the Introduction, in order to link it more to your discussions. Also, more than 50% of your citations are more than 10 years old. You should cite more recent studies. Best regards!
Authors response: Thank you very much for this comment. We understand the reviewer’s concerns, unfortunately, the references in conjunction with thermography and dentistry in the current literature is scarce and is found lacking, therefore, we could not use more recent relevant recent literature to cite. We apologize for this and hope that the reviewer is satisfied with our response.

Reviewer 2 Report

Dear Authors,

Thank you for submitting this manuscript. I think the paper is quite interesting because it refers to a very important topic: the influence of shooting distances on temperature asymmetries detection on the face for dental thermography. I would like to suggest some points to the Authors:

1. In the beginning, the abstract should include a short statement on the current research gap and the reasons to show why this study is unique and worthy of publication.

2. Please add more references in the Introduction section, lines 33 - 40.

3. Line 46 – Please add some references.

4. The Introduction part is a bit brief, please add more information about the significance of your study.

5. The authors should add the null and working hypotheses of the study and highlight them by adding "H0" and "H1"

6. In the Results section, please add some tables and diagrams with the data to clarify the results better.

7. In the Discussion section, you have to include other authors findings and compare their results with yours. Please add more references.

8. In the Conclusion section, please describe the significance of this study. The authors should summarize the significant findings in bullets for clarity in the Conclusion section.

Thank you in advance for all the corrections. Good luck!

Author Response

Thank you for submitting this manuscript. I think the paper is quite interesting because it refers to a very important topic: the influence of shooting distances on temperature asymmetries detection on the face for dental thermography. I would like to suggest some points to the Authors:

1. In the beginning, the abstract should include a short statement on the current research gap and the reasons to show why this study is unique and worthy of publication.
   Authors response: Thank you very much for this comment. We have now added the following sentence, “Thermography has not yet been validated for the screening of oral disorders and no clear guidelines or methodology for this purpose have been defined in literature. The current pilot study aimed, as an initial step to evaluate the influence of shooting distances on the temperature asymmetries detection on the face for the purpose of dental thermography.” We hope that this will be satisfactory.
2. Please add more references in the Introduction section, lines 33 - 40.
   Authors response: Thank you very much for this comment. The following new references have been added in the lines 33-40 (references 6-8 and references 12-14).
3. Line 46 – Please add some references.
   Authors response: Thank you very much for this comment. We have now added new references in lines between 46-48 (references 16-25). We hope that the reviewer will be satisfied.
4. The Introduction part is a bit brief, please add more information about the significance of your study.
   Authors response: Thank you very much for this comment.
5. The authors should add the null and working hypotheses of the study and highlight them by adding "H0" and "H1"
   Authors response: Thank you very much for this comment. We have now labelled the two stated hypotheses in the last paragraph of the introductions section as null and secondary hypotheses and have appropriated highlighted them as “H0” and “H1”.
6. In the Results section, please add some tables and diagrams with the data to clarify the results better.
   Authors response: Thank you very much for this comment. Currently, there are 6 elaborate tables with results. We have presented all the analysis accordingly. We do not have any figures because they would be essentially repeating the tables. Therefore, we chose to leave out diagrams. However, the essential part of the results were the thermographic images and these have been supplied. But if the reviewer would suggest what kind of diagrams he/she would like to see as a part of the results, we will be happy to make them (if possible) and submit them.
7. In the Discussion section, you have to include other authors findings and compare their results with yours. Please add more references.
   Authors response: Thank you very much for this comment. We understand the reviewers request, unfortunately, there are no publications which have published these findings and hence we cannot provide references for the same and contrast our findings. The current paper is, to the best of the authors knowledge, is a concept paper. We hope that we will be able to develop further with future planned studies and provide valuable data in this field.

 

8. In the Conclusion section, please describe the significance of this study. The authors should summarize the significant findings in bullets for clarity in the Conclusion section.
   Authors response: Thank you very much for this comment.
   We have summarised the findings in bullet points in the conclusion and hope that it will now be acceptable for the kind reviewer.

Thank you in advance for all the corrections. Good luck!
Authors response: Thank you dear reviewer for your kind support and help in making this paper better. We hope that this will be published.

Reviewer 3 Report

In the introduction to the publication, the authors devote much attention to the elderly. The information there is true, but how does it relate to the rest of the article? The research group consists of people with an average age of 26. Therefore, the authors should either indicate according to what criteria these 26-year-olds were classified as elderly people or omit information about elderly people in the introduction. If they want to keep this information, they should point it out as a significant limitation of this research.

The study group was described as a group of healthy people. The table containing the characteristics of the participants indicates the drugs they take: Sympathetic blockers, Steroids, and Vasoactive drugs. Are you sure they are healthy study participants? If they are taking these drugs, I suggest using the term healthy volunteers cautiously.

Women dominate the research group. It is reasonable to ask whether the menstrual cycle was taken into account as a criterion that, as is known, affects body temperature.

It seems that the data contained in Table 3 are crucial for the whole study. If this is true, I suggest mentioning them in the abstract.

Author Response

1. In the introduction to the publication, the authors devote much attention to the elderly. The information there is true, but how does it relate to the rest of the article? The research group consists of people with an average age of 26. Therefore, the authors should either indicate according to what criteria these 26-year-olds were classified as elderly people or omit information about elderly people in the introduction. If they want to keep this information, they should point it out as a significant limitation of this research.
   Authors response: Thank you very much for this comment. We understand the kind reviewer’s point of view. The purpose of this pilot experiment was to establish and develop image capturing techniques for dental/oral purposes. We would also like to point out that this study is probably a first of its kind in providing technical aspects for making thermographic images for oral/dental diseases/disorders screening purposes. As a first step we wanted to standardize thermography image capture techniques. In order, to do this we wanted to first establish certain norms; and for this we decided to use young volunteers who were easy to recruit and handle. The bigger picture is then to use these techniques later in elderly patients who are non-communicative or with severe dementia or with care-resistant behaviors to screen for oral and dental disorders. That is why the introduction states the actual future application of this concept and this current pilot has recruited young adult volunteers. We hope that this is now clarified. We are happy to make any changes the reviewer may suggest elucidating this further.
2. The study group was described as a group of healthy people. The table containing the characteristics of the participants indicates the drugs they take: Sympathetic blockers, Steroids, and Vasoactive drugs. Are you sure they are healthy study participants? If they are taking these drugs, I suggest using the term healthy volunteers cautiously.
   Authors response: Thank you very much for this comment. The participants comprised of students in the dental school. Although they were healthy, a few of them (older individuals) did have some medications in their daily life. We understand the reviewers concern and have now replaced the term “healthy volunteers” to “adult volunteers”. We hope that this will be acceptable to the reviewer.
3. Women dominate the research group. It is reasonable to ask whether the menstrual cycle was taken into account as a criterion that, as is known, affects body temperature.
   Authors response: Thank you very much for this comment. Unfortunately, we did not inquire about this element was not included in our study.

4. It seems that the data contained in Table 3 are crucial for the whole study. If this is true, I suggest mentioning them in the abstract.
Authors response: Thank you very much for this comment. Table 3 shows the descriptive values of the findings. The statistical analyses have been spread out in tables 4 through 6. Therefore, if they need to be mentioned in the abstract then all these tables need to be mentioned. Therefore, we feel that this may be too much. However, if the reviewer insists, then we can mention all these tables in the abstracts.

Reviewer 4 Report

Comments for author File: Comments.pdf

Author Response

After reviewing the manuscript "Optimization of image capture distance for facial thermograms in dentistry" the reviewer had the following comments:

1. Study to evaluate temperature changes on the face with thermal imaging distance for the purpose of recording dental thermal image changes. The layout of the manuscript is presented quite clearly and completely. The number of volunteers participating is 30 and the conclusion is at a basic level.
Authors’ response: Thank you very much for this valuable comment. We understand that the number of volunteers was low. However, this number was arrived at based on a power analysis. A previously published study that analyzed the visualization of temperature patterns in the oral cavity used a sample size of 20. Based on this number and taking Cohen’s medium effect size of 0.5 with ⍺ err prob = 0.05 and Power (1-β err prob) = 0.80, the total sample size was calculated as 27 (critical t = 1.706, Df = 26, actual power = 0.8118). Assuming a dropout rate of 10%, a total number of 30 participants were, from the student pool of the ZZM, at the UZH. Sample size calculation was performed using a free software (G*Power, version 3.1.9.6 for Mac OS X, Dusseldorf, Germany). We understand the reviewers’ point of view that the conclusion was at a very basic level,  however, in this pilot study which had a basically evaluated the influence of shooting distances and other parameters in making facial thermograms for dental use, we concluded in a manner to answer our aim.  We could not conclude more further based on our study design and findings. We hope that the kind reviewer will be satisfied with this.

2. The evaluator considers that the main limitation of the study is the number of volunteers who are healthy and have not described signs of dental disease.
Authors’ response: Thank you very much for this comment. We understand the reviewers’ concern, but since this was a pilot study that aimed to evaluate the influence of shooting distances on the temperature asymmetries detection on the face for the purpose of dental thermography. We needed to standardize the shooting distances and the views and therefore we used volunteers without any dental diseases/pain or disorders. Based on our findings in our current research, we will aply the optimized distances and include participants with dental pain to evaluate whether this application may be used to screen oral diseases in older adults. We hope that the kind reviewer is satisfied with our response.

3. The author should describe more carefully how to choose ROI (i.e. location, ROI size, number of pixels, etc.) as this is the determining factor in temperature estimation.
Authors’ response: Thank you very much for this comment. The ROI location and size was determined by the anatomical landmarks on the face. This is explained in the in the section “region of interest”. Since the ROI, although standard was not always the same size because of the size of the participants face or anatomical differences the number of pixels changed depending on the size. Our goal was to achieve the ROI withing the described anatomical boundaries. The rest of the camera parameters set during the capture were standardized and not changed. The emissivity was set to 0.98, reflected temperature was set to 22 ⁰ C, with atmospheric temperature was 21.4 ⁰C and the relative humidity percentage was 27.0%. The external optics temperature and external optics transmission were fixed at 25 ⁰C and 0.800, respectively.

The following paragraph with these details have been added in the section 2.3.2.

“Object parameters
Emissivity was set to 0.98, with the reflected temperature set for 22 ⁰ C and atmospheric temperature of 21.4 ⁰C. The relative humidity percentage during the imaging sessions was 27.0%. The external optics temperature and external optics transmission were fixed at 25 ⁰C and 0.800, respectively. The distances of the captured was fixed at 0.15m, 0.30m and 0.50m, as per the study protocol.”

We hope that this is now fine.  

4. Manuscript should be more carefully presented according to the template of applied sciences.
Authors’ response: Thank you very much for this comment. It has now been presented as per the template.