Association of Cadaveric Factors with the Degree and Region of Discoloration on Pink Teeth: An Approach to Serial Cases

Round 1

Reviewer 1 Report

It was a pleasure to review your manuscript which is well written and full of contents.

I would ask you to add conclusion section in which you carefully specify the limits of your research

 

Author Response

Response to Reviewers

 

Manuscript ID: applsci-1683895

Title: Association of Cadaveric Factors with the Degree and Region of Discoloration on Pink Teeth

Type: Article

 

Reply to the comments of Reviewer #1:

 

Thank you for reviewing our manuscript and providing valuable comments and suggestions. We have responded to your concerns and revised our manuscript as follows. Please find attached the revised version of our manuscript, with changes highlighted in yellow.

 

Comment #1

It was a pleasure to review your manuscript which is well written and full of contents.

 

Response #1

Thank you very much for your kind comments.

 

Comment #2

I would ask you to add conclusion section in which you carefully specify the limits of your research.

 

Response #1

In accordance with your comment, we have added a Conclusion section, which states the limits of our research as follows.

5. Conclusion

We confirmed that time after death was associated with the pink teeth phenomenon by classifying and evaluating the degree and region of discoloration into 3 grades with reference to a method for classifying color as used in the field of prosthodontic dentistry. However, we recognize that this preliminary study did not include sufficient validation of the method and that sample distributions might be insufficient for statistical analysis. The scores were also assessed visually without using analytical equipment because the autopsy photographs were taken under various conditions. Therefore, before we perform further investigations of cases involving early postmortem changes, we need to develop a more standardized methodology. In conclusion, it was suggested that cadaveric decomposition might affect the occurrence of pink teeth, indicating that the phenomenon must not be misinterpreted in medico-legal investigations.

Author Response File: Author Response.docx

Reviewer 2 Report

The problem presented in the article is intriguing. The analyzes carried out by the authors did not explain the connection of the "pink teeth" with the causes of death, the age of the deceased or the sex. Perhaps the reason is the excessive variety of research objects. Perhaps we should focus on a larger group with similar causes of death, age or gender. Perhaps, at the beginning of the research, we should use chemical analysis to determine what factor causes the change in the color of the teeth.

Author Response

Response to Reviewers

 

Manuscript ID: applsci-1683895

Title: Association of Cadaveric Factors with the Degree and Region of Discoloration on Pink Teeth

Type: Article

 

Reply to the comments of Reviewer #2:

 

Thank you for reviewing our manuscript and providing valuable comments and suggestions. We have responded to your concerns and revised our manuscript as follows. Please find attached the revised version of our manuscript, with changes highlighted in yellow.

 

Comment #1

The problem presented in the article is intriguing. The analyzes carried out by the authors did not explain the connection of the "pink teeth" with the causes of death, the age of the deceased or the sex. Perhaps the reason is the excessive variety of research objects. Perhaps we should focus on a larger group with similar causes of death, age or gender. Perhaps, at the beginning of the research, we should use chemical analysis to determine what factor causes the change in the color of the teeth.

 

Response #1

As the reviewer indicated, we did not explain the connection of “pink teeth” with the causes of death, the age of the deceased, or their sex. Instead, we referenced Minegishi et al. [23], which includes the main details (sex, age, time after death, cause of death, and place of recovery) of the 68 pink teeth cases. We agree with the reviewer’s comments that “we should focus on a larger group with similar causes of death, age or gender.” We would like to perform the suggested experiment using a larger sample size in the future. We also agree with the reviewer’s comment that “we should use chemical analysis to determine what factor causes the change in the color of the teeth.” Indeed, we are currently investigating the relationship between various types of hemoglobin and discoloration by using chemical analysis. In accordance with the reviewer’s suggestion, we would like to perform further research to clarify the main factors of discoloration.

Reviewer 3 Report

Dear Authors,

The introduction section does not place the author in the context of the manuscript. It is very confusing and lacks rigor in its content. The first two sentences seem contradictory, the first sentence referenced from 20 articles, and the second is the opinion of this manuscript's authors! Some designations are not correct. For example, in line 46, "young decedents under 60 years of age"! What do the authors mean by "medico-legal criteria for discriminating the degree and region of discoloration"? Lines 51-56 have applicability in prosthodontics, but dentistry is the area with the most significant relevance of color choice (direct restorations).

 

The authors should have first studied the new method's accuracy with the intra- and interobserver error analysis and only then considered its applicability to the proposed objective. The photographic recording also obeys its own rules, and the authors do not consider it. Have the authors calibrated the color for the exposure parameters considered (do we know)? Given the genotyping techniques, I do not understand why the authors do not identify the sex in 2.9% of the sample—considering that the degree of pigmentation is related to the size of the dentinal tubules, which in turn connected to age, the sample does not present a homogeneous distribution. The sample does not deliver a homogeneous distribution either in the conditions at death or following conditions (time interval after death). The authors have not identified the inclusion and exclusion criteria. The dentinogenesis and amelogenesis process or teeth restorations should be pointed out.

Therefore, the methodology used in the manuscript does not follow the guidelines of a scientific paper.

Author Response

Response to Reviewers

 

Manuscript ID: applsci-1683895

Title: Association of Cadaveric Factors with the Degree and Region of Discoloration on Pink Teeth

Type: Article

 

Reply to the comments of Reviewer #3:

 

Thank you for reviewing our manuscript and providing valuable comments and suggestions. We have responded to your concerns and revised our manuscript as follows. Please find attached the revised version of our manuscript, with changes highlighted in yellow.

 

 

Comment #1

The introduction section does not place the author in the context of the manuscript. It is very confusing and lacks rigor in its content. The first two sentences seem contradictory, the first sentence referenced from 20 articles, and the second is the opinion of this manuscript's authors! Some designations are not correct. For example, in line 46, "young decedents under 60 years of age"! What do the authors mean by "medico-legal criteria for discriminating the degree and region of discoloration"? Lines 51-56 have applicability in prosthodontics, but dentistry is the area with the most significant relevance of color choice (direct restorations).

 

Response #1

We apologize for the confusion. We have revised the sentences as follows, “The pink teeth phenomenon was first reported in victims of hanging and drowning by Bell in 1829 [1]. Since then, many other reports have been published [2–22].” We also apologize for the incorrect designations. As for line 46, we have deleted the sentence with the phrase “under 60 years of age.” As for the sentence with the phrase “medico-legal criteria for discriminating the degree and region of discoloration,” we have changed this to “However, because there are no published criteria for classifying the color of pink teeth”. As for lines 51–56, we have deleted most of the text to avoid confusion. We changed this part to “In prosthodontics dentistry, shade guides have been used to determine teeth color, such as VITA-classic, which comprises 4 letter groups (A–D), and as a general principle, the coloration of a given tooth differs according to the region, namely the incisal, middle, and cervical regions, which have different color densities and translucencies [24-26].”

 

 

Comment #2

The authors should have first studied the new method's accuracy with the intra- and interobserver error analysis and only then considered its applicability to the proposed objective. The photographic recording also obeys its own rules, and the authors do not consider it. Have the authors calibrated the color for the exposure parameters considered (do we know)? Given the genotyping techniques, I do not understand why the authors do not identify the sex in 2.9% of the sample—considering that the degree of pigmentation is related to the size of the dentinal tubules, which in turn connected to age, the sample does not present a homogeneous distribution. The sample does not deliver a homogeneous distribution either in the conditions at death or following conditions (time interval after death). The authors have not identified the inclusion and exclusion criteria. The dentinogenesis and amelogenesis process or teeth restorations should be pointed out.

Therefore, the methodology used in the manuscript does not follow the guidelines of a scientific paper.

 

Response #2:

As the reviewer pointed out, we did not examine the intra- and interobserver error analysis because this is a preliminary study and it was not our aim to develop a novel method or to establish criteria for classifying discoloration. However, we agree with the necessity of validating this method. Therefore, we added text discussing this point in the new Conclusion section as follows, “However, we recognize that this preliminary study did not include sufficient validation of the method and that sample distributions might be insufficient for statistical analysis. The scores were also assessed visually without using analytical equipment because the autopsy photographs were taken under various conditions. Therefore, before we perform further investigations of cases involving early postmortem changes, we need to develop a more standardized methodology.” As for the photographic recording and calibration of color and exposure parameters, we used photographs of 68 pink teeth cases from among 324 dental autopsies of unidentified cadavers, which were taken under various conditions. Please understand that we had no control over how the pictures were taken. We have added this as a limitation in the Conclusions section of the revised manuscript. As for the genotyping techniques, we can understand the reviewer’s indication because we have often performed such identification by using DNA typing in our routine work. However, examinations other than dental findings in these forensic autopsy cases were performed by others and we could not obtain further information from police. As for the homogeneous distribution, we recognize that the sample distributions were insufficient for statistical analysis despite being collected over a period of 5 years. We have added text discussing this point to the Conclusion section. As for dentinogenesis and amelogenesis or teeth restorations, their relationship with coloring and fading has not been adequately studied, and the mechanism has not been completely clarified. Therefore, we would like to study this matter further in the future.

Reviewer 4 Report

Do the authors consider that the determination of the pink colour of the teeth can help to determine the time elapsed between death and the discovery of the corpse?

Just as there is a shade guide for enamel (VITA-classic), there is a shade guide for gingiva in dentistry with different shades of pink (IPS Emax gingiva - Ivoclar Vivadent). Have the authors considered using it to determine the Hue and Chroma? This approximation could reduce the subjectivity of colour determination. If not, I would encourage you to create your own standardised guide.

Author Response

Response to Reviewers

 

Manuscript ID: applsci-1683895

Title: Association of Cadaveric Factors with the Degree and Region of Discoloration on Pink Teeth

Type: Article

 

Reply to the comments of Reviewer #4:

 

Thank you for reviewing our manuscript and providing valuable comments and suggestions. We have responded to your concerns and revised our manuscript as follows. Please find attached the revised version of our manuscript, with changes highlighted in yellow.

 

Comment #1

Do the authors consider that the determination of the pink color of the teeth can help to determine the time elapsed between death and the discovery of the corpse?

 

Response #1

We think that it is very hard to estimate the time after death from the determination of pink color because the speed of cadaveric decomposition is affected by various factors, and the degree and region of discoloration is also affected by coloring and fading under various conditions.

 

Comment #2

Just as there is a shade guide for enamel (VITA-classic), there is a shade guide for gingiva in dentistry with different shades of pink (IPS Emax gingiva - Ivoclar Vivadent). Have the authors considered using it to determine the Hue and Chroma? This approximation could reduce the subjectivity of colour determination. If not, I would encourage you to create your own standardised guide.

 

Response #2:

In this study, we simply adopted the shade-guided method of classifying the degree and region of color. We have not determined the detailed criteria of hue and chroma. However, we appreciate the information about the shade guide for gingiva in dentistry with different shades of pink (IPS Emax gingiva - Ivoclar Vivadent). As the reviewer suggested, we think that it is important to create our own standardized guide to evaluate the color of pink teeth. In the Abstract and Introduction, we have changed the relevant text as follows: “we speculated that classification and evaluation of the degree and region of discoloration with reference to how to see of the color used in prosthodontic dentistry may produce novel findings regarding the pink teeth phenomenon.” and "We speculated that classification and evaluation of the degree and region of discoloration with reference to how color is classified in prosthodontic dentistry may produce novel findings regarding the association of the pink teeth phenomenon with various cadaveric factors such as age, sex, time after death, cause of death, and place of discovery.", respectively. In addition, we added the Conclusion section. In the section, we mentioned the sentence “Therefore, before we perform further investigations of cases involving early postmortem changes, we need to develop a more standardized methodology.”

Round 2

Reviewer 3 Report

Dear Authors,

The authors' effort to improve the manuscript was evident, but some topics remain to be clarified. 

The authors consider taking a personal approach without standardizing the procedure. The article's title should be clearly stated—for example, an approach to serial cases. 

I emphasize that forensic photography follows international rules and takes into account extreme forensic scenarios. I suggest that the authors review the color calibration method according to the ABFO (American Board of Forensic Odontology) guidelines.

 

Author Response

Reply to the comments of Reviewer #3:

 

Thank you for reviewing our manuscript and providing valuable comments and suggestions. We have responded to your concerns and revised our manuscript as follows. Please find attached the revised version of our manuscript, with changes highlighted in yellow.

 

Comment #1:

The authors consider taking a personal approach without standardizing the procedure. The article's title should be clearly stated—for example, an approach to serial cases.  

 

Response #1:

In accordance with the reviewer’s comment, we have added “an approach to serial cases” to the title as follows, “Association of Cadaveric Factors with the Degree and Region of Discoloration on Pink Teeth: An Approach to Serial Cases”.

 

Comment #2:

I emphasize that forensic photography follows international rules and takes into account extreme forensic scenarios. I suggest that the authors review the color calibration method according to the ABFO (American Board of Forensic Odontology) guidelines.

 

Response #2:

We apologize for our lack of understanding to the comments. We have confirmed that the photographs were taken almost based on the color calibration method according to the guidelines of the ABFO. We have added the following sentence “The photographs were taken according to the guidelines of the American Board of Forensic Odontology.” to Materials and Methods section.