Concentration in Saliva and Antibacterial Effect of Xylitol Chewing Gum: In Vivo and In Vitro Study
Round 1
Reviewer 1 Report
Concentration in saliva and antibacterial effect of Xylitol chewing-gums: in-vivo and in-vitro study.
The authors present an interesting study showing the levels in saliva of xylitol, after the consumption of chewing gum of two different concentrations of the polyols. Although the paper has scientific merit, in the opinion of this reviewer does not meet the standards of quality to be published in its current form. There are major interpretative issues to be addressed, but also some methodological pitfalls that preclude recommendation to publish in Applied Sciences.
Language: There are several grammar mistakes. It is suggested to use a professional editing service.
Introduction:
- It would be helpful to summarize the effect of Xylitol in caries, so the reader will have a better idea of the relevance of the potential it has on periodontal disease.
- The authors should provide a rationale for detecting xylitol in saliva, what is the importance?
- It seems that there are studies dealing with the concentration of xylitol in saliva, so, what are their main conclusions and why, then, this study would fill a gap of knowledge?
Materials and Methods:
- In the inclusion criteria for participants, did you include the use of medication? This is very important and it is not stated.
- Why did not you exclude smokers? Smoking may alter the oral environment.
- For the antibacterial effect of xylitol, the authors used 4 patients affected of periodontitis. It is likely that the disease was at different stages and different levels of severity. Please add details about the inclusion criteria. A small sample like this is susceptible to have large heterogeneity and the results could have an important bias.
- The procedures for bacterial culture with the chewing gum solution are unclear to me. Bacteria were culture in blood cultures in 96-well plates, but then in line 145 it is mentioned that 2 mL were inserted in the wells. Please clarify.
- Since streptococci associated with caries were evaluated, how did you make them grow in the blood media? These species need glucose to thrive.
Results:
- The SD in the xylitol concentration is way too large. It is difficult to interpret the second peak at minute 10 given those large SDs.
- Differences in bacteria are also difficult to interpret, as the decrease could have been to either a lack of nutrients for streptococci or to inadequate culture conditions. This crucial problem could have been overcome by adding a negative control group, whereby the decrease is not observed.
Discussion:
- The differences between 100% and 22% are straight forward and do not deserve to be extensively discussed, it is just expected.
- Line 203: the explanation provided by the authors of the “bimodal” curve for 100% appears random and not plausible. No mention is done to the extremely large SD. From common experience, chewing gum would be completely mixed and soft after 1 or 2 minutes, so the second peak at 15 sounds really unlikely.
- No discussion is provided about the lack of a negative control for bacterial cultures. It is entirely possible that the decrease is not entirely due to xylitol, but to the decay in bacterial viability over time.
Author Response
Please see Attachment
Author Response File: 
Author Response.docx
Reviewer 2 Report
Pleased to send you some comments to be reflected in the manuscript.
Comments for author File: Comments.docx
Author Response
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Author Response File: Author Response.docx
Reviewer 3 Report
Please see my comments in the attachment
Comments for author File: 
Comments.pdf
Author Response
Please see the Attachment
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The authors have addressed all the comments and provided satisfactory explanations for the most part. There are still some minor issues that need to be considered. Please see the attached file.
Comments for author File: Comments.docx
Author Response
Please see attachment.
Author Response File: Author Response.docx
