The Importance of Atmospheric Microbial Contamination Control in Dental Offices: Raised Awareness Caused by the SARS-CoV-2 Pandemic

Round 1

Reviewer 1 Report

Dear Authors, in the first sentences you mean: "The pandemic caused by SARS-CoV-2 started in the first months of 2020 and raised 44 huge global health issues" The first coronavirus case was already described on 31 December 2019. Have you also taken into consideration the different types of surfaces found inside a dental office?

I suggest to implement with these papers:

1) Sars-cov-2 persistence: data summary up to q2 2020  DOI: 10.3390/data5030081

2)  Covid-19 pandemic and telephone triage before attending medical office: problem or opportunity?  DOI: 10.3390/medicina56050250

 

Author Response

Dear Authors, in the first sentences you mean: "The pandemic caused by SARS-CoV-2 started in the first months of 2020 and raised 44 huge global health issues" The first coronavirus case was already described on 31 December 2019. Have you also taken into consideration the different types of surfaces found inside a dental office?

I suggest to implement with these papers:

1) Sars-cov-2 persistence: data summary up to q2 2020  DOI: 10.3390/data5030081

2)  Covid-19 pandemic and telephone triage before attending medical office: problem or opportunity?  DOI: 10.3390/medicina56050250

 

Esteemed reviewer,

Thank you for your valuable suggestions. The articles you mentioned are a very welcomed addition to our text since they provide relevant information that was not previously included.

We made the following corrections:

L46: The pandemic caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coro-navirus 2) started in the first months of 2020 and raised huge global health issues (The first coronavirus cases have been already reported before the end of 2019)

L64: Despite the many uncertainties, one thing was sure from the very beginning: the fact that prevention is better than any treatment method, a well-known and widely spread rule in medicine. During this pandemic, fields like telemedicine gained lots of attention amongst health workers and patients as well. But since the personal interaction between doctors and patients can not always be done remotely, new and strict protection protocols had to be developed

L146: Medical offices, especially dental practices include several devices that are neces-sary for the medical act. All these complex machines present a variety of surface which are more or less suited and accessible for classical disinfection methods. Since aerosol size is less than 5 μm, droplets containing dangerous pathogens may easily reach these surfaces and not be inactivated by the previously used disinfection protocols [2]. This is why studying more efficient air and surface decontamination methods is so im-portant during this period. Even the materials used for PPE were considerably modi-fied. For instance, new materials containing Zinc pyrithione were used to produce overalls since it presents proven antiviral, antibacterial and antifungal properties. In Romania, such materials were approved by the Center for Medico-Military Scientific Research.

Thank you for your time and for your suggestions which helped improve our paper!

 

Reviewer 2 Report

Overview

The study addresses a pertinent question of high clinical interest, however there are some doubts regarding the methodology. The study has a limited value since none of the procedures were aerosol-generating, which are the ones that raise the most concerns in dental practice.The study  is very preliminary (with a very small sample) and the results cannot be extrapolated.

The manuscript needs major English editing.Formatting must also be strictly checked. 

Why was the study not submitted to an ethics committee? 

Abstract

Doesn’t refer the sample size. Authors indicate “that for every measurement performed during patient treatments we used a total of 8 Petri dishes” .. “A total of 56 dishes were used “ 

In  sampling after treatment, how many plates were used? 

There are 4 types of disinfection methods. In each of them was only one patient treated? 

Results are not indicated in the abstract

Ventilation should be included in keywords 

Introduction

Bibliographic references are missing to support some of the statements.

Other medical specialties such as ENT, gastroenterologists, anesthesiologists also have a high risk of contagion.

The authors say that sterilization protocols will change forever after this pandemic. I disagree, the sterilization protocols used are effective and have not undergone major changes. Most of the changes were at the level of engineering controls and the use of PPE.

Materials and methods

The sample size is not reported.

Why were aerosol-generating procedures excluded?

What type of procedures were performed? It would be interesting to understand the degree of contamination inherent to each type of procedure. What was the duration of the procedures and their relationship with the degree of contamination? 

Did patients rinsed with any antiseptic before the procedures ?

Was a rubber dam used in any type of procedure?

How was the disinfection methods randomized ?

The placement of the petri dishes in only two positions, on the same side and in front of the patient is a limitation of the study.

What is natural ventilation? opening a single window? what are the dimensions of it? Did the cabinet door remain closed? 

There were curtains to block natural light when using the UVC lamp ?

Why was the UVC box also turned on before treatment? 

Some methods like fogging can have a prolonged residual effect. Were the different methods applied on different days? 

It is unnecessary to refer to the coding of the plates in the text.Tables should have captions 

Some images are unnecessary (eg 4 and 5)

Discussion

In view of the methodology used, how can it be said that the method prevents doctor-patient transmission and vice versa ?

It is debatable to say that "waiting 30 minutes between patients is economically viable". Regarding the economic question, has any further analysis been carried out to support the statements?

Study limitations are not properly discussed .

Conclusions

Are not fully supported by the results 

References

Some more up-to-date references could have been used.

Formatting must be corrected.

Authors' contributions

Obtaining funding does not meet the criteria for authorship. However, the authors end up contradicting themselves because the study was not funded. In such a small study, the inclusion of so many authors (14) should be better justified 

Author Response

Rev 2

 

Esteemed reviewer,

Thank you for your extremely thorough review of our paper and for your very pertinent remarks. Each of them will be individually addressed in the following pages.

The study addresses a pertinent question of high clinical interest, however there are some doubts regarding the methodology. The study has a limited value since none of the procedures were aerosol-generating, which are the ones that raise the most concerns in dental practice. The study is very preliminary (with a very small sample) and the results cannot be extrapolated.

The present study is not presented as an exhaustive paper in this field but as a preliminary work, leading to other more elaborate ones. Still, its value is not to be neglected, since so little information on this subject had been published at the moment we started work on this project. We plan on continuing the research in order to get more relevant results that can be extrapolated to almost every situation.

The manuscript needs major English editing. Formatting must also be strictly checked. 

If you find it necessary, we can ask for MDPI English Editing Services and Layout Editing Services. Please indicate where format corrections are necessary. We might have missed some aspects, although we filled all our text in the available template provided by the journal.

Why was the study not submitted to an ethics committee? 

This study did not affect the treatment that the patients received in absolutely any way. The national and international guidelines were strictly respected and our efforts were always aimed towards patient’s and personnel safety.

Abstract

Doesn’t refer the sample size. Authors indicate “that for every measurement performed during patient treatments we used a total of 8 Petri dishes”. “A total of 56 dishes were used “ 

L37: A total of 56 Petri dishes were used to evaluate air contamination.

In sampling after treatment, how many plates were used? 

For UVC, Fogging and Ventilation, 8 plates were used during each patient treatment and 8 plates after each type of decontamination method. For the Sterybox, 8 plates were used during treatment.

There are 4 types of disinfection methods. In each of them was only one patient treated? 

Yes, air contamination was measured for 1 patient for each method.

Results are not indicated in the abstract

L38: All four procedures offered good results but the decontamination time and overall effect varied depending on the chosen method. Fogging was the only method that managed to remove all the identifiable pathogens.

Ventilation should be included in keywords 

Ventilation was added to key words.

Introduction

Bibliographic references are missing to support some of the statements.

Several more references were included to support the uncovered statements. (ex 2, 19, 20, 30, 31)

Other medical specialties such as ENT, gastroenterologists, anesthesiologists, ophthalmologists also have a high risk of contagion.

L72: All other medical branches were affected as well, directly or indirectly. For instance, otolaryngologists had to deal with many Covid patients due to their experience in air-way management, making them very exposed to contamination risks [ ]. Anesthesiologists and emergency personnel were also at high risk. Recently published papers show an increased frequency of the Burnout syndrome in relation with the Covid crisis amongst medical professionals [ ].

The authors say that sterilization protocols will change forever after this pandemic. I disagree, the sterilization protocols used are effective and have not undergone major changes. Most of the changes were at the level of engineering controls and the use of PPE.

By this we referred to aspects like fogging that was not a regular occurrence in dental practices and became mandatory in March 2020 in our country. Now, although it is not mandatory anymore, many dental offices still use it on a regular basis.

Materials and methods

The sample size is not reported.

L193: A total of 56 Petri dishes were used for the present test, as follows: 8 during treatment and 8 after disinfection method application for ventilation, fogging and UVC respectively. While using the Sterybox, 8 dishes were used since there was no separate decontamination phase for this method.

Why were aerosol-generating procedures excluded?

We could only cover emergency treatments during that period because of national regulations, provided they generated the least amount of aerosols.

What type of procedures were performed? It would be interesting to understand the degree of contamination inherent to each type of procedure. What was the duration of the procedures and their relationship with the degree of contamination? 

Procedures took up to 30 minutes, including patient entrance, sitting, preparation etc. They were all endodontic drainages.

Did patients rinse with any antiseptic before the procedures? Was a rubber dam used in any type of procedure?

L229: The dental personnel wore all the required PPE and the treatment protocol was in no way altered by the ongoing of the bacterial recordings. None of the treatments were aerosol generating. They were only emergency treatments done without rotary instruments (Root canal drainage). All patients rinsed their oral cavity (Chlorhexidine 2% solution) and received rubber dams.

 

How was the disinfection method randomized?

The allocation of the disinfection method to each case was random (by using random.org)

The placement of the Petri dishes in only two positions, on the same side and in front of the patient is a limitation of the study.

Following studies will have more dishes/patient and more patients/method.

What is natural ventilation? opening a single window? what are the dimensions of it? Did the cabinet door remain closed? 

L170:The window that was used for ventilation was 220 cm by 80 cm.

L199: open window, no forced ventilation, door of cabinet remained closed

There were curtains to block natural light when using the UVC lamp?

Curtains were not closed.  

Standard window glass, according to the International Ultraviolet Association, will allow UV-A to pass through while almost 100% of the UV-B and UV-C light is blocked.

Why was the UVC box also turned on before treatment? 

The UVC box was turned on before patient admission into the office to be sure that it was on the entire time of the patient’s visit. It could have been 5 minutes as well.

Some methods like fogging can have a prolonged residual effect. Were the different methods applied on different days? 

Every test was done on a different day. The residual effect of fogging is considered to be between 2 and 4 hours. We always waited for 4 hours before entering the room.

It is unnecessary to refer to the coding of the plates in the text. Tables should have captions 

Plates coding was noted in the text for a better understanding of the protocol. The captions are respecting the template design.

Some images are unnecessary (eg 4 and 5)

Image 4 was removed

Discussion

In view of the methodology used, how can it be said that the method prevents doctor-patient transmission and vice versa?

L229: The dental personnel wore all the required PPE and the treatment protocol was in no way altered by the ongoing of the bacterial recordings.

It is debatable to say that "waiting 30 minutes between patients is economically viable". Regarding the economic question, has any further analysis been carried out to support the statements?

A study that focuses on the pure economical aspects was not conducted at this phase. We made those affirmation based on the fact that the shorter the time gap between patients, the less money the office looses. From this point of view, waiting 30 minutes instead of 4 hours between patients is beneficial.

Study limitations are not properly discussed.

L241: Other limitations of the present study, besides the number of Petri dishes, are the number of recordings, dish placement and the investigation of only bacterial and not viral contamination.

Conclusions

Are not fully supported by the results 

L347: Still, both the effectiveness from a biological and especially financial point of view will more accurately be quantified in future studies, for all the methods that were described in the present study.

References

Some more up-to-date references could have been used.

Several references have been introduced.

Formatting must be corrected.

The article was filled into the template. If there are any format issues still, as we said before, we will gladly ask for MDPI English Editing Services and Layout Editing Services.

Authors' contributions

Obtaining funding does not meet the criteria for authorship. However, the authors end up contradicting themselves because the study was not funded. In such a small study, the inclusion of so many authors (14) should be better justified.

Funding was not obtained from an external source but from the common efforts of the authors. “Funding acquisition” was noted for those who contributed most to this part as well, not just to the scientific part of the article. It is true that in normal times a lower number of authors would have been able to complete an article of this size but please keep in mind the huge difficulties that the entire world faced last year, including PPE shortage and an extremely low availability of disinfection devices and substances.  

 

Reviewer 3 Report

Very nice paper and very accurate. The investigators did a nice job. No improvements in the paper needed. 

Author Response

Very nice paper and very accurate. The investigators did a nice job. No improvements in the paper needed. 

Esteemed reviewer,

Thank you for your time and appreciation! We really hope that our present pilot study and the following more exhaustive studies will help in protecting ourselves and our patients during these difficult times.

 

Reviewer 4 Report

Comments to the Author

GENERAL COMMENTS

The subject of the research is quite interesting, but the method of conducting the research and its scope are not entirely convincing. The authors used correct research methods, but they are quite simple. Even though the authors obtained interesting results that were correctly interpreted, they were not statistically compiled at a high level. The introduction lacks a scientific explanation for the virus penetration into the human body. The description of the results is very short, which in turn affects the substantive value, after all, quite interesting discussion. Conclusions are described correctly. Unfortunately, in my opinion, major changes are needed to publish a manuscript.

 

SPECIFIC COMMENTS

Chapter „Introduction”

In my opinion, the introduction lacks a scientific explanation of how the virus enters the cell and its characteristics. On the other hand, the content of the introduction (lines 44-55) is quite biased. This section should be modified to describe the SARS-CoV-2 virus itself.

2. Chapter “Materials and Methods”

The main objection is the lack of description of the statistical analysis of the conducted experiment.

3. Chapter „Results”

The test results are described too generally. There is also a question. Were any steps taken to prepare a given dentist's office for the experiment before starting the research? Was the site routinely prepared for this analysis? Next question. Is it certain that the dental surgery workers during the experiment were fully healthy, not carriers of the virus?

 

 

 

Comments for author File: Comments.docx

Author Response

Esteemed reviewer,

Thank you for your extremely thorough review of our paper and for your very pertinent remarks. Each of them will be individually addressed in the following pages.

GENERAL COMMENTS
The subject of the research is quite interesting, but the method of conducting the research and its scope are not entirely convincing. The authors used correct research methods, but they are quite simple. Even though the authors obtained interesting results that were correctly interpreted, they were not statistically compiled at a high level. The introduction lacks a scientific explanation for the virus penetration into the human body. The description of the results is very short, which in turn affects the substantive value, after all, quite interesting discussion. Conclusions are described correctly. Unfortunately, in my opinion, major changes are needed to publish a manuscript.

This is a preliminary study, done in a period when access to PPE, disinfection systems and solutions was scarce. A larger study, with more dishes and more readings is mandatory and will follow. All these aspects were introduced in the manuscript, after reading your review. Changes are marked in red.

 SPECIFIC COMMENTS

Chapter „Introduction”

In my opinion, the introduction lacks a scientific explanation of how the virus enters the cell and its characteristics. On the other hand, the content of the introduction (lines 44-55) is quite biased. This section should be modified to describe the SARS-CoV-2 virus itself.

L46: The pandemic caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2) started in the first months of 2020 and raised huge global health issues (The first coronavirus cases have been already reported before the end of 2019) [ , ]. In humans, coronaviruses induce respiratory diseases such as the Middle Eastern respiratory syndrome (MERS) or the severe acute respiratory syndrome (SARS). Coronaviruses were first identified in the 1960s. They are spherical in form and covered with a helically symmetrical capsid and a peri-capsid crossed by glycoprotein structures. This layout gives it the typical appearance (crown). The entire viral genome is composed by a single strain of RNA. The virus mainly affects the respiratory and gastrointestinal tract. Although there are more types of coronaviruses that can affect humans, the SARS-CoV-2 is by far the best-known variant since it caused a global health crisis that affects each of us. The incubation period is between 2 and 29 days (most frequently 2-14 days). The main transmission form for this virus is through respiratory droplets (sneeze, cough or direct personal contacts).  Although a lot of uncertainties still exist regarding the different transmission routes, the interest towards air disinfection protocols and ventilation, especially in medical environments is increasing [2].

1. Chapter “Materials and Methods”

The main objection is the lack of description of the statistical analysis of the conducted experiment.

More information on the methodology is provided and marked in red. The present study is a descriptive study, this is why there is no more information regarding the statistical part. The following study will include a thorough statistical analysis.

1. Chapter „Results”

The test results are described too generally. There is also a question. Were any steps taken to prepare a given dentist's office for the experiment before starting the research? Was the site routinely prepared for this analysis? Next question. Is it certain that the dental surgery workers during the experiment were fully healthy, not carriers of the virus?

L207: Before every patient entering the office, current national guidelines (UVC, ventilation and fogging, with a total of 5 hours gap between patients) for disinfection were ap-plied, to ensure maximum patient safety. This also provides a constant disinfection guideline.

Dental surgery workers got PCR tests on a regular basis to ensure that both them and the patients are as safe as possible.

 

Reviewer 5 Report

Dear authors, 

this article aimed to verify whether plain natural ventilation is a sufficient method for ensuring air decontamination in the dental office, or whether more elaborated decontamination methods are required. the authors also aimed that the results of the present study could therefore guide the choice of air disinfection protocols for dental practices 

this study add some knowledge to the recent pandemic study and I encourage the publication in applied science journal.

 

Author Response

Dear authors, 

this article aimed to verify whether plain natural ventilation is a sufficient method for ensuring air decontamination in the dental office, or whether more elaborated decontamination methods are required. the authors also aimed that the results of the present study could therefore guide the choice of air disinfection protocols for dental practices 

this study add some knowledge to the recent pandemic study and I encourage the publication in applied science journal.

Esteemed reviewer,

Thank you for your time and appreciation! We really hope that our present pilot study and the following more exhaustive studies will help in protecting ourselves and our patients during these difficult times.

New information has been added in all the essential parts of the article. New and up to date references were cited. More information on the validity and impact of our present paper was provided. Changes are marked in red.

Round 2

Reviewer 2 Report

The authors answered some of the issues that were raised in the first review.  The manuscript needs english language and style review .

Reviewer 4 Report

Comments to the Author

 

Thank you very much for responding to all my suggestions.

 

In my opinion, each publication and scientific research should be based on statistical dependencies. There are no such designations in this manuscript. Nevertheless, once the changes are made, the scientific value of the publication is higher.

I suggest that in subsequent studies, the methodology of analyzes should be structured in such a way that the results are presented statistically. In my opinion, these studies should also include at least elements of statistical determinations, as far as possible.

 

Comments for author File: Comments.docx