Lower Molar Distalization Using Clear Aligners: Bodily Movement or Uprighting? A Preliminary Study

Round 1

Reviewer 1 Report

Dear authors,

I have revised the manuscript and i have a few comments:

INTRODUCTION section:

-on the first and second paragraphs, the class III is discussed and on the third paragraph, the class II is reminded. Please revise!

-on the penultimate paragraph you briefly discuss about the upper molar distalization, but no references about the inferior molar distalization were given. Please discuss this topic and a few ideas about the Invisalign.

MATERIAL AND METHODS section:

-the age is a factor that can interfere with the success of the treatment?

-”Third molars, if they were present, were extracted before CAT started” the bone loss after the extraction, can be a parameter that can affect the treatment?

RESULT section:

-”No significant variation was reported for overjet and overbite, even if clinically there was an improvement with mean increases of..” what can be the explanation of this result ?

-the quality of the table 1 must be improved 

Author Response

We thank the reviewer for the comments.

INTRODUCTION section:

-on the first and second paragraphs, the class III is discussed and on the third paragraph, the class II is reminded. Please revise!

sorry it was a mistyping. Corrected in the text

-on the penultimate paragraph you briefly discuss about the upper molar distalization, but no references about the inferior molar distalization were given. Please discuss this topic and a few ideas about the Invisalign.

added some ideas in the text

MATERIAL AND METHODS section:

-the age is a factor that can interfere with the success of the treatment?

The study was conducted on adult patients, as the mean age was 25.6 ± 4.5 years, so patients' age could not be considered as a variable.

-”Third molars, if they were present, were extracted before CAT started” the bone loss after the extraction, can be a parameter that can affect the treatment?

The extraction were executed as near as possible to the time of the start of the treatment. this information was added in the text

RESULT section:

-”No significant variation was reported for overjet and overbite, even if clinically there was an improvement with mean increases of..” what can be the explanation of this result ?

Due to the low number of patients this variable did not resulted to be statistically significative, even if 1,2mm of increased overjet could be considered clinically significative

-the quality of the table 1 must be improved 

Quality of the table was improved in the text, thank you

Reviewer 2 Report

I was pleased to review the paper entitled: "Lower molar distalization using clear aligners: bodily movement or uprighting? A preliminary study".

First of all, I would like to congratulate the authors on choosing the topic and preparing the methodology, and writing the paper. The paper is written extremely well.

Class III therapy has always been a challenge. The potential of Aligner is great, it seems to me that this work provides exceptional results worthy of daily clinical work.

Comments by sections:
Summary: Well structured and beautifully written.

Introduction: The authors nicely wrote the introductory part with indications for applied technologies.

Material and methods: The design of the study and the methodology are excellent. The authors provided all the necessary data for a good understanding of the methodology.

Results: Well presented.

Discussion: Very well written and clearly discussed with relevant studies. The authors also mention the disadvantages of the study as well as the advantages of this type of additional learning.

Conclusion: Extensive and unnecessary. The conclusion should be revised and only the most important results of this study should be left, which are in line with the aims. Rewrite the shortcomings and recommendations for the last paragraph in the discussion.

Author Response

I was pleased to review the paper entitled: "Lower molar distalization using clear aligners: bodily movement or uprighting? A preliminary study".

First of all, I would like to congratulate the authors on choosing the topic and preparing the methodology, and writing the paper. The paper is written extremely well.

Class III therapy has always been a challenge. The potential of Aligner is great, it seems to me that this work provides exceptional results worthy of daily clinical work.

Comments by sections:
Summary: Well structured and beautifully written.

Introduction: The authors nicely wrote the introductory part with indications for applied technologies.

Material and methods: The design of the study and the methodology are excellent. The authors provided all the necessary data for a good understanding of the methodology.

Results: Well presented.

Discussion: Very well written and clearly discussed with relevant studies. The authors also mention the disadvantages of the study as well as the advantages of this type of additional learning.

We thank the reviewer for his comments

Conclusion: Extensive and unnecessary. The conclusion should be revised and only the most important results of this study should be left, which are in line with the aims. Rewrite the shortcomings and recommendations for the last paragraph in the discussion.

Thank you, we change conclusion section in the text

Reviewer 3 Report

Dear Authors,

The aim of this study was to assess the efficacy of Invisalign system in distalizing lower molars, with-out any auxiliary and evaluating the quantity of tipping and bodily movement.

The study is of scientific interest and in line with the aims of the journal, but the final number of included subjects was too small. Moreover, the author guidelines have not been respected and the Material and Methods were not well described.

Abstract

Abstract: The abstract should be a total of about 200 words maximum. The abstract should be a single paragraph and should follow the style of structured abstracts, but without headings: 1) Background: Place the question addressed in a broad context and highlight the purpose of the study; 2) Methods: Describe briefly the main methods or treatments applied. Include any relevant preregistration numbers, and species and strains of any animals used. 3) Results: Summarize the article's main findings; and 4) Conclusion: Indicate the main conclusions or interpretations. The abstract should be an objective representation of the article: it must not contain results which are not presented and substantiated in the main text and should not exaggerate the main conclusions.

Please follow the Instruction for Authors (https://www.mdpi.com/journal/applsci/instructions).

Introduction

Please, in all the text add space before the square brackets.

Material and Methods.

Where the subjects were recruited?

When the patients were recruited?

The final number of patients included in the study must be reported in the Result Section, not in the Material and Method Section.

Was the study was approved by the Local Ethics Committee?

Were all participants asked to read and sign an informed consent?

Was the study conducted according to the Declaration of Helsinki?

Was the study was performed in accordance with the STrengthening the Reporting of  Bservational studies in Epidemiology (STROBE) Guidelines?

“adult age (confirmed by CVM method[25])”. What do you mean? CVM>3? CVM>4?

“Class III molar relationship at the beginning of the treatment (T0)”. Full /half cusp class III? 

“≥ 1.5 mm distalization movement programmed on the first Clincheck”. Do you mean that 1.5 mm of distalization movement was required to obtain Class I”.

“good quality pre-treatment and post-treatment radiographs”. Which radiographs?

“signs or symptoms of TMJ[26]”. Firstly, the acronym “TMJ” was not reported previously in the text. Secondly, do you mean Temporomandibular Disorders (TMDs)? 

The final sample consisted of 16 patients (8 males, 8 females; mean age: 25.6 ± 4.5 years). These data must be reported in the Result Section.

Moreover, in my opinion, the final number of included subjects was too small. 

Result and Discussion sections were well explained.

References did not respect the Instruction for Authors.

Journal Articles:
1. Author 1, A.B.; Author 2, C.D. Title of the article. Abbreviated Journal Name Year, Volume, page range.

Please follow the Instruction for Authors (https://www.mdpi.com/journal/applsci/instructions).

Author Response

We thank the reviwer for his time spent in reviewing our paper

Abstract

Abstract was modified in the text following Instruction for Authors, thank you

Introduction

Please, in all the text add space before the square brackets.

Modified in the text, thank you

Material and Methods.

Where the subjects were recruited?

All the patients were treated at the Dental School of the University of Turin and in orthodontic private practice specified in the text

When the patients were recruited?

Patients were retrospectically selected

The final number of patients included in the study must be reported in the Result Section, not in the Material and Method Section.

Information added in Result section, thank you

Were all participants asked to read and sign an informed consent?

yes thank you, specified in the text

Was the study conducted according to the Declaration of Helsinki?

Yes,specified in the text, thank you

“adult age (confirmed by CVM method[25])”. What do you mean? CVM>3? CVM>4?

According to Baccetti et al we considered CVM>4

“Class III molar relationship at the beginning of the treatment (T0)”. Full /half cusp class III? 

Full Class III, specified in the text

“≥ 1.5 mm distalization movement programmed on the first Clincheck”. Do you mean that 1.5 mm of distalization movement was required to obtain Class I”.

In order to select patient sample, only patients that required a distalization >1.5mm to obtain Class I were selected for the study

“good quality pre-treatment and post-treatment radiographs”. Which radiographs?

Specified in the text

“signs or symptoms of TMJ[26]”. Firstly, the acronym “TMJ” was not reported previously in the text. Secondly, do you mean Temporomandibular Disorders (TMDs)? 

Thank you, the acronym was corrected in the text

The final sample consisted of 16 patients (8 males, 8 females; mean age: 25.6 ± 4.5 years). These data must be reported in the Result Section.

Reported in Result section

Moreover, in my opinion, the final number of included subjects was too small. 

It was specified as a limitation of the study, thank you

References did not respect the Instruction for Authors.

References were checked in the text

Reviewer 4 Report

Dear Authors,
This version of manuscript is much better than previous. I see a lot of works done.

But still I have some questions to manuscripts:
- "The final sample consisted of 16 adult patients (8 males, 8 females; mean age: 25.6 ± 4.5 years)."  This sentence is repeated twice, please delete it in one place.
- "a signed informed consent was obtained from the patients’ parents, before collecting the data" why you have informed consent from parents when your patients was mean age: 25.6 ± 4.5 years?
- Figura 1.a - where is figure 1.b? And where is legend for figure 1.a. Figure without legend is redundant
- "All the patients achieved a Class I molar relationship at the end of treatment and the mean duration of CAT treatment was 19.7 months." please add the standard deviation value
- "and no signs or symptoms of TMD were revealed during or after the therapy" How you checked the TMD? any standard protocol?

Author Response

we thank the reviewer for positive comments.

- "The final sample consisted of 16 adult patients (8 males, 8 females; mean age: 25.6 ± 4.5 years)."  This sentence is repeated twice, please delete it in one place.

The sentence was deleted, thank you
- "a signed informed consent was obtained from the patients’ parents, before collecting the data" why you have informed consent from parents when your patients was mean age: 25.6 ± 4.5 years?

It was a mistyping, modified in the text thank you
- Figura 1.a - where is figure 1.b? And where is legend for figure 1.a. Figure without legend is redundant

Sorry, Figure 1 is the only figure in the paper, we changed from Figure 1.a into Figure 1. A legend was not reported as in the text is explained the ceph measurements used. Thank you
- "All the patients achieved a Class I molar relationship at the end of treatment and the mean duration of CAT treatment was 19.7 months." please add the standard deviation value

Thank you, we add the information in the text.
- "and no signs or symptoms of TMD were revealed during or after the therapy" How you checked the TMD? any standard protocol?

As assessed in the text and in the references list, we followed protocols published in scientific literature "Schiffman E, Ohrbach R, Truelove E. Diagnostic criteria for temporomandibular disorders (DC/ TMD) for clinical and research applications: recommendations of the international RDC/TMD Consortium Network and Orofacial Pain Special Interest Group. J Oral & Facial Pain and Headache. 2014;28(1):6-27". Thank you

Round 2

Reviewer 1 Report

The manuscript was improved and from my point of view, it can be published in present form!

Author Response

we thank the reviewer for the positive comment

Reviewer 3 Report

The study is of scientific interest and in line with the aims of the journal, but the final number of included subjects was too small. I encourage authors to recruit more patients. 

Author Response

we thank the reviewer for the comment. In the limitations of the study we underline that the paper is based on small sample, further studies in the future can recruite more patients

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Dear Authors.

Congratulations on your work which, I found interesting.

Manuscript: Lower molar distalization using clear aligners: bodily movement or uprighting?, it is well written with an adequate structure as a scientific paper demands.

I have one major suggestion. As the study group is very small, it would be worth considering changing the title by adding: preliminary or pilot study. It is difficult to draw unambiguous conclusions on such a number of patients

I have some additional minor revisions to propose to you to improve your work. Please refer to the following comments:

- How long was the treatment time for patients? Was it comparable between patients?

- Figure 1.a. a more detailed description of the figure is missing. And is there missing Figure 1.b?

- Line 177 - What do the authors understand by good occlusion? Please explain. Only achieving class I molar and canine is not a good occlusion.

- The literature is old, with many citations (68%) of works from before 2012 - please consider updating it.

Reviewer 2 Report

Comments to the Author

The present study investigated an interesting and clinically relevant topic. Nevertheless, due to the presence of several methodological issues it cannot be considered suitable for publication in the present format. The authors, who are for sure experienced clinicians, are aware of the extremely weakness of the data set which do not add any clinical relevant information to the present evidence. The reported data do not have any internal and external validity. Consequently, the authors are invited to increase the sample size, to re-analyze the data and re-submit the manuscript.

1. Table 1 is a low-quality copy-paste or screen-shot of the calculated values. Such Table is not acceptable.
2. Materials & Methods: This section is the natural reflection of the weakness of the presented data. Retrospective studies do provide relevant data, nevertheless some important information have to be reported:

-It is reported that 21 Caucasian subjects were treated with Invisalign. 21 patients of how many? It is very important to report how large was the original cohort. Moreover, out of the 21 patients only data on 16 patients could be used: this is for sure a major limitation of the study.

-The study settings are 2, however it is not clear how many patients were treated in the 2 centers and it seems obvious to the reviewer that the authors have “pooled” data from 2 different settings to increase the sample size which however remains low. From a methodological point of view this is a MAYOR bias!

-No clear information on the Ethic Committee Approval for BOTH centers are reported. This is not anymore acceptable even for retrospective studies which do not require additional clinical/radiographic examinations.

-The power analysis is a prerequisite of prospective/randomized clinical studies, not of retrospective studies. Nevertheless, if the authors would like to provide this information, it should be performed in relation to the primary outcome. The reviewer was not able to detect which parameter has been defined as such. Finally, a post-hoc analysis is advisable especially in retrospective studies.

3. Results: This section is poorly written and is a mix of M&M and results. The terminology is not appropriate since the term “Significant” is wrong. Do the authors mean: “Statistically significant”??? Do the authors think that a results section of 17 lines is enough? This section is the reflection of the weakness of the data setting and data reporting.