Reviewer’s report
Title: 
Is the use of contraceptives associated with periodontal diseases? A
systematic review and meta-analyses
Version: 
1 
Date: 
02 Mar 2020
Reviewer's report:
This is an interesting and important article on the epidemiological link between
the use of hormonal contraceptives and the severity of periodontal diseases.
This is a revised manuscript, and it seems that authors have well taken into
account previous comments. 
As a new reviewer, I have some concerns to still improve the paper. 
Introduction section:
The existence - or not - of prior systematic reviews in the field should be
discussed. If applicable, what are their limitations in justifying this one? 
Material and methods
* please make sure that the information presented in the article corresponds to
the information reported in the prospero registration (it is important for every
section, original report should be consistent with the prosper registration); for
example: 
- Article: "Narrative reviews, case reports, descriptive studies, technical articles,
animal and in-vitro studies were discarded"
vs
- Prospero: 
Inclusion: clinical studies, performed in humans, investigating the effects of oral
contraceptives in periodontitis.
Exclusion: pilot studies, case reports, descriptive studies, review articles, opinion
articles, technique articles and guidelines, studies investigating the use of barrier
contraceptives, and studies which do not report on the clinical parameters of
periodontitis.
- Article : "The searches were performed between May and November 2018."
- Prospero: only preliminary searches completed in november 2018. 
* p7 l133: typo "confouNding"
* p8 l148: typo "I2" (also p11 and 12)
* please justify why CAL and PB were chosen as clinical parameters (not only in
the discussion) 
* p10 l202: typo e a aceptability
* p10 l202 : "absence of description of the randomization" please avoid the word
"randomization" here (usually used for RCTs)
* Please give the information on authors from primary studies that gave
additional information in response to "The authors of the studies were contacted
if relevant data were absent in the articles"
Results 
OK
Discussion: 
It should be interesting for the reader to learn a bit more on the biological
mechanisms potentially explaining the association. 
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Yes
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the
authors.
Yes
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Yes
Are you able to assess any statistics in the manuscript or would you
recommend an additional statistical review?
If an additional statistical review is recommended, please specify what aspects
require further assessment in your comments to the editors.
I am able to assess the statistics
Quality of written English
Please indicate the quality of language in the manuscript:
Acceptable
Declaration of competing interests
Please complete a declaration of competing interests, considering the following
questions:
1
. 
Have you in the past five years received reimbursements, fees, funding, or
salary from an organisation that may in any way gain or lose financially
from the publication of this manuscript, either now or in the future?
2
. 
Do you hold any stocks or shares in an organisation that may in any way
gain or lose financially from the publication of this manuscript, either now
or in the future?
3
. 
Do you hold or are you currently applying for any patents relating to the
content of the manuscript?
4
. 
Have you received reimbursements, fees, funding, or salary from an
organization that holds or has applied for patents relating to the content of
the manuscript?
5
. 
Do you have any other financial competing interests?
6
. 
Do you have any non-financial competing interests in relation to this
paper?
If you can answer no to all of the above, write 'I declare that I have no competing
interests' below. If your reply is yes to any, please give details below.
I declare that I have no competing interests
I agree to the open peer review policy of the journal. I understand that my name
will be included on my report to the authors and, if the manuscript is accepted
for publication, my named report including any attachments I upload will be
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(
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). I understand that any comments
which I do not wish to be included in my named report can be included as
confidential comments to the editors, which will not be published.
I agree to the open peer review policy of the journal