The Main Bacterial Communities Identified in the Sites Affected by Periimplantitis: A Systematic Review

Round 1

Reviewer 1 Report

The manuscript entitled ‘The Main Bacterial Communities Identified In The Sites Affected By Periimplantitis’ has been peer-reviewed. In the present work, the authors have highlighted the exact bacterial flora involved in the occurrence of Periimplantitis collecting the publications from PubMed, Embase, and Web of Science databases. We recommend the manuscript be accepted as we don’t find any mistakes. 

Author Response

Dear Editors,

 

 

            Thank you for allowing us to resubmit a revised version of our manuscript. Please accept our revised version for further consideration. We would like to express our gratitude to the reviewers for providing constructive feedback by identifying the areas of our manuscript that needed further improvements. We appreciate the tremendous effort and time the reviewers have devoted to strengthening our manuscript. Accordingly, we have uploaded the revised manuscript with all the changes indicated with red. Please find below our response to each of the reviewers comments. We hope this will make the paper easier to read and we are confident that the new version of the manuscript is significantly improved. Thus, we look forward to hearing from you and responding any other questions or comments you may have. As the audience of your prestigious journal deserves discussion on the topic of the bacterial flora involved in the occurrence of periimplantitis, we are submitting the revised version of the manuscript and we will appreciate your quick response.

                                                                                   

 

 

With my best regards,

Prof. Dr. Ondine Patricia Lucaciu.

(on behalf of all coauthors)

 

 

 

 

 

 

 

 

 

Reviewer 1

 

Open Review

( ) I would not like to sign my review report

(x) I would like to sign my review report

English language and style

( ) Extensive editing of English language and style required

( ) Moderate English changes required

(x) English language and style are fine/minor spell check required

( ) I don't feel qualified to judge about the English language and style

Yes      Can be improved         Must be improved       Not applicable

Does the introduction provide sufficient background and include all relevant references?

(x)        ( )         ( )         ( )

Are all the cited references relevant to the research?

(x)        ( )         ( )         ( )

Is the research design appropriate?

(x)        ( )         ( )         ( )

Are the methods adequately described?

( )         ( )         ( )         (x)

Are the results clearly presented?

( )         ( )         ( )         (x)

Are the conclusions supported by the results?

(x)        ( )         ( )         ( )

Comments and Suggestions for Authors

The manuscript entitled ‘The Main Bacterial Communities Identified In The Sites Affected By Periimplantitis’ has been peer-reviewed. In the present work, the authors have highlighted the exact bacterial flora involved in the occurrence of Periimplantitis collecting the publications from PubMed, Embase, and Web of Science databases. We recommend the manuscript be accepted as we don’t find any mistakes.

Thank you very much for the time you dedicated to this manuscript and for appreciating our work.

 

Reviewer 2 Report

TITLE:  The Main Bacterial Communities Identified In The Sites 2 Affected By Periimplantitis

The aim of the present investigation was to assess the effectiveness of the NCITs on four surface sites at various ambient temperatures, and further formulate a unified screening scheme in fever screening.

GENERAL COMMENTS

The article is in-line with the journal topic, but severe flaws should be improved.  The investigation is interesting, and the present paper is recommended for publication to the present journal after major revision.

Title: The title should indicate the type of study that has been conducted: (f.e.: systematic review)

 

Introduction

1.     Line 51-55: The Part should integrate also the different Sars-CoV-2

2.     This section should be empowered with the different applications of commercial zirconia for monolithic implants according to the biological properties and mechanical behavior.

3.     Moreover, a description of the most frequent prosthetic failure of zirconia crown’s should be introduced in this part of the manuscript as a important component of the rationale of the present study.

Materials and methods

The PROSPERO register number should be provided. Why did the authors chosen a bibliometric database (Web of Sciences? No Scopus). The authors could expand the search also on Google Scholars and Cochrane library.

The authors identified a total of 980 papers from the search and after the elimination of duplicates, 201 articles remained, but we replicated the search methodology (only on PUBMED!) with the following output:

·       (bacteria) AND (periimplantitis), 799 papers

·       (biofilm) AND (periimplantitis), 450 papers

·       (microorganisms) AND (periimplantitis), 133 papers

·       (microbiota) AND (periimplantitis), 154 papers

·       (biofilm) AND (dental implant), 976 papers

·       ((bacteria) AND (dental implant)) AND (periimplantitis), 698 papers

·       (microbiome) AND (periimplantitis ) 171 papers

·       ("Bacterial strains and periimplantitis" or "biofilms and periimplantitis" or "bacterial cultures and periimplantitis" or "types of bacteria and periimplantitis") 578 papers

The authors are encouraged to reformulate the search in a more punctual way.

Results

The PRISMA flowchart should include also the web of sciences search.

Table. 1 Very poor informations have been provided by the authors and the presentation seems to be a little bit superficial (type of study, study design, samples, study timeline, test/control groups, population characteristics).

A final output of 25 studies seems a little bit limitating. Why the authors did not include also a manual search strategy to improve the review findings.

Discussion

The present investigation presented strong flaws with no risk of bias assessment of the studies included. This important aspect should be discussed in this section. In my opinion, an improved analytical approach could strongly potentiate the study findings. No reference to the limits of the present investigation have been included in this section. It is not evident from this part the novelty of the present investigation. Moreover, no references to the peri-implantitis grades have been introduced in the paper. I suggest to improve the discussion after reading the follow paper: PMID: 27391491

The null-hypothesis should be discussed in this part of the manuscript.

Author Response

Dear Editors,

 

 

            Thank you for allowing us to resubmit a revised version of our manuscript. Please accept our revised version for further consideration. We would like to express our gratitude to the reviewers for providing constructive feedback by identifying the areas of our manuscript that needed further improvements. We appreciate the tremendous effort and time the reviewers have devoted to strengthening our manuscript. Accordingly, we have uploaded the revised manuscript with all the changes indicated with red. Please find below our response to each of the reviewers comments. We hope this will make the paper easier to read and we are confident that the new version of the manuscript is significantly improved. Thus, we look forward to hearing from you and responding any other questions or comments you may have. As the audience of your prestigious journal deserves discussion on the topic of the bacterial flora involved in the occurrence of periimplantitis, we are submitting the revised version of the manuscript and we will appreciate your quick response.

                                                                                   

 

 

With my best regards,

Prof. Dr. Ondine Patricia Lucaciu.

(on behalf of all coauthors)

 

 

 

 

 

 

 

 

 

 

 

 

 

Reviewer 2

Open Review

( ) I would not like to sign my review report

(x) I would like to sign my review report

English language and style

( ) Extensive editing of English language and style required

( ) Moderate English changes required

( ) English language and style are fine/minor spell check required

(x) I don't feel qualified to judge about the English language and style

            Yes      Can be improved         Must be improved       Not applicable

Does the introduction provide sufficient background and include all relevant references?

( )         (x)        ( )         ( )

Are all the cited references relevant to the research?

( )         (x)        ( )         ( )

Is the research design appropriate?

( )         (x)        ( )         ( )

Are the methods adequately described?

( )         (x)        ( )         ( )

Are the results clearly presented?

( )         (x)        ( )         ( )

Are the conclusions supported by the results?

( )         (x)        ( )         ( )

 

Comments and Suggestions for Authors

TITLE:  The Main Bacterial Communities Identified In The Sites 2 Affected By Periimplantitis

 

The aim of the present investigation was to assess the effectiveness of the NCITs on four surface sites at various ambient temperatures, and further formulate a unified screening scheme in fever screening.

 

GENERAL COMMENTS

 

The article is in-line with the journal topic, but severe flaws should be improved.  The investigation is interesting, and the present paper is recommended for publication to the present journal after major revision.

 

Title: The title should indicate the type of study that has been conducted: (f.e.: systematic review)

Thank you for your suggestion, we made the suggested change in the manuscript.

The Main Bacterial Communities Identified in the Sites Affected by Periimplantitis: A Systematic Review

 

Introduction

 

1. Line 51-55: The Part should integrate also the different Sars-CoV-2

Thank you for your suggestion, we added this information in the manuscript.

With the emergence of a new disease, Covid 19, caused by the infection with SARS-CoV-2, the possible link between this viral infection and periimplantitis has been studied. It is shown that SARS-CoV-2 is present in the saliva and crevicular fluid of patients with COVID-19. [14,15]. Patients with periodontal or periimplant disease, such as periimplantitis, are at increased risk of developing COVID-19-associated complications, and patients with COVID-19 risk worsening periodontal or periimplant lesions. [16] During the pandemic, due to the transmission of SARS-CoV-2 through aerosols, the dental offices adapted to the new global situation, so that the access of patients suffering from chronic diseases, such as periimplantitis, to dental treatments was limited, this aggravating their condition. [14] At the same time, the increased level of stress and depression in the population, accentuated by the pandemic, caused the aggravation of periodontal diseases by increasing plaque accumulation and gingival bleeding due to neglect of oral hygiene, lack of regular visits to the dental office, as well as by decreasing the healing capacity of the tissues and affecting the body's response to treatment [14,16,17]. Patients with periodontal disease or periimplantitis have a higher risk of developing complications associated with COVID-19, studies suggesting that lesions in the periodontal and periimplantar pockets are an entry point for the virus into the general circulation. [15,16]. Certain constituents of plaque in the periimplant sulcus, such as Treponema denticola, Porphyromonas gingivalis or Candida, release proteases that degrade the basement membrane facilitating viral and bacterial invasion. [15] Periodontal and periimplants pockets, rich in aggressive pathogens, can also be a starting point for microorganisms that can be aspirated by people infected with SARS-COV-2, leading to various complications. [16]

2. This section should be empowered with the different applications of commercial zirconia for monolithic implants according to the biological properties and mechanical behavior.

Thank you for your constructive feedback. As requested by the reviewer, we have made some changes in the Introduction and we wrote about the different applications of commercial zirconia in dental implantology according to the biological properties and mechanical behavior.

 

There are several types of biomaterials from which dental implants can be made, the most used being titanium  and titanium alloys, materials with high biocompatibility, high success rates over long periods of follow-up and good mechanical properties. [1] Although titanium implants are widely used, they also have drawbacks such as the gray color that can be visible in the frontal area with thin gingival tissue, which is why more aesthetic alternatives have been found. One of these is the use of Zirconia for dental implants, a material that has aesthetic properties as translucency, the color similar to natural teeth and biocompatibility with the surrounding soft and hard tissues [1, 2, 3]. The mechanical properties of Zirconia are encouraging, as it has high flexural strength, increased resistance to fracture and corrosion, as well as a low thermal conductivity [3]. Regarding osseointegration, most studies show that the two materials have similar properties [3, 4]. Colonization of the surface of zirconium implants by pathogenic bacteria has been shown to be lower compared to implants made of titanium alloys, leading to optimal healing and a low rate of infectious complications [1, 3, 4].

3. Moreover, a description of the most frequent prosthetic failure of zirconia crown’s should be introduced in this part of the manuscript as a important component of the rationale of the present study.

Thank you very much for your suggestion. As requested by the reviewer, we wrote about the most frequent prosthetic failure of zirconia crown’s.

Regarding the prosthetic rehabilitation on implants, several comparative studies were performed between the dental prostheses made of metal-ceramic and those of zirco-nia-ceramic, following the main causes of failure. Current information in the literature on the success of monolithic zirconia rehabilitation is limited. According to the studies, the most common causes of failure of crowns and bridges on implants are the fracture of materials, more common in the case of zirconia, either the fracture of the coating ceramics or the fracture of the zirconia structure. Biological complications such as periimplantitis are also more common in zirconia-ceramics than in metalo-ceramics. [5, 6].

 

Materials and methods

 

The PROSPERO register number should be provided. Why did the authors chosen a bibliometric database (Web of Sciences? No Scopus). The authors could expand the search also on Google Scholars and Cochrane library.

Thank you for your suggestion.

The protocol of the review was registered within the International Prospective Register of Systematic Reviews (PROSPERO) under registration number CRD42022335476.

We have chosen those three databases (PubMed, Embase, Web of Science) because they ensured the reproducibility of our search, allowing us to use both the same search terms and the same filters. Also, we did not search on Cochrane Library because it is a database for reviews articles, and we excluded reviews from our study.

The authors identified a total of 980 papers from the search and after the elimination of duplicates, 201 articles remained, but we replicated the search methodology (only on PUBMED!) with the following output:

 

• (bacteria) AND (periimplantitis), 799 papers

 

• (biofilm) AND (periimplantitis), 450 papers

 

• (microorganisms) AND (periimplantitis), 133 papers

 

• (microbiota) AND (periimplantitis), 154 papers

 

• (biofilm) AND (dental implant), 976 papers

 

• ((bacteria) AND (dental implant)) AND (periimplantitis), 698 papers

 

• (microbiome) AND (periimplantitis ) 171 papers

 

• ("Bacterial strains and periimplantitis" or "biofilms and periimplantitis" or "bacterial cultures and periimplantitis" or "types of bacteria and periimplantitis") 578 papers

 

The authors are encouraged to reformulate the search in a more punctual way.

 

Thank you for your constructive feedback, we reformulated the search strategy more clearly. There was also a redaction mistake in the text and we apologise for that. There should be 2012 instead of 2002, but an error crept in when we drafted the text. We conducted the search for the articles publicated in the last ten years, between 2012 until 2022.

Search strategy

The methodological design of this study is in line with the PRISMA 2020 criteria and guidelines [18]. The protocol of the review was registered within the International Prospective Register of Systematic Reviews (PROSPERO) under registration number CRD42022335476. In this study we address the following question: "Which are the most common bacterial species in periimplantitis?" To answer this question, a systematic literature search was carried out in 3 databases: PubMed, Embase, and Web of Science. The search strategy consisted of different combinations of MeSH keywords: "periimplantitis", "bacteria", "biofilm", "microorganisms", "microbiota", "dental implant": (bacteria) AND (periimplantitis), (biofilm) AND (periimplantitis), (microorganisms) AND (periimplantitis), (microbiota) AND (periimplantitis), (biofilm) AND (dental implant), ((bacteria) AND (dental implant)) AND (periimplantitis), (microbiome) AND (periimplantitis ), ("Bacterial strains and periimplantitis" or "biofilms and periimplantitis" or "bacterial cultures and periimplantitis" or "types of bacteria and periimplantitis"), the filters applied being: Clinical Study, Clinical Trial, Randomized Controlled Trial, Other Animals, Humans, in the last 10 years. Two researchers performed independently the database literature search and subsequently the results were confronted.

Inclusion and exclusion criteria

The inclusion criteria were the articles published in the three databases mentioned above, in the last ten years, between January 2012 until March 2022.  We selected studies performed on patients with dental implants suffering from periimplantitis and those in which samples of bacterial plaque were collected from peri-implant sulcus affected by periimplantitis, analyzed and provided results on the microbial flora involved in periimplantitis.

Between the exclusion criteria were: articles published in a language other than English or French, articles other than those mentioned above, such as systematic reviews or meta-analyzes, experimental or in vitro studies.

 

Results

 

The PRISMA flowchart should include also the web of sciences search.

 

Thank you for your suggestion, we included the Web of Science search, but it wasn’t visible due to page alignemment and we apologize for that. We managed the corrections, as requested by the reviewer.

 

 

 

				Records identified through database researching: PubMed: 185 Embase: 661 Web of Science: 134

 

 

 

 

 

 

 

 

 

 

 

 

              

			Studies included in review (n = 25)

 

 

 

 

 

 

 

 

 

 

 

Table 1. Very poor informations have been provided by the authors and the presentation seems to be a little bit superficial (type of study, study design, samples, study timeline, test/control groups, population characteristics).

 

Thank you for your suggestion, as recommended by the reviewer we have improved the table presentation.

 

 

Article title	Authors	Year of publication	Study design	Study samples	Population characteristics	Bacterial isolation technique	Isolated bacteria
Diversity analysis of subgingival microbial bacteria in periimplantitis in Uygur population	Gao et al. [9]	2018	Observational Study	40 samples of gingival crevicular fluid divided into two groups: healthy implants (Control group) and periimplantitis (Case group)	Uygur patients who had treatment with dental implants from 2013 to 2016	DNA extraction, PCR amplification and 16S rRNA gene sequencing	Prevotella, Streptococcus, Acinetobacter, Fusobacterium, Neisseria, Porphyromonas, Treponema, Leptothrix, Capnocytophaga
Efficiency of photodynamic therapy in the treatment of periimplantitis – A three-month randomized controlled clinical trial	Rakašević  et al. [19]	2016	Randomized controlled clinical trial	Samples from 52 periimplantitis sites divided into two groups( Study group and Control group)	Patients with periimplantitis who presented in two dental clinics in Belgrade between January 2014 until February 2015	Bacterial culture for the diagnosis of aerobic and anaerobic pathogens	Veillonella spp. , Prevotella intermedia, Peptostreptococcus spp., Peptostreptococcus asaccharolyticus., Porphyromonas gingivalis, Fusobacterium nucleatum, Actinomyces odontolyticus
Bacterial profiles and proteolytic activity in periimplantitis versus healthy sites	Neilands et al. [20]	2015	Non- randomised, controlled, clinical study	50 samples (25 from healthy subjects, 25 from periimplantitis sites)	Patients with dental implants treatment in the past, attending maintanance appointments in a dental clinic in Sweden	Bacterial culture on Brucella agar	Porphyromonas/Prevotella, Fusobacterium , Tannerella, Streptococcus oralis,  Streptococcus mitis, Streptococcus anginosus, Streptococcus constellatus, Streptococcus intermedius
Short-term effects of hyaluronic acid on the subgingival microbiome in periimplantitis: A randomized controlled clinical trial	Soriano-Lerma et al. [21]	2020	Randomized controlled trial	108 samples divided into 3 groups ( Test group, Control group 1, Control group 2)	Patients diagnosticated with periimplantitis in a private dental office in Spain	DNA isolation, PCR amplification and 16S rRNA gene sequencing	Fusobacterium, Prevotella, Porphyromonas, Ralstonia, Sphingomonas, Streptococcus, Treponema, Propionibacterium, Alloprevotella, Veillonella, Lactobacillus, Haemophilus, Staphylococcus, Campylobacter, Tannerella,
A randomized clinical trial of an adjunct diode laser application for the nonsurgical treatment of periimplantitis	Arısan et al. [22]	2015	Randomized clinical trial	Samples collected from 24 implants affected by periimplantitis at baseline and 1 month after intervention	10 patients diagnosticated with periimplantitis who went to the departament clinic in Istanbul University between February 2010 and May 2013	DNA extraction, PCR amplification and hy bridization procedures	Actinomyces odontolyticus, Actinomyces viscosus, Aggregatibacteractinomycetemcomitans, Campylobacter concisus, Campylobacter gracilis, Campylobacterrectus/showae, Capnocytophaga gingivalis/ sputigena/ ochracea, Eikenella corrodens, Eubacterium nodatum, Fusobacterium nucleatum, Peptostreptococcus micros, Porphyromonas gingivalis, Prevotella intermedia, Prevotellanigrescens, Streptococcus constellatus group, Streptococcusgordonii group, Streptococcus mitis group,Tannerella forsythia (Bacteroides forsythus; Tannerella forsythensis), Treponema denticola, and Veillonella parvula.
The effects of Lactobacillus reuteri probiotics combined with azithromycin on periimplantitis: A randomized placebo-controlled study	Tada et al. [23]	2017	Randomized placebo- controlled study	Samples collected from periimplantitis sites at baseline and 4, 12, 24 weeks after allocated treatment	30 patients diagnosticated with periimplantitis from 7 different institutions including Kyushu Dental University Hospital, Japan, divided into 2 groups , placebo and probiotics	DNA isolation, PCR amplification and 16S rRNA gene sequencing	Treponema denticola,  Fusobacterium nucleatum,  Peptostreptococcus micros,  Streptococcus constellatus, Prevotella nigrescens, Tannerella forsythia, Campylobacter gracilis. Prevotella intermedia, Campylobacter rectus, Porphyromonas gingivalis, Veillonella parvula, Streptococcus gordonii, Capnocytophaga,  Streptococcus mitis
Effectiveness of enamel matrix derivative on the clinical and microbiological outcomes following surgical regenerative treatment of periimplantitis. A randomized controlled trial	Isehed et al. [24]	2016	Randomized controlled trial	Samples collected from the deepest pocket of the each implant at baseline, 2 weeks, 3,6 ,12 months after surgery treatment	29 patients diagnosticated with periimplantitis from a periodontology clinic in Sweden	DNA extraction with Gen Elute Bacterial Geno-mic DNA kit (Sigma Aldrich, St.Louis, MO, USA), bacterial characterization  by the HOMIM microarray	Fusobacteria (cluster probe), Parvimonas micra, Porphyromonas sp., Eubacterium nodatum, Porphyromonas gingivalis, Ochrobactrum anthropi, Tannerella forsythia and Campylobacter concisus/Campylobacter rectus.
Adjunctive Systemic and Local Antimicrobial Therapy in the Surgical Treatment of Periimplantitis: A Randomized Controlled Clinical Trial	Carcuac et al. [25]	2016	Randomized Controlled Clinical Trial	Samples collected from perimplantitis sites at baseline, 3,6 and 12 months after surgery	100 patients with severe periimplantitis who were reffered to 2 clinics specialized in  periodontics in Sweden	Culture and checkerboard DNA-DNA hybridization analyses.	Fusobacterium nucleatum, . Prevotella intermedia/ Prevotella nigrescens, Campylobacter rectus, Porphyromonas gingivalis, Tannerella forsythia, Porphyromonas endodontalis, Parvimonas micra
Comparison of the effects of air-powder abrasion, chemical decontamination, or their combination in open-flap surface decontamination of implants failed for periimplantitis: an ex vivo study	Pranno et al. [26]	2021	Single-blind, randomized, controlled, ex vivo study	80 samples collected from the retrieved implants	20 patients  from  Oral Surgery Unit University of Rome with minimum 4 implants affected by periimplantitiswhich need to be explanted	Bacterial culture tehniques: for aerobic bacteria - Columbia sheep blood agar plates and for anaerobic - Schaedler sheep blood agar	Staphylococcus aureus, Streptococcus mitis/oralis,  Staphylococcus epidermidis and Streptococcus salivarius. Enterococcus faecalis,  Candida albicans Pseudomonas aeruginosa and Neisseria flavescens
The Efficacy of a Diode Laser on Titanium Implants for the Reduction of Microorganisms That Cause Periimplantitis	Wawrzyk et al. [27]	2021	Clinical study	Samples collected from saliva, the surfaces of the crowns and dental implants components	3 patients with advanced periimplantitis	Bacterial culture tehnique of anaerobic using Schaedler horse blood agar	Staphylococcus aureus, Streptococcus constellatus, Streptococcus oralis, Streptococcus pneumoniae, Rothia mucilaginosa, and Rothia aeria, and the following Gram-negative bacteria: Haemophilus parainfluenzae, Klebsiella pneumoniae, Klebsiella oxytoca, and Veilonella parvula. Candida guilliermondii, Actinomyces odontolyticus
Investigation of antibiotic susceptibility of the bacterial isolates and local flora changes after complex therapy in chronic periodontitis and periimplantitis	Ciobanu et al. [28]	2018	Clinical study	Samples collected from sites with periimplantitis before and after therapy	Patients diagnosticated with chronic periimplantitis	Culture examination	Capnocytophaga spp., Prevotella oralis, S. intermedius, S. gordonii, Veillonella spp.
Shift of microbial composition of periimplantitis-associated oral biofilm as revealed by 16S rRNA gene cloning	Al-Ahmad et al. [29]	2018	Cross-sectional study	Samples collected from the deepest sites of periimplantitis and from the periimplantar healthy sulcus	10 patients with at least one implant affected by periimplantitis and one healthy implant	DNA extraction and PCR amplification of 16S rRNA genes	Streptococcus spp, Prevotella spp, Fusobacterium spp, Eubacterium spp, Porphyromonas gingivalis, Treponema spp, Campylobacter spp,  Filifactor alocis, Abitrophia defectiva, Alloprevotella tannarae, Neisseria spp,  Parvimonas micra, Selenomonas spp, Capnocytophaga spp, Atopobium spp, , Peptostreptococcus spp, Tannerella forsythia,  Scadovia wiggisiae, Bacteroidetes bacterium, Eikenella Corodens, Fretibacterium fastidiosum, Johnsonella ignava, Synergistales bacterium, Dialister invisus, Raoultella sp.
Subgingival microbiome in patients with healthy and ailing dental implants	Zheng et al. [30]	2015	Clinical study	Samples collected from periimplantar sulcus and pokets	10 patients with healthy implants, 8 pacients with perimucositis and 6 with periimplantitis	Microbial DNA extraction, 16S rRNA gene library preparation, and pyrosequencing	Leptotrichia hofstadii, Eubacterium infirmum, Kingella denitrificans, Actinomyces cardiffensis, Eubacterium minutum, Treponema lecithinolyticum, and Gemella sanguinis were higher in PI sites Streptococcus, Leptotrichia, Actinomyces, Capnocytophaga, Prevotella, Fusobacterium, Neisseria
Microbiota in Gingival Crevicular Fluid Before and After Mechanical Debridement With Antimicrobial Photodynamic Therapy in Periimplantitis	Wang et al. [31]	2022	Clinical study	61 samples collected from all the implants: before treatment and 7, 14, 30, 60 and 180 days after treatment	9 patients presented at  Department of Stomatology in Beijing Hospital with 14 implants affected by periimplantitis	Bacterial 16S rRNA was amplified and sequenced using an Illumina MiSeq platform	Bacteroidetes, Proteobacteria, Firmicutes, Fusobacteria, Spirochaetes, Synergistetes,and Actinobacteria            Prevotella, Neisseria, Fusobacterium, Porphyromonas, Treponema, Streptococcus, Haemophilus, Capnocytophaga, Leptotrichia, and Fretibacterium
Microbiological findings in early and late implant loss: an observational clinical case-controlled study	Korsch et al. [32]	2021	Observational clinical case‑controlled study	Samples collected from implants affected by severe periimplantitis without any chance of preservation and from healthy implants as controls	48 patients with 53 implants were introduced in the study;	DNA extraction, PCR amplification and 16S rRNA gene sequencing	Treponema sp, Streptococcus,, Fretibacterium, Anaerovoracaceae uncl, Desulfobulbus sp, Pseudoramibacter alactolyticus, Dialister pneumosintes, Streptococcus sanguinis, Shewanella sp, Pantoea sp, Haemophilus sp, Haemophilus parainfluenzae, Pseudomonas sp, Lautropia mirabilis, Actinomyces naeslundii
Strong oral plaque microbiome signatures for dental implant diseases identified by strain-resolution metagenomics	Ghensi et al. [33]	2020	Clinical study	Samples collected from each implant and from contralateral healthy implant or tooth for every patient included in the study	80 patients enrolled in the study: 28 with healthy implants, 28 with mucositis and 24 with periimplantitis	DNA extraction	P. gingivalis, T. forsythia, Treponema denticola,  P. endodontalis,  F. fastidiosum, Filifactor alocis, Desulfobulbus spp. T. lecithinolyticum
Cluster of bacteria associated with periimplantitis	Persson  et al. [12]	2014	Retrospective clinical study	Samples collected at one implant with periimplantitis in each of 166 patients and from 47 healthy implants	166 patients with periimplantitis and 47  patients with healthy dental implants	Checkerboard DNA–DNA hybridization.	Actinomyces odontolyticus , A. actinomycetemcomitans (a), Campylobacter gracilis, Campylobacter rectus, Campylobacter showae, Helicobacter pylori, Haemophilus influenzae, Leptothrichia buccalis, P. intermedia, Propionybacterium acnes, Porphyromonas endodontalis, P. gingivalis, Staph. aureus, Staph. anaerobius, Streptococcus intermedius, Streptococcus mitis, T. forsythia, T. denticola, and Treponema socranskii.
Microbiological diversity of periimplantitis biofilm by Sanger sequencing	da Silva et al. [34]	2014	Clinical study	Samples collected from the deepest pocket depth in the test group and from mesial site of healthy implants	20 individuals, 10 with healthy implants and 10 with at least one implant with periimplantitis, both groups with minimum 10  periodontally healthy teeth	Extraction of DNA, PCR amplification of universal 16S rRNA	Fusobacterium nucleatum, Campylobacter gracilis, Dialister invisus, Streptococcus sp, Eubacterium infirmum, Filifactor alocis and Mitsuokella sp., Parvimonas micra and Prevotella intermedia
Analysis of bacterial flora associated with periimplantitis using obligate anaerobic culture technique and 16S rDNA gene sequence	Tamura et al. [35]	2013	Clinical study	Samples collected from the deepest sites of the both groups, test and control	30 patients, 15 diagnosticated with periimplantitis, 15 with healthy implants	Culture technique and 16S rDNA gene sequence	Streptococcus, Eubacterium ,  Prevotella, Actinomyces,  Fusobacterium, Eubacterium nodatum, Prevotella intermedia, Fusobacterium nucleatum, Filifactor alocis, E brachy, Parascardovia denticolenns, Parvimonas micra
Microbial profiles of peri-implant mucositis and periimplantitis: submucosal microbial dysbiosis correlates with disease severity	Shi et al.  [36]	2022	Cross-sectional study	Samples collected from 64 patients, 27 with perimucositis and 37 with periimplantitis	Patients with periimplantitis or perimucositis presented in Dep. Of Oral Implantology in Zhejiang University School of Medicine, China	DNA extraction, PCR amplification and 16S rRNA gene sequencing	Porphyromonas, Fusobacterium , Treponema and Prevotella, Campylobacter, Filifactor, Alloprevotella
Exploring the microbiome of healthy and diseased peri-implant sites using Illumina sequencing	Sanz-Martin et al. [37]	2017	Clinical study	Sample collection from 32 healthy implants and from 35 implants affected by perimplantitis	Patients with healthy implants and with periimplantitis presented in  Center of Dental Medicine at the University of Zürich	Bacterial nucleic acids  isolation, sample DNA analyzed by sequencing the 16S rRNA gene V3-V4 hypervariable region	Porphyromonas (phylum Bacteroidetes), Treponema (phylum Spirochetes), Filifactor (phylum Firmicutes), Fretibacterium (phylum Synergistetes and Tannerella (phylumBacteroidetes)
Intra-oral single-site comparisons of periodontal and peri-implant microbiota in health and disease	Yu  et al. [38]	2019	Clinical study	Samples collected from 4 sites for each patient: Healthy implant, healthy tooth, periimplantitis site and periodontitis site	18 Chinese partial dentate patients with both periimplantitis and periodontitis	DNA extraction, PCR amplification	Bacteroidetes and Prevotella taxa (including P. denticola, P. multiformis and P. fusca).
Identification of microbiota in periimplantitis pockets by matrixassisted laser desorption/ionization time-of-flight mass spectrometry	Yeh et al. [39]	2019	Clinical study	Samples collected from perimplantitis pockets	12 patients with periimplantitis	Culture examination	Neisseria flavescen, Streptococcus constellatus, Slackia exigua, Streptococcus intermedius, Fusobacteriumnucleatum, Gemella morbillorum and gram-positive anaerobic Bacillus
Intraindividual variation in core microbiota in periimplantitis and periodontitis	Maruyama et al. [40]	2014	Clinical study	Samples collected from the deepest pokests in periimplantitis sites and in periodontitis sites	20 Patients with both periimplantits and periodontitis	DNA extraction and PCR amplification of 16S rRNA genes	Olsenella, Sphingomonas, Peptostreptococcus, unclassified Neisseriaceae, genus Desulfomicrobium, Actinomyces johnsonii, Fusobacterium nucleatum, Porphyromonas gingivalis, Streptococcus oralis, Treponema denticola, and Treponema socranskii  Achromobacter xylosoxidans, Actinomyces massiliensis, and Porphyromonas sp.
The severity of human periimplantitis lesions correlates with the level of submucosal microbial dysbiosis	Kröger et al. [41]	2018	Cohort study or case-control study	Samples collected from all 45 implants affected by periimplantits	30 patients with at list one implant with periimplantitis	DNA extraction and PCR amplification of 16S rRNA genes	Eubacteriaceae, Fretibacterium sp., Fretibacterium fastidiosum, Peptostreptococcaceae, Alloprevotella sp., Fastidiosipila sanguinis, Filifactor alocis, Peptostreptococcaceae, Bacteriodetes bacterium, Treponema parvum, Clostridiales bacterium, and Orobacterium, Granulicatella elegans, Rothia aeria, Corynebacterium durum, Veillonella dispar, Acinetobacter

 

 

 

A final output of 25 studies seems a little bit limitating. Why the authors did not include also a manual search strategy to improve the review findings.

There manual search was performed independently by two of the authors of the manuscript and all the studies were analysed in order to respect inclusion and exclusion criteria and the duplicates were removed.

 

Discussion

 

The present investigation presented strong flaws with no risk of bias assessment of the studies included. This important aspect should be discussed in this section. In my opinion, an improved analytical approach could strongly potentiate the study findings. No reference to the limits of the present investigation have been included in this section. It is not evident from this part the novelty of the present investigation. Moreover, no references to the peri-implantitis grades have been introduced in the paper. I suggest to improve the discussion after reading the follow paper: PMID: 27391491

 

The null-hypothesis should be discussed in this part of the manuscript.

 

Thank you for your suggestion, as recommended by the reviewer we have improved the discussion.

All the studies included in this review were assessed for risk of bias with NOS Scale Tool[42], independently by two authors. Divergences in the assessment were solved by disscution and by re-evaluating the article. According to NOS Scale there are 3 groups of risk of bias: low risk of bias (7-9 NOS scores), high risk of bias (4-6 NOS scores) and very high risk of bias (0-3 NOS scores) [44]. The majority of the studies included in this review are at low risk of bias and only one study is considered at very high risk of bias.

The main limitations of this review are primary caused by the relatively heterogeneity of the studies included in this research. The articles have different study design, different methods of identifying the clusters of bacteria involved in periimplantitis and the studies are performed on different types of implants. Also, the results of counting bacteria are reported in different measurements units. Analysis of the differences in bacterial colonisation regarding the type, material and surface design of the implants was impossible because this information was not available in all the articles included in this review. 

 

Regarding the null hypothesis we cannot discuss about null hypothesis because our review is a systematic review, not a meta-analysis.  We did not compare in our research two variables (e.g. main bacterial species in periimplantitis vs healthy sites). The review being observational, descriptive, assessing only the main bacterial species in periimplantitis, we cannot formulate null hypothesis.

 

 

 

Round 2

Reviewer 2 Report

The paper has been improved and is acceptable now.