Prevalence of carpal tunnel syndrome among dentists: a systematic review and meta-analysis

Purpose: To estimate the prevalence of carpal tunnel syndrome (CTS) among dental surgeons and the effect of possible moderators on it. Methods: A systematic literature search (Medline and Scopus databases) was conducted independently by two reviewers. Only observational studies that examined specifically the prevalence rates of CTS among dentists were included. Quality assessment was performed. The pooled prevalence with 95% confidence intervals (CI) was estimated. Outlier and influential analysis were conducted. Moderator analysis was performed in order the effect of categorical and continuous variables on the estimated prevalence to be investigated. Results: In total, ten eligible studies (3,547 participants) were finally included in this meta-analysis. Two of them were estimated as high quality (low risk of bias) and the remaining ones as moderate quality (moderate risk of bias). The overall prevalence of CTS among dental surgeons was estimated as 9.87% (95%CI 6.84%-14.03%) with significant heterogeneity between studies. No study was identified as influential. Potential sources of heterogeneity were not identified through meta-regression analysis. In the subgroup analysis the prevalence was 12.47% (95%CI 6.38%-22.95%) for the group identified as having CTS through medical history and at least clinical examination or electrodiagnostic testing and 8.56% (95%CI 5.53%-13.01%) among those who identified solely through questionnaire. Conclusions: Our findings are important to provide the pooled prevalence of CTS among dentists. Our results were based on highly heterogeneous studies. Our study reports a considerable prevalence, consequently, significance of awareness among dental surgeons regarding the etiology of this issue is more than necessary. More studies need to be conducted that could guide researchers in order this issue to be fully investigated.


Introduction
Carpal tunnel syndrome (CTS) is one of the most frequent and well-studied entrapment neuropathies with a prevalence in middle-aged general population estimated at around 4.0% to 5.0%. 12 As per its' pathophysiology, CTS occurs as the median nerve is being compressed and damaged through its passage within the narrow osteofibrous canal (carpal tunnel). 27,34 Among the great variety of symptoms that may occur, CTS is also identified by patients as pain, paraesthesias (especially, during the night) and dysaesthesias in the distribution of the median nerve (in the first three and a half digits of the affected hand), are the predominant ones. As CTS pathophysiology evolving, all muscles innervated by branches of the median nerve (flexor pollicis brevis, abductor pollicis brevis, opponens pollicis) are being atrophied and weakened, resulting the patient's declined functionality. 9,14,23,24 On a regular basis, the diagnosis of CTS can be made throughout the combination of a comprehensive patient's history and a thorough clinical examination (including Tinel, Phalen and Durkan's tests). Yet, in specific patients, advanced procedures (electrodiagnostic tests) such as the nerve conduction studies, can be utilized both in the diagnosis as well as in treatment decision making. 27 Many risk factors have been identified throughout the years including the obesity, diabetes, hypothyroidism, pregnancy, lupus erythematosus and Reynaud's phenomenon.
In the recent years, specific interest exists regarding the occurrence of CTS in certain occupations such as the dental surgeons, 2,13,20,21 that is expected to be higher than the general occupation 31 given that the procedures that are usually performed require the use of vibratory tools, strong griping, uncomfortable hand position and the performance of longlasting repetitive tasks. 29 Therefore, the aim of this study is to review the available literature for data related to the occurrence of CTS in dental surgeons and to obtain an accurate estimate of its' prevalence. On a secondary basis, an attempt to identify factors that may be associated with its' prevalence will be performed.

Methods
This review is reported in line with the PRISMA guidelines. 38 Search strategy A literature search of Medline (PubMed search engine) and Scopus database was conducted through inception up to December 16 th , 2022, following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. 28 The literature search was independently performed by two reviewers, using the following algorithm: (carpal tunnel syndrome OR CTS OR entrapment neuropathy OR median nerve compression) AND ("dentists" OR "dental surgeon").
The reference lists of all identified eligible studies were evaluated by both reviewers for potentially missed articles from the initial literature search. Following the aforementioned procedure, all studies were stored in the Zotero reference management software (version 6.0.18) and the duplicate citations were removed. 36 The remaining articles were independently screened by two investigators to identify studies that met the pre-determined inclusion criteria. The study selection was conducted in two stages. First, article titles and abstracts were reviewed and those that did not meet our inclusion/exclusion criteria were removed. Secondly, the full texts of the remaining articles were retrieved and evaluated.
If an absence in studies selection procedure was notified, the final decision was reached by team consensus.

Criteria for study selection and data extraction
Articles that examined specifically the prevalence rates of CTS among dentists were included. Only observational studies written in English language were inserted with no restriction on publication date. Case reports, case series with less than ten participants, review articles, clinical trials, animals studies, letters to the editor, books, expert opinion, conference abstracts, studies with no full-text available, studies not written in English language, articles reported solely the prevalence of CTS' symptoms, studies regarding dental laboratory technicians, dental hygienists and dental practitioners (such as the studies conducted from Anton D., et al. 3

REVISED Amendments from Version 2
Only minor changes were made to the original text, specifically to the methods and discussion sections. However, all of the reviewer's comments were carefully considered, and in cases where no changes were made, detailed explanations were provided.
Any further responses from the reviewers can be found at the end of the article In articles with overlapping populations, the most recent or most complete publication was considered eligible. The following variables were obtained from each study: the first author's name, year of publication, study design, continent of origin, study period, total number of patients, proportion of males, mean age, participants with CTS and diagnostic procedures.

Quality assessment
Quality appraisal was independently performed by two investigators using the National Heart, Lung, and Blood Institute (NHLBI) Quality Assessment Tools. The NHLBI quality assessment tool for Observational Cohort and Cross-Sectional Studies was employed. Individual studies were assessed for potential flaws in accordance the study methodology or the conduct of each survey that could jeopardize internal validity. For each of the fourteen questions, investigators could select one of the following answers: "yes", "no", "cannot determine" (e.g. data were unclear or contradictory) or "not reported" (e.g. missed data) or "not applicable" (e.g. not relevant question regarding this type of study). Study quality was defined as "low", "moderate" or "high" risk of bias. 25

Statistical analysis
Statistical analysis was carried out using RStudio (version: 022.12.0+353) software (RStudio Team (2022)). 32 The metaanalysis was conducted through metafor package. 33 The DerSimonian and Laird random-effects model was used to estimate the pooled prevalence and its respective 95% confidence intervals (CI). Logit transformation was performed. Heterogeneity presence between studies was evaluated through visual inspection of the forest plot and by using the  Cochran's Q statistic and its respective p value. The Higgins I 2 statistic and its respective 95% CI were used for quantifying the magnitude of true heterogeneity in effect sizes. An I 2 value of 25%, 50%, and 75% indicated low, moderate, and high heterogeneity, respectively. To determine if the potential outlying effect sizes (as evaluated in the forest plot) were also influential (influence diagnostics are statistical methods used to identify individual studies that have a substantial impact on the overall results) (as an example, the covariance ratio can be used to evaluate the influence of each individual study in a meta-analysis, assisting in the identification of studies that might have a disproportionate impact on the overall pooled effect estimate), screening for externally studentized residuals with z-values larger than two in absolute value and leave-one-out diagnostics (through this process, each study's influence on the overall findings was evaluated) were performed. 34 Due to high heterogeneity remaining, subgroup and meta-regression analysis were performed. In the conducted subgroup analysis, the continent of origin and the diagnostic procedure (verified during the implementation of each study or previously diagnosed) were chosen as the categorical moderators on effect sizes. In the performed meta-regression analysis with continuous variables, the year of publication and the proportion of males were assessed as moderators on effect sizes. Owing to the limited availability of data (less than ten studies for each covariate) regarding other variables (e.g mean age, obesity, diabetes, hypothyroidism, pregnancy, autoimmune diseases), these data were not included in this analysis. 17 Unless otherwise stipulated, the statistical significance was established at p=0.05 (two-tailed). Tests to evaluate publication bias, such as Egger's test, 10 Begg's test 5 and funnel plots, were developed in the context of comparative data. They assume studies with positive results are more frequently published than studies with negative results, however in a meta-analysis of proportions there is no clear definition or consensus about what a positive result is. 4 Therefore, publication bias in this current meta-analysis was assessed qualitatively.

Results
Search results and characteristics of the included studies In total, ten (n=10) eligible studies (3,547 participants) were finally included in this analysis (see Figure 1 for the PRISMA flow chart). 37 In 6 of the eligible studies CTS was diagnosed through questionnaire and in the rest of them through medical history and at least clinical examination or electrodiagnostic testing. The descriptive characteristics of the incorporated research are presented in Table 1. All articles were published from 2001 to 2021 (conducted from 1997 to 2019). All of them were found to be of cross-sectional design. Most studies were contemplated in Asia (Iran, Lebanon, Saudi Arabia, n=6), followed by America (USA, Brazil, n=2) and Europe (Czech, Germany, n=2). The average percent of males was 54.22% while the mean age of participants ranged from 35 years to 46.4 years (median=38.2 years). Lastly, two studies were estimated as high quality (low risk of bias) and the remaining ones as moderate quality (moderate risk of bias).

Prevalence of CTS among dentists
A random-effects model analysis yielded an initial overall CTS prevalence of 9.87% (95%CI 6.84%-14.03%) with significant heterogeneity between studies I 2 =90.55% (95%CI 79.29%-97.31%, p<0.01) ( Figure 2). The influence diagnostics are presented in Figure 3. The forest plot illustrating the results of the leave-one-out analysis is presented in Figure 4. As per them, no study was identified as being influential. In other words, there was no study identified that was capable of turning the effect of the analysis into some direction.

Subgroup and meta-regression analysis
To investigate the effect of potential risk factors in the heterogeneity, a moderator analysis was performed. Forest plots of the subgroup analysis are illustrated in Figure 5 and Figure 6. The prevalence was 7.02% (95%CI 1.44%-27.99%) among studies conducted in Europe, 8.06% (95%CI 2.88%-20.60%) among studies conducted in America and higher among those conducted in Asia (11.71%) (95%CI 8.25%-16.35%). The prevalence was 12.47% (95%CI 6.38%-22.95%) for the group identified as having CTS through medical history and at least clinical examination or electrodiagnostic testing and 8.56% (95%CI 5.53%-13.01%) among those who identified solely through questionnaire (previously diagnosed, selfreported). Heterogeneity remained high in the subgroup analysis by both continent of origin and type of diagnostic procedure. In the meta-regression analysis with continuous variables, the year of publication and the proportion of males, no statistically significant (positive or inverse) modification was found as presented in Table 2.

Discussion
CTS is one of the most frequently diagnosed entrapment neuropathy, accounting for high disability among different occupations. 24 To date, only systematic reviews regarding musculoskeletal disorders (which is a general term referring to injuries in muscles, ligaments, tendons, nerves, blood vessels, bones and joints) among dental healthcare providers exist in the scientific literature. One indicative example of the above is the meta-analysis conducted by Chenna et al., in which   the authors combined data from 88 studies and found out that seven out of ten dental healthcare workers (including dentists, dental students, dental hygienists and dental auxiliaries) experienced a musculoskeletal disorder. As per the location of the disorders, the most affected sites were the neck, the back, the lower back, the shoulder, the upper back and the wrist with a prevalence of 51%, 50%, 46%, 41%, 35% and 31%, respectively. 7 To the best of our knowledge, this is the first attempt to calculate the prevalence of CTS among dentists, through a systematic review. We do not have previously published data to compare our pooled estimate with. The prevalence of the existing observational studies varies considerably in the scientific literature. Our study provides evidence for 9.87% (95% CI 6.84%-14.03%) prevalence of CTS among dentists. Overall, the results are based on highly heterogeneous articles. Through the moderator analysis, we do not manage to identify sources of heterogeneity between the eligible studies. In the subgroup analysis, the prevalence was 12.47% (95%CI 6.38-22.95) for the group identified as having CTS through medical history and at least clinical examination or electrodiagnostic testing while, the prevalence was 8.56% (95%CI 5.53%-13.01%) among those who identified solely through questionnaire (previously diagnosed, self-reported). It should be noted that the latter pooled estimate may underestimate the dental surgeons with CTS due to the diagnostic method used. In matter of other oral health care professionals, Anton D., et al., found an 8.4% prevalence of CTS among 95 dental hygienists 3 while, Cherniack M., et al., calculated a 14.9% prevalence among 94 dental hygienists. 8 In a recent metaanalysis, Epstein S., et al., combining data from seven eligible studies, found a 9% (95%CI 5%-16%) prevalence of CTS among 2449 physicians (from different specialties including general surgeons, plastic surgeons, orthopedic surgeons and urologists) with significant heterogeneity between studies I 2 =94.5%. 11 All the aforementioned results align with our estimation, providing more evidence that CTS can be considered as an occupational hazard among health care professionals.  It should be noted that there are many treatments available for this entrapment neuropathy. Patients developing mild or moderate symptoms should be treated conservatively through splinting, local corticosteroid injection or oral prednisone.
Other treatments available, such as physical therapy, have not proven their effectiveness yet. Surgical decompression is the treatment of choice for patients developing severe symptoms. 16,35 Our study reports a considerable prevalence, consequently, the importance of awareness among dentists, regarding the etiology of this issue is more than necessary. More research should be conducted in order to explore the association between CTS among dentists and potential risk factors, such as gender, obesity, endocrine conditions (hypothyroidism, acromegaly and diabetes) and trauma. The findings of this systematic review and meta-analysis reveal a concerning prevalence of CTS among dental surgeons, with an overall prevalence rate of 9.87%. These results underscore the significance of addressing ergonomic concerns and implementing preventive measures to protect the occupational health and well-being of dental surgeons.

Study's strengths and limitations
The main strength was the comprehensive methodology applied for literature search, study selection, specific inclusion/ exclusion criteria, screening for eligibility, quality assessment and pooling analysis of prevalence data from ten studies. Nonetheless, the present study had several limitations. It should be noted that the unidentified heterogeneity remained on high levels, therefore, the results should be interpreted with caution. The highly heterogenous outcomes across the included studies were expected due to the nature of this type of studies. Owing to the limited availability of data (less than ten studies for each covariate) regarding variables such as mean age, obesity, diabetes, hypothyroidism, pregnancy, autoimmune diseases, these data were not included in this analysis. Lastly, only observational studies written in English language were included resulting in the occurrence of reporting bias.

Conclusion
In conclusion, the prevalence of CTS among dentists is estimated at 9.87% (95%CI 6.84%-14.03%). Our results were based on highly heterogeneous studies. Sources of heterogeneity were not identified. Our findings point to several directions for future research. Therefore, further studies, both prospective and retrospective need to be conducted in order this issue to be fully investigated. Open Peer Review analysis paper titled "Prevalence of carpal tunnel syndrome among dentists: a systematic review and meta-analysis.

Data availability
This systematic review and meta-analysis were conducted to estimate the prevalence of carpal tunnel syndrome (CTS) among dental surgeons and the effect of possible moderators on it. As I do not work in this field, I need to be made aware of the importance of CTS in this occupation. However, using the explanation about CTS in the introduction, the prevalence of this problem is high among dental surgeons. Although the authors provide the reason for the high prevalence of this disease among surgeons, the reason for conducting the SR and MA is unclear. There is no reasonable justification for conducting this study. I would like to see the heterogeneity in the studies in this field, which shows the necessity for conducting this systematic review. I cannot understand how the results will add to the present knowledge of CTS among dental surgeons and the benefits of the results in practice. The results could be applied in daily practice by adding these points to the introduction and discussion. On the other hand, the audience for this study could be more precise for me. Are the audiences physicians involved in treating these patients, or dental surgeons, who should be aware of this occupational problem and do the preventive interventions themselves?
In addition to these points, some methodologic aspects should be considered.
First: in the PRISMA figure, in the first stage, in addition to the duplicates, the authors mentioned that those 24 were also excluded due to other reasons. In the footnote, other reasons include reviews, clinical trials and .... How is it possible to determine clinical trials, reviews and ... before title and abstract?
In PRISMA, authors mentioned that they retrieved 51 articles in Pubme, while in the text, they searched Medline. PubMed is the public library of Medline, and although these two search engines are similar but are not the same. As far as I know, the most popular search engine for Medline is OVID. I believe that the search is not comprehensive. Some important search engines are missing, such as PsycINFO and CINAHL.
I think adding two subtitles and inclusion and exclusion criteria is better.
The first three lines of the results are methods, and better to explain them in the method section.
Cross-sectional studies are specific studies that measure the prevalence of a study. So, I think if the aim is to find the prevalence of CTS, the authors should include just C/S studies and explain this in the method section.
Please explain the diagnostic graphs and their application in MA in statistical analysis.
Some grammar and typo errors need special attention. For example, line one of the results should be "the manuscripts." Or et al should be written as et al., or the first paragraph of discussion line five and sic, dentist, and hygienist should be pleural.

Is the statistical analysis and its interpretation appropriate? Yes
Are the conclusions drawn adequately supported by the results presented in the review? Yes Competing Interests: No competing interests were disclosed.

I confirm that I have read this submission and believe that I have an appropriate level of expertise to confirm that it is of an acceptable scientific standard, however I have significant reservations, as outlined above.
Author Response 25 Jul 2023

Ευάγγελος Κωσταρές
Dear Reviewer, On behalf of all authors, we would like to thank you for your kind words and valuable input regarding our manuscript.
Please find a point-to-point response to each of your comments.

Comment #1
This systematic review and meta-analysis were conducted to estimate the prevalence of carpal tunnel syndrome (CTS) among dental surgeons and the effect of possible moderators on it. As I do not work in this field, I need to be made aware of the importance of CTS in this occupation. However, using the explanation about CTS in the introduction, the prevalence of this problem is high among dental surgeons. Although the authors provide the reason for the high prevalence of this disease among surgeons, the reason for conducting the SR and MA is unclear. There is no reasonable justification for conducting this study. I would like to see the heterogeneity in the studies in this field, which shows the necessity for conducting this systematic review. I cannot understand how the results will add to the present knowledge of CTS among dental surgeons and the benefits of the results in practice. The results could be applied in daily practice by adding these points to the introduction and discussion. On the other hand, the audience for this study could be more precise for me. Are the audiences physicians involved in treating these patients, or dental surgeons, who should be aware of this occupational problem and do the preventive interventions themselves?

Response #1
Thank you for your remark. We greatly appreciate your feedback and understand your concerns regarding the necessity of our systematic review and meta-analysis on the prevalence of carpal tunnel syndrome (CTS) among dental surgeons.
Firstly, regarding the necessity of conducting a meta-analysis in this field, it is essential to consider that individual studies might provide varying estimates of CTS prevalence due to differences in study designs, populations, and methodologies. By conducting a systematic review and meta-analysis, we aimed to pool data from multiple studies to obtain a more precise and robust estimate of CTS prevalence among dental surgeons. The use of a metaanalysis is particularly relevant in cases where studies exhibit heterogeneity, as it helps to explore potential sources of variation and enhances the statistical power to detect significant associations.
Secondly, we believe it is crucial to inform dental surgeons about the high prevalence of CTS in their profession due to its occupational significance. The repetitive and forceful hand movements involved in dental procedures can lead to an increased risk of developing CTS. By raising awareness of this issue, dental surgeons can better understand the importance of ergonomics and the implementation of preventive measures in their practice. Simple adjustments in posture, instrument handling, and regular breaks can significantly reduce the risk of developing CTS and other related musculoskeletal disorders. Furthermore, our study's results add value by providing an evidence-based assessment of CTS prevalence among dental surgeons, which can serve as a foundation for future research and guideline development. By informing dental surgeons and healthcare professionals involved in treating CTS patients, our findings encourage proactive measures to mitigate the impact of CTS on the dental workforce and improve the overall well-being and long-term health of dental professionals. Nevertheless, a comprehensive statement has been incorporated into the discussion section.

Comment #2
First: in the PRISMA figure, in the first stage, in addition to the duplicates, the authors mentioned that those 24 were also excluded due to other reasons. In the footnote, other reasons include reviews, clinical trials and .... How is it possible to determine clinical trials, reviews and ... before title and abstract?

Response #2
Thank you for your thoughtful review of our PRISMA figure. We appreciate your keen observation regarding the exclusion of 24 articles in the first stage. As you correctly pointed out, in addition to duplicates, these articles were excluded due to other reasons, including reviews, clinical trials, and more.
Regarding your question on how it is possible to determine clinical trials, reviews, and other categories before reading the title and abstract, we agree that it would be challenging to do so manually. However, in PubMed, many articles indicate their classification, such as clinical trials, in the footnotes. This information can be valuable for initial filtering without having to read the entire title or abstract. Additionally, PubMed offers filters that allow users to specifically select clinical trials, reviews, and other types of articles, streamlining the search process and enabling quick exclusion of irrelevant articles from the beginning.

Comment #3
In PRISMA, authors mentioned that they retrieved 51 articles in Pubme, while in the text, they searched Medline. PubMed is the public library of Medline, and although these two search engines are similar but are not the same. As far as I know, the most popular search engine for Medline is OVID. I believe that the search is not comprehensive. Some important search engines are missing, such as PsycINFO and CINAHL.

Response #3
Thank you for your remark. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines are essential for conducting high-quality systematic reviews and meta-analysis. One of the fundamental principles emphasized by PRISMA is the need for a comprehensive search strategy to identify all relevant studies. Regarding your point about the differences between PubMed and Medline, we completely agree. While PubMed includes the Medline database, they are not exactly the same. Medline is a comprehensive bibliographic database of life sciences and biomedical literature, while PubMed is a free search engine that accesses the Medline database and also includes additional content ( https://pubmed.ncbi.nlm.nih.gov/about/). We chose to focus on PubMed and Scopus as these databases are widely recognized and widely used in the medical and scientific community. We understand your concern about the search potentially being incomplete by excluding other important databases such as PsycINFO and CINAHL. However, if the topic of a review directly pertains to the primary focus of specialized subject databases, like CINAHL for nursing and allied health or PsycINFO for behavioral sciences and mental health, they should indeed be added to ensure a comprehensive search (DOI: https://doi.org/10.1186/s13643-017-0644-y). By clearly stating the databases used and the search strategy employed, we aimed to uphold the highest standards of academic integrity. This practice helps to establish a strong foundation for our findings, enabling readers and fellow researchers to assess, validate, and build upon our work with confidence. Keeping a transparent approach ensures that our contributions to the scientific community are robust and reliable.
In conclusion, our research was conducted using two prominent databases, namely PubMed and Scopus, supplemented by examining the reference lists of the available articles. The decision to utilize two databases was based on the understanding that such an approach enhances both coverage and recall, thus reducing the likelihood of overlooking relevant studies (DOI: https://doi.org/10.1016/j.jclinepi.2022.05.022).

Comment #4
The first three lines of the results are methods, and better to explain them in the method section.

Response #4
Thank you for your remark. The relevant amendments have been performed.

Comment #5
Cross-sectional studies are specific studies that measure the prevalence of a study. So, I think if the aim is to find the prevalence of CTS, the authors should include just C/S studies and explain this in the method section.

Response #5
Thank you for your remark. You rightly pointed out that cross-sectional studies are specific types of research that measure the prevalence of a particular condition or characteristic within a population at a specific point in time. We agree that these studies can be valuable in determining the prevalence of CTS among dentists.
In our article, we aimed to investigate the prevalence rates of CTS among dentists specifically. To achieve this objective, we included observational studies written in the English language with no restriction on publication date. By employing this broad inclusion criteria, we aimed to gather comprehensive and up-to-date information on the prevalence of CTS in the dental profession.
While cross-sectional studies are indeed useful for measuring prevalence, they are not the only study design that can provide valuable insights into this topic. By including various types of observational studies, such as cohort and case-control studies, we sought to capture a more comprehensive view of CTS prevalence, potential risk factors, and associations with dentistry-related factors.
In the Method section of our article, we did clarify the inclusion criteria, explaining that we aimed to encompass all relevant observational studies that examined the prevalence rates of CTS among dentists. This broader approach allowed us to explore the topic from multiple angles and provide a more robust understanding of the prevalence and potential factors associated with CTS in the dental community.
We acknowledge that cross-sectional studies alone can offer certain advantages, such as assessing prevalence in a specific time frame. However, combining different study designs can enhance the overall quality of evidence and allow for a more well-rounded discussion of the topic.

Comment #6
Please explain the diagnostic graphs and their application in MA in statistical analysis.

Response #6
Thank you for your remark. The statistical analysis section has been revised accordingly.

Comment #7
Some grammar and typo errors need special attention. For example, line one of the results should be "the manuscripts." Or et al should be written as et al., or the first paragraph of discussion line five and sic, dentist, and hygienist should be pleural

Ευάγγελος Κωσταρές
Dear Reviewer, On behalf of all authors, we would like to thank you for your kind words and valuable input regarding our manuscript.
Please find a point-to-point response to each of your comments.

Comment #1
This systematic review (SR) assessed the prevalence of CTS among dentists. The study is of interest.

Response #1
Thank you for your remark. Yet, please note that our attempt exceeds the spectrum of a systematic review by utilizing statistical methods (meta-analysis) to summarize the results of the studies identified through the systematic review of the available literature.

Comment #2
Abstract: The authors should clearly state the inclusion criteria, as well as the predictor and outcome variables in the abstract. The results of the risk of bias assessment should be included in the results section and not in the conclusion.

Response #2
Thank you for your comment. Taking into consideration your input, the abstract has been reformed accordingly. Yet, if additional modifications should be performed, please provide us with some guidance to amend the relevant section as soon as possible.

Comment #3
Introduction: The authors should state the rationale for the study and summarize the results of previous studies on CTS.

Response #3
Thank you for your comment. Taking into consideration your input, the rationale, the results of other studies as well as the aim of the current study have been altered and stated in the two last paragraphs of the introduction. Yet, please note that within this section, the results of other studies on CTS are only being reported as findings, since they are being analyzed in the results and discussion section later within the same document as well as given that they are not "systematic" or "meta-analytic" data.

Comment #4
Method: This SR should be prepared in accordance with PRISMA guidelines and should follow the PRISMA checklist (which is mandatory).

Response #4
Thank you for your comment. Please be aware that without any change of the original manuscript, the requested information can be found in two sections of the manuscript: (a) the first line of the Methods and (b) The Data availability -Underlying data. Additionally, the PRISMA flow chart is illustrated as Figure 1. Yet, in case there are additional requirements set by the PRISMA guidelines that oblige the authors on reporting additional information that are not being included, please, provide us with a response to conform our manuscript as soon as possible.

Comment #5
The inclusion criteria should be based on PICOS criteria.

Response #5
Thank you for your comment. To the best of our knowledge, the PICO(S) criteria, are being used in a way of formulating one or several research questions (Aslam, S., & Emmanuel, P. Therefore, their main use is related to the basis on which the whole research will be made while the inclusion criteria, are more associated with the methodology that will be followed for data identification, selection and extraction given that different criteria may apply in various occasions (such as in times where language restrictions exist). In such scenario, manuscripts that would be included in the original pool can be excluded if these restrictions are valid and are being reported in the methodology to produce a repetitive result. Therefore, even if not mentioned, our inclusion criteria were based on PICO(S) criteria and their selection was not only justified through them but through the methodology that was used as reported in "Criteria for study selection and data extraction" subsection. Yet, if additional information should be included, please provide us with some guidance to amend the relevant subsection as soon as possible.

Comment #6
The authors should clearly define how CTS was diagnosed in the included studies.

Response #6
Thank you for your comment. Please be aware that without any change of the original manuscript, the requested information can be found in Table 1 (Column 10 -Diagnosis). Nevertheless, a brief explanation has been included in "Search results and characteristics of the included studies" subsection (line 6-8).

Comment #7
If the authors estimated proportions or used subgroup analyses, the synthesis of results (statistics) should be clearly explained.

Response #7
Thank you for your comment. Please be aware that without any change of the original manuscript, the requested information can be found in the Statistical Analysis and Results sections. To the best of our understanding, by re-evaluating the provided in-text explanations, the methodology that was used (that may be referred to as the standard one utilized for the conduction of proportional meta-analyses) as well as the content of other meta-analyses available in the literature (in form of a brief comparison), we strongly believe that the information reported in this manuscript are adequate to enable a reader with a medium or less experience in meta-analyses to understand the approach that was followed. Yet, in case you believe that additional information should be included, please, provide us