A Systematic Evaluation of the Quality of Meta-analyses in Endodontics

Methodological assessment and overall confidence in the results of systematic reviews with meta-analyses focusing on traumatic dental injuries: A cross-sectional study

BACKGROUND/AIMS

High methodological quality is required to interpret results of systematic reviews (SRs) in a reliable and accurate manner. The primary aim of this study was to appraise the methodologic quality of SRs with meta-analysis within the field of traumatic dental injuries using the A MeaSurement Tool to Assess systematic Reviews (AMSTAR) 2 tool and assess overall confidence in their results. A secondary aim was to identify potential predictive factors associated with methodological quality.

MATERIALS AND METHODS

SRs with meta-analyses published in English in the field of traumatic dental injuries from inception to March 2023 were identified. The methodological quality of the included reviews was assessed using the AMSTAR 2 checklist. Two independent evaluators scored each AMSTAR 2 item as "yes" if it was adequately addressed, "partial yes" if it was partially addressed, and "no" if it was not addressed. The overall confidence in the results of each review was classified as "High," "Moderate," "Low," or "Critically low." Using multiple regression, the relationship between five predictor variables (journal impact factor, year of publication, number of authors, journal adherence to Preferred Reporting Items for Systematic reviews and Meta-analyses [PRISMA] guidelines and a priori protocol registration) and the total AMSTAR 2 scores was analyzed. The p-value was 5%.

RESULTS

Forty-one SRs were included. The overall confidence in the results of 13 reviews was categorized as "Critically low," 18 as "Low," 3 as "Moderate" and 7 as "High." Among the five predictor variables analyzed statistically, impact factor of the journal and year of publication significantly influenced the total AMSTAR 2 scores. The number of authors, adherence to PRISMA guidelines, and a priori protocol registration had no significant impact on AMSTAR 2 scores.

CONCLUSION

The overall confidence in the results of SRs with meta-analysis within the field of traumatic dental injuries was "Low" or "Critically Low" in the vast majority of studies (31 of 41). SRs with meta-analyses published in journals with higher impact factors and more recent publications had significantly higher methodological quality.

A Methodological Quality Assessment of Meta-Analysis Studies in Dance Therapy Using AMSTAR and AMSTAR 2

Although earlier meta-analysis studies have provided evidence-based information useful for decision-making, debate regarding their quality continues. This study aimed to evaluate the quality of meta-analysis studies in the field of dance therapy (DT) using the Assessment of Multiple Systematic Reviews (AMSTAR) and AMSTAR 2 assessment tools. Meta-analysis studies on DT were collected from various databases. Seven meta-analysis studies were selected for this study. Our findings showed that the quality level of the meta-analysis studies related to DT was “High” on the AMSTAR evaluation, but their quality decreased to “Low” on the AMSTAR 2 evaluation. Moreover, using AMSTAR 2, 71.43% of the studies fell within the category of “Moderate” or below. There was no statistically significant difference in the quality scores of the characteristics of these studies. Our results suggest that (1) education on meta-analysis guidelines is required to improve the quality of DT-related meta-analysis studies, and (2) methodological caution is warranted, since different outcomes in evaluation scores for each tool may be obtained when using AMSTAR and AMSTAR 2. Based on this study, it is expected that common and specific guidelines for meta-analysis in DT can be established.

Quality assessment of systematic reviews and meta-analyses published in Saudi journals from 1997 to 2017

Objectives:

To assess the quality of the meta-analyses (MAs) and systematic reviews (SRs) in Saudi journals indexed in PubMed using 2 scales: A MeaSurement tool to assess systematic reviews (AMSTAR) and the overview quality assessment questionnaire (OQAQ).

Methods:

This study focused on SRs/MAs published in 8 Saudi journals. We investigated, screened, and extracted the data, which included recording the main topic of each SRs/MAs and the date of publication. Furthermore, we assessed the quality of each included SRs/MAs using the AMSTAR and the OQAQ. The reviews concluded in January 2018.

Results:

The search uncovered 201 unique articles; of these, the researchers screened 110 full texts and included 103 in this review. Most of the included studies were published in Saudi Medical Journal (50 articles, 48.5%), followed by Saudi Journal of Gastroenterology (21 articles, 20.4%), and Annals of Saudi Medicine (16 articles, 15.5%). The main topics in these published articles were gastroenterology (20 articles, 19.5%), followed by oncology (14 articles, 13.7%), and pharmacology (9 articles, 8.7%). The AMSTAR and the OQAQ scales showed that most SRs/MAs were of medium quality.

Conclusion:

Quality of SRs and MAs published in Saudi journals was distributed in all categories (low, medium, and high) and it can be improved using critical evaluation by authors, journal editors, and readers.

PROSPERO REG. NO. CRD: 42018102210

Methodological and Reporting Quality of Systematic Reviews and Meta-analyses in Endodontics

INTRODUCTION

The aim of this systematic review (SR) was to evaluate the quality of SRs and meta-analyses (MAs) in endodontics.

METHODS

A comprehensive literature search was conducted to identify relevant articles in the electronic databases from January 2000 to June 2017. Two reviewers independently assessed the articles for eligibility and data extraction. SRs and MAs on interventional studies with a minimum of 2 therapeutic strategies in endodontics were included in this SR. Methodologic and reporting quality were assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR) and Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA), respectively. The interobserver reliability was calculated using the Cohen kappa statistic. Statistical analysis with the level of significance at P < .05 was performed using Kruskal-Wallis tests and simple linear regression analysis.

RESULTS

A total of 30 articles were selected for the current SR. Using AMSTAR, the item related to the scientific quality of studies used in conclusion was adhered by less than 40% of studies. Using PRISMA, 3 items were reported by less than 40% of studies, which were on objectives, protocol registration, and funding. No association was evident comparing the number of authors and country with quality. Statistical significance was observed when quality was compared among journals, with studies published as Cochrane reviews superior to those published in other journals. AMSTAR and PRISMA scores were significantly related.

CONCLUSIONS

SRs in endodontics showed variability in both methodologic and reporting quality.

La version franco-canadienne de l'outil Assessment of Multiple Systematic Reviews (AMSTAR)

Objectives: The primary objective was to produce a French-Canadian translation of AMSTAR (a measurement tool to assess systematic reviews) and to examine the validity of the translation's contents. The secondary and tertiary objectives were to assess the inter-rater reliability and factorial construct validity of this French-Canadian version of AMSTAR. Methods: A modified approach to Vallerand's methodology (1989) for cross-cultural validation was used.1 First, a parallel back-translation of AMSTAR2 was performed, by both professionals and future professionals. Next, a first committee of experts (P1) examined the translations to create a first draft of the French-Canadian version of the AMSTAR tool. This draft was then evaluated and modified by a second committee of experts (P2). Following that, 18 future professionals (master's students in physiotherapy) rated this second draft of the instrument for clarity using a seven-point scale (1: very clear; 7: very ambiguous). Lastly, the principal co-investigators then reviewed the problematic elements and proposed final changes. Four independent raters used this French-Canadian version of AMSTAR to assess 20 systematic reviews that were published in French after the year 2000. An intraclass correlation coefficient (ICC) and kappa coefficient were calculated to measure the tool's inter-rater reliability. A Cronbach's alpha coefficient was also calculated to measure internal consistency. In addition, factor analysis was used to evaluate construct validity in order to determine the number of dimensions. Results: The statements on the final version of the AMSTAR tool received an average ambiguity rating of between 1.0 and 1.4. No statement received an average rating below 1.4, which indicates a high level of clarity. Inter-rater reliability (n=4) for the instrument's total score was moderate, with an intraclass correlation coefficient of 0.61 (95% confidence interval [CI]: 0.29, 0.97). Inter-rater reliability for 82% of the individual items was good, according to the kappa values obtained. Internal consistency was excellent, with a Cronbach's alpha coefficient of 0.91 (95% CI: 0.83, 0.99). The French-Canadian version of AMSTAR is a unidimensional tool, as confirmed by factor analysis and community values greater than 0.30. Conclusion: A valid French-Canadian version of AMSTAR was created using this rigorous five-step process. This version is unidimensional, with moderate inter-rater reliability for the elements overall, and with excellent internal consistency. This tool could be valuable to French-Canadian professionals and researchers, and could also be of interest to the international Francophone community.

Association between exogenous testosterone and cardiovascular events: an overview of systematic reviews

Given the conflicting evidence regarding the association between exogenous testosterone and cardiovascular events, we systematically assessed published systematic reviews for evidence of the association between exogenous testosterone and cardiovascular events. We searched PubMed, MEDLINE, Embase, Cochrane Collaboration Clinical Trials, ClinicalTrials.gov, and the US Food and Drug Administration website for systematic reviews of randomised controlled trials published up to July 19, 2016. Two independent reviewers screened 954 full texts from 29 335 abstracts to identify systematic reviews of randomised controlled trials in which the cardiovascular effects of exogenous testosterone on men aged 18 years or older were examined. We extracted data for study characteristics, analytic methods, and key findings, and applied the AMSTAR (A Measurement Tool to Assess Systematic Reviews) checklist to assess methodological quality of each review. Our primary outcome measure was the direction and magnitude of association between exogenous testosterone and cardiovascular events. We identified seven reviews and meta-analyses, which had substantial clinical heterogeneity, differing statistical methods, and variable methodological quality and quality of data abstraction. AMSTAR scores ranged from 3 to 9 out of 11. Six systematic reviews that each included a meta-analysis showed no significant association between exogenous testosterone and cardiovascular events, with summary estimates ranging from 1·07 to 1·82 and imprecise confidence intervals. Two of these six meta-analyses showed increased risk in subgroup analyses of oral testosterone and men aged 65 years or older during their first treatment year. One meta-analysis showed a significant association between exogenous testosterone and cardiovascular events, in men aged 18 years or older generally, with a summary estimate of 1·54 (95% CI 1·09-2·18). Our optimal information size analysis showed that any randomised controlled trial aiming to detect a true difference in cardiovascular risk between treatment groups receiving exogenous testosterone and their controls (with a two-sided p value of 0·05 and a power of 80%) would require at least 17 664 participants in each trial group. Therefore, given the challenge of adequately powering clinical trials for rare outcomes, rigorous observational studies are needed to clarify the association between testosterone-replacement therapy and major adverse cardiovascular outcomes.

Critical Assessment of Search Strategies in Systematic Reviews in Endodontics

INTRODUCTION

The aim of this study was to perform an overview of literature search strategies in systematic reviews (SRs) published in 2 endodontic journals, Journal of Endodontics and International Endodontic Journal.

METHODS

A search was done by using the MEDLINE (PubMed interface) database to retrieve the articles published between January 1, 2000 and December 31, 2015. The last search was on January 10, 2016. All the SRs published in the 2 journals were retrieved and screened. Eligible SRs were assessed by using 11 questions about search strategies in the SRs that were adapted from 2 guidelines (ie, AMSTAR checklist and the Cochrane Handbook).

RESULTS

A total of 83 SRs were retrieved by electronic search. Of these, 55 were from the Journal of Endodontics, and 28 were from the International Endodontic Journal. After screening, 2 SRs were excluded, and 81 SRs were included in the study. Some issues, such as search of grey literature and contact with study authors, were not fully reported (30% and 25%, respectively). On the other hand, some issues, such as the use of index terms and key words and search in at least 2 databases, were reported in most of the SRs (97% and 95%, respectively). The overall quality of the search strategy in both journals was 61%. No significant difference was found between the 2 journals in terms of evaluation criteria (P > .05).

CONCLUSIONS

There exist areas for improving the quality of reporting of search strategies in SRs; for example, grey literature should be searched for unpublished studies, no language limitation should be applied to databases, and authors should make an attempt to contact the authors of included studies to obtain further relevant information.

Quality assessment of systematic reviews on alveolar socket preservation

The aim of this overview was to evaluate and compare the quality of systematic reviews, with or without meta-analysis, that have evaluated studies on techniques or biomaterials used for the preservation of alveolar sockets post tooth extraction in humans. An electronic search was conducted without date restrictions using the Medline/PubMed, Cochrane Library, and Web of Science databases up to April 2015. Eligibility criteria included systematic reviews, with or without meta-analysis, focused on the preservation of post-extraction alveolar sockets in humans. Two independent authors assessed the quality of the included reviews using AMSTAR and the checklist proposed by Glenny et al. in 2003. After the selection process, 12 systematic reviews were included. None of these reviews obtained the maximum score using the quality assessment tools implemented, and the results of the analyses were highly variable. A significant statistical correlation was observed between the scores of the two checklists. A wide structural and methodological variability was observed between the systematic reviews published on the preservation of alveolar sockets post tooth extraction. None of the reviews evaluated obtained the maximum score using the two quality assessment tools implemented.

Methodological quality assessment of paper-based systematic reviews published in oral health

OBJECTIVES

This study aimed to conduct a methodological assessment of paper-based systematic reviews (SR) published in oral health using a validated checklist. A secondary objective was to explore temporal trends on methodological quality.

MATERIAL AND METHODS

Two electronic databases (OVID Medline and OVID EMBASE) were searched for paper-based SR of interventions published in oral health from inception to October 2014. Manual searches of the reference lists of paper-based SR were also conducted. Methodological quality of included paper-based SR was assessed using an 11-item questionnaire, Assessment of Multiple Systematic Reviews (AMSTAR) checklist. Methodological quality was summarized using the median and inter-quartile range (IQR) of the AMSTAR score over different categories and time periods.

RESULTS

A total of 643 paper-based SR were included. The overall median AMSTAR score was 4 (IQR 2-6). The highest median score (5) was found in the pain dentistry and periodontology fields, while the lowest median score (3) was found in implant dentistry, restorative dentistry, oral medicine, and prosthodontics. The number of paper-based SR per year and the median AMSTAR score increased over time (median score in 1990s was 2 (IQR 2-3), 2000s was 4 (IQR 2-5), and 2010 onwards was 5 (IQR 3-6)).

CONCLUSION

Although the methodological quality of paper-based SR published in oral health has improved in the last few years, there is still scope for improving quality in most evaluated dental specialties.

CLINICAL RELEVANCE

Large-scale assessment of methodological quality of dental SR highlights areas of methodological strengths and weaknesses that can be targeted in future publications to encourage better quality review methodology.

Systematic reviews addressing microsurgical head and neck reconstruction

BACKGROUND

Systematic reviews frequently form the basis for clinical decision making and guideline development. Yet, the quality of systematic reviews has been variable, thus raising concerns about the validity of their conclusions. In the current study, a quality analysis of systematic reviews was performed, addressing microsurgical head and neck reconstruction.

MATERIALS AND METHODS

A PubMed search was performed to identify all systematic reviews published up to and including December 2012 in 12 surgical journals. Two authors independently reviewed the literature and extracted data from the included reviews. Discrepancies were resolved by consensus. Quality assessment was performed using AMSTAR.

RESULTS

The initial search retrieved 1020 articles. After screening titles and abstracts, 987 articles were excluded. Full-text review of the remaining 33 articles resulted in further exclusion of 18 articles, leaving 15 systematic reviews for final analysis. A marked increase in the number of published systematic reviews over time was noted (P = 0.07). The median AMSTAR score was 5, thus reflecting a "fair" quality. No evidence for improvement in methodological quality over time was noted.

CONCLUSIONS

The trend to publish more systematic reviews in microsurgical head and neck reconstruction is encouraging. However, efforts are indicated to improve the methodological quality of systematic reviews. Familiarity with criteria of methodological quality is critical to ensure future improvements in the quality of systematic reviews conducted in microsurgery.

Epidemiology, quality, and reporting characteristics of systematic reviews and meta-analyses of nursing interventions published in Chinese journals

OBJECTIVES

Systematic reviews (SRs) and meta-analyses (MAs) of nursing interventions have become increasingly popular in China. This review provides the first examination of epidemiological characteristics of these SRs as well as compliance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses and Assessment of Multiple Systematic Reviews guidelines. The purpose of this study was to examine epidemiologic and reporting characteristics as well as the methodologic quality of SRs and MAs of nursing interventions published in Chinese journals.

METHODS

Four Chinese databases were searched (the Chinese Biomedicine Literature Database, Chinese Scientific Journal Full-text Database, Chinese Journal Full-text Database, and Wanfang Database) for SRs and MAs of nursing intervention from inception through June 2013. Data were extracted into Excel (Microsoft, Redmond, WA). The Assessment of Multiple Systematic Reviews and Preferred Reporting Items for Systematic Reviews and Meta-analyses checklists were used to assess methodologic quality and reporting characteristics, respectively.

RESULTS

A total of 144 SRs were identified, most (97.2%) of which used "systematic review" or "meta-analyses" in the titles. None of the reviews had been updated. Nearly half (41%) were written by nurses, and more than half (61%) were reported in specialist journals. The most common conditions studied were endocrine, nutritional and metabolic diseases, and neoplasms. Most (70.8%) reported information about quality assessment, whereas less than half (25%) reported assessing for publication bias. None of the reviews reported a conflict of interest.

CONCLUSIONS

Although many SRs of nursing interventions have been published in Chinese journals, the quality of these reviews is of concern. As a potential key source of information for nurses and nursing administrators, not only were many of these reviews incomplete in the information they provided, but also some results were misleading. Improving the quality of SRs of nursing interventions conducted and published by nurses in China is urgently needed in order to increase the value of these studies.

[Review of meta-analysis research on exercise in South Korea]

PURPOSE

The purpose of this study was to evaluate the quality of meta-analysis regarding exercise using Assessment of Multiple Systematic Reviews (AMSTAR) as well as to compare effect size according to outcomes.

METHODS

Electronic databases including the Korean Studies Information Service System (KISS), the National Assembly Library and the DBpia, HAKJISA and RISS4U for the dates 1990 to January 2014 were searched for 'meta-analysis' and 'exercise' in the fields of medical, nursing, physical therapy and physical exercise in Korea. AMSTAR was scored for quality assessment of the 33 articles included in the study. Data were analyzed using descriptive statistics, t-test, ANOVA and χ²-test.

RESULTS

The mean score for AMSTAR evaluations was 4.18 (SD=1.78) and about 67% were classified at the low-quality level and 30% at the moderate-quality level. The scores of quality were statistically different by field of research, number of participants, number of databases, financial support and approval by IRB. The effect size that presented in individual studies were different by type of exercise in the applied intervention.

CONCLUSION

This critical appraisal of meta-analysis published in various field that focused on exercise indicates that a guideline such as the PRISMA checklist should be strongly recommended for optimum reporting of meta-analysis across research fields.

Methodological quality and descriptive characteristics of prosthodontic-related systematic reviews

Ideally, healthcare systematic reviews (SRs) should be beneficial to practicing professionals in making evidence-based clinical decisions. However, the conclusions drawn from SRs are directly related to the quality of the SR and of the included studies. The aim was to investigate the methodological quality and key descriptive characteristics of SRs published in prosthodontics. Methodological quality was analysed using the Assessment of Multiple Reviews (AMSTAR) tool. Several electronic resources (MEDLINE, EMBASE, Web of Science and American Dental Association's Evidence-based Dentistry website) were searched. In total 106 SRs were located. Key descriptive characteristics and methodological quality features were gathered and assessed, and descriptive and inferential statistical testing performed. Most SRs in this sample originated from the European continent followed by North America. Two to five authors conducted most SRs; the majority was affiliated with academic institutions and had prior experience publishing SRs. The majority of SRs were published in specialty dentistry journals, with implant or implant-related topics, the primary topics of interest for most. According to AMSTAR, most quality aspects were adequately fulfilled by less than half of the reviews. Publication bias and grey literature searches were the most poorly adhered components. Overall, the methodological quality of the prosthodontic-related systematic was deemed limited. Future recommendations would include authors to have prior training in conducting SRs and for journals to include a universal checklist that should be adhered to address all key characteristics of an unbiased SR process.

Quality assessment of systematic reviews on periodontal regeneration in humans

BACKGROUND

Systematic reviews represent the highest form of evidence in the current hierarchy of evidence-based dentistry. Critical analysis of published systematic reviews may help to analyze their strengths and weaknesses and to identify areas that need future improvement. The aim of this overview is to determine and compare the quality of systematic reviews published in the field of periodontal regeneration using established checklists, such as the Assessment of Multiple Systematic Reviews (AMSTAR) guidelines.

METHODS

A systematic search was conducted to retrieve reviews on periodontal regeneration in humans. A total of 14 systematic reviews were selected using a set of inclusion and exclusion criteria. Two independent reviewers appraised the quality of the selected reviews using AMSTAR guidelines. Each article was given an AMSTAR total score, based on the number of AMSTAR criteria that were fulfilled. The quality of included reviews was further assessed using a checklist proposed in 2003.

RESULTS

Only one of the selected systematic reviews satisfied all the AMSTAR guidelines, whereas two reviews satisfied just two of the 11 items. This study shows that published systematic reviews on periodontal regeneration exhibit significant structural and methodologic variability. Quality assessment using the additional checklist further confirmed the variability in the way systematic reviews were conducted and/or reported.

CONCLUSION

Consideration of guidelines for quality assessment, such as AMSTAR, when designing and conducting systematic reviews may increase the validity and clinical applicability of future reviews.

Cochrane and non-Cochrane systematic reviews in leading orthodontic journals: a quality paradigm?

The aims of this study were to assess and compare the methodological quality of Cochrane and non-Cochrane systematic reviews (SRs) published in leading orthodontic journals and the Cochrane Database of Systematic Reviews (CDSR) using AMSTAR and to compare the prevalence of meta-analysis in both review types. A literature search was undertaken to identify SRs that consisted of hand-searching five major orthodontic journals [American Journal of Orthodontics and Dentofacial Orthopedics, Angle Orthodontist, European Journal of Orthodontics, Journal of Orthodontics and Orthodontics and Craniofacial Research (February 2002 to July 2011)] and the Cochrane Database of Systematic Reviews from January 2000 to July 2011. Methodological quality of the included reviews was gauged using the AMSTAR tool involving 11 key methodological criteria with a score of 0 or 1 given for each criterion. A cumulative grade was given for the paper overall (0-11); an overall score of 4 or less represented poor methodological quality, 5-8 was considered fair and 9 or greater was deemed to be good. In total, 109 SRs were identified in the five major journals and on the CDSR. Of these, 26 (23.9%) were in the CDSR. The mean overall AMSTAR score was 6.2 with 21.1% of reviews satisfying 9 or more of the 11 criteria; a similar prevalence of poor reviews (22%) was also noted. Multiple linear regression indicated that reviews published in the CDSR (P < 0.01); and involving meta-analysis (β = 0.50, 95% confidence interval 0.72, 2.07, P < 0.001) showed greater concordance with AMSTAR.

Coherence of evidence from systematic reviews as a basis for evidence strength - a case study in support of an epistemological proposition

BACKGROUND

This article aims to offer, on the basis of Coherence theory, the epistemological proposition that mutually supportive evidence from multiple systematic reviews may successfully refute radical, philosophical scepticism.

METHODS

A case study including seven systematic reviews is presented with the objective of refuting radical philosophical scepticism towards the belief that glass-ionomer cements (GIC) are beneficial in tooth caries therapy. The case study illustrates how principles of logical and empirical coherence may be applied as evidence in support of specific beliefs in healthcare.

RESULTS

The results show that radical scepticism may epistemologically be refuted on the basis of logical and empirical coherence. For success, several systematic reviews covering interconnected beliefs are needed. In praxis, these systematic reviews would also need to be of high quality and its conclusions based on reviewed high quality trials.

CONCLUSIONS

A refutation of radical philosophical scepticism to clinical evidence may be achieved, if and only if such evidence is based on the logical and empirical coherence of multiple systematic review results. Practical application also requires focus on the quality of the systematic reviews and reviewed trials.

The methodological quality of systematic reviews of animal studies in dentistry

Systematic reviews and meta-analyses of animal studies are important for improving estimates of the effects of treatment and for guiding future clinical studies on humans. The purpose of this systematic review was to assess the methodological quality of systematic reviews and meta-analyses of animal studies in dentistry through using a validated checklist. A literature search was conducted independently and in duplicate in the PubMed and LILACS databases. References in selected systematic reviews were assessed to identify other studies not captured by the electronic searches. The methodological quality of studies was assessed independently and in duplicate by using the AMSTAR checklist; the quality was scored as low, moderate, or high. The reviewers were calibrated before the assessment and agreement between them was assessed using Cohen's Kappa statistic. Of 444 studies retrieved, 54 systematic reviews were selected after full-text assessment. Agreement between the reviewers was regarded as excellent. Only two studies were scored as high quality; 17 and 35 studies were scored as medium and low quality, respectively. There is room for improvement of the methodological quality of systematic reviews of animal studies in dentistry. Checklists, such as AMSTAR, can guide researchers in planning and executing systematic reviews and meta-analyses. For determining the need for additional investigations in animals and in order to provide good data for potential application in human, such reviews should be based on animal experiments performed according to sound methodological principles.

Extent and quality of systematic review evidence related to minimum intervention in dentistry: essential oils, powered toothbrushes, triclosan, xylitol

OBJECTIVE

To investigate extent and quality of current systematic review evidence regarding: powered toothbrushes, triclosan toothpaste, essential oil mouthwashes, xylitol chewing gum.

METHODS

Five databases were searched for systematic reviews until 13 November 2010.

INCLUSION CRITERIA

relevant to topic, systematic review according to title and/or abstract, published in English. Article exclusion criteria were based on QUOROM recommendations for the reporting of systematic review methods. Systematic review quality was judged using the AMSTAR tool. All trials included by reviews were assessed for selection bias.

RESULTS

119 articles were found, of which 11 systematic reviews were included. Of these, six were excluded and five accepted: one for triclosan toothpaste; one for xylitol chewing gum; two for powered toothbrushes; one for essential oil mouthwashes. AMSTAR scores: triclosan toothpaste 7; powered toothbrushes 9 and 11; xylitol chewing gum 9; essential oil mouthwashes 8. In total, 75 (out of 76) reviewed trials were identified. In-depth assessment showed a high risk of selection bias for all trials.

CONCLUSIONS

The extent of available systematic review evidence is low. Although the few identified systematic reviews could be rated as of medium and high quality, the validity of their conclusions needs to be treated with caution, owing to high risk of selection bias in the reviewed trials. High quality randomised control trials are needed in order to provide convincing evidence regarding true clinical efficacy.

Fixed-Effects Modeling of Cohen's Weighted Kappa for Bivariate Multinomial Data: A Perspective of Generalized Inverse

Cohen's kappa and weighted kappa statistics are the conventional methods used frequently in measuring agreement for categorical responses. In this paper, through the perspective of a generalized inverse, we propose an alternative general framework of the fixed-effects modeling of Cohen's weighted kappa, proposed by Yang and Chinchilli (2011). Properties of the proposed method are provided. Small sample performance is investigated through bootstrap simulation studies, which demonstrate good performance of the proposed method. When there are only two categories, the proposed method reduces to Cohen's kappa.

Effectiveness of treadmill training in children with motor impairments: an overview of systematic reviews

PURPOSE

The purpose of this review was to synthesize current evidence from systematic reviews on the effectiveness of treadmill training (TT), including partial body-weight support (PBWS) TT (PBWSTT), TT only, robotic-assist PBWSTT, and mixed TT, in children with motor impairments.

METHODS

Systematic literature searches were conducted in 10 databases through May 2010. Two reviewers independently selected titles, abstracts (k = 0.78), and full-text articles (k = 1.0). Of the 1166 titles retrieved, 5 studies met the inclusion criteria. Quality of included studies was assessed using AMSTAR criteria.

RESULTS

Results of each systematic review were tabulated on the basis of levels of evidence, with outcomes categorized according to the International Classification of Functioning, Disability, and Health framework. Conflicting interpretations of outcomes were found between reviews, yet conclusions were similar.

CONCLUSIONS

TT demonstrates encouraging results, but more rigorous research is needed before clinicians can be confident of its effectiveness and clinical guidelines can be developed.