Systematic Reviews of Topical Fluorides for Dental Caries: A Review of Reporting Practice

This paper aims to assess systematic reviews on the cariespreventive effect of topical fluorides, identifying key content and reporting quality issues to be considered by researchers planning a review in this area. Published systematic reviews and meta-analyses of any topical fluoride intervention for caries control were included. Relevant databases were searched (December 2009), along with reference lists of included publications. Thirty-eight reports were identified and assessed. A majority of these focused on the child/adolescent population, fluoride toothpastes, no treatment/placebo comparisons, and had caries increment as the main outcome. Complete reporting of eligibility criteria (PICOS) was uncommon, except in Cochrane reviews. Less than half reported searching multiple sources and only one third reported a search strategy. Duplicate study selection and data extraction was reported in 27 (71%) and 16 (42%) reviews, respectively; quality assessment of included studies was not reported in one third of the reviews. Meta-analysis was reported in 20 (52%) reviews, with six not reporting the methods of synthesis used, 17 formally assessing heterogeneity, and 12 reporting analyses for its exploration. This study Received: August 16, 2010 Accepted after revision: October 19, 2010 Published online: December 10, 2010 Sharea Ijaz Clinical and Diagnostic Oral Sciences Barts and the London Institute of Dentistry 4 Newark Street, London E1 2AT (UK) Tel. +44 20 7882 8625, Fax +44 20 7377 7064, E-Mail shareaijaz @ yahoo.com © 2010 S. Karger AG, Basel 0008–6568/10/0446–0579$26.00/0 Accessible online at: www.karger.com/cre D ow nl oa de d by : 54 .7 0. 40 .1 1 11 /2 3/ 20 17 2 :4 3: 22 A M Ijaz/Croucher/Marinho Caries Res 2010;44:579–592 580 tistry though [Marinho, 2003], and there is still room for improvement in the quantity, in terms of subject areas covered, and quality of both the conduct and the reporting of systematic reviews in the field [Glenny et al., 2003; Bader and Ismail, 2004; Richards, 2004; Major et al., 2006]. The various topical fluoride interventions have over six decades of experimental research supporting their value as anticaries measures, and these were the focus of some of the first meta-analyses in dentistry [Stamm et al., 1984; Clark et al., 1985]. Existing systematic reviews of topical fluoride interventions may reflect the available primary research in the field, and their reporting quality may vary. Nevertheless, the breadth of topical fluoride interventions, comparisons, populations, and outcomes covered by published systematic reviews and meta-analyses, and the methodological quality of these reviews, have not been reported previously. Highlighting which direction future reviews in this area should take based on past practice to avoid duplication of effort while advancing knowledge reliably is important, and this should be done in the light of ongoing methodological advancements so as to enhance their validity and applicability. In 1996, an international group developed a reporting guideline, the QUOROM Statement ( QU ality O f R eporting O f M eta-analyses), to improve the reporting of systematic reviews and meta-analyses in healthcare research [Moher et al., 1999]. The recent publication of ‘Preferred reporting items for systematic reviews and meta-analyses’, the PRISMA statement, is an improvement on that guideline [Liberati et al., 2009; Moher et al., 2009]. In addition to the QUOROM items, PRISMA now asks the review authors to make a protocol for the review accessible; to report at least one complete electronic search; to assess risk of bias in and across included studies (along with the selective reporting of outcomes); to report limitations of the review, future research implications and sources of funding. The PRISMA statement has made it clear that the quality and content of systematic reviews is constantly being improved, and has also identified The Cochrane Collaboration as the leader in the field since all these new items are already an essential part of Cochrane reviews. Thus, new reviews incorporating these advancements should have enhanced quality and generate more reliable estimates of treatment effects. The aim of this paper is to describe the most important features of systematic reviews and meta-analyses on topical fluorides for caries prevention and treatment in terms of content and reporting quality by collating those published up to and including 2009. A comprehensive search and an appraisal in the light of current reporting guidelines (PRISMA) has enabled us to identify important issues that need consideration by researchers planning a systematic review in this area of dentistry. Materials and Methods An electronic search without date or language restrictions was undertaken in December 2009 of: MEDLINE (via OVID including old MEDLINE), The Cochrane Database of Systematic Reviews (CDSR) and The Centre for Reviews and Dissemination (CRD) databases [including DARE (Database of Abstracts of Reviews of Effects), NHSEED (National Health Service Economic Evaluation Database), and HTA (Health Technology Assessment)]. The search terms ‘caries AND fluoride’ were used in all the searches performed, but a more detailed search strategy was used in MEDLINE (online supplementary material, www. karger.com/doi/10.1159/000322132). This was supplemented by searching the reference lists of the included reviews. Only completed published intervention systematic reviews and meta-analyses, including any types of study design, assessing the anticaries effects of any topical fluoride therapy (TFT), including toothpaste, mouthrinse, gel, varnish, paint-on solution, whether used alone, or in combination with another TFT, or as part of a larger group of anticaries interventions in any population group were considered relevant for inclusion. Any review that incorporated at least two of the key characteristics of a systematic review outlined in section 1.2.2 of The Cochrane Handbook of Systematic Reviews of Interventions [Higgins and Green, 2008] was considered. For each of the identified reviews included in this study, the following data were then extracted on a standard form: year of publication; whether a clear objective and eligibility criteria (in terms of participants, interventions, comparisons and outcomes – PICOS) were stated in the review; types of intervention(s), comparison(s) and population group(s) addressed; main outcomes addressed; number and types of studies included; methods used for study identification, study selection, quality assessment (risk of bias) and data extraction of included studies; effect measures used; whether a quantitative synthesis was done; statistical methods used in the synthesis (fixed effect or random effects); assessment, exploration and factors explored for heterogeneity; assessment and exploration of publication or reporting bias; whether cost/economic evaluation was reported and in what format. These data were then summarized so as to identify the most important issues in the conduct and reporting of topical fluoride reviews. Search strategy development, study selection and data collection were done by one author (S.I.) in consultation with the other (V.C.C.M.).