A quantitative and qualitative evaluation of reports of clinical trials published in six Brazilian dental journals indexed in the Scientific Electronic Library Online (SciELO)

Open access publishing is becoming increasingly popular within the biomedical sciences. SciELO, the Scientific Electronic Library Online, is a digital library covering a selected collection of Brazilian scientific journals many of which provide open access to full-text articles. This library includes a number of dental journals some of which may include reports of clinical trials in English, Portuguese and/or Spanish. Thus, SciELO could play an important role as a source of evidence for dental healthcare interventions especially if it yields a sizeable number of high quality reports. Objective The aim of this study was to identify reports of clinical trials by handsearching of dental journals that are accessible through SciELO, and to assess the overall quality of these reports. Material and methods Electronic versions of six Brazilian dental Journals indexed in SciELO were handsearched at www.scielo.br in September 2008. Reports of clinical trials were identified and classified as controlled clinical trials (CCTs - prospective, experimental studies comparing 2 or more healthcare interventions in human beings) or randomized controlled trials (RCTs - a random allocation method is clearly reported), according to Cochrane eligibility criteria. Criteria to assess methodological quality included: method of randomization, concealment of treatment allocation, blinded outcome assessment, handling of withdrawals and losses and whether an intention-totreat analysis had been carried out. Results The search retrieved 33 CCTs and 43 RCTs. A majority of the reports provided no description of either the method of randomization (75.3%) or concealment of the allocation sequence (84.2%). Participants and outcome assessors were reported as blinded in only 31.2% of the reports. Withdrawals and losses were only clearly described in 6.5% of the reports and none mentioned an intention-totreat analysis or any similar procedure. Conclusions The results of this study indicate that a substantial number of reports of trials and systematic reviews are available in the dental journals listed in SciELO, and that these could provide valuable evidence for clinical decision making. However, it is clear that the quality of a number of these reports is of some concern and that improvement in the conduct and reporting of these trials could be achieved if authors adhered to internationally accepted guidelines, e.g. the CONSORT statement.

pen access publishing is becoming increasingly popular within the biomedical sciences. SciELO, the Scientific Electronic Library Online, is a digital library covering a selected collection of Brazilian scientific journals many of which provide open access to full-text articles. This library includes a number of dental journals some of which may include reports of clinical trials in English, Portuguese and/or Spanish. Thus, SciELO could play an important role as a source of evidence for dental healthcare interventions especially if it yields a sizeable number of high quality reports. Objective: The aim of this study was to identify reports of clinical trials by handsearching of dental journals that are accessible through SciELO, and to assess the overall quality of these reports. Material and methods: Electronic versions of six Brazilian dental Journals indexed in SciELO were handsearched at www.scielo.br in September 2008. Reports of clinical trials were identified and classified as controlled clinical trials (CCTs -prospective, experimental studies comparing 2 or more healthcare interventions in human beings) or randomized controlled trials (RCTs -a random allocation method is clearly reported), according to Cochrane eligibility criteria. Criteria to assess methodological quality included: method of randomization, concealment of treatment allocation, blinded outcome assessment, handling of withdrawals and losses and whether an intention-totreat analysis had been carried out. Results: The search retrieved 33 CCTs and 43 RCTs. A majority of the reports provided no description of either the method of randomization (75.3%) or concealment of the allocation sequence (84.2%). Participants and outcome assessors were reported as blinded in only 31.2% of the reports. Withdrawals and losses were only clearly described in 6.5% of the reports and none mentioned an intention-totreat analysis or any similar procedure. Conclusions: The results of this study indicate that a substantial number of reports of trials and systematic reviews are available in the dental journals listed in SciELO, and that these could provide valuable evidence for clinical decision making. However, it is clear that the quality of a number of these reports is of some concern and that improvement in the conduct and reporting of these trials could be achieved if authors adhered to internationally accepted guidelines, e.g. the CONSORT statement.

INTRODUCTION
There has been an increased trend over the last decade towards open access publishing of health science literature 8 , the main goals of which are the improvement of scholarly interaction, the creation of options for sharing knowledge without cost and with a perception that this will lead to a reduction in the barriers to the growth of science.
In practical terms, published articles should be available on the internet and should permit users to read, print and distribute the documents without  As this was a descriptive study, data for quality assessment was presented only as frequency counts.

RESULTS
The initial search retrieved six titles for eligible journals (Figure 2). The titles A, B and C were for three independent journals, whereas the titles D  Quality assessment of the reports illustrated that 75.3% of the reports did not explain how participants were randomized, and 84.2% did not indicate the methods used to conceal the allocation sequence ( Figure 3A). Of the included reports, 13.2% and 5.3% respectively, confirmed inadequate methods for the randomization and concealment of allocation criteria.
The most frequently used method for control of bias was blinding of participants or assessment of outcomes, which were both described in 31.6% of the reports. Blinding of caregivers was much less frequent (9.2%); whereas data analysts were  The blinding of outcome assessors, if feasible, can also reduce detection bias, attributed to systematic differences between groups during outcome assessment 12 .
Attrition bias which was a further concern in our findings refers to systematic differences between groups due to the loss of participants during a study 14 . Despite its relevance, only 5 reports adequately cited how many enrolled participants completed the studies. Not a single study cited the use of intention-to-treat analysis, which was quite surprising in view of the generally inadequate description of withdrawals and losses.
Missing data is a common theme even in studies published in leading medical journals 10 , it is tempting therefore to assume that several of the reports assessed in this study did not conduct an intention to-treat-analysis if appropriate, more

CONCLUSIONS
A substantial number of reports of clinical trials are available in dental journals accessible through the SciELO database. Although these trials can provide valuable evidence for clinical decision making, the present assessment showed that the quality of many of these reports is a concern, and that future improvements in trial conduction are likely to be driven by authors adhering more closely to internationally accepted guidelines.