Objectives:The English language is generally perceived to be the universal language of science. However, the exclusive reliance on English-language studies may not represent all of the evidence. Excluding languages other than English (LOE) may introduce a language bias and lead to erroneous conclusions.Study Design and Setting:We conducted a comprehensive literature search using bibliographic databases and grey literature sources. Studies were eligible for inclusion if they measured the effect of excluding randomized controlled trials (RCTs) reported in LOE from systematic review-based meta-analyses (SR/MA) for one or more outcomes.Results:None of the included studies found major differences between summary treatment effects in English-language restricted meta-analyses and LOE-inclusive meta-analyses. Findings differed about the methodological and reporting quality of trials reported in LOE. The precision of pooled estimates improved with the inclusion of LOE trials.Conclusions:Overall, we found no evidence of a systematic bias from the use of language restrictions in systematic review-based meta-analyses in conventional medicine. Further research is needed to determine the impact of language restriction on systematic reviews in particular fields of medicine.

The evidence suggests that preoperative antiseptic showers reduce bacterial colonization and may be effective at preventing SSIs. The antiseptic application method is inconsequential, and data are lacking to suggest which antiseptic solution is the most effective. Disinfectant products are often mixed with alcohol or water, which makes it difficult to form overall conclusions regarding an active ingredient. Large, well-conducted randomized controlled trials with consistent protocols comparing agents in the same bases are needed to provide unequivocal evidence on the effectiveness of one antiseptic preparation over another for the prevention of SSIs.

Background: Traditionally, amalgam has been used for filling cavities in posterior teeth, and it continues to be the restorative material of choice in some low-and middle-income countries due to its effectiveness and relatively low cost. However, there are concerns over the use of amalgam restorations (fillings) with regard to mercury release in the body and the environmental impact of mercury disposal. Dental composite resin materials are an aesthetic alternative to amalgam, and their mechanical properties have developed sufficiently to make them suitable for restoring posterior teeth. Nevertheless, composite resin materials may have potential for toxicity to human health and the environment. The United Nations Environment Programme has established the Minamata Convention on Mercury, which is an international treaty that aims "to protect the [sic] human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds". It entered into force in August 2017, and as of February 2021 had been ratified by 127 governments. Ratification involves committing to the adoption of at least two of nine proposed measures to phase down the use of mercury, including amalgam in dentistry. In light of this, we have updated a review originally published in 2014, expanding the scope of the review by undertaking an additional search for harms outcomes. Our review synthesises the results of studies that evaluate the long-term effectiveness and safety of amalgam versus composite resin restorations, and evaluates the level of certainty we can have in that evidence. Objectives: To examine the effects (i.e. efficacy and safety) of direct composite resin fillings versus amalgam fillings. Search methods: An information specialist searched five bibliographic databases up to 16 February 2021 and used additional search methods to identify published, unpublished and ongoing studies SELECTION CRITERIA: To assess efficacy, we included randomised controlled trials (RCTs) comparing dental composite resin with amalgam restorations in permanent posterior teeth that assessed restoration failure or survival at followup of at least three years. To assess safety, we sought non-randomised studies in addition to RCTs that directly compared composite resin and amalgam restorative materials and measured toxicity, sensitivity, allergy, or injury.

Objective The objective of this study was to investigate the impact of the peer review of literature search strategies prepared in support of rapid reviews. Methods A sample of 200 CADTH rapid reviews was selected. For each rapid review meeting the inclusion criteria, the pre–peer‐reviewed and corresponding post–peer‐reviewed search strategies were run, and the search results were compared. Bibliographic records retrieved solely by the post–peer‐reviewed search strategy and included in the rapid review report were identified as representing “included studies.” The publication type of each included study was determined, and the attributes of the corresponding record were analyzed to determine the reason for its retrieval by the post–peer‐reviewed search. Results The peer review of search strategies resulted in the retrieval of one or more additional records for 75% of the searches investigated, but only a small proportion of these records (4%) represented included studies. The main publication types of the included studies were nonrandomized studies (60%) and narrative reviews (20%). The principal changes to search strategies that resulted in the retrieval of additional included studies were the inclusion of more keywords or subject headings or a change in the way concepts were combined. Conclusions The peer review of literature search strategies aids in the retrieval of relevant records particularly those representing nonrandomized studies. The scrutiny of keywords, subject headings, and the relation between search concepts are key components of the peer review process.

Objective: To identify or develop a critical appraisal instrument (CAI) to aid in the selection of search filters for use in systematic review searching. The CAI is to be used by experienced searchers without specialized training in statistics or search filter design. Methods: Through extensive searching and consultation, one candidate instrument was identified. Through expert consultation and several rounds of testing, the instrument was extensively revised to become the Canadian Agency for Drugs and Technologies in Health (CADTH) CAI. Results: The CADTH CAI consists of ten questions and can be applied by experienced searchers with a moderate knowledge of search filter methodology. Conclusion:The CADTH CAI provides experienced searchers with a means of selecting the search filter that is most methodologically sound. Key Messages Implications for Practice• The CADTH CAI provides information specialists with the means of selecting search filters based on relative methodological quality.• The CADTH CAI provides search filter creators with a checklist of factors to consider in creating filters and in reporting on their filters for publication. Implications for Policy• With the CADTH CAI it is possible to make evidence-based decisions on filter selection, based on the methodological quality of the search filters.• Using the CADTH CAI to measure the quality of search filters used in systematic review searching introduces a new dimension to the evaluation of the overall quality of a systematic review.