Objectives: Systematic reviews and meta-analyses aim to identify and synthesize all available evidence to answer a research question. Over the past twenty years, these studies have become widespread in dentistry. Because the goal of a systematic review is to incorporate all evidence on a given question, the search methods used for a review are crucial to judge its validity. This project aimed to characterize the reporting of searches and sources searched for systematic reviews recently published in dental journals. Understanding the current landscape will better enable librarians to help dental researchers navigate systematic reviews, both as readers and authors.
Methods: PubMed was searched in February 2021 for English-language articles identified as systematic reviews or meta-analyses by their authors. A title search for “systematic review" or "meta-analysis" was conducted. The Dental journals, English language, and date range 2016-2021 filters were applied. This produced 3,172 results. A representative sample size was calculated, and a list of 343 articles was randomly generated. The full texts of these articles were obtained.
Search details were taken from the methods sections. Search reporting was characterized as full, terms only, or absent. All languages included and sources searched were recorded.
Results were summarized with descriptive statistics.
Results: Of the 343 articles, 24 (7%) didn’t report searches. 68 (20%) provided a list of terms. 243 (71%) provided a full strategy for at least one database. 8 (2%) had inaccessible search information.
42 (12%) articles didn’t report which languages were searched. 118 (35%) reviews placed no restriction on language.
MEDLINE was the most-searched database, searched for 341 (99%) articles. Most articles (215, 63%) searched a Cochrane Collaboration resource. No other database was searched for a majority of reviews. Almost half (161, 46.7%) included some grey literature search.
Conclusions: This data provides a snapshot of current practices in searching for systematic reviews and meta-analyses in dentistry. In addition to characterizing favored sources, it suggests ways librarians can help to improve dental systematic reviews.
Librarians can encourage researchers to search non-English literature and offer guidance on grey literature searching. The latter will be especially important going forward, as OpenGrey, a favored grey literature source, has since shut down. Finally, over a quarter of systematic reviews and meta-analyses did not fully report their searches. While this project did not evaluate the quality of reported searches, librarians can help ensure both that searches are more consistently fully reported, and that those searches are as rigorous as possible.
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