A Descriptive Analysis of Oral Health Systematic Reviews Published 1991–2012: Cross Sectional Study

Abstract

ObjectivesTo identify all systematic reviews (SRs) published in the domain of oral health research and describe them in terms of their epidemiological and descriptive characteristics.DesignCross sectional, descriptive study.MethodsAn electronic search of seven databases was performed from inception through May 2012; bibliographies of relevant publications were also reviewed. Studies were considered for inclusion if they were oral health SRs defined as therapeutic or non-therapeutic investigations that studied a topic or an intervention related to dental, oral or craniofacial diseases/disorders. Data were extracted from all the SRs based on a number of epidemiological and descriptive characteristics. Data were analysed descriptively for all the SRs, within each of the nine dental specialities, and for Cochrane and non-Cochrane SRs separately.Results1,188 oral health (126 Cochrane and 1062 non-Cochrane) SRs published from 1991 through May 2012 were identified, encompassing the nine dental specialties. Over half (n = 676; 56.9%) of the SRs were published in specialty oral health journals, with almost all (n = 1,178; 99.2%) of the SRs published in English and almost none of the non-Cochrane SRs (n = 11; 0.9%) consisting of updates of previously published SRs. 75.3% of the SRs were categorized as therapeutic, with 64.5% examining non-drug interventions, while approximately half (n = 150/294; 51%) of the non-therapeutic SRs were classified as epidemiological SRs. The SRs included a median of 15 studies, with a meta-analysis conducted in 43.6%, in which a median of 9 studies/1 randomized trial were included in the largest meta-analysis conducted. Funding was received for 25.1% of the SRs, including nearly three-quarters (n = 96; 76.2%) of the Cochrane SRs.ConclusionEpidemiological and descriptive characteristics of the 1,188 oral health SRs varied across the nine dental specialties and by SR category (Cochrane vs. non-Cochrane). There is a clear need for more updates of SRs in all the dental specialties.

The Quality of the Evidence According to GRADE Is Predominantly Low or Very Low in Oral Health Systematic Reviews

“…These figures are in keeping with a large survey of the Cochrane Database of Systematic Reviews involving analysis of 2,321 systematic reviews which highlighted a median of 6 meta-analyses per review and a median of 3 studies per meta-analysis [ 29 ]. A similar previous review [ 30 ] of dental systematic reviews reported a median of 9 studies were included in the largest meta-analysis within dental systematic reviews involving 9 dental specialties, with the largest meta-analysis having no more than 4 studies in 19% of reviews. Similarly, the largest meta-analysis involved a median number of just two randomized clinical trials, although that review referred back to systematic reviews from as long ago as 1991 when randomized clinical trials were considerably less prevalent in oral health than is now the case.…”

Protocol registration improves reporting quality of systematic reviews in dentistry

“…Over the last years, a considerable increase in SRs has been noticed [4], including in dentistry [5,6]. However, Page et al [4] along with Ioannidis (2016) [7] observed that the increase of such publications was accompanied by an increase of poorly conducted, reported and/or unnecessary SRs.…”

Acceptance of systematic reviews as Master/PhD theses in Brazilian graduate programs in dentistry

“…Importantly, a vast number of SRs had been published in recent years, all of the varying quality 3‐6 . Thus, graduate programs should set guidelines for SR use in a master or PhD thesis in order to avoid “empty reviews.” Further, graduate programs must encourage researchers and students to be trained in all methodological aspects, including high‐quality SRs.…”

“…In dentistry, the same trend exists. Saltaji et al 5 found that 1 188 SRs were published between 1991 and 2012, while Bassani et al 6 stated that 495 SRs were indexed in the PubMed database in 2017.…”