The findings of the present report highlight the potential lack of knowledge and experience by researchers and authors in the orthodontic field, aiming to conduct a review with a scoping methodology perspective. It is concerning that about half of the currently existing ScRs about orthodontics, irrespective of the journal of publication and other predictors, fail to provide a clear justification for the selection of this methodological route to map existing evidence; the concurrent impact on the identification of knowledge gaps and/or contribution to the recognition of areas and domains in need of further study is profound.
In essence, suboptimal knowledge of research methodology and reporting issues is not new to both dental and orthodontic literature. Previous studies on the reporting quality of systematic reviews in orthodontics have indicated several domains of non-standard, transparent and consistent methodological perspectives being followed [12,13,14,15]. Moreover, it has been reported that a quarter of primary research studies do not correctly identify a relevant systematic review of a topic to be adequately justified [16].
Evidence on Scoping Reviews, especially regarding dentistry and orthodontics, is rather recent. The sole empirical study on the justification of conducting ScRs in dentistry was that of Zauza et al. [11], which informed the literature in the field about the necessity for improvement in justification practices, by the authors of the ScRs, when deciding to undertake such an initiative. This report included ScRs from various dentistry specialty domains, and overall, the investigators concluded that only half of the examined studies correctly identified and justified why they followed this type of review methodology [11]. It was notable that ScRs related to orthodontics in this study constituted only a small fraction of the sample, contributing to approximately 4% of it, or 7 studies in absolute number. Furthermore, the vast majority of ScRs in oral health represented in this first report were held in the disciplines of Dental Public Health, Paediatric Dentistry, Oral and Maxillofacial Surgery and Pathology and Periodontology, thus leaving orthodontics lagging far behind; although no differences between the groups of dental scientific fields were identified, this cannot preclude effects of inadequate power assumptions stemming from underrepresentation of specific domains. Only a fourth to a tenth of the identified ScRs by Zauza et al. were found to be associated with an existing protocol and preregistration practices. The latter was apparently in agreement with the findings of the present study, where we identified that only 16% of the ScRs in orthodontics were previously registered. Registration practices have been reported to bear implications regarding research integrity, clarity and transparency overall and have been associated also with other research design and conduct flaws across the dental and orthodontics literature [17,18,19].
Lately, an extension to PRISMA guidelines for Scoping Reviews has been developed in order to facilitate the completeness and transparency in reporting the increasing number of this type of reviews appearing in the biomedical literature [20]. This document has followed prior but not systematic efforts to map scoping review methodology [21, 22], as determined by the Joanna Briggs Institute guidance document. It highlights the importance of increasing the level of complete and accurate reporting of this type of knowledge synthesis, as well as their relevance to decision-making. Of the key elements of this approach is the clear identification and description of rationale by the authors, in the context of the justification and relevance of the selection of this approach. It has been reported that researchers and authors aiming to conduct a ScR often fail to distinguish the differences from systematic reviews of the literature, or potentially misinterpret scoping methodology framework as the one used for the well-known and established systematic reviews, thus, resulting in a final document of an uncertain or questionable value [23]. It has also been argued that authors select to “promote” their research as a scoping framework document, in order to skip the internal validity assessment of the included studies in the form of a risk of bias assessment, for reasons of ignorance, apparent simplicity in conducting and reporting their findings, to expedite the whole process or for other reasons [24]. This might pose additional concerns if one considers the apparent cross-linking of evidence synthesis to clinical recommendations for decision-making; for example, no clinical recommendations may be considered reliable in order to provide a recommendation of an intervention for clinical practice, when based on synthesized evidence from a ScR without any further assessment of the quality and risk of bias of the included and contributing studies.
Our results are indicative of the status of the very recent and most probably almost all published ScRs in orthodontics. The findings showcase the need to improve and advance education, knowledge and expertise of the scientific community in this field, including authors, journal editors, reviewers and stakeholders, so as to avoid a considerable portion of research waste [25]. The strength of the present meta-epidemiological study lies on the fact that it constitutes the first empirical approach to search preliminary evidence on the conducted, reported and published ScRs in orthodontics; although no further associations with potential predictor factors could be established, possibly due to power assumptions and limitations, it follows that publication of the existing ScRs in the field was at least non-adequately justified. We followed an all-inclusive approach and search strategy covering three international databases supplemented with electronic searching within eleven journals in the specialty, with no other filters or restrictions. The sample that constituted our pool of examined ScRs is considered adequate, although not large, and probably frames all evidence that exists in the field, with the vast majority of the included studies being published over the last 2 years. For this reason, it follows that the rationale for the present study is evidently well justified in order to expose the state-of-the-art of the ScRs in orthodontics and provide a twofold basis for investigation: first, facilitate early assessment of evidence on this type of knowledge synthesis and also pledge for action in the direction of early improvement in the field prior to massive publication rates; second, further in-depth examination of the reporting quality of the existing ScRs in the field, according to the PRISMA ScR guidelines.
