Product advertisements in orthodontic journals: Are they evidence-based?

Introduction
Previous research has suggested orthodontic advertisements are poorly supported by evidence. The primary aim of this study was to identify the type and quality of evidence supporting advertisement claims in leading orthodontic journals.
Methods
A cross-sectional study was undertaken to assess all advertisements published between January 2015 and December 2017 in 6 major orthodontic journals. Only advertisements implying superior product performance in clinical practice or patient care were selected for further evaluation. Study variables were collected using a prespecified data collection form. In the presence of a supporting citation, the reference article was obtained, and the quality was assessed in duplicate. Associations between advertisement variables and quality of evidence were explored using contingency tables (Fisher exact test).
Results
A total of 1753 advertisements were identified. After the application of eligibility criteria, 124 were included in the final analysis. Advertisements promoting bracket systems predominated. Of these, 34.7% were supported by evidence, of which 10.5% (n = 13) included accessible references. Only 6 out of 13 studies involved orthodontic patients. Primarily expert opinion and observational study types were referenced. Less than 2% of advertisements were supported by high-value evidence. There was an association between the quality of evidence in advertisements and the product category (P = 0.003).
Conclusions
There is a lack of both references and high-value evidence cited in orthodontic manufacturers' advertisements. Without critical appraisal of references cited in advertisements, clinicians need to be cautious before implementing manufacturers' recommendations in clinical practice. Efforts should be made to ensure appropriate high-value evidence is cited in advertisements to support manufacturers’ claims.