The Characteristics and Level of Evidence of Clinical Studies Published in 5 Leading Orthodontic Journals

OBJECTIVES: The objective of this study was to assess the characteristics and level of evidence (LOE) of clinical studies recently published in leading orthodontic journals and to explore the association between the LOE and potentially related factors.

METHODS: The official online archives of 5 leading orthodontic journals were hand-searched to identify clinical research articles published during the period 2015-2017. The LOE of all included studies was assessed using a modified LOE classification system developed based on the Oxford LOE and Grading of Recommendations Assessment, Development and Evaluation (GRADE). Univariable and multivariable logistic regression analyses were performed to identify the association between the LOE of each article (high LOE vs. low LOE) and 7 factors.

RESULTS: A total of 637 studies were included and assessed. Of these, 8 (1.3%) were of level 1, 160 (25.1%) level 2, 326 (51.2%) level 3, and 143 (22.4%) level 4. According to multivariable logistic regression analyses, journal of publication (P < .001), funding status (P = .003), and the geographic origin of the first author (P = .006) were significantly associated with the LOE.

CONCLUSIONS: The number of studies with high LOE in leading orthodontic journals was limited. There is still need for further improvement in the overall LOE of clinical studies in orthodontics.