Publication bias in oral and maxillofacial surgery journals: an observation on published controlled trials

Publication bias (PB) diminishes the full distribution of research, distorts and discredits the scientific record, and thus compromises evidence-based practice. The objective of this study was to analyse published controlled trials with regard to PB in leading oral and maxillofacial surgery (OMS) journals.

All controlled trials published in the International Journal of Oral and Maxillofacial Surgery, Journal of Cranio-Maxillofacial Surgery, Journal of Oral and Maxillofacial Surgery, and British Journal of Oral and Maxillofacial Surgery in 2008 were analysed for a primary outcome, country of authors, sample size, gender of the first author, funding source and location of the study.

Of 952 published articles, 53 controlled trials (5.7%) were identified. The OMS journals preferentially published controlled trials with a positive outcome (77.4%) and from high-income countries (73.6%). Single-centred trials (86.8%) with low sample size (n<100; 69.8%) were published more frequently. The majority of the first authors were male (75.5%). Funding source disclosure was missing in most studies (73.6%) [corrected].

Our results suggest the possible existence of PB in the OMS literature. Hence, it should be borne in mind that the published articles may not be representative of all scientific works, especially when systematic reviews and meta-analyses are conducted or read. In the meantime, journals should establish measures to eliminate PB to uphold scientific integrity. However, this study was an observation based on the published articles. An analysis of all submitted manuscripts would provide more accurate estimates of PB. Ethical considerations on PB are also discussed.