Selective outcome reporting in paediatric dentistry restorative treatment randomised clinical trials-A meta-research

Selective outcome reporting (SOR) is a bias that occurs when the primary outcome of a randomised clinical trial (RCT) is omitted or changed.

To evaluate the prevalence of SOR in RCTs on restorative treatment in primary teeth.

We conducted an electronic search on ClinicalTrials.gov and the World Health Organization platform (International Clinical Trials Registry Platform) on 1^st of April 2021, with no registry time or language restrictions. We included RCT protocols that evaluated restorative treatments in primary teeth and excluded trials that did not have a complete publication in a scientific journal. The chi-squared test was used to identify the association between SOR and variables as a discrepancy in the follow-up period, the timing of registration, the type of sponsorship and the type of study design (α = 5%).

Of the 294 identified protocols, 30 were included in the study. 83.3% of trials were registered retrospectively. SOR was observed in 53.3% (n = 16) of the published trials and was significantly associated with a discrepancy in the follow-up period (p = .017).

The high prevalence of SOR in RCTs on restorative treatment proves that this is a prominent threat. A proper preregistered protocol, declaration of any protocol deviation and allowance of stakeholders to compare the protocol with that of the submitted papers will achieve transparency.