Spin in the Abstracts of Randomized Controlled Trials in Operative Dentistry: A Cross-sectional Analysis

Objective: To assess the presence and characteristics of spin in recently published RCT abstracts in operative dentistry and to investigate potential factors associated with the presence of spin. Methods and Materials: The PubMed database was searched to identify parallel-group RCTs published between 2015 and 2019 in the field of operative dentistry, which compared two or more groups and had nonsignificant results for the primary outcome. Two authors evaluated independently the presence and characteristics of spin among these abstracts. Multivariable logistic regression analyses were conducted to identify factors associated with the presence of spin in the Results and the Conclusions sections, respectively. Results: A total of 77 RCT abstracts were included, among which 58 (75.3%) showed at least one type of spin. Spin was identified in the Results and Conclusions sections of 32 (41.6%) and 45 (58.4%) abstracts, respectively. 19 RCTs (24.7%) presented spin in both the Results and the Conclusions section of abstracts. The presence of spin in the Results section of abstracts was significantly associated with source of funding (OR=8.10; p=0.025) and number of treatment arms was associated with the presence of spin in the Conclusions section of abstracts (OR=5.66; p=0.005). Conclusion: The occurrence rate of spin in the sample of operative dentistry RCTs abstracts is high.