Objectives: To present the characteristics and level of evidence (LOE) of clinical studies published in leading oral implantology journals during 2008-2018, and to explore whether the LOE of a study is associated with its scientific and social impact.
Materials and methods: Clinical studies with direct relevance to the evaluation of healthcare interventions published in 2008, 2013 and 2018 in six oral implantology journals were identified via hand searches. A modified 4-level Oxford 2011 LOE tool was used to assess the LOE of all eligible studies. The citation count and Altmetric Attention Score (AAS) of each study was extracted from Web of Science and Altmetric Explorer, respectively. Thereafter, multivariable generalized estimation equation analyses were used to investigate the association between LOE, citation counts and AAS, adjusting for potential confounding factors and clustering effects.
Results: A total of 763 clinical studies were included, among which the proportion of level-1, level-2, level-3 and level-4 studies was 2.4%, 30.4%, 40.2% and 27.0%, respectively. During 2008-2018, the proportion of high LOE studies (level-1 and level-2) increased substantially from 24.6% to 43.1%, although the number of systematic reviews that only include randomized controlled trials has remained limited. According to multivariable analyses, the citation count (p=0.002) and AAS (p=0.005) of high LOE studies were both significantly greater than those of low LOE studies.
Conclusions: During the past decade, the proportion of high LOE studies has increased substantially in the field of oral implantology. Clinical studies with higher LOE tend to have greater scientific and social impact.