Methodological quality of systematic reviews in dentistry including animal studies: a cross-sectional study

Background: The overall confidence in the results of systematic reviews including animal models can be heterogeneous. We assessed the methodological quality of systematic reviews including animal models in dentistry as well as the overall confidence in the results of those systematic reviews. Material & methods: PubMed, Web of Science and Scopus were searched for systematic reviews including animal studies in dentistry published later than January 2010 until 18th of July 2022. Overall confidence in the results was assessed using a modified version of the A MeaSurement Tool to Assess systematic Reviews (AMSTAR-2) checklist. Checklist items were rated as yes, partial yes, no and not applicable. Linear regression analysis was used to investigate associations between systematic review characteristics and the overall adherence to the AMSTAR-2 checklist. The overall confidence in the results was calculated based on the number of critical and non-critical weaknesses presented in the AMSTAR-2 items and rated as high, moderate, low and critical low. Results: Of initially 951 retrieved systematic reviews, 190 were included in the study. The overall confidence in the results was low in 43 (22.6%) and critically low in 133 (70.0%) systematic reviews. While some AMSTAR-2 items were regularly reported (e.g. conflict of interest, selection in duplicate), others were not (e.g. funding: n = 1; 0.5%). Multivariable linear regression analysis showed that the adherence scores of AMSTAR-2 was significantly associated with publication year, journal impact factor (IF), topic, and the use of tools to assess risk of bias (RoB) of the systematic reviews. Conclusion: Although the methodological quality of dental systematic reviews of animal models improved over the years, it is still suboptimal. The overall confidence in the results was mostly low or critically low. Systematic reviews, which were published later, published in a journal with a higher IF, focused on non-surgery topics, and used at least one tool to assess RoB correlated with greater adherence to the AMSTAR-2 guidelines.