What is of interest in Endodontology? A bibliometric review of research published in the International Endodontic Journal and the Journal of Endodontics from 1980 to 2019

Aim To report the most common terminology used in titles of scientific papers published in the International Endodontic Journal (IEJ) and Journal of Endodontics (JOE) between 1980 and 2019 and to identify the most-cited papers in these journals. Methodology The Web of Science database was searched to retrieve all the manuscripts published in the IEJ and JOE between 1980 and 2019. The articles were analysed using the VOS viewer software and the terms within the titles extracted. The top-10 terms were categorized according to the number of occurrences and the decade of publication. Maps were created using the text data for each decade of publication. Classic papers were identified when the number of citations was >400. During the same period of time, highly cited studies were identified including the authors, institutions and countries associated with these papers. Results Terms such as canal, molar and periapical lesion were the most commonly used in titles between 1980 and 1999. The terms instruments, expression, case report and cell were the most often terms used between 2000 and 2019. During the last 10 years, an increase in the number of reviews and papers on cone beam computed tomography occurred. The organizations with the largest number of citations in each decade were University of Sao Paulo, University College London, Loma Linda University and United States Army. The country with the largest number of citations and greatest number of top 10 and top 100 manuscripts was the United States. A paper had to be associated with more than 167 citations to be included in the top-100 most-cited list; at least 14 papers met the criteria to be categorized as a citation classic (>400 citations). Conclusion While many diverse areas of endodontics have been explored in the last 40 years within the IEJ and JOE, only a relatively few topics are highly cited and can be considered as classics.