Top cited articles in Oral Radiology: A bibliometric network analysis

Background The present study aimed to identify and analyze the 100 top-cited articles published in oral radiology. Material and Methods Web of Science was used to conduct a comprehensive search from inception until 22 November 2023 in dental radiology. Basic information of the 100 top-cited articles was recorded. Biblioshiny and VOSviewer tools were employed for conducting thematic map and author keyword, title, and abstract terms analysis to elucidate the research trends and hotspots. Elsevier Scopus database was also used for citation comparisons. Results The citation count for the 101 most-cited articles ranged from 105-587. Most of them were original research studies with observational design conducted in diagnosis, dose, geometric measurements, and image analysis topics. Cone beam computed tomography was the most studied radiologic technique as author keyword co-occurrence analysis revealed and appeared as a basic theme for the transdisciplinary research field’s development. While making infant steps, artificial intelligence was adequately represented in top cited list, as it received increasing citation numbers in very few years, concentrating the highest citation densities. Conclusions Bibliometric analysis of the most affecting publications in oral radiology depicts the science’s evolution and enhances the understanding of scientific research progress. Key words:Bibliometrics, citation analysis, oral radiology, top-cited.


Introduction
Bibliometric analysis combines science with statistical mathematics in order to describe trends of knowledge within a research field and provide an in depth perceptive of scientific literature evolution (1).As a statistical tool, it facilitates the understanding and evaluation of the scientific performance and impact of a paper, as well as the recognition of prominent authors, countries and institutions within a specific scientific community (1,2).Many general or specialized fields of dentistry have been Two study investigators reviewed independently and assessed the articles for appropriateness for inclusion.In cases of disagreement, a third reviewer resolved any difference of opinion by consensus review.As long as the "Oral surgery Oral Medicine Oral Pathology Oral Radiology" is not fully dedicated to radiology, only relevant articles were considered in citation analysis.The search provided a list of 100 publications appearing in the radiology journals ranked by citation count.Elsevier's Scopus was also used to crossmatch the citation counts of the top cited papers.Basic information of the top-cited articles was recorded including number of citations, publication year, publishing journal, authorship, institution and country of origin, type of article, radiologic technique, study design and field of study.The type of article was classified as original, review, position paper, editorial, systematic review, and meta-analysis.According to study design, original scientific papers were further categorized into basic science and prospective or retrospective observational studies.Articles were also categorized according to the radiologic technique and topic.Topic and research trends analysis was based on the high-frequency keywords, abstract and title terms of each included paper.Software VOSviewer (version 1.6.11)and R package "Bibliometrix" was used for co-occurrence network (15,16) and science mapping analysis (17).shed in dental radiology journals, by order of decreasing number of citations.The most cited article received 587 (WoS) and 648 (Scopus) citations, and the least-cited paper counted 105 and 86 citations (WoS and Scopus), respectively.There were 21 articles in WoS and 24 articles in Scopus that received more than 200 citations.The most represented journal was "Oral surgery Oral Medicine Oral Pathology Oral Radiology", containing 52 highly cited articles, followed nearly by "Dentomaxillofacial Radiology" (48 articles).Figure 1a shows the distribution of the 100 articles by Through the previous decades, the publication race was stable.

-Citations, publication sources and years
-Country of origin, institution, and authorship pattern According to the institutional address of the correspon-ding author, researchers from 21 countries contributed the 101 top-cited papers, with USA publishing the largest number of them (n=40).The University of North Carolina in USA was also the most productive institution.A total of 367 different researchers authored highly cited papers, with 17 publishing at least 3 articles.Six "frequent authors" held authorship for more than 4 papers.Relative data regarding countries, institutions and authors with the highest number of manuscripts are presented in Table 2.
Most of the most-cited papers considered original research (n=78), followed distally by narrative reviews (n=12), position statements(n=5), systematic reviews and meta-analyses(n=3) and others (n=3) (Fig. 1b).Original research papers were further classified as having observational study design (n=44) with retrospective (n=21), prospective (n=13) approach, case reports (n=6), cross-sectional (n=5) and basic science content (n=33 Major topics of interest covered in the top-cited list are presented in Table 3.Most top-cited papers investigated several aspects of CBCT. -Field of study, author keyword, title and abstract term analysis Author keyword co-occurrence analysis indicated cone beam computed tomography (n=10) as the most prevalent term, followed by x-ray computed (n=7) (Fig. 2a).
Figure 4 displays the results of the thematic map analysis of author keywords."CBCT", "diagnosis", and "orthodontics" were identified as niche themes in the top left quadrant (Q2)."Artificial intelligence", "deep learning" and "panoramic radiography" centrally located with high centrality and medium density were sandwiched as niche (Q2) and motor themes (Q1), simultaneously.In the same way, "tomography", "x-ray computed"  and "radiography" was found to be motor (Q1) and basic theme (Q4), concurrently.The lower right quadrant (Q4) included basic central themes with clusters of "cone beam", "computed tomography" and "cone beam computed tomography".Cluster of "Housefield units" in "dentistry" was identified as a declining theme in the lower left quadrant (Q3).e824

Discussion
Oral and maxillofacial radiology has been evolved into an innovative and rapidly expanding field of imaging concentrating several important achievements, following technological advancements.As far as the authors are aware, this is the first citation analysis in oral and maxillofacial radiology.The number of citations for the 101 top-cited articles presented herein ranged from 105 to 587 (WoS) or 86 to 648 (Scopus) during the period 1953-2020.
According to the results of the present report, top 4 contributing countries included USA, Japan, Germany, and Belgium.It is notable here that the first two countries, contributed 40 and 13 manuscripts, respectively, consisting 53% of the sample.As evidenced in the present citation analysis and in accordance with previous investigations, USA led the top-cited list (5)(6)(7)9).This could be attributed to the large community of active researchers and sufficient finances for conducting health science research.In addition, a tendency of U.S. authors to cite local papers along with the recorded preference of U.S. reviewers for U.S. manuscripts has been documented and could explain USA dominance (18,19).Consistently, top institution also originated from USA, producing 11 top-cited articles during the period 1997-2015.
As it was expected, 78 highly cited papers included original research, with 45 of them having observational study design and 33 being published within the basic science field.The dominance of original research in oral radiology results from the specialty's nature and indicates the inclination of many researchers to integrate the existing information and knowledge of basic studies into clinical practise.No randomized clinical trial (RCT) was included in the top-cited list.Considering the time depended requirements in meeting the demands of highly evidenced RCTs along with concerns prohibiting comparison of radiographic modalities in humans, documentation of clinical approaches to oral radiology by observational studies offers treatment modalities directly in less time.This study demonstrated a slight preeminence of clinical rather than basic science articles, a trend that has already been evidenced in various disciplines of clinical dentistry (6,7).Contradictory results had been recorded in medical imaging literature, with preclinical studies being highly represented in the top-cited list (8).The previous citation analysis in CBCT exhibited the predominance of basic-technical studies, which was attributed to the fact that imaging research is highly dependent on advances in other fields such as computer science and physics (13).Indeed, basic preclinical radiologic research represents an important chapter in radiology for conducting dosimetry studies and evaluating the effectiveness of new modified techniques and modalities.Similar to our study, Brinjikji and colleagues demonstrated that, six of the top-cited articles presented major technical advancements by introducing new techniques or technologies (8).Interesting observations arisen from the inclusion of 5 position papers in the top-cited list, 1 editorial paper and 1 opinion statement.This reveals the urgent need of establishing clinical therapeutic protocols on dental radiology by utilizing knowledge from new techniques presented worldwide and reflects a citation analysis characteristic, named as "snowball effect", where researchers tended to cite previous highly cited articles (20).
Moreover, the inclusion of 3 systematic reviews and one meta-analysis among the top-cited publications designated research allocation towards evidence based dentistry.
CBCT was the most prevalent radiologic technique among the top-cited list, a fact that was also evidenced in the abstract term co-occurrence analysis and indicative of this innovative radiographic modality's constant research evolution for oral and maxillofacial imaging tasks.It should be noted here that the majority of studies dealing with CBCT were published from 1999 until 2015, which is consistent with the emergence of the CBCT use in oral and maxillofacial region in the beginning of the 21st century.Taken all the research topics together, linear and dose measurements, osteoporosis, presentations of new techniques and modalities as well as TMJ and impacted teeth imaging occupied the leading positions in the top-cited list, a fact indicative of the importance of the above topics in dental community.Artificial intelligence, an emerging applied computer software science was an adequately represented research field in the top-cited papers concentrating the highest citation density values, despite its recent development, which points out the critical driving power and prevailing capabilities of AI in data analysis.In spite of its infant steps, AI has emerged in dentistry and has heralded an era of disruptive technology with the potential to play assistive and supplementary role to medical community (21).
Regarding the thematic map analysis using author keywords, "CBCT" uses in "orthodontic" "diagnosis" were represented as niche themes with high density and low centrality, signifying that they are nonetheless very specialized of rapid development topics.Notably from the figure, themes such as tomography, x-ray computed and radiography sandwiched between motor and basic themes are well developed and capable of structuring the research field.The left bottom quadrant contains "cone beam computed tomography", "Housefield units" in "dentistry" that have been adequately developed and yet have experienced a downward trend, as indicated by low centrality and density "AI, deep learning and panoramic radiography" appear to transverse from niche to motor themes and tend to become more central essential for the understanding but still of marginal contribution to the development of oral radiology field.Finally, the-e825 mes such as "cone beam computed tomography" seen as basics are very important for transdisciplinary research field's development.
Regarding the use of specific databases, an appropriate source should be selected to have accurate and reliable data analysis.Citation indexes like WoS databases', mainly focus on journals and less on other means of scientific knowledge diffusion (books and proceedings).
As articles published in non WoS-cited journals are excluded, it is still unclear whether WoS represents the best available tool that could be used for research evaluation.
Both databases WoS and Elsevier's Scopus were included for the citation calculations to overcome methodological limitations, as citation counts have been shown to differ significantly between these two databases.This study identified and analyzed the top-cited articles in dental radiology journals to describe the research trends and progress of this rapidly evolving field of dentistry.Identification of top cited list may be of substantial interest to dental clinicians providing an auxiliary guide for educational and training purposes.Within its limited scope, the results of the present citation analysis provide a historical perspective on evolution of oral radiology discipline and highlight the most impactful authors, institutions, and countries.Original studies with observational study design conducted in diagnosis were the mainstay of the top-cited papers in oral and maxillofacial radiology.The United States ranked first with the highest number of top-cited publications.Understanding the characteristics of highly cited articles in imaging literature of dental radiology journals emphasizes important advancements achieved in this field.

Fig. 1 :
Fig. 1: a,b) Number of the 100 top-cited articles per year and their study design. e823

Fig. 2 :Fig. 3 :
Fig. 2: a. Co-occurrence network map of author keywords.Each node represents a keyword in the network and its size is directly proportional to its number of occurrences in the including papers.Colors indicate clusters to which keywords are assigned together.b.Term network map extracted from the title and abstract fields of the top-cited publications.

Fig. 4 :
Fig. 4: Thematic map analysis of top cited author keywords.

Table 1
summarizes the 100 most cited articles publi-

Table 2 :
). Countries, institutions of origin and authors with four or more top cited articles in dental radiology journals.

Table 3 :
Radiographic technique and research topics of 100 top cited papers.