Research interest on dental sealant in dentistry based on the 100 most cited articles: bibliometric analysis

Abstract The aim of this study was to identify and analyze the characteristics of the 100 most cited articles about dental sealants (DS) in dentistry. In September 2023, a search was performed in the Web of Science Core Collection (WoS-CC) database. The following information was extracted from each article: number and density of citations, year of publication, authorship, journal, impact factor, keywords, study design, theme, continent, country, and institution. The citations of the WoS-CC were compared with those of the Scopus and Google Scholar databases. The VOSviewer software was used to generate collaborative networks. The number of citations ranged from 33 to 205. The articles were published between 1961 and 2016. Buonocore MG (7%) was the most prominent author among the most cited. The Journal of the American Dental Association was the most frequent journal (25%) and Journal of Dental Research (7.6) had the highest impact factor. Most studies had interventional (41%) and laboratory (31%) designs, mainly addressing DS effectiveness in the prevention and control of dental caries (86%). There was a predominance of publications from North America (46%) and the USA was the country with the highest number of articles (44%). The most frequent institutions were the Centers for Disease Control and Prevention (USA) and the University of Rochester (USA) (6% each). “Retention” was the most frequent keyword. In conclusion, the 100 most cited articles were mostly interventional and laboratory studies, addressing the retention and efficacy of DS. Most of the articles were concentrated in North America and Europe, demonstrating a little collaboration from other continents.


Introduction
A comprehensive review of the global epidemiology of dental caries showed a high prevalence of this condition, with untreated caries being the most common. 1 According to Kassebaum et al. 2 cavitated carious lesions in permanent teeth remained the most prevalent health condition worldwide in 2010, affecting 2.4 billion people.In addition, untreated cavitated carious lesion in dentin of primary teeth was the 10th most prevalent health condition, affecting 621 million children worldwide. 2lso, the tooth surface most affected by the disease was the occlusal surface of first permanent molars, which, due to their location, are less visible, making cleaning more difficult and increasing the risk of developing carious lesions. 3he use of dental sealants (DS) is an alternative for preventing and controlling initial carious lesions. 4Sealants, which are mainly based on resin or glass ionomer, were developed to be applied to the occlusal surfaces of teeth at risk of developing carious lesions, preventing plaque stagnation in these areas. 5The presence of pits and fissures on the occlusal surfaces of posterior teeth makes this area highly susceptible to biofilm accumulation and challenging to clean. 6In addition, posterior teeth are the most difficult to access, especially during eruption. 7DS act as a physical barrier, forming a protective layer that prevents food retention and bacterial proliferation in areas vulnerable to dental caries. 8DS are also an efficient alternative to paralyze non-cavitated carious lesions before destroying dental structures. 9,10ystematic reviews agree on the recommendations of DS to prevent or control the development of carious lesions, but diverse clinical data are available on the application of DS and types of material used. 11,12hus, due to the relatively large number of published studies on DS and specific information, mapping the scientific evidence through a bibliometric analysis is essential to identify trends in research and the existence of knowledge gaps on the subject, as already reported in other areas of dentistry. 13,14,15Such a study can help researchers identify the development and scientific status of publications on DS to stimulate new investigations.Thus, the present study aimed to analyze the 100 most cited articles in the literature on DS through a bibliometric analysis.

Methodology
The primary search was conducted in September 2023.The database selected was the Clarivate Analytics Web of Science Core Collection (WoS-CC).The filter "Dentistry, oral surgery and medicine" was used.No restrictions were applied regarding language of studies and year of publication.The following search strategy was used: TS= ("Pit and Fissure Sealants" OR "Fissure Sealant" OR "Dental Sealant" OR "Teeth Sealants" OR "Dental Sealants" OR "Pit Fissure Sealants" OR "Sealant, Pit Fissure" OR "Fissure Sealant, Pit" OR "Sealants, Tooth" OR "Sealants, Dental" OR "Glass Ionomer Sealant" OR "Resin Sealant" OR "Sealing of Pits and Fissures" OR "Pit and Fissure Sealing" OR "Pit and Fissure Surfaces" OR "Pits and Fissures Sealed" OR "Adhesive Sealing of Pits and Fissures" OR "Sealing of Pits and Fissures and Adhesive Resin" OR "Pits and Fissures in Human Molars").
The list of articles obtained in WoS-CC was organized in descending order according to the number of citations.Articles addressing topics related to dental sealants were included.Editorial and conference articles were excluded.Two independent reviewers (MSSS and AOR) selected the 100 most cited articles.A third reviewer (MC) was consulted for the resolution of doubts.For the selection of the articles, the title and abstract were initially read, and the full texts were accessed when there were doubts about the eligibility criteria.Then, the full texts were read to collect the study data.In case of a tie in the number of citations, the position of the article in the list was based on the highest citation density of the WoS-CC (average number of citations received per year).][15] The following items were extracted from each study: title, authors, number of authors, number of citations, citation density, institution, country, and continent (based on the corresponding author's affiliation), year of publication, journal title, journal impact factor (2022), keywords, study design, and theme.The study designs were classified as follows: systematic reviews, literature reviews, laboratory studies, observational studies, intervention studies, and case reports.All articles were grouped according to the most prevalent themes: sealant retention and effectiveness against caries, the release of bisphenol-A, sealant application technique, and others.Topics that appeared only once were classified as "other".
The Visualization of Similarities Viewer (VOSviewer) software was used to generate a graphical representation of collaborative networks between keywords and between authors (both with at least three occurrences).The most important terms for the keyword map were represented by larger circles, and the strongly related terms were interconnected and represented by similar coloring.Words in the larger circles were those with higher occurrence.In contrast, words in smaller circles presented a lower occurrence.Words connected by bibliometric networks indicated the use of both keywords in the same study.For the author's map, names in the same cluster indicated collaboration between authors, and the author's relevance was indicated by color; the closer to red, the more frequent this author was, and the closer to yellow the lower the frequency of this author in the 100 most cited articles. 16,17tatistical analysis was performed by comparing the number of citations among the three databases.The statistical software SPSS for Windows (SPSS, version 21.0;IBM Corp, Armonk, N.Y., USA) was used.The Kolmogorov-Smirnov test was used to verify the data distribution normality.Spearman's correlation coefficient was used, as the data had non-normal distribution, and classified as very high positive correlation (between 0.900 to 1.000); high positive correlation (0.700 to 0.900); moderate positive correlation (0.500 to 0.700); low positive correlation (0.300 to 0.500); and negligible correlation (0.000 to 0.300). 18Significance level was set at 5%.

Results
A total of 1,111 documents were retrieved and listed in descending order of number of citations.Subsequently, the 100 most cited articles on DS were selected (Table 1).The 100 articles were cited 6,513 times in the WoS-CC, including 384 self-citations (5.9%).The number of citations of the 100 most cited articles in WoS-CC ranged from 33 to 205, with 13% of articles cited at least 100 times.In the other databases, a greater number of citations were observed, 7,309 (ranging from 29 to 269) in Scopus and 15,610 (ranging from 48 to 526) in Google Scholar.There was a high positive correlation between number of citations in WoS-CC and Google Scholar (r=0.859) and between Google Scholar and Scopus (r = 0.890), and a very high positive correlation between WoS-CC and Scopus (r = 0.910).
The most cited article in WoS-CC (205 citations) was entitled "Retention and effectiveness of dental sealants after 15 years", an intervention study by Simonsen RJ, published in 1991, which had an average of 6.61 citations per year, being also the most cited in Scopus (269 citations) and Google Scholar (526 citations).The earliest paper was published in 1961, "Thickness of enamel at the base of pits and fissures in human molars and bicuspids", by Gillings B and Buonocore MG.Among the 100 most cited articles on DS, the highest number of publications was concentrated between 2001 to 2010 (36%), followed by 1991 to 2000 (31%) (Figure 1).
The Journal of the American Dental Association was the most prominent journal in several publications and citations in the top 100 (25%; 2,155 citations), followed by Community Dentistry and Oral Epidemiology (12%; 691 citations) (Table 2).According to the Journal of Citation Reports (2022), the journal with the highest impact factor in this study was the Journal of Dental Research (7.6), while the most frequent journal has an impact factor of 3.9.

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the number of publications by country, the United States led with 44 articles (44%) that together add up to 3,340 citations in the WoS-CC, followed by Germany (9%; 669 citations).A total of 66 institutions were associated with the studies.Table 3 presents the ten institutions with the highest number of publications and citations.We highlight the Center for Disease Control and Prevention of the University of Rochester with six publications each (640 and 581 citations, respectively).Regarding keywords of the 100 most cited DS articles, 341 different terms appeared, with emphasis on "Retention" (25 occurrences), followed by "Pit" and "Pit and Fissure Sealants" (22 occurrences each).Figure 3, generated in VOSviewer, presents the most frequent keywords and their relationship.The words related by color represent the period of greatest occurrence for the terms.The dark blue color represents the period closer to the year 2000 and the yellow color, the period closer to the year 2010.
Three-hundred fifty-four authors were identified among the 100 most cited DS articles.Their frequency of appearance and the co-authorships between them is represented in Figure 4.The names represented by red/orange coloration are associated with authors with the highest occurrence, Buonocore MG, Meyer-Lueckel H, and Paris S. In contrast, the names associated with yellow correspond to authors with a lower occurrence.In addition, the interrelation between the groups of authors who collaborated when associated with the same cluster is shown.Table 4 shows the top 10 authors with the highest number of publications among the 100 most cited articles on DS.Buonocore MG, with seven articles, was the author with the highest number of publications, accounting for 618 citations, followed by Meyer-Lueckel H and Paris S, with six articles and 476 citations each.

Discussion
This is the first bibliometric study to identify and discuss the 100 most cited articles related to DS through a quantitative approach.It can be stated that the high citation rates of these studies have been significantly associated with scientific development in the field of DS in dentistry, mostly addressing the   clinical implication of the use of DS against dental caries.The total number of citations was higher in Google Scholar and Scopus when compared to WoS-CC.This can be justified by the fact that each database has exclusive and distinct methods for recording and counting citations. 13However, strong positive correlations were found between the number of citations in WoS-CC and the other two databases.
Articles that exceed 100 citations in a given area are considered classics. 19The most cited paper of this study stands out with 200 citations. 20Although published 31 years ago, this research had a 15-year follow-up with a sample of 200 patients. 20In another article, 21 an extended follow-up between 15 and 20 years was also conducted, but with a sample of 70 patients and published ten years after the most cited    article. 21The extended follow-up period may justify the large number of citations in the most cited article.Among the most cited articles, 35% had follow-up periods.However, most of these studies had followups of one to three years.For many years, it has been discussed whether the use of DS is necessary and effective.5][6] Currently, WHO considers sealing the occlusal surface as a primary preventive measure, and one of the most effective and least invasive means available to ensure the protection of this surface against tooth decay. 22he oldest article was published by Gillings B and Buonocore M 23 and mainly addressed the anatomy of the occlusal surface with its pits and fissures with the purpose of indicating an ideal material for the adequate filling of these structures during dental sealing.According to Liu BY et al., 24 the often deep and sinuous anatomy of pits and fissures is the most significant risk factor for dental caries, since controlling the accumulation and the removal of dental biofilm in these areas is often difficult or even unsatisfactory.To Beslot-Neveu A et al., 25 the DS must have a high degree of wettability and a degree of viscosity that allows its penetration into microcracks of the tooth enamel, ensuring a complete seal and strong adhesion of the material.In addition, the surface tension of the tooth structure must be reduced to increase the DS degree of wettability.For this purpose, Buonocore MG 26 proposed the pre-conditioning of the tooth surface before the DS placement to improve its adhesion.
The two materials most commonly used are resin-based sealants and glass ionomer cement. 4,5he American Dental Association recommends the use of resin sealants as a more effective alternative for sealing pits and fissures because of their higher retentive properties compared to glass ionomer sealants. 27However, the latter can be considered an excellent alternative when adequate isolation of the tooth for sealant placement is unfeasible. 27he FDI World Dental Federation defined minimal intervention approach as a preventive philosophy, focusing on early detection of carious lesions and efforts to remineralize non-cavitated lesions, providing immediate preventive care to minimize surgical interventions and loss of tooth structure. 28The application of pit and fissure sealants in patients with high caries risk is one of the strategies recommended by the Minimal Intervention Dentistry approach.With the advent of this philosophy, there was an increase in the use of DS, as this material helps in the prevention and remineralization of initial dental caries lesions, preserving as much of the dental structure as possible. 24Thus, the consolidation of the Minimal Intervention Dentistry precepts may also explain the increase in the number of publications with DS theme from the year 2000 onwards.
The most prominent author in this review was Buonocore MG, with the highest number of demonstrates the great contributions of this author to this theme. 29Buonocore was responsible for developing innovative research in the preparation of the enamel surface with a weak acid to increase the adhesion of an organic plastic chemical sealant and polymerization of a sealant with ultraviolet light.He was also pioneer in relation to minimizing the removal of enamel and dentin in the preparations. 29n addition, it has been demonstrated that dental sealants are economical and have excellent retention rates. 29This information is in line with the data of the top 100 article, where Buonocore mainly conducted clinical studies on the effectiveness and retention of this material.Other prominent authors in this review were Mayer-Lueckel and Paris S, mostly addressing laboratory studies on DS efficacy and retention.With many citations, Gooch BF and Griffin SO developed five studies together, mainly literature reviews on the efficacy and retention of DS.The Journal of the American Dental Association and Community Dentistry and Oral Epidemiology journals were those with the highest number of articles in the 100 most cited list.The Journal of the American Dental Association was founded in 1913 to promote research through clinical information. 30ommunity Dentistry and Oral Epidemiology is one of the leading international journals in the field of epidemiological dentistry. 31Both journals comprise studies of high relevance in DS and are therefore understood and used as references to assist clinicians make clinical decisions and researchers interpret data and conduct research. 30,31he study designs with the greatest predominance among the most cited articles were intervention studies and laboratory studies, which mainly addressed the theme of DS retention and effectiveness in paralyzing carious lesions.These studies mainly address the performance of sealed teeth in dental caries arrest and prevention compared with unsealed teeth. 32,33nlike other bibliometric analyses published in the literature, 15,34 this bibliometric review focused on intervention studies.As dental caries is considered one of the most prevalent diseases in dentistry, it was probably easier to obtain samples for this type of study. 1 The term retention was the most frequent theme and the most used keyword by the 100 most cited studies on dental sealants.
The second most addressed theme in this study was the release of bisphenol A (BPA).DS consists mainly of BPA-containing monomers. 35BPA was recognized in the 1930s as an endocrine-disrupting chemical that alters hormonal function. 35However, Fung EY et al. 36 showed that BPA released orally from a DS might not be absorbed or be present in undetectable amounts in the systemic circulation.This fact explains the several types of research involving this dental material in other areas and the fact that the most addressed theme was DS retention and effectiveness against dental caries.Still, the BPA exposure theme was associated with the top 100 DS studies published in dental research journals and dental materials.
North America was the most prevalent continent in this bibliometric analysis, as the USA was the country with the highest number of articles among the 100 most cited.This is explained by the high level of government investment in American universities and research centers. 13Among these centers, the Center for Disease Control and Prevention stands out as one of the institutions with the most articles among the most cited.Such finding is associated with prominent authors from this center (Griffin SO and Gooch BF).The University of Rochester, also located in the USA, was also important in this study and the institution to which Buonocore MG (most frequent author) is affiliated.
One of the strengths of this study is the detailed analysis of the main characteristics of the most frequently cited articles on dental sealants without restricting by year of publication or language.With this, the countries, continents, and institutions that most intensely investigate this topic were identified, providing an outlook on future global scientific progress in this field.The exclusive use of the WoS-CC database can be cited as a limitation of this study, as there are other bibliometric databases such as Scopus and Google Scholar.Based on other important bibliometric analyses in the field of dentistry, 13,14 it was decided to use only the WoS-CC since this database is widely recommended and used for this type of study. 37

Conclusion
In conclusion, the 100 most cited articles on DS were published mainly by North American and European authors, indicating little collaboration with other continents.Buonocore MG, Meyer-Lueckel H, and Paris S were the authors with the highest number of articles.In addition, there was a predominance of interventional and laboratory studies, addressing the retention of DS and its effectiveness in arresting initial dental caries lesions.

Figure 1 .
Figure 1.Distribution of the number of publications among the years.

Figure 2 .
Figure 2. Map of countries and continents present among the top 100 most cited articles.

Figure 3 .
Figure 3. Density map of most used keywords among the 100 most cited articles.

Figure 4 .
Figure 4. Density map of authors and collaborative co-authorships for the 100 most cited articles.

Table 2 .
Top 10journals with the highest number of articles in the list of the 100 most cited.

Table 3 .
Top 10institutions with the highest number of articles among the 100 most cited.

Table 4 .
Top 10authors with the highest number of articles among the 100 most cited.