Periodontal disease causes inflammation and destruction of the tooth-supporting periodontal tissues due to bacteria and toxic substances present in the dental tartar and tartar. It starts with gingivitis initially to change color and texture and tends to hemorrhage. If neglected, it progresses to periodontitis, a chronic inflammatory state, forming pathological periodontal cysts, and the inflammation spreads to deep tissues, destroying periodontal ligament, alveolar bone, and cement, eventually resulting in tooth loss [1].

Practicing effective prevention methods is essential to prevent periodontal disease, and dental tartar management is the important first step to prevent periodontal disease. Dental tartar management includes brushing and scaling. While the gingiva is maintained in a healthy state for 24-48 hours when those who are well trained in brushing remove supragingival tartar by brushing, most adults can remove an average of 40% and thus require scaling that mechanically removes local factors such as tartar, tartar, and food residues to manage periodontal disease [2].

After the health insurance financial safety measures in July 2001, the National Health Insurance covered scaling only in the case of gum treatment for therapeutic purposes or tartar removal accompanied by surgery. However, since July 2013, even treatment completed only by removing tartar without follow-up measures has been covered by the National Health Insurance once a year [3].

In recent years, analysis of public opinion trends and market trends in various academic fields have often used topic modeling and text network analysis based on text mining. Topic modeling is a probabilistic algorithm that identifies topics in many documents and summarizes and classifies documents according to topics [4].

It estimates all topics from literature based on the words appearing in each literature and automatically extracts topics corresponding to individual literature and words constituting each topic based on probability distribution. Later Dirichlet Allocation (LDA) is a leading topic modeling technique and a generative probabilistic model that probabilistically determines which topics exist in each literature [5].

The purpose of this study is to classify study data on scaling, a treatment to prevent periodontal disease, through big data analysis, define the topic name of the detailed topic analyzed with the topic modeling technique, and identify the study trend based on the topic names. The results of this study can be the basic data for future studies.

1. Subjects

In this study, we conducted an online search with “dental scaling” as the keyword in the Research Information Sharing Service (www.riss.kr) search engine [6]. Duplicate papers were removed using the Excel 2016 program (Microsoft, Redmond, WA, USA), and studies without Korean or English abstracts were excluded. The data search period was set from the time the first publication of the related paper to December 2021, and a total of 215 cases were analyzed [6].

2. Methods

This study analyzed academic papers collected from the Research Information Sharing Service (www.riss.kr) [6] with NetMiner (ver. 4.4.1; Cyram Inc., Seongnam, Korea). NetMiner is a social network analysis software released by Cyram and supports integrated analysis, including statistical analysis and data mining functions. Moreover, it can extract keywords by inputting unstructured text data such as speeches, academic paper abstracts, social media posts, and newspaper articles and analyze semantic networks between words [7].

Therefore, the data used for topic identification and keyword analysis in topic modeling using NetMiner were refined, and only those with a TF-IDF (Term Frequency-Inverse Document Frequency) coefficient of 0.5 or higher were extracted. Moreover, the LDA topic modeling analysis was performed to identify the topic.

1. Published papers

There were 215 academic papers on dental scaling with abstracts until December 2021. Table 1 shows the status of published academic papers each year. While the number of published papers each year showed a single digit from 1986 to 2012, it gradually increased from 2013 and reached more than 30 papers in 2016. Analyzing the trend of the number of papers published each year showed 18 papers from 1986 to 2000, 33 papers from 2001 to 2010, and 157 papers from 2011 to 2020. Figure 1 shows the change in the number of published papers on dental scaling each year.

Table 1 . Number of published papers in each year

Year	Number of papers	Year	Number of papers	Year	Number of papers	Year	Number of papers	Year	Number of papers	Year	Number of papers
1986	1	1996	1	2002	8	2007	1	2012	9	2017	22
1992	1	1997	3	2003	2	2008	1	2013	11	2018	17
1993	2	1998	3	2004	3	2009	9	2014	10	2019	13
1994	3	2000	2	2005	1	2010	4	2015	23	2020	15
1995	2	2001	3	2006	1	2011	6	2016	31	2021	7

Figure 1. Trend in the number of papers published in each year.

2. Topic modeling

Only keywords with a weight of 0.5 or higher were extracted through the TF-IDF analysis, which determines the importance of words in the paper on dental scaling.

After that, the LDA topic modeling analysis identified five topics. The identified topics are “Health insurance coverage of scaling,” “Study on oral health behavior,” “Study on factors related to tartar removal experience,” “Study on musculoskeletal diseases of dental hygienists,” and “Experience in oral health education.” Table 2 shows each keyword supporting the topic identified by the topic modeling analysis.

Table 2 . Results of topic modeling analysis

Core keywords	Topic name
	Topic-1: Health insurance coverage of scaling	Topic-2: Study on oral health behavior	Topic-3: Study on factors related to tartar removal experience	Topic-4: Study on musculoskeletal diseases of dental hygienists	Topic-5: Experience in oral health education
1st keyword	scaling	health	calculus	dental hygienist	experience
2nd keyword	insurance	behavior	removal	condition	analysis
3rd keyword	dental	management	factor	adult	education
4th keyword	insurance coverage	region	dental	disease	convergence
5th keyword	comparison	actual condition	effect	worker	satisfaction
6th keyword	medical	college student	patient	instrument	medical
7th keyword	student	action	difference	clinical	regular
8th keyword	use	ultrasound	use	behavior	youth
9th keyword	change	patient	society	before and after	consumer
10th keyword	prevention	elderly	tooth	musculoskeletal system	laboratory
No. of articles (%)	55 (25.6)	54 (25.1)	48 (22.3)	36 (16.7)	22 (10.2)

It lists ten keywords assigned to each topic in the order of their probability distribution.

Figure 2 visualizes them to examine them at a glance.

Figure 2. Visualizes them to examine them at a glance.

The keywords constituting the first topic were “scaling,” “insurance,” “dental,” “insurance coverage,” “comparison,” “medical,” “student,” “use,” “change,” and “prevention.” Many studies related to the first topic were on the perception of various age groups on the health insurance coverage of scaling, their interest in oral health care, and changes in dental hygienists and dental clinics. Based on these contents, the first topic name was set to “Health insurance coverage of scaling.” The topic was covered by 55 out of 215 papers, accounting for 25.6%.

The keywords constituting the second topic were “health,” “behavior,” “management,” “region,” “actual condition,” “college student,” “action,” “ultrasound,” “patient,” and “elderly.” Many studies related to the second topic investigated oral health status and behaviors that determine the quality of life. Based on these contents, the second topic name was set to “Study on oral health behavior.” The topic was covered by 54 out of 215 papers, accounting for 25.1%.

The keywords constituting the third topic were “calculus,” “removal,” “factor,” “dental,” “effect,” “patient,” “difference,” “use’, “society,” and “tooth.” Many studies related to the third topic were on the effects of awareness and experience of tartar removal and scaling experience on treatment satisfaction and dental fear and stress factors. Based on these contents, the third topic name was set to “Study on factors related to tartar removal experience.” The topic was covered by 48 out of 215 papers, accounting for 22.3%.

The keywords constituting the fourth topic were “dental hygienist,” “condition,” “adult,” “disease,” “worker,” “instrument,” “clinical,” “behavior,” “before and after,” and “musculoskeletal system.” Many studies related to the fourth topic investigated the tartar removing posture and musculoskeletal disease awareness of dental hygienists working at dental clinics and musculoskeletal pain and discomfort of dental hygiene students in the scaling practice process. Based on these contents, the fourth topic name was set to “Study on musculoskeletal diseases of dental hygienists.” The topic was covered by 36 out of 215 papers, accounting for 16.7%.

The keywords constituting the fifth topic were “experience,” “analysis,” “education,” “convergence,” “satisfaction,” “medical,” “regular,” “youth,” “consumer,” and “laboratory.” Many studies related to the fifth topic were on analysis of differences between dental hygienists’ and patients’ perception of tartar removal and oral health education, comparison of oral health knowledge between groups experienced and inexperienced of oral health education, the experience of oral health education and regular checkups for various age groups, comparison of experience in dental health education and awareness of necessity, and analysis of oral health education during scaling by dental hygienists. Based on these contents, the fifth topic name was set to “Experience in oral health education.” The topic was covered by 22 out of 215 papers, accounting for 10.2%.

According to the status of frequent morbidity treatment for each disease subcategory for all insurance recipients in the “2020 Medical Benefit Statistical Yearbook” by the Health Insurance Review and Assessment Service, gingivitis (gum inflation) and periodontal disease were the most common with 433,560 people. Moreover, among recipients over 65 years of age, gingivitis (gingivitis) and periodontal disease took second place with 167,129 people [8].

Periodontal disease, caused by supragingival and subgingival tartar and dental plaque, is the main cause of tooth loss [3]. Scaling is a treatment that eliminates these incidence factors, and since July 2013, the National Health Insurance has been applied to preventive scaling that does not require follow-up periodontal treatment once a year for those 19 years or older [9].

Therefore, in this study, we analyzed the trend of studies on dental scaling with a topic modeling analysis technique using LDA of academic papers collected from the Research Infor-mation Sharing Service (www.riss.kr) [6].

The analysis identified five topics: “Health insurance coverage of scaling,” “Study on oral health behavior,” “Study on factors related to tartar removal experience,” “Study on musculoskeletal diseases of dental hygienists,” and “Experience in oral health education.” The keywords constituting the first topic, “Health insurance coverage of scaling,” were “scaling,” “insurance,” “dental,” “insurance coverage,” “comparison,” “medical,” “student,” “use,” “change,” and “prevention.”

The results of examining the status of treatment after the covering of tartar removal by the National Health Insurance showed that 0.7 out of 10 people received tartar removal in 2013, but in 2019, 1.7 out of 10 people received it, indicating that the number of people receiving tartar removal at dental clinics has significantly increased [10].

The study by Jung et al. [11] reported that the cost aspect of scaling became a large part of the level of interest in oral health care after the National Health Insurance had covered it. It suggested the necessity of a policy to strengthen further benefits and coverage of medical services [11]. Kim et al. [12] reported that encouraging patients voluntarily to visit the dentist for scaling with insurance coverage had a positive effect on disease prevention, and the treatment frequency of periodontal disease, nerve, and tooth decay increased.

Lee et al. [13] reported that it was necessary to raise public awareness and interest in preventive measures in dental care and suggested proper knowledge transfer, education, and PR of scaling to the public for the gradual expansion of preventive dental care items.

As such, domestic studies on health insurance coverage of scaling and policies included studies on the perception after the insurance coverage and receiving the scaling treatment, evaluation of the effectiveness of the policy of covering scaling by the National Health Insurance, and the survey on consumers’ awareness and satisfaction on the National Health Insurance. Necessary further studies include checking changes and trends in medical usage patterns after the insurance coverage of scaling and evaluating the effectiveness of the policy covering scaling by the National Health Insurance.

The keywords constituting the second topic, “Study on oral health behavior,” were “health,” “behavior,” “management,” “region,” “actual condition,” “college student,” “action,” “ultrasound,” “patient,” and “elderly.”

Oral health behavior is a generic term for a series of actions and attitudes to maintain or improve oral health and has the characteristic of a complex process of secondary cultural, social, and psychological processes rather than a simple biological process [14].

Many studies on it classified study subjects into various age groups. Park [15] conducted a study for the students in the dental hygiene department responsible for oral health work to induce the proper oral health care and have correct oral health beliefs by understanding the effect of oral health belief on oral care behavior. Shim et al. [16] intended to establish measures for international students to improve their quality of life by identifying the effect of oral health management behaviors. Moreover, Heo et al. [17] conducted a study on oral health status and oral health behavior that subjectively perceives the quality of life related to the oral health of pregnant women. Jun [18] conducted a study on oral health behavior of medical consumers who visited dental clinics, and Yoon and Jang [19] conducted a study on the relationship between oral health knowledge and oral health behavior of 198 and 203 college student in the health and non-health departments, respectively.

Most of these studies investigated the relationship between age, education level, the total number of teeth brushing per day, self-oral health awareness, the dental health insurance system, satisfaction, and oral health knowledge with oral health behavior.

It is expected that studies on oral health behavior will continue in the future. However, it is necessary to present standardized guidelines for the promotion of oral health through oral health behavior.

The keywords constituting the third topic, “Study on factors related to tartar removal experience,” were “calculus,” “removal,” “factor,” “dental,” “effect,” “patient,” “difference,” “use’, “society,” and “tooth.” Many studies related to this topic were on factors to the experience of tartar removal of various study subjects. The factors included age, official position, oral care aids in use, regular oral examinations, and awareness of insurance coverage of tartar removal.

Lee et al. [20] judged that considering these factors, increasing the tartar removal experience rate by improving the working environment and increasing the awareness of tartar removal would positively affect the periodontal management of workers in the future.

Park and Lim [21] reported that factors related to the experience of tartar removal among multicultural adolescents were the experience of a dental sealant and fruit intake and suggested the development of a prevention program for multicultural adolescents to enhance their preventive behavior for oral health.

Nam et al. [22] reported that music intervention during tartar removal reduced the patient's fear and anxiety and the pulse rate among vital signs.

Efforts to reduce inequality in tartar removal experience according to various age groups, regions, and occupational groups are necessary. Moreover, it is considered that policy measures to mitigate regional differences in individual and regional factors should be taken to increase the tartar removal experience rate effectively.

The keywords constituting the fourth topic, “Study on musculoskeletal diseases of dental hygienists,” were “dental hygienist,” “condition,” “adult,” “disease,” “worker,” “instrument,” “clinical,” “behavior,” “before and after,” and “musculoskeletal system.”

Work-related musculoskeletal disorders refer to diseases occurring in the human body's musculoskeletal system due to occupation [23]. Repetitive work, improper working posture, long work, and insufficient rest can cause microdamage to muscles, blood vessels and nerves, mainly in joints such as the neck, shoulder, elbow, wrist, finger, waist, and leg, leading to patients complaining of pain and sensory abnormalities [24].

Jeong and Choi [25] reported that since dental hygienists' poor indirect examination ability is related to shoulder pain, they should be proficient in indirect visualization to induce a balanced neutral posture to prevent musculoskeletal symptoms, especially shoulder pain. They also reported that even if the risk factors for musculoskeletal disorders cannot be completely avoided in the working environment, dental hygienists should identify and control the ergonomic risk factors themselves.

Lee and Chun [26] analyzed the self-reported symptoms of musculoskeletal neck system, working posture, and movement using video recording techniques to evaluate the risk of musculoskeletal disease in the neck, which dental hygienists commonly experience. The neck flexion angle and fixed posture maintenance time were in serious conditions, and the angle and fixed posture were evaluated as important factors influencing musculoskeletal diseases in the neck.

Since July 2013, scaling for adults aged 20 years or older has been included in the health insurance coverage once a year, so the number of patients undergoing scaling has increased rapidly. Therefore, it can be considered that dental hygienists who often move with their head and neck bent and shoulders and hands twisted or perform treatment in an inappropriate posture are highly exposed to musculoskeletal disorders [27,28].

Dental hygienists should actively correct their pastures and tilt behaviors, especially to efficiently relax their fixed posture for a long time to alleviate the risk of developing musculoskeletal diseases in the neck of dental hygienists, and it is imperative to prepare appropriate guidelines to efficiently relax the state of maintaining the fixed posture is for a long time while the neck is bent. It is judged that separate measures such as training dental hygienists on incorrect work methods and postures and preparing programs to prevent musculoskeletal disorders are required.

The keywords constituting the fifth topic, “Experience in oral health education,” were “experience,” “analysis,” “education,” “convergence,” “satisfaction,” “medical,” “regular,” “youth,” “consumer,” and “laboratory.”

Oral health education is a goal-attainment process that changes interest, knowledge, behaviors, and attitudes about oral health so that all people can maintain and manage oral health more rationally [29].

Oral health attitudes and behaviors can be changed through continuous oral health education, and educational methods with oral health education media or oral products have been used [30]. Min and Jung [31] identified oral health education experience, oral health knowledge level, and requirement for oral health education and investigated the relationship between the oral health evaluation index of the elderly and oral health-related quality of life, emphasizing the importance of oral health education to improve the oral health of the elderly.

Kang [32] analyzed the effect of oral health education through oral environment tests using Qraycam, oral health behavior, and a before and after comparison of the oral health management behavior score.

Lim [33] reported the need for an oral health education program or school oral health projects for adolescents and argued that there should be changes in oral health beliefs and behaviors to manage their own oral health.

Since oral health education experience has many factors that affect oral health management, such as brushing behavior, oral health knowledge, attitude, and practice, it is expected that more systematic and standardized oral health education programs will be presented.

This study attempted to examine the topics of previous studies by analyzing the trend of studies on dental scaling using topic modeling and drawing implications for future studies based on it. However, this study had a limit to identifying a wide range of topics as it was limited to domestic dental scaling studies. We expect future studies to investigate the relevance and effectiveness of topics according to the expansion of health insurance coverage.

This study conducted an online search with “dental scaling” as the keyword in the Research Information Sharing Service (www.riss.kr) to analyze the trend of studies on dental scaling. The searched papers were pre-processed with the Excel 2016 program, and then 5 topics were derived with the LDA topic modeling using NetMiner. The analysis results are summarized as follows:

Firstly, there were 215 academic papers on dental scaling with abstracts until December 2021. Analyzing the trend of the number of papers published each year showed 18 papers from 1986 to 2000, 33 papers from 2001 to 2010, and 157 papers from 2011 to 2020.

Secondly, the topic modeling analysis derived five topics. The identified topics were “Health insurance coverage of scaling,” “Study on oral health behavior,” “Study on factors related to tartar removal experience,” “Study on musculoskeletal diseases of dental hygienists,” and “Experience in oral health education.”

This study analyzed the trend of studies on dental scaling using topic modeling. Based on the topics and contents derived from this study, study topics and subjects can be inferred for each period. We expect multi-faceted studies based on the derived topics in the future.

No potential conflict of interest relevant to this article was reported.