Community Oral Health & Practice, a part of the Dental Hygiene (Department) curriculum, is devoted to various activities such as education and prevention for oral health promotion by community dental hygienists for local residents at home, school, and industrial sites. It is to develop the necessary professional knowledge and skills. This is expressed as public oral health science, community oral health science, community practice, etc., and is an essential educational content in the field of dental hygiene.

As the community oral health project shifted from treatment-oriented to oral health education and prevention for the entire community and into an integrated health promotion project, the role and proportion of health and dental hygienists are expanding. Therefore, it is a process that requires the ability to integrate dental hygiene knowledge, apply it to practice, and solve the problems of the subject. Effort is required [1]. However, the standardization of dental hygiene practice in the current community is insufficient and the evaluation system for each health center, which is the field of practice, is different, causing problems in the fairness of education accepted by students. Practical training is a major task that must be carefully dealt with from planning to practical training students, advisors, and practice instructors, and problems must be found and improved for desirable practical training [2]. An efficient curriculum and field practice at a health (branch) center should be implemented considering both the instructor's and learner's positions.

Previous research related to public health center practice includes a study on the validation of learning goals through community dental hygiene practice, a satisfaction survey and performance evaluation content analysis of health center practice, a teaching method of community class, a case report on community practice, and a proposal for dental hygiene field practice evaluation index, job competency education requirements for health and dental hygienists, research on the elderly visiting public health centers, oral health center development plans [3-10], and there are no studies on public health center practice experiences through reflection.

In order to operate practice in a desirable way, it is important to understand the range of introspection and characteristics of learners to understand the inner side of practice students. In addition, systematic efforts are needed to develop the curriculum and teaching and learning methods accordingly. Learning is the driving force of personal competency development, and reflection is the key to linking learning to performance. Introspection is essential to achieve performance and improve competency by applying various experiences experienced in a rapidly changing organizational environment and knowledge acquired in the field.

The dictionary meaning of 'Reflection' is 'to deeply look back on one's work', and it is a process of realizing the meaning while experiencing changes in thoughts, emotions, and states while experiencing daily life [11]. There are many different concepts and approaches to reflection. Reflection in education started from Dewey's (1933) 'reflective thinking'. Introspective thinking was viewed as a type of thinking and was defined as “actively and constantly carefully considering the cause and effect based on a certain belief or knowledge”. There is also a view that reflective thinking is part of the problem-solving process. This is mainly used for the purpose of looking back on one's learning experience and facilitating learning, which later turns into desirable outcomes. This is seen as the growth and development of personal learning [12].

Therefore, the purpose of this study was to analyze the self-reflection journals written by 4th grade dental hygiene students' perspectives and experiences in their own language after practice at the public health center, and try to use them as materials for improving the education of health center practice leaders. In addition, it is intended to provide basic data for health center practice instructors to understand the description of the experience of practice students and to develop and establish efficient guidance and related educational programs.

1. Research design

This study is a qualitative study to comprehensively understand the essential structure and meaning of dental hygiene students' health center practice experience by analyzing the reflection diary submitted after practice at the community health center.

2. Subject of research

Health center training for dental hygiene (department) and 4th year students at B University located in City A is conducted at some public health centers located in cities and provinces. Community dental hygiene and practice courses are 3 credits, 3 hours, selected one day out of a week, and conducted once in a visit and 4 visits over 4 weeks. Among public health centers located in some cities and provinces, we selected places where students can commute. The reflection journals of 34 current students who understood the purpose of the study and agreed to use the data were analyzed.

3. Data collection

Data were collected and analyzed from 34 students from May 13 to June 7, 2019, when the community health practice of dental hygiene students began. Public health center practice is designated on thursday and friday according to the schedule and situation of the public health center, and students practice as a team of 5 to 6 people over a period of 4 weeks, or as a team of 3 people depending on the situation, and the researcher is he toured public health centers and led conferences. Also, at the practice site, employees and practice students go on business trips to kindergartens, social welfare facilities, schools, etc. If the meeting could not be held due to overlapping time, the meeting was held the next day according to the school schedule. In the reflection journal, questions were created and presented for each major theme. As for the first question, when you said you were going to practice at a public health center, what were your thoughts before the practice? Second, what did you find new in the public health center practice? Third, what kind of expectations did you have for practicing at the public health center? What were the emotional experiences, or emotions, at the fourth health center? As a dental hygienist at the fifth public health center, what did you experience as professional?

Sixth, how was the practice system at the public health center? In other words, what is your opinion on the training period or the field leader? Did communication work well during the seventh practice period? The questions were written as questions in the reflection diary and allowed to be answered freely. The questions were modified and supplemented by referring to the literature of Park and Lee [2].

4. Data analysis

For the data of this study, the phenomenological data analysis method of Colaizzi was used after reading the part of the reflection journal submitted after practice.

After practice in community oral health at the public health center, practice diaries, reports, and reflection diaries are submitted as results. Learners evaluate themselves while looking back on how they practiced, what they thought, what they did well and what they did wrong.

After practice at the public health center, students were allowed to write a reflection journal freely. Instructors can predict the feelings before practice, the practice environment, the content of practice, the practice process, and the atmosphere of the practice field from the contents of the reflection journal written by the students, and can evaluate whether the learning has been successful [13].

In the first step of the data analysis method, the submitted reflection journal was read intensively several times and the meaningful contents of the part directly related to the phenomenon of the public health center practice experience were underlined. In the second step, after classifying the language data with common meaning, the meaning was given by setting the category. In the process of organizing the derived themes and categories, if the stated data could not be explained, the meaning of the statement was confirmed by returning to the original data.

5. Theoretical background

Introspection started from Dewey's (1933) 'reflective thinking'. Reflective thinking is seen as part of the problem-solving process, and is mainly used for the purpose of looking back on one's own learning experiences and facilitating learning [12].

The phenomenological method using reflection journals is one of various types of qualitative methods to overcome the limitations and problems of quantitative analysis methods. Phenomenology is the description of living human experience and requires a holistic approach to contact the subject's reality. The purpose of phenomenology is to explain the nature of behavior based on human understanding and contemplative thinking [14]. It is an inductive and descriptive research method that reveals the meaning of the phenomena experienced by humans. The phenomenological data analysis method is presented by Giorgi, Colaizzi, and Van Kaam.

Giorgi's method focuses on revealing the meaning of living experience through in-depth research on the subject's description. It is general through identification of the original semantic unit, theme, central meaning, structural description integrating central meaning, and situational structural statements. Analyze the data in the order in which the structural description was created.

Colaizzi's method emphasizes matching appropriate data sources with appropriate data collection methods, while analytic methods provide meaningful interpretation from phrases and sentences that involve reading and exploring the subject's protocols to get a feel for the data. Deriving a significant statement, a general restatement of a meaningful statement in a more general form, deriving a formulated meaning from a meaningful statement and restatement, and deriving the derived meaning from a theme; Organize them into theme clusters, categories, and make a complete, exhaustive description with a clear statement relating the theme to the phenomenon of interest.

Van Kaam's method is to listen to the recorded interview with the subject over and over again, record it literally, extract meaningful statements from the described contents, and convert the extracted meaningful statements, that is, the raw data (row data). By reading repeatedly, each statement is collected into categories, subtopics, and themes, and the attributes of the themes are collected and categorized, and the themes in the categorized data are ranked in order of priority of the data, and analysis and integration are performed through classified categorization. Through the description of the phenomenon.

In this study, Colaizzi's analysis method was applied among the three phenomenological analysis methods. The reason for choosing this analysis method is that the meaning was constructed by carefully looking at the meaningful statements derived from the original data (protocols), and the meaning was constructed by using the expressions of the research participants as they were and restating them in a more general form. Colaizzi's analysis method of deriving and categorizing by selecting topics [15] was appropriate and applied.

As a result of phenomenologically analyzing the contents of the dental hygiene (department) students' reflection diary on the practice experience at the public health center, it is classified into categories such as change in perception of the public health center, rediscovery of dental hygienists in the community, emotional experience, professional experience, practice system, and communication. It became.

This study is a qualitative study that analyzes the reflection diary written from the student's point of view through community dental hygiene practice and organizes the meaning and essence in a phenomenological method. This study was attempted to find out how students felt through the analysis of dental hygiene students' reflection diaries after practice at public health centers, and to provide basic data for developing and establishing effective guidance and education-related programs for health center practice instructors.

As a result of the analysis, six categories were derived: change in perception of public health centers, rediscovery of dental hygienists in the community, emotional experience, professional experience, practice system, and communication.

The first category derived from community health center practices is 'awareness of health centers'. I didn't get a lot of jobs at the public health center, so I had negative thoughts about whether it was necessary to practice at the health center, but while practicing, there were more various projects in the community than I thought, and I was impressed by the use of good drugs at the health center and the kindness of the teachers at the health center to the local residents. It was an awareness of new knowledge. This perception of students had been practiced only in the clinical field until they started practicing at the public health center, and they were not aware of it at all because they learned mainly the contents of practice related to clinical practice in the school, and there was a lot of scope. It is believed that he had a negative mind as he proceeded. It is judged that it will be very helpful to have various experiences and interpersonal relationships about the duties that can be performed as dental hygienists.

The second category is the rediscovery of community dental hygienists. I felt moved by the dental hygienist working at the public health center promoting the health of the local residents and helping the disabled, multicultural families, and the elderly to receive more benefits, and the dental hygienists at the public health center created various ideas and materials for the target people. He said it was impressive. Hospitals, clinics, and public health centers, which are the main practice institutions for dental hygiene students, communicate and interact with various people, including dentists, dental hygienists, nursing assistants, other health care service providers, patients and their guardians, and community residents. In particular, it is more convenient for the vulnerable to visit public health centers than general hospitals and clinics, and the dental hygienists at public health centers respond to this as a natural response to the subjects, such as data, utilization, and intervention. It can appear as a sight that is difficult to see in general hospitals and clinics. It grows through this series of repeated processes and experiences.

The third category is emotional experiences. Since it was a public health center practice, I expected a lot, it was not too busy compared to hospitals and clinics, and I had a leisurely commute. It seems that there are parts where time is not used properly because it is not done. Dental hygienists at public health centers should allocate time and create opportunities to demonstrate their abilities so that subjects and practice students can have a variety of experiences. In addition, flexible management of practice time is necessary because there are times when you do only simple tasks because there is no exchange with other departments, or when you have free time, you just sit without work. As an emotional experience, 'comfortable practice environment' and 'accessibility' were the same as the results analyzed as positive factors influencing satisfaction in [4].

The fourth category is professional experience. I learned at school that there is a large elderly population, but I did not realize the reality. I realized that there was a large elderly population while doing a project for the elderly at a public health center. I prepared and performed a role play through brushing education through a visit to a daycare center, and the children responded well, so it was worthwhile. Through feelings and introspection on professional experiences, such as the fact that there was a need to learn about communication and control with students while visiting elementary schools for oral health education, and the fact that education was promoted to social welfare facilities, senior citizens' centers, and maternal and child health subjects. It was found that students are growing through practice in the part where they think they need to have the necessary capabilities for themselves. As such, it was said that a continuous reflection process is necessary to acquire competence [14].

The fifth category is the contents of the practice system. In the practice system, the practice period was during the period of 'once a week for 4 weeks' in this study, but they said that the practice period was too short and the activity time felt too short. In [4], as a result of practice for 'once a week for 6 weeks', 82.9% responded that the practice period was appropriate, and it is considered necessary to adjust the practice period of this curriculum. In addition, it was found that the practice time of the students was not efficient because there was no on-site leader of the public health center, that is, the person in charge of student practice, and the time was not systematically allocated. There is a need to conduct an effective practice program with a manager in charge of managing and guiding students' educational programs.

Table 1 . Statements by category

Category	Topic	Meaningful statement
Awareness of public Health center	Negative prejudice	'It's hard to get a job at a public health center and I don't get a lot of jobs, so I thought, 'Is it really necessary to practice at a health center?' Thought, 'I used dental hospitals or clinics rather than public health centers, but how many people would use them?' 'The quality of medical treatment at the public health center is low, and the medicines are cheap, 'but I was using effective medicines such as the latest advertisement products. 'The public health center teachers are also a bit administrative and rigid', but I was moved by the attitude of treating the local residents.
	What's new	I thought, 'Is there a special public health center program?', but I was surprised by the variety. 'It is a vital institution for the community'. 'There are more health center projects for community residents than expected'.
Rediscovering community dental hygienists	Central role of public health center	'The human resource needed by the residents is a dental hygienist working at a public health center, and there was a lot of interest in improving the health of local residents'. 'It was touching to see the dental hygienists and workers at the public health center help the disabled, multicultural families, and the elderly to receive more benefits.
	Creation of new programs	It was impressive to create various ideas and materials for the target audience. The appearances of discussions for the oral health campaign were similar to our serious group discussions.
Emotional experience	Anticipation	It was a public health center practice, so I went with high expectations. I feel comfortable hearing from another group that it is less busy and comfortable than hospital practice. I am looking forward to my first public health center practice. It seems to be less stressful than the hospital.
	Relaxed	The practice health center is close to my home, so I have time. It's good that I can afford to go to work later than the hospital practice. The work hours were suitable and I was not late for work, so I was not physically tired.
	Fear and anxiety	I am a little afraid of what will happen if I go to the health center. Can I treat the patients who come to the health center well? Will the teachers at the health center understand us well?
	Regret	Department seems to be closed It seems that there is no interaction with other departments. There seems to be a lot of work to do, but not many local residents come to visit. I think it needs a lot of publicity. It seems that there is less work to do than the hospital.
	Embarrassment	It's my first time practicing at a public health center and I don't know the detailed work, but I was confused when the teachers at the health center instructed me to do something. The teacher asked the patient to pack the items, but I was embarrassed about where they were.
	Kindness	I felt that it was cool to see them respond kindly to the elderly. It was nice that they treated us kindly and relaxed more than when we practiced at the hospital.
	Thank you	It was nice to have a place for students to relax.
	Ignored	I was not comfortable and my pride was hurt by those who spoke short words or similar words when calling students. 'Don't you know that? Didn't you learn that in school? Hearing what he said hurts his pride. When I'm not working, I'm so free that there are times when I'm just doing nothing. I just thought it would be nice if he told me to go to work.
Professional experience	Elderly population related projects	I learned at school that there is a large elderly population, but I didn't really realize it, but when I came to the public health center, I could feel that there is a large elderly population. 'The health center seems to be used a lot by the elderly'.
	Daycare visit	'I prepared a role play for brushing education through plays and songs, and the children's response was good. It was rewarding'. 'I was serious about controlling the children, but I was respectful to see the teachers who went with me skillfully'.
	Elementary school visit	'I was proud of giving oral health education using the media to the oral health office of an elementary school'. 'When I was educating the lower grades of elementary school students, I had a lot of questions, so I was busy and busy answering them, but I felt like I had to learn how to communicate with these students'.
	Oral health event	'Through community practice, I learned that there are more public health center projects than I thought'. 'I was surprised that so many community residents came to the oral health day event at the public health center.
	Various support projects	There was also oral care for the disabled in social welfare facilities. Oral care was also provided to the elderly. Education and publicity for those eligible for the maternal and child health program.
Practice system	Use of practice time	'The public health center is going on a business trip in the afternoon unlike other training centers. It was a bit difficult to manage time because there was no specific word on how to spend the time other than activities'. It's a relaxed place, but I wish the teachers would give a more detailed explanation.
	Practice period	'It seems that the interns come out and there is nothing they can do'. I think the training period is too short. 'I feel that the activity period during the practice period is too short'
	Lack of field leaders	'Almost some days I just sit there waiting for the target person to come and I don't think I did anything. Even the teachers didn't teach us anything. It seems that there is no teacher who gave detailed orientation.
Communication	Opportunities to communicate with older people	I learned at school that there are a lot of elderly people, but in reality, most of them were elderly people, and it was difficult to listen to and talk with grandparents. The pronunciation of the elderly was not straight, so it was difficult to understand.
	Participation in various programs	During the practice period, I had many experiences that I could not have at the hospital. I did an oral health campaign, but I was a little shy. I didn't know that public health centers had so many programs for various subjects.

The sixth category is communication. 'There was a large number of elderly people, and I had the opportunity to communicate with them, but it was difficult to understand them because their pronunciation was not straight. Also, it was not easy to have a conversation with various subjects, and I did not know that there were so many different programs for the subjects.' Considering that they had communication difficulties in conversation with the elderly, it is thought that education on conversation and communication methods for various subjects should be provided. In addition, it is necessary to fully learn about the various oral health programs that are being conducted in public health centers and to practice them.

The results of this study showed in-depth the inner side of the students, such as the atmosphere and practice environment of the practice field, the difficulties of the students, and the rewarding and improving points for the practice. I was able to grasp the psychological state of the students through the reflection journal for the parts that could not be directly expressed to the professors, and the atmosphere of the practice field was also well grasped. However, there is a limitation that generalization of all results to students in one region is not possible. It is meaningful that teachers in charge of practice were able to grasp the inner side of students that they had not recognized before, set the right direction for practice guidance, and provided basic data for developing meaningful programs.

This study is a qualitative study that analyzes the reflection diaries of 34 students after practice in order to understand the nature of the experience and meaning of the overall practice in a public health center where dental hygiene practice in the community of dental hygiene students is practiced.

Public health center is a public health system and a local health care institution that plays an important role in preventing diseases and promoting health of local residents as a front-line organization. Therefore, since the role of dental hygienists in the community is important, it is necessary to strengthen the capacity to perform the role through public health center practice.

In this study, as a result of analyzing the introspection log after performing practice at the public health center, the content of the change in perception of the public health center, rediscovery of dental hygienists in the community, emotional experience, professional experience, practice system, and communication. It was possible to grasp the psychological inner changes of the students, and through this, the prejudice against the practice at the health center was eliminated, the change in the positive image of the health center, the attitude toward the health center staff and the re-recognition in the work area, and the feeling that the practice, which was tense, was worthwhile. I came to construct the meaning by changing the perception of the role I want to play.

Based on the results of the study, it was an important process to fully understand the role and information about public health centers before practicing practice, and it is expected that the role of dental hygienists in public health centers will be fully understood and improved through this practice process and reflection. Based on the research results, I would like to suggest a study on the relationship between the work-related reflections of dental hygienists at public health centers and students' practice satisfaction.

This study was supported by research fund from Songwon University 2020 [A2020-52].

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