Background This study aimed to evaluate periapical radiolucency of endodontically treated teeth before and after orthodontic treatment using cone-beam computed tomography (CBCT). Methods Patients who underwent orthodontic treatment at Wonkwang University Daejeon Dental Hospital between January 2009 and June 2022 were included based on the following criteria: root canal treatment, and availability of CBCT images taken before and after orthodontic treatment with an interval of > 1 year between both scans. Patients with primary teeth or orthodontic tooth extractions were excluded. The size of the periapical radiolucency (SPR) of the endodontically treated tooth was evaluated using CBCT. Pre-orthodontic treatment CBCT images and the latest post-orthodontic treatment CBCT images were analyzed. The selected teeth were further categorized based on the orthodontic duration, CBCT interval, the patient sex and age, the tooth type and position (maxilla or mandible), and quality of root canal obturation. Statistical analyses were performed to evaluate changes in SPR using the paired t-test and multiple regression analysis. Results In total, 115 teeth (37 anterior teeth, 22 premolars and 56 molars) from 61 patients (age, 14–54 years) were included, with 39 teeth from male patients and 76 teeth from female patients. The age was ranged between 14 and 54 years old, and mean age was 25.87 years old. The mean CBCT interval and orthodontic treatment period were 43.32 months and 36.84 months, respectively. Seventy-five teeth showed good obturation quality, 80 were not used as anchors during orthodontic treatment, and 71 were maxillary. The SPR size increased after orthodontic treatment for 56 teeth and decreased for 59 cases. The average change in SPR was -0.102 mm and the difference was not significant. Significant decrease of SPR were observed between female patients (p = 0.036) and maxillary teeth (p = 0.040). Conclusion Orthodontic treatment had no significant impact on the changes in the SPR in endodontically treated teeth in most categories. However, there was a significant difference among females and the maxillary teeth. In both categories, the size of radiolucency decreased significantly.

The elderly population with dementia is rapidly growing in South Korea. The aim of this study was to investigate the relationship between dementia and oral health in 197 subjects aged ≥65 years. The questionnaire included questions on subjective health status, subjective health concern, subjective oral health status and behavior, mastication ability, Oral Health Impact Profile-14 (OHIP-14), and Korean Dementia Screening Questionnaires (KDSQ). Oral examination was conducted by a single dentist to evaluate upper or lower denture use, and determine the numbers of remaining and functioning teeth, including implant and fixed prosthesis. The subjects who required a dementia test (KDSQ-C [cognition] of ≥6) had significant differences in systemic disease prevalence rate, subjective health status, subjective health concern, KDSQ-V (vascular disease) score, KDSQ-D (depression) score, subjective oral treatment need, key food mastication ability and OHIP-14 score compared to the healthy subjects. The proportion of denture wearers, total remaining teeth, total functioning teeth, toothbrushing frequency, oral pain severity, symptoms of periodontal disease, subjective oral health status, and subjective oral health concern showed no significant differences between the two groups. KDSQ-C and OHIP-14 scores showed a strong positive relationship, while KDSQ-C score and total remaining teeth or key food mastication ability showed a weak negative relationship. In the multiple regression analysis, the KDSQ-D, KDSQ-V, and OHIP-14 scores influenced the KDSQ-C scores. We suggest a relationship between oral health and cognitive impairment.

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·············································································································································································Current trends note that individuals utilize the information provided through online knowledge search services, to solve their curiosity for news and world events, as well as to read information written by others and acquire new knowledge on a variety of subjects. The purpose of this study was to analyze the questions about dental hygienists, in an effort to know which information they would want to gain through a web-based question and answer service. The questions were available through the service from October 2002 to March 2017, and it was through the web-based question-answer service in Naver that is called knowledge iN which was searched, using the key words of chigwawiseangsa and chiwiseangsa in the Korean language. As a result, there were a total of 1693 questions about the profession of the dental hygienist occupation which were extracted and analyzed. In particular, it was noted that the high school students asked about the occupation of dental hygienists the most. The middle and high school students required the information about the required entrance examination and employment in this growing field of study, and it was noted that the university students and dental hygienists wanted to know more information regarding statistics of available employment of dental hygienists (such the job options that would be available as upon graduation from their certificate program, etc.). The information orders that the questioners wanted answered were determined and identified as follows: employment (39.3%), entrance examination (18.8%), working conditions (11.5%), tasks (11.3%), and curriculum (9.4%). When the information captured from the questions from the participants and questioners were assorted in detail, the detail information orders that the questioners wanted were as follows: information on applicable places of study, such as the available university (13.0%), annual salary (11.5%), prospects (10.3%). overseas employment (9.3%), and public dental hygienists (8.7%). KEY WORDS: Dental hygienist, Job, Online 서 론 정보통신기술의 발달로 소비자의 정보 요구 및 이에 대 한 충족이 인터넷을 기반으로 하는 경우가 점점 많아지고 있다[1]. 지식검색이란 네티즌끼리 묻고 답하며 정보를 만 들어 가는 커뮤니티서비스로서 누군가 질문을 올리면 자 신이 아는 범위 내에서 답변을 해 일종의 온라인 백과사 전을 만들어가는 형식으로 이루어진다. 지식검색은 네티 즌이 자발적으로 참여해 질문과 답변을 한다는 점에서 관 련 사이트 안내 수준에 그치던 기존의 검색서비스와 차별 화된 쌍방향 검색이다. 이제 사람들은 수많은 궁금증에 대 해 지식검색서비스를 이용하여 궁금증을 해소하고 지식을 습득한다[2]. 2000년 10월 인터넷 한겨레에서 만든 국내 지식검색서 비스의 최초 모델인 디비딕을 시작으로 2002년 10월 네이 버가 선보인 지식iN이 선풍적 인기를 끌면서 네티즌들의 참여가 본격화 되었다[3]. 1990년대 후반부터 IT열풍을 타 고 인터넷 포털 사업자들이 경쟁적으로 검색서비스를 제 공해 온 가운데, NHN 네이버의 경우 2011년 기준 국내 검색 서비스 시장에서 60~70%의 시장을 점유하였고[4], 2016년 48%로 감소하기는 하였으나(http://www.pitchone.co.kr/7235/) 국내 검색시장의 지배적사업자로 여전히 위치하고 있는 상황이다. 현재 우리나라에서는 네이버의 지식iN을 통하 여 자기 자신이 가지고 있는 전문지식에서 생활상식까지 손쉽게 교환하거나 공유할 수 있다[5]. 치과를 방문하기 전에 인터넷을 통해 정보를 습득하는 사람이 33.6%이고[6] 치위생학과 입학 지원 시 포털사이 트 검색을 하는 사람이 55.9%에 이른다[7], 온라인 정보를 Case Report

The shortage of dental hygienists has been a long-standing problem in Korea. Small-scaled dental clinics suffer from a lack of dental hygienists, who seem to prefer working at large-scaled dental clinics. The purpose of this study was to confirm the differences in the working conditions according to the scales of dental clinics. We collected the working information registered via job advertisements through the web-sites of Korean Dental Hygienists Association, Dental Jobs, and Nurse Jobs from July to August 2016. The results were as follows: 96.7% of the advertisements wanted regular workers, while the proportion of part-time workers was the highest (34.8%) in the group with less than 3 employees. The average workdays per week was 5.32±0.55 days, and the group with less than 3 employees had significantly longer workdays than the other groups. The daily working time was 8.99±0.44 hours, and there was no difference among the groups. Night overtime hours were needed by 54.4%, 45.0%, and 31.3% of the groups with of the groups with 4∼7 employees, more than 8 employees, and less than 3 employees, respectively. Information regarding annual leave (60.5%), monthly leave (63.9%), half a day off (32.4%) and vacations (43.1%) were presented in the job advertisements, and these proportions were significantly higher by the group with more than 8 employees. Information on overtime pay (14.4%), night-work pay (13.4%), incentives (34.1%), lunches (60.2%), vacation bonuses (33.8%), and self-development (20.4%) were presented in job advertisements. The group with 4∼7 employees had significantly higher proportions in severance pay, vacation bonuses, self-development, and major national insurance. It is necessary to consider the improvement of working conditions, diversity of working styles, and welfare of dental hygienists, and it is suggested that small dental clinics provide more precise working conditions.

In accordance with the aged society, oral health care for the elderly is considered important to maintain general health. Although the role of dental hygienists is essential for proper health management of the oral cavity, research on the care system for the elderly people's oral health and on the role of dental hygienists in the field of elderly welfare is still insufficient. Hence, the aim of this study is to investigate the status of Korean elderly welfare system and dental hygienists by comparing them with those in Japan, a precedent of aged society. First, we compared and investigated the Japanese long-term insurance system, which provides an institutional basis for a long-term care system for the elderly in Korea. Second, the elderly welfare law and care system, focusing on oral care, were examined. Lastly, in elderly care, we analyzed the distinctions between Korea and Japan regarding dental hygienists' role and scope of work. Taken together, as a precedent of aged society, Japan has shown well-specialized and systematic welfare for the elderly compared with Korea. With the development of the welfare system for the elderly in Japan, the role and the work scope of dental hygienists have been expanded to improve quality of life of elderly people, as a key professional for elderly oral care. Therefore, we should perceive the need for improvement of long-term care insurance and the expansion of dental hygienists' work in Korea. In conclusion, these results could be used as basic data for improving the elderly welfare system and developing dental hygienists in Korea.

Background: As the importance of the esthetic function of teeth increases, the use of esthetic restoration materials and whitening treatment are increasing. The purpose of this study was to investigate the color change of esthetic restoration materials upon using staining and whitening toothpaste. Methods: Light curing (LC) packable composite resin, LC flowable resin, LC glass ionomer (GI), and self-curing GI specimens were colored in coffee or curry for three hours a day for seven days. After that, regular toothpaste, whitening toothpaste containing hydrogen peroxide, and whitening toothpaste containing activated charcoal were applied for three minutes three times a day for two weeks. Luminosity (L), chromaticity a (a), and chromaticity b (b) were measured using a spectrophotometer once a week. Results: In the coffee-colored group, the change in L 2 *a 2 *b 2 (E 2 ) with time was significant (p=0.004), there was no difference for different toothpaste types (p=0.646), and there was significant difference (p＜0.001) for different esthetic restorative materials. The change of E 2 in the curry-colored group was significant only for different esthetic restorative materials (p＜0.001). In the coffee-colored group, the L, a, and b values of the light-curing GI showed greater change than other materials after staining and one week after whitening, turning dark, red, and yellow. In the curry-colored group, L did not differ for different materials and times, and a and b showed the greatest difference in light-curing GI after staining and one and two weeks after whitening. Conclusion: The use of whitening toothpaste for two weeks was not different from the use of general toothpaste in the removal of staining or whitening. Since light-curing GI is the most vulnerable to coloration, it is recommended that coloring by food chromogen should be explained in advance, before using light-curing GI for teeth restoration.

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