• Restorative Dentistry and Endodontics
• /
• 제16권1호
• /
• pp.41-59
• /
• 1991

This study was performed to elucidate the distribution and correlation of immunoglobulin G subclasses with the degree of inflammation in the experimentally induced rat pulp and periapical pathoses. The pulp exposures were made in 108 mandibular 1st molars of 54 rats and the teeth were left open to the oral environment The animals were sacrified at 3, 7, 15, 30, 60 and 90 days after pulp exposure, and examined microscopically and radiographically Seventy one specimens were routinely sectioned at the thickness of 4 - $6{\mu}$ and stained with Hematoxylin - eosin for histologic examination, with toluidine blue for mast cells, and with the primary antibodies against rat IgG subclasses by using the Avidin - Biotin complex method. The following results were obtained: 1. As the degree of inflammation of rat pulp and periapeces intensified, the number of IgG subclass containing cells per unit area, especially IgG2a and IgG2c, decresased. 2. The IgG2c cells were most predominantly found in the lesions with slight inflammation, IgG1 cells in mild or severe inflammation, and IgG2a cells in moderate inflammation. 3. IgG subclass containg cells were more predominantly observed in the periapical granuloma than periapical abscess or cyst(p<0.01). 4. IgG2a containing cells were predominant in pulp inflammation, IgG1 containing cells in periapical granuloma, IgG2a cells and IgG1 cells in periapical abscess, and IgG2a cells were significantly predominant in periapical cyst. 5. The number of IgG subclass containing cells and mast cells in periapical tissue decreased with time lapse after pulp exposure. And correlation index between mast cells and IgG1, IgG2a, IgG2b was stastically high.

• Restorative Dentistry and Endodontics
• /
• 제26권4호
• /
• pp.341-349
• /
• 2001

Dental caries is the most common oral disease. There are many factors contributing to its development, but complete understanding and prevention are not fully known. However, it is possible to remineralize the early enamel curious lesion by fluoride containing remineralization solution. Recently the pH-cycling model has been used to examine the effect of fluoride solution on remineralization of artificial caries in vitro as it can closely simulate the conditions encountered in vivo within a carefully controlled environment. The aim of this study was to evaluate the remineralizing effects of supersaturated buffer solutions under pH-cycling model. The specimen with 3mm-diameter was made using mature bovine incisors which has no caries and has sound enamel surface. Early curious lesions were produced by suspending each specimens into demineralization solution at pH 5.0 for 33 hours and the specimen whose surface hardness value ranged from 25 to 45 VHN were used. The pH cycling treatment regimen consisted of 5 min soaks of three treatment solutions four times per days for 15 days and the continuous cycling of demineralization and remineralization were carried out for 15 days. Following the pH-cycling treatment regimen, the specimens' surface microhardness were measured by the Vickers hardness test (VHN) and analyzed by ANOVA and Duncan's multiple-range test. 1. The surface microhardness value of supersaturated solution, Senstime, and Gagline groups were increased after pH cycling, and that of supersaturated solution was significantly Increased compared to saline group(P<0.05). 2. The surface remineralization effect of fluoride containing solutions was accelerated by saliva under pH-cycling mode 3. The pH cycling model was considered appropriate to mimic the intra-oral pH changes when evaluating demineralization and remineralization in vitro. Under the results of above study, salivary remineralization effect can be improved by fluoride containing remineralization solution. The pH-cycling model was considered appropriate to mimic the intra-oral pH changes when evaluating demineralization and remineralization in vitro.

• 대한치과마취과학회지
• /
• 제13권3호
• /
• pp.95-102
• /
• 2013

Background: Sedation or outpatient general anesthesia is a necessary method for a successful dental treatment for children and the disabled who have a difficulty of cooperation. The aim of this study was to assess the patients who had dental treatment under sedation or outpatient general anesthesia at department of pediatric dentistry, Chonnam national university dental hospital and Gwangju dental clinic for the disabled. Methods: 875 patients who had sedation from January 2009 to September 2013 and 88 patients who had outpatient general anesthesia after May 2011 were assessed for this study. Patient's distribution and treatment patterns were examined. Results: The number of patients has been increasing in both sedation and outpatient general anesthesia. In case of sedation, the proportion of male patients was higher and 4-6 years age group was the highest. Most patients have resided in Gwangju buk-gu and the percentage of restorative treatment was the highest. In case of outpatient general anesthesia, the proportion of male patients was higher than that of sedation. Two groups, 10-19 and 20-29 years age, consisted most of patient. Most patients have resided in Gwangju buk-gu and Jeollanam-do, and the percentage of periodontic and preventive treatment was the highest. Conclusions: Sedation or outpatient general anesthesia for dental treatment has been increasing for children and the disabled who have a difficulty of cooperation. Therefore, it is important to improve treatment environment under sedation and general anesthesia through continuous research and studies.

• 한국조경학회지
• /
• 제30권3호
• /
• pp.57-63
• /
• 2002

This landscape design was proposed for the Buchon Special School Competition, held by the Kyonggi Province Office of Education. The authors collaborated on this design and won first prize in November of 2001. In the design proposal, on the basis of the knowledge of; mentally retarded children the children's activities, nature and health, and the healing gardens, the special school outdoor spaces were designed to meet the particular needs of the users. The school outdoor spaces are design for various types of users-children, adolescents, parents, siblings, staff, volunteers and visitors. The following are some of the basis concerns in the design of the school outdoor spaces : garden site planning, garden location, security, microclimate, entering and exiting, accessibility, usability, user group territories, supervision, attracting trained volunteers, a range of high-quality social settings, accommodation of different student types, accommodation of needs for both challenge and rest, child nature interaction, diversity of natural settings, hands-on activity, integrating the arts, and maintenance. The following are some of the major features in the design of school outdoor spaces : pleasant and inviting entry areas, sports grounds with different levels of challenge, gardens with plants having strong fragrances and/or tactile qualities, resting places with many types and forms of seating and weather-mitigating features, play grounds for all student types, roof gardens for users to experience nature in man-made environments, and walkways and winding paths with various trees, shrubs and flowers. In the special school outdoor spaces, people would perceive a unique sense of place through the various types of spaces and features described above. An example of the true meaning of a playing and resting place and a restorative and therapeutic environment is provided in the school outdoor spaces.

• Restorative Dentistry and Endodontics
• /
• 제20권2호
• /
• pp.843-855
• /
• 1995

Occupational Dentistry was introduced in Korea about 70 years ago. During the colonial period occupied by Japan till 1945, there were few documents about industrial dentistry, furthermore most cases of occupational diseases and accidents might have been concealed intentionally by the colonial government. After being an independent country, several dentists made efforts to set up 'Preventive Dentistry for Workers' performing specific oral health surveys, even though which were stopped by Korean War. In 1960s' and 1970s', some investigations of oral status were carried out intermittently for specific small groups;white-collar workers, mentally retarded person, buddhist monks and crews of ocean liners. At the same time there was important study in Korean history of occupational dentistry, which was 'a comparison of the oral hygiene conditions in the female workers of a spinning factory at intervals of 30 years.' In 1980s', young researchers began to give attention to erosion of the teeth due to sulphuric acid in the acid-related industry and dental caries due to sugar and flour in the sweets industry. After being democratic labor union movement activated in 1987, hidden and suppressed occupational diseases under the military dictatorship were exposed and flushed in the newspapers. It was shocking for all people that 15-year old boy had been dead due to mercury intoxication after 3-month employment in 1988. In 1990s', the activity for studying oral status of workers in their workplaces was launched and 'Occupational Accidents and Diseases in Oral and Maxillofacial Field' was published. And also The Korean Association of Occupationl Dentistry was established. Oral health examination of workers at the time of employment and of workers exposed to 5 special chemicals at the time of routine special health examination was adopted in 1992, and epocally oral health examination was also included in periodic routine examination of workers' health in 1995. So, occupational dentistry in Korea should cope with the changing needs of working environment and the altering scheme of health examination.

• Restorative Dentistry and Endodontics
• /
• 제39권4호
• /
• pp.288-295
• /
• 2014

Objectives: This study was designed to evaluate the synergistic antibacterial effect of xylitol and ursolic acid (UA) against oral biofilms in vitro. Materials and Methods: S. mutans UA 159 (wild type), S. mutans KCOM 1207, KCOM 1128 and S. sobrinus ATCC 33478 were used. The susceptibility of S. mutans to UA and xylitol was evaluated using a broth microdilution method. Based on the results, combined susceptibility was evaluated using optimal inhibitory combinations (OIC), optimal bactericidal combinations (OBC), and fractional inhibitory concentrations (FIC). The anti-biofilm activity of xylitol and UA on Streptococcus spp. was evaluated by growing cells in 24-well polystyrene microtiter plates for the biofilm assay. Significant mean differences among experimental groups were determined by Fisher's Least Significant Difference (p < 0.05). Results: The synergistic interactions between xylitol and UA were observed against all tested strains, showing the FICs < 1. The combined treatment of xylitol and UA inhibited the biofilm formation significantly and also prevented pH decline to critical value of 5.5 effectively. The biofilm disassembly was substantially influenced by different age of biofilm when exposed to the combined treatment of xylitol and UA. Comparing to the single strain, relatively higher concentration of xylitol and UA was needed for inhibiting and disassembling biofilm formed by a mixed culture of S. mutans 159 and S. sobrinus 33478. Conclusions: This study demonstrated that xylitol and UA, synergistic inhibitors, can be a potential agent for enhancing the antimicrobial and anti-biofilm efficacy against S. mutans and S. sobrinus in the oral environment.

• 대한건축학회논문집:계획계
• /
• 제34권10호
• /
• pp.83-94
• /
• 2018

In many theoretical and empirical studies on the design issues of therapeutic healthcare facilities, spatial configuration that promotes users' wayfinding behavior, has been emphasized as a significant factor to mitigate stressful experiences and to enhance restorative quality in the healthcare environment. This is also applicable to the healthcare setting for children. However, not much evidence has been reported with regard to the relationship between spatial configuration and wayfinding behaviors in this specific setting. Moreover, healthcare facilities for children with physical disabilities need more attention to provide easy wayfinding due to various physical restrictions. The aim of this study is therefore, to unfold the relationship between spatial configuration and visual cognitive qualities of outpatient spaces in the selected children's rehabilitation hospitals in Seoul, by examining visual cognitive attributes such as visibility, accessibility, and intelligibility. In the first phase, the spatial layout of the hospitals was analyzed, with an emphasis on the major outpatient areas such as the entrance lobby, doctors' examination, and physical therapy zones. In the second phase, a space syntax tool was implemented to examine visual cognitive characteristics of the spatial configuration. The spatial configuration parameters measured were integration, integration core, visual isovist field continuity, correlation between integration and step depth, and the correlation between integration n and integration 3. As a result, the integration was higher in the hall type configuration. Circulation intersections acted mostly as integration cores for better visibility. Some areas showed the lack of continuity in the visual isovist fields overlap and irregular correlation between integration and step depth. The intelligibility was higher in the circulation area and social interaction spaces such as a cafe, reception waiting, and therapy waiting areas. Based on the analysis, design implication and possible future improvement were discussed to enhance wayfinding experiences in the hospitals for children with physical disabilities.

• The Journal of Advanced Prosthodontics
• /
• 제14권6호
• /
• pp.360-368
• /
• 2022

PURPOSE. This study assessed the physical and mechanical properties of interim crown materials fabricated using various digital techniques after accelerated aging. MATERIALS AND METHODS. Three groups of interim dental restorative materials (N = 20) were tested. The first group (CO) was fabricated using a conventional manual method. The second group (ML) was prepared from prefabricated resin blocks for the milling method and cut into specimen sizes using a cutting disc. The third group (3D) was additively manufactured using a digital light-processing (DLP) 3D printer. Aging acceleration treatments using toothbrushing and thermocycling simulators were applied to half of the specimens corresponding to three years of usage in the oral environment (N = 10). Surface roughness (Ra), Vickers microhardness, 3-point bending, sorption, and solubility tests were performed. A 2-way analysis of variance (ANOVA) and Fisher's multiple comparison test were used to compare the results among the groups. RESULTS. The mean surface roughness (Ra) of the resin after accelerated aging was significantly higher in the CO and ML groups than that before aging, but not in the 3D group. All groups showed reduced hardness after accelerated aging. The flexural strength values were highest in the 3D group, followed by the ML and CO groups after accelerated aging. Accelerated aging significantly reduced water sorption in the ML group. CONCLUSION. According to the tested material and 3D printer type, both 3D-printed and milled interim restoration resins showed higher flexural strength and modulus, and lower surface roughness than those prepared by the conventional method after accelerated aging.

• 한국환경과학회지
• /
• 제33권3호
• /
• pp.217-226
• /
• 2024

Manufacturing workers face increased fatigue and stress due to environmental factors in workplace such as noise and vibration. Addressing this issue requires creating conducive rest spaces; however, the existing conditions of rest spaces in manufacturing workplace are subpar and lack sufficient scholarly evidence. This study investigated the effect of nature-based rest spaces on the physical and emotional recovery from fatigue on manufacturing workers. Three manufacturing complexes with nature-friendly rest spaces were selected, and 63 manufacturing workers participated in the study. The measurement tools included the Multidimensional Fatigue Scale (MFS) for fatigue levels, physiological indicators (blood pressure and heart rate), and emotional indicators (Zuckerman Inventory of Personal Reaction Scale; ZIPERS, Perceived Restorativeness Scale; PRS, Profile of Mood States; POMS and State-Trait Anxiety Inventory; STAI). The study compared recovery levels during a 7-minute rest between a space without plants and a space with natural elements. The results indicated a significant reduction in systolic and diastolic blood pressure of participants in green rest spaces compared with those in conventional rest spaces. Regarding fatigue levels, green rest spaces showed a decrease in systolic blood pressure in the middle-fatigue and high-fatigue groups. Positive feelings increased in green spaces, whereas negative emotions decreased, suggesting that short breaks in nature-friendly environments effectively promote workers' physical and emotional recovery. Furthermore, this study emphasizes the importance of green space in various work environments to promote well-being in workers.

• Restorative Dentistry and Endodontics
• /
• 제26권5호
• /
• pp.418-435
• /
• 2001

Root canal preparation process is of utmost importance in successful treatment of root canal. Also, one of the most important purpose of the root canal preparation is to enlarge the root canal three dimensionally without changing the curvature of the root canal However as the curvature of the root canal increases, there are many difficulties involved in formation of optimum root canal. Therefore in order to solve the above mentioned problems, new developments in methods of root canal preparation and equipments for such purposes were made. Recently, vigorous studies about newly introduced engine-driven nickel-ti-tanium rotary file are conducted. As shown in research results to dates, it is well established that the use of nickel-titanium file is better suited for curved root canal than stainless steel file in maintaining the curvature or root canal and reducing the deformation of root canal. However it is also acknowledged that there are a few discrepancies in research results according to protocol, due to failure to remove variables in experiments. In addition, although it is recommended by the manufacturer that the GT rotary file should maintain a low rotational speed of 150~350rpm and 'light pressure' as light as not to break the lead of a pencil, academic studies about the vertical force which is not yet standardized are not sufficiently explored. Therefore, this research devised and utilized a special research equipment to standardize the appropriate range of vertical force for GT rotary file through experiments by breaking of the lead of a pencil as expressed by the manufacturer and to accurately measure factors involved through repeating and recreating the environment of root canal preparation. Forming nine experimental groups by varying the vertical forces (150g. 220g, 300g) and rpm (150rpm, 250rpm, 350rpm), the effects of changing vertical forces and rpm on working efficiency were measured in terms of time expended in root canal preparation by crown-down method using a transparent resin block with 35 degree curvature and GT rotary file (z-test). The following research using this special research equipment that involved nine experimental groups and varying the vertical force for root canal preparation from 300g which is within the normal vertical force range to 700g and 1000g which fall outside the normal rpm range. The results were as follows : 1. Analysis of the experiment results revealed that the time spent in root canal preparation decreased as the vertical forces and rpm increased (p<0.05). Also, the effects of rpm were greater than those of the vertical forces within the normal vertical force range ($\beta$-weight test). 2. Observation of the deformation of GT rotary file revealed that deformation increases in a direct correlation with the vertical force increase and in a reverse correlation with the rpm decrease. In the case of the vertical forces close to the normal range, the probability of GT rotary file deformation were quite different depending on the rpm changes. In the case of greater vertical forces, the occurrences of deformation of the file were more frequent regardless of the rpm changes. 3. Deformation and breakage of file were also commonly observed in the expended time measurement experiments and GT rotary file deformation experiments in which low speed rpm (150rpm) was used and at the curved portion of the resin block.