• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.469-481
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• 2006

Among the etiologic factors of enamel corrosion, daily intake has been considered with a profound interest, especially the intake of acidic drinks. It is thought that the rapid consumption of acidic drinks will not only results in the affection to the teeth but also to the surface of the tooth-colored restorative materials. Therefore, the puopose of this study is to examine the alterations occurred in the surface of the tooth-colored materials according to the exposed time, with 3 most common acidic drinks in contact with daily life. Resin-modified glass-ionomer, polyacid-modified composite resin, composite resin were immersed on 0.9% NaCl, Coke, orange juice, sports beverages as 4 groups in each. The surface hardness and the surface roughness of specimens were measured with following methods: before immersion, 1 day after immersion, 1-,2-,3-,4- weeks after immersion. Results were as follows. 1. Tooth-colored restorative materials, with the exception of composite resin, showed statistically significant changes in surface hardness and roughness when immersed on acidic drinks(p<0.05). 2. The degree of change in surface hardness and roughness occurred as follows, in order of severity from greatest to least resin-modified glass-ionomer, polyacid-modified composite resin, composite resin 3. Sports beverages resulted in greater alterations to surfaces than Coke and orange juice. 4. In the SEM image of the groups immersed in acidic drinks, resin-modified glass-ionomer and polyacid-modified composite resin showed loss of filer. Severe cracks were observed, especially on the resin-modified glass-ionomer.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.6
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• pp.339-346
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• 2023

Objectives: This analysis details the characteristics of dental trauma in South Korea during the coronavirus disease 2019 (COVID-19) (DC) pandemic and compares them in patients before and after COVID-19 (BC and AC, respectively). Materials and Methods: Data were collected from medical records of patients who visited Seoul National University Bundang Hospital's Emergency Dental Care Center during three 12-month periods: BC, DC, and AC (BC from March 1, 2019 to February 29, 2020; DC from March 1, 2020 to February 28, 2021; AC from March 1, 2022 to February 28, 2023). A retrospective review was conducted to investigate patient age, sex, time of visit, cause, and diagnosis. The study included 1,544 patients: 660 BC, 374 DC, and 510 AC. Results: Significant difference in age and sex was not observed among the three periods; 1-9 years of age was the largest group (38.3% in BC, 29.6% in DC, and 27.8% in AC), and the percentage of male patients was greater than of female patients (male proportion as 63.5% in BC, 67.4% in DC, and 64.9% in AC). The number of patients generally peaked at a Saturday night in spring (for BC: May, Saturday, 18:00-19:59; for DC: March, Saturday, 18:00-19:59; for AC: April as the second most (October as the most peaked), Saturday, 20:00-21:59). The primary etiology of the dental trauma was identical in the three periods: falls, followed by sports. The most frequent diagnosis was laceration, followed by tooth avulsion and jaw fracture. Conclusion: Significant differences were not found between the characteristics and patterns of dental trauma in the BC, DC, and AC periods. However, due to the pandemic and social distancing, activities decreased and associated dental trauma-related incidents declined.

• Restorative Dentistry and Endodontics
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• v.35 no.1
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• pp.20-23
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• 2010

Mouthguards were used to protect boxers from lip lacerations and other soft tissue injuries in the late 19th century. Now they are used various parts of dental treatment, which are sports protective aid, bleaching tray, orthodontic retainer, implant insertion guide tray, splint and so on. Repeated dislodgement of Class V restoration due to habitual clenching stress should be restored with stress control. Mouthguard can be used as stress relief device. This case describes methods that can relieve occlusal force to teeth by using mouthguard. Satisfactory results can be obtained by using mouthguard for retention of repeated dislodgement Class V restorations. If patients suffered from repeated restorations of Class V due to clenching, mouthguard can be used additional device to relieve the occlusal stress in conservative dentistry.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.6
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• pp.253-258
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• 2014

Purpose: Maxillofacial fractures are rapidly increasing from car accidents, industrial accidents, teenaged criminal activity, and sports injuries. Accurate assessment, appropriate diagnosis, and preparing individual treatment plans are necessary to reduce surgical complications. We investigated recent trends of facial bone fracture by period, cause, and type, with the objective of reducing surgical complications. Methods: To investigate time trends of maxillofacial fractures, we reviewed medical records from 2,196 patients with maxillofacial fractures in 1981~1987 (Group A), 1995~1999 (Group B), and 2008~2012 (Group C). We analyzed each group, comparing the number of patients, sex ratio, age, fracture site, and etiology. Results: The number of patients in each period was 418, 516, and 1,262 in Groups A to C. Of note is the increase in the number of patients from Group A to C. The sex ratios were 5.6:1, 3.5:1, and 3.8:1 in Groups A, B, and C. The most affected age group for fracture is 20~29 in all three groups. Traffic accidents are the most common cause in Groups A and B, while there were somewhat different causes of fracture in Group C. Sports-induced facial trauma was twice as high in Group C compared with Group A and B. Mandible fracture accounts for a large portion of facial bone fractures overall. Conclusion: We observed an increase in facial bone fracture patients at Kyungpook National University Dental Hospital over the years. Although facial injury caused by traffic accidents was still a major cause of facial bone fracture in all periods, the percentage decreased. In recent years, isolated mandible fracture increased but mandible and mid-facial complex fracture decreased, possibly because of a reduction in traffic accidents.

• Restorative Dentistry and Endodontics
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• v.41 no.4
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• pp.246-254
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• 2016

Objectives: The aim of this investigation was to give insights into the impact of carbohydrate-electrolyte drinks on the likely capacity of enamel surface dissolution and the influence of human saliva exposure as a biological protective factor. Materials and Methods: The pH, titratable acidity (TA) to pH 7.0, and buffer capacity (${\beta}$) of common beverages ingested by patients under physical activity were analyzed. Then, we randomly distributed 50 specimens of human enamel into 5 groups. Processed and natural coconut water served as controls for testing three carbohydrate-electrolyte drinks. In all specimens, we measured surface microhardness (Knoop hardness numbers) and enamel loss (profilometry, ${\mu}m$) for baseline and after simulated intake cycling exposure model. We also prepared areas of specimens to be exposed to human saliva overnight prior to the simulated intake cycling exposure. The cycles were performed by alternated immersions in beverages and artificial saliva. ANOVA two-way and Tukey HDS tests were used. Results: The range of pH, TA, and ${\beta}$ were 2.85 - 4.81, 8.33 - 46.66 mM/L and 3.48 - $10.25mM/L{\times}pH$, respectively. The highest capacity of enamel surface dissolution was found for commercially available sports drinks for all variables. Single time human saliva exposure failed to significantly promote protective effect for the acidic attack of beverages. Conclusions: In this study, carbohydrate-electrolyte drinks usually consumed during endurance training may have a greater capacity of dissolution of enamel surface depending on their physicochemical proprieties associated with pH and titratable acidity.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.1
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• pp.50-54
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• 2007

This report constitutes a 7-year study of facial fractures based on a series of 616 patients who were treated for facial fractures as in-patients at Chosun University Dental Hospital between 1998 and April 2005. The following results were obtained : 1. The ratio of men to women was 5 : 1. 2. The major etiological factors were falls (36.2%), traffic accidents (23.4%), punches (18.1%), sports (8.3%), and accidents related to work (2.8%). 3. They were most frequent in the second (28.8%), first (26.6%), and third (12.3) decades, in that order. 4. The sites of frequent mandible fracture are the symphysis (32%), left mandibular angle (25.3%), and right mandibular angle (10.9%). 5. The most frequent maxillary fractures were zygomatic fractures (46.4%), Le Fort I fractures (28.8%), and Le Fort II (12.0%) fractures.

• The Journal of the Korean dental association
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• v.48 no.9
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• pp.647-652
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• 2010

FDI World Dental Federation is organization representing more than one million dentists worldwide with its more than 100 years of long history. Now FDI headquarter is located in Geneve, Switzerland and serves for developing health policy and continuing education programs, speaking as a unified voice for dentistry in international advocacy and supporting member association in oral health promotion activities worldwide. Korean Dental Association has been a member of FDI since 1959 and participated actively in the FDI's worldwide activities. Past Dr. Heung-Ryul Yoon was a president of FDI from 2003 for 2 years and we also have an experience in 1997 of hosting FDI Annual World Dental Congress successively in Seoul. The image of a country reflects the country's culture as well as affects to its economical and social development and it decides the national brand toward the world. Currently, Korean people realized that and put their efforts for promoting diverse aspects of Korea to the world such as multimedia culture called Han-Ryu, electric industry, automotive industry, sports represented by soccer. We have advanced technique and skill in various fields and now it's time to show ourself better to the world. It's same to the dentistry. It's true that Korean dentistry is top-class in the world and the dental industry is prosperous and also has best technique in the world. I think and strongly hope that the 2013 FDI Seoul Annual World Dental Congress would be best opportunity for Korean dentistry and dental industry to promote ourselves and make a big step to the world. Not only for the dentistry, it will also be very good chance to all the Korean people to improve Korean national brand. I believe that we can accomplish if we, all dental societies, stand together and join our effort to use this good chance the best. I know we can make it.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.5
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• pp.365-372
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• 2021

Objectives: Mandibular fractures vary significantly with respect to epidemiological and demographic parameters among populations. To date, no study has evaluated these aspects of mandibular fractures in Nuh, Mewat, Haryana, India. To retrospectively analyze the incidence, age and sex distributions, etiology, anatomic distribution, occlusal status, treatment modality provided, and their correlation in patients who suffered isolated mandibular fractures. Materials and Methods: The records of maxillofacial injury patients who reported to the Department of Dentistry, SHKM Government Medical College from January 2013 to December 2019, were retrieved from our database, and necessary information was collected. The data collected were analyzed statistically using IBM SPSS ver. 21. Results: Totals of 146 patients and 211 fractures were analyzed. There were 127 males and 19 females with an age range of 3-70 years (mean age, 26 years). Road traffic accident (RTA) was the most common cause of fracture (64.4%), followed by fall (19.9%), assault (15.1%), and sports injury (0.7%). Of all patients, 42.5% had bilateral fractures, 31.5% had left side fracture, 21.2% had right side fracture, 3.4% sustained midline symphyseal fracture, and 1.4% had symphyseal fracture along one side of the mandible. Site distribution was as follows: parasymphysis (34.6%), angle (23.7%), condyle (20.4%), body (12.8%), symphysis (4.3%), ramus 2.4%, and dentoalveolar 1.9%. The most common facture combination was angle with parasymphysis (17.8%). Occlusion was disrupted in 69.2% patients. Closed reduction was the predominant treatment modality. Conclusion: The data obtained from retrospective analyses of maxillofacial trauma increase the understanding of variables and their outcomes among populations. The results of the present study are comparable to those of the literature in some aspects and different in others.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.4
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• pp.405-417
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• 2010

Previous studies have already shown that mouthguard is effective in protecting jaw bone, teeth and oral tissue against sports trauma. However, other than severe trauma, repetitive force, such as disorders like clenching, cause teeth or oral tissue damage. These kinds of disorders usually present pathologic attrition in the posterior teeth, resorption in alveolar bone, loss of teeth and destruction of occlusion. Wearing a mouthguard is believed to be effective in preventing these disorders. But its effect is not examined thoroughly enough. The purpose of this study is to identify whether mouthguard is effective in reducing strain caused by clenching. Mandibular first molars in the normal occlusal relationship without any history of dental treatment were chosen. Biaxial type strain gauge was placed on the buccal surface of the tooth. Having maximum occlusal force, measured by load cell, as a standard, clenching intensity were divided into three stages; moment of slightly tooth contact, medium bite force (50% of maximum bite force), maximum bite force. Strain occurring in dentition in each stage with and without mouthguard was measured. Changes in strain (on dentition) between each stage and difference in strain, between with or without mouthguard were recorded by PCD-300 analyzer and PCD-30 soft ware. The data was statistically analyzed by Wilcoxon signed rank test. The following results were drawn; Without mouthguard, strain given on dentition increased as the clenching force increased. With mouthguard, strain given on dentition also increased as the clenching force increased. With mouthguard, strain decreased, in all cases of clenching force stages. Data on the moment of slightly tooth contact stage, had no statistical significance. However, with mouthguard, 50-90% of decrease in strain could be obtained in maximum occlusal force, compared to the group without mouthguard. Mouthguard decreased the strain on the dentition, caused by clenching. Therefore, mouthguard seems to be effective in preventing damage on dentition, by acting against clenching, which occurs both consciously and unconsciously during sports activities.

• Journal of Technologic Dentistry
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• v.31 no.2
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• pp.31-38
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• 2009

In recent year, the population for sports has been increased and lots of wounded patients at the oral & facial portion were troubled with the accidents. So, it was needed to protect them from the sports accident, by the use of the mouthguard appliance. This study was done as ae guide for selection of the mouthguard materials. Such mouthguards classified as E.V.A., PE, silicone as material, Scheu(Germany), Tru-Tain(U.S.A.), Dreve(Germany) as companies, 1.5mm, 3.0mm, and 4.0mm as thickness and single sheet, soft double sheet, hard double sheet methods were selected for experiment to compare the fracture protect test. The obtained results are as follows. 1. All types of mouthguards, whatever differences there are in material, production company, procedure and the thickness, were effective for fracture protect effect. 2. The most effective one for fracture protection was recommended as E.V.A. in material, and Tru-Tain in company. 3. More thick, and soft & hard multi sheets productions were more effective for fracture protection.