• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.206-225
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• 2012

General status of pediatric dentistry in Korea is to conduct vigorous academic activities and specialized medical care centering the Korean Association of Pediatric Dentistry (KAPD) that has about 1,000 pediatric dentists as members, pediatric dentistry departments of 11 Colleges of Dentistry, numbers of pediatric dentistry training institutions and private clinics specialized in children. From 1996, the accredited pediatric dentists were produced by the KAPD and from 2008, the state began to produce the accredited pediatric dentists. Since then, doctors with expertise in pediatric care had opened private clinics in addition to the university hospitals, it became the basis of a momentum to deepen the specialty of pediatric dentistry. The Dentistry community of Korea is going through rapid and profound changes recently, and the underlying reasons for such changes can be classified largely into a few categories: (1) Decreasing population and structural changes in population (2) Increase in numbers of dentists, (3) Changes in the pattern of dental diseases and (4) Changes in medical environment. In Korea, the children population in the age range of 0 ~ 14 years old had been decreased by 2 million in 2010 compared to that of 2000 due to reduction of birth rate. The current population of children in the age range of 0 ~ 4 years old in 2010 takes up 16.2% of the total population, but it is estimated that such percentage would decrease to 8.0% by 2050. Such percentage is largely behind the estimated mean global population of 19.6% by 2050. On the other hand, the number of dentists had been largely increased from 18,000 in 2000 to 25,000 in 2010. And it is estimated that the number will be increased to 41,000 by 2030. In addition, the specialized personnel of Pediatric dentistry had been shown as increased by 2.5 times during past 10 years. For the changes in the pattern of dental diseases, including dental caries, each df rate of 5 years old children and 12 years old children had been decreased by 21.9% and 16.7% respectively in 2010 compared to 2000. Each df Index also had been decreased by 2.5 teeth and 1.2 teeth respectively. The medical expenditure of Korea is less than that of OECD and more specifically, the expenditure from the National Health Plan is less than OECD but the expenditure covered by households is larger than OECD. These facts indicate that it is considered as requiring the coverage of the national health plan to be reinforced more in the future and as such reinforcement needs continuous promotion. In medical examination pattern of Pediatric dentistry, the preventive and corrective treatment were increased whereas the restorative treatment was decreased. It is considered that such change is caused from decrease of dental caries from activation of the prevention project at national level. For the restorative treatment, the restorations in use of dental amalgam, pre-existing gold crowning and endodontic treatment had been decreased in their proportion while the restorative treatment in use of composite resin had been increased. It is considered that such changes is caused by the change of demands from patients and family or guardians as they desired more aesthetic improvement along with socio-economic growth of Korean society. Due to such changes in dentistry, the pediatric dentistry in Korea also attempts to have changes in the patterns of medical examination as follows; It tends to implement early stage treatment through early diagnosis utilizing various diagnostic tools such as FOTI or QLF. The early stage dental caries so called white spot had been included in the subjects for dental care or management and in order to do so, the medical care guidelines essentially accompanied with remineralization treatment as well as minimally invasive treatment is being generalized gradually. Also, centering the Pediatric dentists, the importance of caries risk assessment is being recognized, in addition that the management of dental caries is being changed from surgical approach to internal medicinal approach. Recently, efforts began to emerge in order to increase the target patients to be managed by dentists and to expand the application scope of Pediatric dentistry along with through such changes. The interest and activities of Pediatric dentists which had been limited to the medical examination room so far, is now being expanded externally, as they put efforts for participating in the preventive policy making process of the community or the state, and to support the political theories. And also opinions are being collected into the direction that the future- oriented strategic political tasks shall be selected and researches as well as presentations on the theoretical rationale of such tasks at the association level.

• Journal of dental hygiene science
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• v.16 no.4
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• pp.272-283
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• 2016

This study compared and analyzed the occluding effects of fluoride compounds and desensitizers, which are commonly used in dental clinics, on dentinal tubules. This study also evaluated the persistence of the active ingredients over time by performing toothbrushing with an electric toothbrush. Thirty-five molar teeth, which had been extracted within the past 3 months from healthy people without tooth decays, amalgam fillings, or dental crowns, were divided into 4 pieces each. Of these, 135 teeth pieces were used as study specimens. These specimens were divided into a control group, an untreated group, and 5 experimental groups (acidulated fluoride gel, fluoride varnish, Gluma, Super Seal, and SE-Bond). The specimens were then subjected to toothbrushing equivalent to 1 week (140 times), 2 weeks (280 times), and 4 weeks (560 times), and the occluding effects on dentinal tubules in 3 regions of each specimen were examined under a scanning electron microscope. The fluoride varnish treated group showed the highest degree of dentinal tubule occlusion effects during the first, second, and fourth weeks of toothbrushing, with the SE-Bond treated group showing the second highest degree and the Gluma treated group showing the lowest degree. After 4 weeks of toothbrushing, the Gluma treated group and the Super Seal treated group showed the lowest degrees of dentinal tubule occlusion effects. In summary, the fluoride varnish treated group and the SE-Bond treated group displayed higher occlusion effects even after 4 weeks of treatment than did the other experimental groups. Therefore, it is the authors' belief that fluoride varnish and SE-Bond are effective for treating dentinal hyperesthesia.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.519-528
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• 2002

It is not a rare occasion that certain dental procedures involving tooth reduction being peformed under inadequate water cooling due to a variety of reasons. This situation could possibly inflict the critical insult to the pulpal tissue of indicated tooth. The purpose of this experiment was to study the pattern of diffusion of external heat produced during routine dental procedures into the pulpal tissue. 30 stone blocks containing three lower second primary molars were used for certain restorative procedures and the temperature of the indicated tooth surface was measured by thermography(Inframetrics 600) and further used as a baseline data for the finite element analysis model fabrication designed in order to evaluate the pattern of thermal diffusion. The ranges of highest surface temperature measured from several dental procedures under water cooling and non-water cooling were $30.8^{\circ}C{\sim}43.6^{\circ}C$ and $51.2^{\circ}C{\sim}103.4^{\circ}C$ respectively. Among procedures studied, crown preparation showed the highest value and amalgam removal showed the lowest. Comparisons between data measured under water cooling and non-water cooling conditions have shown the statistically significant difference(p<0.05). All the non-cooling conditions have shown the relatively larger increment of temperature change at the pulp horn area than the cooling conditions. The results of this study strongly indicate that the water coolant is the essential element in restorative procedures for the maintenance of healthy pulp. Further related studies involving more procedures and conditions are recommended.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.1
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• pp.97-101
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• 2010

The practice pattern of pediatric dentistry in the university dental hospital has been changing for the last several decades, due to socioeconomic changes, developments in dental materials and increasing number of private pediatric dental clinics. The purpose of this study is to survey the changing patterns of pediatric dental treatment in the university dental hospital and to present the future direction for pediatric dentistry. Patient distribution and practice trends were reviewed based on the OCS (order communication system) records of the department of pediatric dentistry, Seoul National University Dental Hospital from 2001 to 2008. Results were as follows; 1. The number of patients increased up to 2005 and decreased in 2006, and has remained constant up to 2008. 2. The proportion of preventive and orthodontic treatment increased and the proportion of restorative and pulpal treatment decreased. 3. In restorative treatment, amalgam restoration decreased and resin restoration increased. 4. Frequency of sedation decreased in 2006, 2007 and increased in 2008. 5. Frequency of general anesthesia increased up to 2008.

• Journal of Environmental Health Sciences
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• v.33 no.5
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• pp.386-391
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• 2007

Mercury contamination and its health effects have become major concern of environmental health study in Korea. Mercury exposure of some group were investigated to get the accurate data for policy making and study. About 2,000 children at 26 elementary schools participated in this survey to evaluate the exposure levels and to investigate main exposure source of mercury. Analysis of mercury levels in the whole blood and urine samples were conducted and questionnaire survey was done about the factors influencing exposures simultaneously. Mercury exposure levels of domestic children were N.D. to 17.26 ppb in blood, 0.17 to $21.67{\mu}g/g$-creatinine in urine. The mean(arithmetic) levels are 2.42 ppb in blood and $2.53{\mu}g/g$-creatinine in urine. Both of them were below the recommendation levels of US EPA and German CHBM I $5.8{\mu}g/l$ and $5{\mu}g/l$ in blood, $5{\mu}g/g$-creatinine of German CHBM I in urine. But 1%, 0.51% of levels in blood exceed the level of CHBM I and US EPA, 8%, 0.85% of children were over the level of CHBM I and CHBM II in urine. Multi-valuable regression analysis showed that the existence of road near the residence in addition to the preference for fish have significance with blood mercury exposure level of domestic children. The existence of factory near the house and the experience of dental amalgam treatment had statistical relations with urine mercury level.

• Imaging Science in Dentistry
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• v.41 no.4
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• pp.143-150
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• 2011

Purpose : The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography (CBCT) images and bitewing images in detection of secondary caries. Materials and Methods : One hundred and twenty proximal slots of Class II cavities were randomly prepared on human premolar and molar teeth, and restored with amalgam (n=60) and composite resin (n=60). Then, artificial secondary caries lesions were randomly created using round steel No. 4 bur. The teeth were radiographed with a conventional bitewing technique and two CBCT systems; Pax-500ECT and Promax 3D. All images were evaluated by five observers. The area under the receiver operating characteristic (ROC) curve ($A_z$) was used to evaluate the diagnostic accuracy. Significant difference was tested using the Friedman test (p value<0.05). Results : The mean $A_z$ values for bitewing, Pax-500ECT, and Promax 3D imaging systems were 0.882, 0.995, and 0.978, respectively. Significant differences were found between the two CBCT systems and film (p=0.007). For CBCT systems, the axial plane showed the greatest $A_z$ value. Conclusion : Based on the design of this study, CBCT images were better than bitewing radiographs in detection of secondary caries.

• Journal of Preventive Medicine and Public Health
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• v.45 no.6
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• pp.344-352
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• 2012

Mercury is a toxic and non-essential metal in the human body. Mercury is ubiquitously distributed in the environment, present in natural products, and exists extensively in items encountered in daily life. There are three forms of mercury, i.e., elemental (or metallic) mercury, inorganic mercury compounds, and organic mercury compounds. This review examines the toxicity of elemental mercury and inorganic mercury compounds. Inorganic mercury compounds are water soluble with a bioavailability of 7% to 15% after ingestion; they are also irritants and cause gastrointestinal symptoms. Upon entering the body, inorganic mercury compounds are accumulated mainly in the kidneys and produce kidney damage. In contrast, human exposure to elemental mercury is mainly by inhalation, followed by rapid absorption and distribution in all major organs. Elemental mercury from ingestion is poorly absorbed with a bioavailability of less than 0.01%. The primary target organs of elemental mercury are the brain and kidney. Elemental mercury is lipid soluble and can cross the blood-brain barrier, while inorganic mercury compounds are not lipid soluble, rendering them unable to cross the blood-brain barrier. Elemental mercury may also enter the brain from the nasal cavity through the olfactory pathway. The blood mercury is a useful biomarker after short-term and high-level exposure, whereas the urine mercury is the ideal biomarker for long-term exposure to both elemental and inorganic mercury, and also as a good indicator of body burden. This review discusses the common sources of mercury exposure, skin lightening products containing mercury and mercury release from dental amalgam filling, two issues that happen in daily life, bear significant public health importance, and yet undergo extensive debate on their safety.

• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.205-213
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• 1993

The purpose of the study was to evaluate the degree of the marginal leakage of esthetic restorative materials on root caries restoration. 120 cavities were prepared to $90^{\circ}$ butt joint on all margins on the crown and root portion, and divided into 4 groups. The four groups of cavity were filled with Amalgam(Dongmuyung Dental Alloy Co., Ltd, KOREA), Silux$^{(R)}$(3M Co., USA)-Scotch Bond 2$^{(R)}$(3M Co., USA), Silux$^{(R)}$-All Bond$^{(R)}$(BISCO USA), and GC Fuji II$^{(R)}$(G-C Co., JAPAN) respectively. The apical margin of the preparation was finished to leave a flash of restorative material. The coronal margin of the preparation was finished not to leave a flash of restorative material. All specimens were sectioned longitudinally with Isomet Low speed saw(Buether Ltd, USA). The degree of dye penetration was evaluated as the parameter of marginal leakage under the stereoscope. The results were as follows. 1. At the enamel and dentin/cementum margins, the margin were finished to leave a flash of material showed less marginal leakage than that were finished not to leave a flash of material (P<0.001). 2. The enamel margins showed less marginal leakage than the dentin/cementum margins(P<0.001). 3. There was no significant difference in the degree of the marginal leakage between Silux$^{(R)}$-Scotch Bond 2$^{(R)}$ group and Silux$^{(R)}$-All Bond$^{(R)}$ group.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.2
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• pp.179-185
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• 2010

Molar Incisor Hypomineralization(MIH) have recently gained intensive research interests and various clinical trials. Most prevalence, etiology, treatment studies in MIH were carried out in the European countries, and data from the Korean were seldom. This study aimed to investigate the prevalence of MIH and the status of dental caries and treatment on the first permanent molars in primary school children. For this study, 1,344 primary school students in Busan and Ulsan cities were examined directly the permanent incisors and first molars. The results of the survey were as follows: 81 MIH cases were identified among 1,344 cases. The prevalence of MIH in this group of children was 6.0%. Children with MIH showed a significantly higher DMFT value for permanent teeth than children without MIH. The mean number of decayed, missed, and filled in 1st permanent molars(DMFT index) was 1.17. The rate of children with restoration on 1st permanent molar was 13.6% and the sequence of restoration materials was as follows : composite resin, amalgam, gold inlay.

• Molecular & Cellular Toxicology
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• v.4 no.3
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• pp.235-245
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• 2008

Exposure to mercury was assessed in 125 Korean (Gwangju and Busan) and 373 Chinese primary school students (Xinguang village, Goumen town) using hair mercury analysis from November 2006 to September 2007. The geometric mean concentration of mercury was higher among Korean children with recording 0.73 ${\mu}g$/g, compared to Chinese children of 0.12 ${\mu}g$/g, which indicated statistically difference (P<0.01). The mean concentration of Korean children living near incineration facilities was higher by recording 0.76 ${\mu}g$/g while the average concentration of their counterpart in Korea reached 0.69 ${\mu}g$/g. In case of Chinese children, those who are living near power plants showed higher level with posting 0.16 ${\mu}g$/g while the others recorded 0.10 ${\mu}g$/g (P<0.01). Intake of fish was found to be related to hair mercury level. In case of Korean children, those with high fish intake recorded 0.79 ${\mu}g$/g in terms of the geometric mean concentration while the others with low fish intake posted 0.61 ${\mu}g$/g. Among Chinese children, those who often eat fish recorded 0.13 ${\mu}g$/g compared to the others with low fish intake of 0.11 ${\mu}g$/g. On the other hand, amalgam dental fillings have limited influence on mean hair mercury level. As for vaccination, within a month of vaccination, the geometric mean concentration of Korean children reached 0.76 ${\mu}g$/g, and in case of 15 days after injection, the level was 1.20 ${\mu}g$/g. In China, the level of children at one month after receiving injection stood at 0.15 ${\mu}g$/g while the level within 15 days was 0.13 ${\mu}g$/g. Multiple regression analysis showed that BMI, passive smoking, and fish consumption are closely related to hair mercury level among the Korean subjects. In China, hair mercury level was affected by age, location, passive smoking, fish consumption, and vaccination. Explanatory power was 21.6% with $R^2$=0.216.