• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.600-612
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• 2001

The purpose of this study is concerned with an investigation of the actual condition of traumatic injuries of teeth and supporting structures in children to set up possible criteria for prevention and treatment of injured teeth. The materials consisted of the clinical records of 431 traumatically injured teeth of 212 children, accumulated during two years from the first of April in 1998 to the end of March in 2000, supplied from the Dept. of Pediatric Dentistry, Chonbuk National University Hospital. The incidence of injuries in boys was extremely high for permanent teeth, twice as high as in girls. Accidents to primary teeth were most common from 1 to 2 years of age and to permanent teeth were most from 8 to 9 years of age. The most common cause of trauma was a fall for both primary and permanent teeth, followed by collision. The anterior teeth in maxilla was most frequently affected by trauma in both the primary and permanent teeth. The most common type of trauma were loosening for the primary teeth, followed by luxation types which included the intrusion, displacement and extrusion and complete avulsion types. For the permanent teeth, the most common type of trauma were tooth fracture. The most common trauma of soft tissue was laceration of upper lip, lower lip and gingiva of maxilla Concerning treatment at the first visit, primary teeth with only loosening and concussion were not usually treated. Permanent teeth were often treated by crown restorations for crown fractures and by endodontic procedures for pulpal exposure. Though we could elucidate actual condition of traumatic injuries of teeth in children, we should make a follow-up survey to ensure the prognosis of injured teeth and establish the most desirable criteria for traumatized teeth in children.

• Analytical Science and Technology
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• v.20 no.4
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• pp.261-267
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• 2007

The 20 L small chamber test method is to evaluate pollutants such as TVOC, formaldehyde emitted from building materials. This method was only designed to evaluate the surface emission of sample exposed in the chamber. In this method, building materials cut with a fixed standard size are fixed in a sample sealing box. The sample sealing box is put into the 20 L test chamber. This chamber is ventilated at a standard air change rate with purified air for 7 days then the sample from the chamber is collected and analyzed to measure the emission rate of TVOC and formaldehyde. In this method, however, if the sealing box does not guarantee airtightness, accurate evaluation for the building materials can not be achieved due to the pollutants emitted from edge of the sample so called, edge effect. This edge effect can be much greater when evaluating panels such as plywood, flooring due to their surface treatment. In this study, flooring was tested to check airtightness of the sample sealing box with analytic results between 1L and 20 L test chamber. Furniture materials like LPM coated one side surface treatment and MDF coated both sides surface treatment with LPM were tested to identify whether the improvement of the sample sealing box airtightness is possible with the comparison between existing and improved test method that low VOC emission tape was used to seal the sample edge. After 7 days, MDF TVOC emission rate was different according to the existence and nonexistence of tape. The emission rate of the existing test method was $0.009mg/m^2h$ and that of improved test method was $0.003mg/m^2h$. Relative standard deviation for the existing test method was $0.004mg/m^2h$ and relative standard deviation for the improved test method was $0.002mg/m^2h$ when the same sample was analyzed three times. The improved test method in this study using low VOC emission tape was effective and able to reduce the heterogeneous effect of the edge from the sample sealing box.