• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.4
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• pp.727-733
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• 1997

Autotransplantation is a procedure which transplants teeth from the original position to other positions in the same individual. It is classified surgical reposition by intraalveolar autotransplantation and transalveolar autotransplantation. The prognosis for successful autotransplantation is dependent on a number of factors such as root development, surgical technique, patient's age, endodontic treatment, time and type of splinting, preservation of periodontal ligament and storage medium. The most important factor is preservation of periodontal ligament. The cause of the failure of transplantation include damage of the transplant during removal from deep palatal malposition, poor regeneration of the bone around the transplant and chronic periodontal infection. In case I, Impacted maxillary canine for which surgical exposure and orthodontic treatment was impossisle was transplanted. After 2 weeks, It showed periapical radiolucency and external root resorption. So, endodontic treatment was done. One year later, permanent filling was done with gutta percha. In case II, Transpositioned maxillary central incisor was transplanted after extraction of impacted mesiodens. Pulp vitality was maintained during 5 months without other clinical symptons.

• Journal of Preventive Medicine and Public Health
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• v.28 no.4 s.51
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• pp.765-771
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• 1995

This study was performed to investigate the possibility of temporary threshold shift (TTS) of vibration sense could induced by exposure to high-frequency vibration or by work position taking by dentists in drilling or polishing. The vibratory perception thresholds (VPT) of 28 healthy men were measured on the index fingertip pulp of dominant hand at 250 Hz. The vibrating tool used in test was a low-speed handpiece of 34,000 rpm. For the TTS test, the dominant hand was exposed to high-frequency vibration and to work position for five minutes, respectively. The VPTs before and after vibratory exposure were $23.5{\pm}3.5dB,\;30.8{\pm}4.2dB$, respectively and VPT after work position was $23.7{\pm}4.6dB$. The difference between before and after vibartory exposure was statistically significant (p<0.001). The correlation of height, weight and BMI with baseline VPTs was not statistically significant. Also, there was no difference of VPTs by smoking. These results suggest that high-frequency vibration from dental handpieces might cause the impairment of vibration sensation.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.91-95
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• 2009

The use of stainless steel crowns are indicated for restoration of primary or permanent molars with proximal dental caries, extensive dental caries, or previous pulp treatment with increased danger of tooth fracture. Stainless steel crowns were introduced by Humphrey in 1950. For their improved durability, longevity, and success rate, they have been strongly considered for restoring extensive and multi-surfaced dental caries of molars in pediatric dentistry. However, they also have shortcomings, such as possibility of pulpal exposure or damaging proximal surface of adjacent teeth. In addition, when oversized stainless steel crowns are used, eruption of the adjacent permanent teeth may be disturbed by their prominent margin. As a means to compensate the shortcomings of stainless steel crowns, use of orthodontics bands may be considered. It is an alternative restoration method, where an orthodontic band is placed on a tooth first and cavity is restored with filling material, such as composite resin, glass ionomer, or amalgam. The use of an orthodontic band is indicated for molar restoration with cervical dental caries, extensive dental caries, enamel hypoplasia, or previous pulp treatment. Because it requires shorter chair time compared to stainless steel crown, its application is very useful for children with poor behavior. However, restoration using an orthodontic band requires good oral hygiene after its application. This case report illustrates the conservative restoration of primary molars and permanent molars with extensive dental caries using orthodontic bands.

• Toxicological Research
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• v.18 no.1
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• pp.13-22
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• 2002

In Korea, 2,320 tonnes of acetanilide were mostly wed as intermediates for synthesis in phar-maceuticals or additives in synthesizing hydrogen peroxide, varnishes, polymers and rubber. Only small amount of 120 kg were wed as a stabilizer for hydrogen peroxide solution for hair colouring agents in 1998. Readily available environmental or human exposure data do not exist in Korea at the present time. However, potential human exposures from drinking water, food, ambient water and in work places are expected to be negligible because this chemical is produced in the closed system in only one company in Korea and the processing factory is equipped with local ventilation and air filtering system. Acetanilide could be distributed mainly to water based on EQC model. This substance is readily biodegradable and its bioaccumulation is low. Acute toxicity of acetanilide is low since the L $D_{50}$ of oral exposure in rats is 1,959 mg/kg bw. The chemical is not irritating to skin, but slightly irritating to the eyes of rabbits. horn repeated dose toxicity, the adverse effects in rats were red pulp hyperplasia of spleen, bone marrow hyperplasia of femur and decreased hemoglobin, hematocrit and mean corpuscular hemoglobin concentration. The LOAEL for repeated dose toxicity in rats was 22 mg/kg/day for both sexes. Acetanilide is not considered to be genotoxic. In a reproductive/developmental toxicity study, no treatment-related changes in precoital time and rate of copulation, impregnation, pregnancy were shown in all treated groups. The NOAELs for reproduction and developmental toxicity (off-spring toxicity) are considered to be 200 mg/kg bw/day and 67 mg/kg bw/day, respectively. Ecotoxicity data has been generated in a limited number of aquatic species of algae (72 hr- $E_{b}$ $C_{50}$; 13.5 mg/l), daphnid (48hr-E $C_{50}$ > 100 mg/l) and fish (Oryzias latipes, 96hr-L $C_{50}$; 100 mg/l). Form the acute toxicity values, the predicted no effect concentration (PNEC) of 0.135 mg/1 was derived win an assessment factor of 100. On the basis of these data, acetanilide was suggested as currently of low priority for further post-SIDS work in OECD.in OECD.D.

• Journal of the Korean Wood Science and Technology
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• v.34 no.3
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• pp.90-98
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• 2006

The purpose of this study was to estimate natural dyeing properties of Korean traditional paper (Hanji). Korean traditional paper, which made from bleached bast fiber pulp of Broussonetia kazinoki was used as base paper. As dyestuffs, hot water extractives of Phellodendron amurense bark, Rosa multiflora leaf and stalk, and Rubia cordifolia root and methanol extractives of Lithospermum erytrorhizon root were used. $Al_2(SO_4)_3$ and $Fe(OH)(CH_3COO)_2$ 0.5% solution were used as mordant. Soybean juice (10%), chitosan (0.1%), and skim milk (2%) solutions were used as auxiliary dyeing agents. Accelerated aging treatments of natural dyed Korean traditional papers were undergone at following conditions: exposure temperature, $80^{\circ}C$ relative humidity, 60%; wavelength, 340 nm; UV irradiance, $0.67W/m^2/nm$ exposure time, 24, 48, and 72 hours. Colors, color difference, and color fastness were examined for estimation of natural dyeing characteristics. The auxiliary dyeing agents treated Korean traditional papers were more superior the dyeing effectiveness about dyestuffs than untreated Korean traditional papers. The dyeing effectiveness of soybean juice treated Korean traditional paper was superior to the others. The color fastness of Korean traditional paper, which was dyed with Rubia cordifolia root extractives, was most inferior to the others.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.58-65
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• 2012

The crown-root fracture is defined as a fracture of tooth that contains enamel, dentin and cementum with or without pulp exposure. Generally the fracture lines place obliquely from labial surface, between incisal edge of the crown and marginal gingiva, to palatal surface subgingivally. If the fracture line is located supragingivally, the removal of tooth fragment and supragingival restoration can be performed. In subgingival fracture line, the surgical exposure, orthodontic eruption or surgical eruption can be considered. If the fracture line is too deep to restorate, extraction or decoronation can be selected. In children and adolescents, the extraction should be the last option. Another option to select before extraction is the restoration using fiber-reinforced post and the reattachment of tooth fragment. The fiber-rainforced post enhances the retention and the durability of tooth fragment. The reattachment of crown fragment using resin adhesive system is considered minimal invasive treatment biologically. This case reports the treatment of crown-root fracture using the reattachment of crown fragment and the insertion of fiber-reinforced post.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.2
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• pp.154-162
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• 2017

Tooth wear, one of the physiological changes in the elderly patient's mouth, generally does not require treatment, but requires prosthodontic restoration when occlusal disharmony, poor masticatory function, pulp exposure occurs. One of the primary considerations in prosthodontic restoration for tooth wear is vertical dimension. It is necessary to make an accurate diagnosis and analysis, correct judgement of the interdental relationship for predictive treatment plan. A step-by-step approach considering dental care for aged is also required. In this case, a 93-year-old male patient presented with worn dentition and mobility of existing fixed dental prosthesis. After diagnosis and evaluation, maxillary rehabilitation without any change in the occlusal vertical dimension was performed and this shows satisfactory results both functionally and morphologically.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.2
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• pp.281-286
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• 2001

The treatment method of impacted tooth is various from simple observation to surgical exposure and orthodontic methods, autotransplantation is concerned to severe malposed impacted tooth. Autotransplantation is the transplantation of embedded, impacted, of unerupted tooth, into extraction socket of surgically prepared in the same individual. Autotransplantation of tooth with $\frac{1}{2}{\sim}\frac{3}{4}$ root development provides a good chance of easily extracted, a little complication, pulp survival, and complete root formation. Transplantation of uncompleted root apex tooth is aim to pulpal healing, not endodontic treatment. The case which were treated with autotransplantation is reported, and induced normal physiologic eruption and good dental alignment.

• Restorative Dentistry and Endodontics
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• v.34 no.1
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• pp.61-68
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• 2009

This study was performed to assess the radiopacity of a variety of root canal sealers according to the specification concerning root canal sealers. Ten materials including Tubli-$Seal^{TM}$. Kerr Pulp Canal $Sealer^{TM}$, AH $26^{(R)}$, AH $plus^{(R)}$, AH plus $jet^{TM}$, Ad sea $1^{TM}$. $Sealer^{TM}$, $NOGENOL^{TM}$, ZOB $seal^{TM}$, $Epiphany^{TM}$ and dentin were evaluated in this study. In the first part, densitometric reading of an each step of aluminum step wedge on occlusal film was performed at different voltage and exposure time. In the second part, ten specimens were radiographed simultaneously with an aluminum step wedges on the occlusal films under decided condition. The mean radiographic density values of the materials were transformed into radiopacity expressed equivalent thickness of aluminum (mm Al). The following results were obtained. 1. Among the various conditions, the appropriate voltage and exposure time that meet the requirement density was 60 kVp at 0.2 s 2. All of the materials had greater radiopacity than 3 mm Al requirement of ANSI/ADA specification No. 57 (2000) and ISO No. 6876 (2001) standards. 3. The radiopacity of materials increased as thickness of materials increased. 4. The mm Al value of each specimen at 1mm in thickness has a significant difference in the statistics. It suggests that root canal sealers have a sufficient radiopacity that meet the requirement.

• Progress in Medical Physics
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• v.26 no.3
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• pp.160-167
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• 2015

Radiation exposure from medical diagnostic imaging procedures to patients is one of the most significant interests in diagnostic x-ray system. A miniature x-ray intraoral tube was developed for the first time in the world which can be inserted into the mouth for imaging. Dose evaluation should be carried out in order to utilize such an imaging device for clinical use. In this study, dose evaluation of the new x-ray unit was performed by 1) using a custom made in vivo Pig phantom, 2) determining exposure condition for the clinical use, and 3) measuring patient dose of the new system. On the basis of DRLs (Diagnostic Reference Level) recommended by KDFA (Korea Food & Drug Administration), the ESD (Entrance Skin Dose) and DAP (Dose Area Product) measurements for the new x-ray imaging device were designed and measured. The maximum voltage and current of the x-ray tubes used in this study were 55 kVp, and 300 mA. The active area of the detector was $72{\times}72mm$ with pixel size of $48{\mu}m$. To obtain the operating condition of the new system, pig jaw phantom images showing major tooth-associated tissues, such as clown, pulp cavity were acquired at 1 frame/sec. Changing the beam currents 20 to $80{\mu}A$, x-ray images of 50 frames were obtained for one beam current with optimum x-ray exposure setting. Pig jaw phantom images were acquired from two commercial x-ray imaging units and compared to the new x-ray device: CS 2100, Carestream Dental LLC and EXARO, HIOSSEN, Inc. Their exposure conditions were 60 kV, 7 mA, and 60 kV, 2 mA, respectively. Comparing the new x-ray device and conventional x-ray imaging units, images of the new x-ray device around teeth and their neighboring tissues turn out to be better in spite of its small x-ray field size. ESD of the new x-ray device was measured 1.369 mGy on the beam condition for the best image quality, 0.051 mAs, which is much less than DRLs recommended by IAEA (International Atomic Energy Agency) and KDFA, both. Its dose distribution in the x-ray field size was observed to be uniform with standard deviation of 5~10 %. DAP of the new x-ray device was $82.4mGy*cm^2$ less than DRL established by KDFA even though its x-ray field size was small. This study shows that the new x-ray imaging device offers better in image quality and lower radiation dose compared to the conventional intraoral units. In additions, methods and know-how for studies in x-ray features could be accumulated from this work.