• Development and Reproduction
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• v.4 no.1
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• pp.53-59
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• 2000

Endocrine disruptors (EDs) are exogenous chemicals which interfere several aspects of natural hormone properties. EDs with estrogenic activity have been recently reported to cause animal reproductive problems. This study was performed to investigate the effects of bisphenol A (BPA) on the mouse spermatogenesis in vivo. Male ICR mice were orally injected on a daily basis with low dose of BPA 20 mg/kg, high dose of BPA 200 mg/kg, or corn oil (vehicle control) for 7 days, and litter size and weights of body, testis, and cauda epididymis were measured. The level of serum testosterone and the expression of TGF- $\beta$$_1$ mRNA were also analyzed using RIA and RT-PCR, respectively. Also, morphological differences of testes after treatments were examined. Sperm concentration and level of serum testosterone showed a decreasing tendency detected as untreated >corn oil >low >high dose BPA treated mice, although there were no significant statistical differences. Interestingly, in mice treated with a high dose of BPA, partial disappearance of spermatozoa in seminiferous tubular lumen and the expression of TGF-$\beta$$_1$ mRNA were observed. Spermatogenesis was disrupted through TGF-$\beta$ system in the seminiferous tubules, resulting in no development of germ cells. Similarly, the litter size treated with a high dose of BPA was significantly different from that of untreated control group. In conclusion, these results that a high dose of BPA (200 mg/kg) acts as an endocrine disruptor during apermatogenesis in male mice md that there are BPA-specific lesions in the adult male reproductive tract might represent a permanently altered responsiveness to testosterone by BPA in the affected target tissue.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.5
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• pp.386-395
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• 2011

Introduction: Osteoporosis is a major health problem in the elderly that involves changes in the properties of bone as well as impaired bone healing around a titanium implant in both humans and animals. This study examined effect of low intensity pulsed ultrasound (LIPUS) on the bone healing process around a titanium implant in osteoporosis-induced rats. Materials and Methods: Sixteen rats were divided into two groups. A control group with osteoporosis induced by removing both ovaries and an experimental group of rats that were applied with LIPUS after osteoporosis had been induced. A screw type titanium implant (diameter, 2.0 mm: length, 3.5 mm, Cowell-Medi, KOREA) was placed into the tibias of 16 rats. The control and experimental group contained 8 rats each. The rats were sacrificed at 1, 2, 4, and 8 weeks after implantation to examine the histopathology and immunochemistry. Results: The histopathology examination revealed earlier new bone formation in the experimental group than the control group. In particular, at 1 week after implantation, more new bone matrix and collagen were observed around the implant of the experimental group compared to the control group. Immunochemistry analysis showed that the level of OPG expression of the experimental group was higher in the early stages than in the control group. After 8 weeks, the levels of OPG expression were similar in both groups. The expression level of receptor activator of nuclear factor kB ligand (RANKL) was stronger in the experimental group than the control group. After 4 weeks, the level of RANKL expression was similar in both groups. Conclusion: These results suggest that the application of LIPUS to implantation can promote bone healing around titanium in osteoporosis animals.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.2
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• pp.161-164
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• 2002

In recent, distraction osteogenesis has been used to correct skeletal malformations and discrepancies in the craniofacial area. It also seems to be considered as an alternative in the treatment of severe midfacial hypoplasia. There are some types of distractors for midfacial distraction such as subcutaneous distractors and rigid external distractors. We used a rigid external distractor for correction (RED) of craniofacial hypoplasia. Seven patients underwent a midfacial distraction osteogenesis with a rigid external distractor between April 2000 and July 2001. Three patients suffered from Apert's syndrome, three patients from Crouzon's syndrome, and one patient suffered from midfacial hypoplasia due to midfacial radiotheraphy during childhood. On average, the mean distance of distraction was 19.8mm ($10{\sim}25mm$) and the distraction lasted for 24 days. The patients showed no severe complications like infections, optic disturbance, or wrong distraction vectors. One patient complained pain on the site of the occipital fixation of the distractor. In one patient who underwent subtotal craniectomy 3 months before Le Fort III distraction, the distractor was dislocated as the cranial bone was too weak to support the distractor. This report reveals that the application of rigid external distractor and transfacial pull results in an exact control of the distraction vectors and an excellent correction of midfacial hypoplasia without any severe complications.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.403-409
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• 2013

The purpose of this study was to evaluate the correlation between caries experience, Quantitative Light-Induced Fluorescence-Digital (QLF-D) redings and new caries activity test (Cariview) results in preschool children. Fifty-seven healthy kindergarten children (male 28, female 29) were participated this study. The calibrated dentist investigated the caries experience of children and new caries activity test. Cariview samples were incubated in the activated medium at $37^{\circ}C$ for 48 hours. All QLF-D taking and readings were performed by one experienced and trained operator under identical conditions in a dental unit chair located in a darkened room. Analysis range was limited to the maxillary and mandibular anterior teeth. QLF-D redings (white spot and dental plaque) were analysed using QLF system. The dft index had a relatively high correlation with the QLF-D redings (white spot: r=0.617, simple plaque score: r=0.500) (p<0.01). Also, there was significant correlation between dft index and the Cariview score (r=0.286) (p<0.05). However, the Cariview score had no significant correlation between dt index and ft index (p>0.05). QLF-D can be evaluated objectively the initial caries lesions and dental plaque correlated with caries experience. Therefore, QLF-D will be useful to the study of caries prediction.

• Journal of Oral Medicine and Pain
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• v.19 no.1
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• pp.73-91
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• 1994

The author used rabbits in order to examine the effect of Ga-As low power generating semiconductor laser on artificially produced injuries of experimental animals. Artificially produced injuries include surgical wound of 3mm length, 2mm depth in size on ventral skin surface of rabbit and buccal mucosa, and electrical injury formed on opposite side of skin and buccal mucosa by electrical cauterization of same length and depth, and chemical injury formed by FC(Formocresol) solution applied on the anterior dorsal part of tongue. And then, on the experimental group, Ga-As laser was irradiated beginning on the day after the wound formation and continued to irradiate every each other day for five minutes. After1, 3, 6, 9, 13th day, certain number of animals of control and experimental group were sacrified, and wound site tissue was excised to make samples and was observed under light microscope. The following is the conclusions after comparing the healing procedure of experimental and control group. The following results were obtained : 1. Inflammation was decreased more rapidly in the experimental group than the control group. 2. In the surgical, the electrical and the chemical injuries in the oral mucosa, re-epithelialization was completed more rapidly in the experimental group than the control group. In the electrical injury on the skin, re-epithelialization was completed about 6 days after wound formation on both groups. 3. In the electrical and the surgical injuries on the oral mucosa, granulation tissue formation started at 3 days after injury on both groups, but in the chemical injury, it was completed about 3 days faster in the control group than the experimental group. In the surgical wound on the skin, it was completed about 9 days after injury, but faster in the experimental group. In the electrical injury on the skin, it was faster in the control group than the experimental group. 4. In the electrical and the surgical injuries on the oral mucosa, fibrosis was started at 6~9 days after injury on both groups, but regeneration of connective tissue in the experimental group was observed much more than the control group. 5. When comparing the effect of wound healing on skin and oral mucosa of control and experimental group, granulation tissue formation and re-epithelialization in the oral mucosa was more vigorous. In conclusion, the difference of timing and the sequence of wound healing process(inflammation, re-epithelialization, granulation tissue formation, fibrosis) following Laser irradiation between control and experimental group was not observed, but the healing tissue was observed much more in the Laser irradiated group.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.517-523
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• 2000

Nasopharyngeal closure is a sphincter mechanism between the activities of the soft palate, lateral pharyngeal wall and the posterior pharyngeal wall, which divides the oral cavity and the nasal cavity. It participates in physiological activities such as swallowing, breathing and pronunciation. In case of an error in this mechanism, it is called a nasopharyngeal incompetence. The causes of this error are defects in (1) length, function, posture of the soft palate (2) depth and width of the nasopharynx, (3) activity of the posterior and lateral pharyngeal wall. The purpose of this study is to analyze the nasopharynx of cleft palate patients using lateral cephalograms and at the same time, evaluate the degree of hypernasality of each vowels to find its relationship with nasopharyngeal incompetence. The following results were obtained: 1. The length of the soft palate was markedly short than normal. 2. The adequate ratio was smaller than the normal value. 3. As the adequate ratio decreased, when articulating vowels, anatomic mVPI increased. 4. When articulating each vowels, anatomic VPI was in proportion with the degree of hypernasality. 5. The degree of hypernasality was greater in high vowels(/i/, /u/) than low vowel(/a/). From the above results, it can be concluded that in cleft palate patients, lateral cephalograms can be used effectively in diagnosing and evaluating nasopharyngeal incompetence. The anatomic structure of the nasopharynx has close relation to the degree of hypernasality.

• Food Science and Preservation
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• v.20 no.1
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• pp.121-126
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• 2013

The present study was carried out to investigate the in vivo single-dose acute toxicity of Leuconostoc citreum GR1 (Leuc. citreum GR1), a lactic acid bacteria isolated from kimchi, in ICR male and female mice. The test article was orally administered once to both sexes of mice. The mortalities, clinical findings, autopsy findings, and body weight changes were monitored daily for two weeks. The male and female mice were gavaged with Leuc. kimchi GR1 of four doses (625, 1,250. 2,500 and 5,000 mg/kg). The oral $LD_{50}$ of Leuc. citreum GR1 was considered higher than 5,000 mg/kg. No significant changes in the general conditions, body weights, clinical signs and presence of gross lesions were observed in both sexes of mice to whom Leuc. citreum GR1 was administered orally. The results indicated that the 5,000 mg/kg dose of Leuc. citreum GR1 showed no adverse effect.

• Journal of dental hygiene science
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• v.4 no.3
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• pp.97-102
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• 2004

In order to find out the rate of error according to intraoral standard radiographic techniques, this study analyzed 3,251 standard films, and conducted a questionnaire with 120 Daegu Health College students who have used the bisecting angle technique and the paralleling technique. Followed are the results of the study: 1. The rate of error was the highest in canine from both maxilla and mandible when used by the bisecting angle technique. 2. The rate of error was the highest in premolar from both maxilla and mandible when used by the paralleling technique. 3. The technical error was occurred most frequently in elongation. 4. The rate of error and distortion was higher in the bisecting angle technique than in the paralleling technique. 5. The processing error was occurred most frequently in light film. 6. In applying radiographic techniques, the subjects indicated that the vertical angulation of central radiation in the bisecting angle technique and the oral fixation of film holder in the paralleling technique were the most difficult.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.122-128
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• 2021

Short root anomaly (SRA) is a rare dental condition with abnormally short and blunt root morphology. It mostly affects maxillary central incisors symmetrically and only has been observed in permanent teeth. A 9-year-old girl was referred from a local dental clinic for short root development in mixed dentition with no symptoms. Radiographic and intraoral examinations revealed SRA on upper and lower incisors and mandibular first molars along with other dental anomalies such as enamel hypoplasia and dens invaginatus. During long - term follow - up for 5 years, her mixed dentition has changed to permanent dentition and generalized SRA was observed in all permanent teeth. Cephalometric radiograph also revealed the calcification between the anterior and posterior clinoid processes described as a sella turcica bridge which was reported associating with dental anomalies. Early diagnosis of SRA is emphasized for successful management and prevention of root resorption and tooth loss. This report aimed to present a rare case of generalized SRA along with other dental anomalies and sella turcica bridging in a female patient through long - term follow - up.

• Journal of the korean academy of Pediatric Dentistry
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• v.50 no.2
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• pp.192-204
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• 2023

This study aimed to determine the criteria for quantifying developmental defects of enamel in primary teeth in premature babies and to investigate the severity of developmental defects according to the gestational age, birth weight, systemic complications, and treatments received after preterm birth. Birth information, a history of complications, the duration of parenteral nutrition, and endotracheal intubation were investigated by retrospectively reviewing the admission and discharge records of premature babies in the neonatal intensive care unit. The Preterm Developmental Defects of Enamel (PDDE) index was designed by modifying the existing developmental defects of enamel index. Based on PDDE index, the evaluator scored developmental defects of enamel by classifying them as enamel hypomineralization and hypoplasia. The PDDE scores in the extremely preterm and extremely low birth weight groups were significantly higher than those in other groups. Furthermore, PDDE scores of premature babies with bronchopulmonary dysplasia, rickets, intraventricular hemorrhage, or necrotizing colitis were significantly higher than those in the control group. In addition, more than 50 days of endotracheal intubation and more than 20 days of parenteral nutrition were associated with significantly higher PDDE scores than those in the control group and were risk factors for developmental defects of enamel. This study provides basic information for identifying risk factors for developmental defects of enamel in premature babies.