• Journal of Periodontal and Implant Science
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• v.33 no.2
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• pp.159-166
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• 2003

The purpose of this study was to investigate and compare the frequence of 4 periodontal pathogens in the supra- and subgingival plaque in periodontally healthy subjects. Twenty adult individuals aged 22 to 28 years (mean age 23.65 years) participated in this study. All subjects had no pocket sites more than 3 mm deep, and the sites selected for sampling were all negative for bleeding. After drying and isolation of the sites with cotton rolls, supragingival plaque was sampled using sterile periodontal curette. Each plaque sample was placed in individual tubes containing 500 ml of 1X PBS. After removal of the supragingival sample and any remaining supragingival plaque, subgingival plaque samples were taken from the same sites using sterile curette and placed in similar individual tubes. Identification of 4 putative periodontal pathogens from the samples was performed by polymerase chain reaction based on 16S rDNA. Chi-square test was employed to identify significant explanatory variables for the presence of the 4 periodontal pathogens. The data show that Actinobacillus actinmycetemcomitans, Porphyromonanas gingivalis, Bacteroides forsythus, and Fusobacterium nucleatum occurred in 16.9%, 14.4%, 52.5%, and 80.6%, respectively. No significant differences were noted in the periodontal pathogens between supra- and subgingival plaques according to the kind of teeth. However, the incisors were at higher risk for harboring F. nucleatum (p <0.05). Conclusion: These results reveal that anaerobic periodontal pathogens can be detected in supragingival plaques. Supragingival plaque may function as a reservoir of peri-odotopathogens.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.3
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• pp.176-183
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• 2012

Purpose: This study examined the clinical success rate of Mg titanate implants (M Implant system, Shinhung, Korea), which employ a Mg coating method, by evaluating the marginal bone loss and implant stability using radiographs and Osstell$^{(R)}$, over a 1 year. Materials and methods: The locations of the implants placement were divided into 4 areas; the maxillary and mandibular premolars and molars. In the maxilla, 8 and 9 implants were inserted in the premolar and molar areas, respectively. In the mandible, 11 and 51 implants were inserted in the premolar and molar areas. Marginal bone loss and ISQ of all implants (79) were measured after insertion, mounting the prosthetic appliance, and 1, 3, 6, and 12 months after loading. The marginal bone loss was measured from the radiograph using XCP bite, which was customized, and the implant stability measured using Osstell$^{(R)}$. Fisher's exact test (${\alpha}$=.05) was used to compare the success rates of each region. Results: The mean marginal bone loss for the upper and lower jaws were 1.537 mm and 1.172 mm. The mobility showed a non-significant reduction or increase according with time. The success rates were accounted for 94.12% and 98.39% in the upper and lower jaws; the premolars and molars were accounted for 100% and 96.67%. The two cases of early failure resulted from failure of primary stability during implant insertion. The late failures were not observed for 1 year after adding a loading to the implants. Conclusion: The Mg titanate implant showed good primary stability and good clinical results in both healing and function.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.3
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• pp.453-458
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• 2004

Mandibular fracture is less common in children than in adults. However, children are more susceptible to ankylosis and developmental disorders, and don't respond as well to intermaxillary fixation compared to adults. On the other hand, bone fracture is healed more quickly in children and complications are scarce. Mandibular fracture in children is usually treated successfully with acrylic splint therapy with or without the use of eyelet wires and intermaxillary fixation. Severe complications that include ankylosis and developmental disorders may occur. The frequency and severity of such complications can be mitigated with a shorter duration of intermaxillary fixation and good post-operative care. Encouraging mandibular physical therapy by increasing patient motivation may be necessary in such cases where the patient's response is poor and the duration of intermaxillary fixation increases; when the patient is unable to undergo physical therapy, or when intermaxillary fixation is not necessary with the patient showing only minor symptoms such as trismus. In this case report, a 6 year-old girl with bilateral condylar fracture was treated with elastic in both the upper and lower jaws to allow mandibular physical therapy using a Benoist's appliance, which allows opening, lateral, and protrusive retrusive movements of the mandible. A 7-month follow-up showed beneficial therapeutic effects such as increased mandibular movement and prevention of condylar ankylosis.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.92-101
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• 2003

Under this thesis, 235 patients with dental problems treated under general anesthesia at the Pediatric Dentistry Clinic of Yonsei Dental College were surveyed and their age distribution, reasons for taking general anesthesia, duration of anesthesia, duration of dental procedure, dental treatment peformed and complications were analyzed. A questionnaire survey was also conducted to analyze degrees of anxiety and satisfaction among their parents according to the parents' age, educational background and experience of general anesthesia, as well as the patients' age and past dental history. Following are the results. 1. When the patients were treated under general anesthesia, the degree of anxiety of their mothers was higher than that of their fathers. It appeared that the higher the parents' educational background was, the less their anxiety. 2. The higher the parents' educational level was, the higher the degree of satisfaction after treatment under general anesthesia. 95 cases (87.2%) responded that they would accept such treatment again, if needed. From the result, dental treatment under general anesthesia causes anxiety for parent but the parent's satisfaction level was high. And that was the way gives good quality of dental service to unmanagable patients.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.3
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• pp.344-351
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• 2020

Amelogenesis imperfecta (AI) occurs either in isolation or in association with other dental abnormalities and systemic disorder. A rare syndrome associating AI with nephrocalcinosis was named as Enamel Renal Syndrome (ERS; OMIM #204690). This syndrome is characterized by severe enamel hypoplasia, failed tooth eruption, intra pulpal calcifications, enlarged gingiva, and nephrocalcinosis. Nephrocalcinosis is a condition where calcium salts are deposited in renal tissue, and this may lead to critical kidney complications. This rare syndrome shows pathognomonic oral characteristics that are easily detectable at an early age, which proceeds the onset of renal involvement. Pediatric dentists are the first oral health practitioners whom ERS patients will meet at early age. The role of pediatric dentists is critically important for early diagnosis and referral of patients to both nephrologists for renal assessment and geneticists for identification of causative mutation and diagnosis. Early detection of renal involvement may provide chances to prevent further undesired renal complications.

• Molecules and Cells
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• v.40 no.6
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• pp.386-392
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• 2017

Periodontal ligament stem cells (PDLSCs) are multipotent stem cells derived from periodontium and have mesenchymal stem cell (MSC)-like characteristics. Recently, the perivascular region was recognized as the developmental origin of MSCs, which suggests the in vivo angiogenic potential of PDLSCs. In this study, we investigated whether PDLSCs could be a potential source of perivascular cells, which could contribute to in vivo angiogenesis. PDLSCs exhibited typical MSC-like characteristics such as the expression pattern of surface markers (CD29, CD44, CD73, and CD105) and differentiation potentials (osteogenic and adipogenic differentiation). Moreover, PDLSCs expressed perivascular cell markers such as NG2, ${\alpha}-smooth$ muscle actin, platelet-derived growth factor receptor ${\beta}$, and CD146. We conducted an in vivo Matrigel plug assay to confirm the in vivo angiogenic potential of PDLSCs. We could not observe significant vessel-like structures with PDLSCs alone or human umbilical vein endothelial cells (HUVECs) alone at day 7 after injection. However, when PDLSCs and HUVECs were co-injected, there were vessel-like structures containing red blood cells in the lumens, which suggested that anastomosis occurred between newly formed vessels and host circulatory system. To block the $SDF-1{\alpha}$ and CXCR4 axis between PDLSCs and HUVECs, AMD3100, a CXCR4 antagonist, was added into the Matrigel plug. After day 3 and day 7 after injection, there were no significant vessel-like structures. In conclusion, we demonstrated the perivascular characteristics of PDLSCs and their contribution to in vivo angiogenesis, which might imply potential application of PDLSCs into the neovascularization of tissue engineering and vascular diseases.

• Journal of Korean society of Dental Hygiene
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• v.12 no.3
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• pp.563-576
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• 2012

목적 : 본 연구는 업무형태에 따른 측두하악장애의 유병률과 업무 시 노출되는 직무스트레스 및 구강 내 악습관이 측두하악장애와 어떠한 연관성이 있는지 알아보아 보건학적 기초자료를 제공하고자 실시되었다. 방법 : 본 연구의 자료 수집을 위하여 서울과 경기 일부지역에 근무하고 있는 일반사무직, 서비스직, 교직원으로부터 편의 추출된 452명을 대상으로 2010년 1월부터 2010년 4월까지 설문조사를 실시하였고, 수거된 353명을 연구대상으로 하였다. 설문지는 측두하악장애의 증상, 하악사용에 관한 구강 내 악습관, 직무스트레스, 인구사회학적 특성으로 구성되었다. 측두하악장애의 증상의 정도를 구분하기 위해 설문지의 양성응답 수의 빈도에 따라 무증상인 1단계에서 양성응답 수가 가장 많은 4단계 까지 총 4그룹으로 나누었다. 측두하악장애의 유병률을 알아보기 위하여 빈도분석을 시행하였고, 측두하악장애의 증상의 정도에 따른 여러 요인들 간의 연관성 및 관련요인을 알아보기 위하여 교차분석 및 경향성 분석과 다항로지스틱회기 분석을 시행하였다. 결과 : 측두하악장애의 유병률은 75.4%였고, 측두하악장애에 대한 주관적 증상으로는 관절잡음이 56.4%로 가장 주된 증상 중 하나였으나 남녀 간의 차이는 통계적으로 유의하지 않았다. 다음으로는 두통이나 목의 통증이 36.5%이었고, 귀, 관자놀이, 볼 주위의 통증이 22.1%로 높았다. 측두하악장애의 주관적인 증상 수에 따른 인구사회학적 특성은 증상이 없는 경우 여성에서 19.1%, 남성에서 36.6%로 여성에서 더 높은 유병률을 보였다. 연령별로는 40세 이상의 그룹보다 20 - 30대그룹에서 측두하악장애 증상수가 높아지는 경향을 보였다. 하악 사용과 관련된 악습관 및 직무스트레스는 측두하악장애 증상수와 유의한 관련성이 있는 것으로 나타났는데, 하악 사용과 관련된 습관의 개수가 많아질수록 측두하악장애의 증상의 개수도 많아졌고, 습관이 한 가지씩 늘어날수록 측두하악장애 증상이 없는 1단계보다 3단계가 될 위험이 1.45배, 4단계가 될 위험이 1.57배 높아졌다. 스트레스 수준도 가장 하위단계에서 한 단계 높아지면 측두하악장애 1단계에서 4단계가 될 위험이 2.49배, 두 단계 높아지면 3.43배 높아졌다. 결론 : 본 연구의 결과 측두하악장애와 업무특성에 따른 연관성은 설명하지 못하였지만, 직무스트레스가 높은 경우 측두하악장애 증상의 개수 또한 높아짐을 확인할 수 있었다. 이는 측두하악장애의 주관적인 증상을 발생시키는데 있어서 업무형태 보다는 심인적인 부분이 더 중요한 인자임을 의미한다. 그러므로 측두하악장애 평가 시 신체적인 문제뿐 아니라 행동적, 심리 사회적 문제로 예측인자를 폭넓게 인식함으로써 다각적인 접근을 하는 것이 필요하며, 측두하악장애 증상이 발생된 경우 임상적 치료뿐 아니라 행동요법 및 심리 치료와 자가 관리 등이 함께 수반되어 기여요인 조절을 조절하는 것이 중요하다 하겠다.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.4
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• pp.321-327
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• 2013

Ameloblastic fibroma (AF) is a rare odontogenic ectomesenchymal tumor that is frequently seen in the first two decades of life, and occurs in the mandible. The most proper management of AF has been a recent topic of debate because of its recurrence and malignant transformation. This report describes AF in a 4-year-old male, which was a unilocular radiolucency on the maxillary right primary molar area with a scalloped border and corticated margin. The tumor was treated conservatively with enucleation and curettage, and the decision was made to preserve the right primary second molar. A biopsy confirmed it as AF. During the 43 months of follow-up, the patient had no evidence of recurrence or malignant transformation. Moreover, the radiographic examination revealed the generation of tooth germ to be a permanent second premolar. This report shows a case of AF in the posterior maxilla of a 4-year-old boy and discusses the conservative therapeutic approach to this tumor. Therefore, the age of the patients should be an important consideration when choosing conservative or radical surgery in a young AF patient.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3495-3501
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• 2014

Melanoma-associated antigen (MAGE) family genes have been considered as potentially promising targets for anticancer immunotherapy. MAGED4 was originally identified as a glioma-specific antigen. Current knowledge about MAGED4 expression in glioma is only based on mRNA analysis and MAGED4 protein expression has not been elucidated. In the present study, we investigated this point and found that MAGED4 mRNA and protein were absent or very lowly expressed in various normal tissues and glioma cell line SHG44, but overexpressed in glioma cell lines A172,U251,U87-MG as well as glioma tissues, with significant heterogeneity. Furthermore, MAGED4 protein expression was positively correlated with the glioma type and grade. We also found that the expression of MAGED4 inversely correlated with the overall methylation status of the MAGED4 promoter CpG island. Furthermore, when SHG44 and A172 with higher methylation were treated with the DNA demethylating agent 5-aza-2'-deoxycytidine (5-AZA-CdR) reactivation of MAGED4 mRNA was mediated by significant demethylation in SHG44 instead of A172. However, 5-AZA-CdR treatment had no effect on MAGED4 protein in both SHG44 and A172 cells. In conclusion, MAGED4 is frequently and highly expressed in glioma and is partly regulated by DNA methylation. The results suggest that MAGED4 might be a promising target for glioma immunotherapy combined with 5-AZA-CdR to enhance its expression and eliminate intratumor heterogeneity.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.10
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• pp.4335-4338
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• 2015

Background: Oral cancer is the third most common malignancy in Saudi Arabia, the highest incidence of which is reported from Jazan province. The objective of this study was to evaluate the association of various locally used substances, especially shamma, with oral cancer in the Jazan region of Saudi Arabia. Materials and Methods: A hospital-based case-control study was designed and patient records were scanned for histologically confirmed oral cancer cases. Forty eight patients who were recently diagnosed with oral cancer were selected as cases. Two healthy controls were selected for each observed case and they were matched with age (+/- 5 years) gender and location. Use of different forms of tobacco such as cigarettes, pipe-smoking and shamma (smokeless-tobacco) was assessed. Khat, a commonly used chewing substance in the community was also included. Descriptive analysis was first performed followed by multiple logistic regression (with and without interaction) to derive odds ratios (ORs) and 95% confidence interval (CIs). Results: Mean age of the study sample (56% males and 44% females) was 65.3 years. Multinomial regression analysis revealed that shamma use increased the odds of developing oral cancer by 29 times (OR=29.3; 10.3-83.1). Cigarette (OR=6.74; 2.18-20.8) was also seen to have an effect. With the interaction model the odds ratio increased significantly for shamma users (OR=37.2; 12.3-113.2) and cigarette smokers (OR=10.5; 2.88-3.11). Khat was observed to have negative effect on the disease occurrence when used along with shamma (OR=0.01; 0.00 - 0.65). Conclusions: We conclude that shamma, a moist form of smokeless tobacco is a major threat for oral cancer occurrence in the Jazan region of Saudi Arabia. This study gives a direction to conduct further longitudinal studies in the region with increased sample size representing the population in order to provide more substantial evidence.