• Journal of Yeungnam Medical Science
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• 제40권4호
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• pp.373-380
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• 2023

Background: The association between dental amalgam fillings and urine mercury concentrations was investigated in this study to assess the health risks associated with dental amalgams. Methods: This cross-sectional study included 99 women in their 20s who visited the dental clinic in Daegu, Korea. The 99 participants were composed of 68 subjects who had dental amalgam fillings (exposure group) and 31 subjects who did not have dental amalgam fillings (nonexposure group). Oral examinations were conducted by a single dental hygienist, sociodemographic features were investigated as confounding variables, and urine mercury concentrations were measured using an automatic mercury analyzer. Results: The mean±standard deviation of the urine mercury concentrations of the exposure and nonexposure groups were 1.50±1.78 ㎍/g creatinine and 0.53±0.63 ㎍/g creatinine, respectively. The exposure group showed significantly higher levels than the nonexposure group (p<0.01). The urine mercury concentration significantly increased with an increase in the number of teeth filled with amalgam, cavity surfaces involved, and number of defective amalgam fillings, and according to the latest exposure time (p<0.001). In the multiple regression analysis of amalgam-related factors and urine mercury concentrations after correction for confounding factors, the urine mercury concentration in the group with six or more amalgam-filled teeth, 11 or more cavity surfaces, and two or more defective amalgams was significantly higher than that in the nonexposure group (p<0.001). Conclusion: According to this study, exposure to dental amalgams was confirmed to significantly affect urine mercury concentrations.

• Journal of Periodontal and Implant Science
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• 제53권6호
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• pp.453-466
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• 2023

Purpose: This study aimed to quantify alveolar bone morphology, demonstrate the relationship between tooth angulation and alveolar bone thickness, and introduce a new classification for anterior mandibular teeth related to immediate implant placement (IIP). Methods: Cone-beam computed tomography (CBCT) images of 211 anterior mandibular teeth were analyzed in sagittal slices to measure the thickness of the facial alveolar bone crest (FAB1) and apex (FAB2), and the lingual alveolar bone crest (LAB1) and apex (LAB2). Tooth angulation was classified as 1°-10°, 11°-20°, and >20° according to the tooth's long axis and alveolar bone wall. Spearman correlation coefficients were used to evaluate correlations between the variables. Results: FAB1 and LAB1 were predominantly thin (<1 mm) (84.4% and 73.4%, respectively), with the lateral incisors being thinnest. At the apical level, FAB2 and LAB2 were thick in 99.5% and 99.1% of cases, respectively. Significant differences were documented in FAB2 (P=0.004), LAB1 (P=0.001), and LAB2 (P=0.001) of all mandibular teeth. At all apical levels of the inspected teeth, a significant negative correlation existed between TA and FAB2. Meanwhile, TA showed a significant positive correlation with LAB2 of the lateral incisors and canines. These patterns were then divided into class I (thick facial and lingual alveolar bone), class II (facially inclined teeth) with subtype A (1°-10°) and subtype B (11°-20°), and class III (lingually inclined teeth) with subtype A (1°-10°) and subtype B (11°-20°). Conclusions: Mandibular anterior teeth have predominantly thin facial and lingual crests, making the lingual bone apical thickness crucial for IIP. Although anchorage can be obtained from lingual bone, tooth angulation and tooth types had an impact on IIP planning. Hence, the new classification based on TA and alveolar bone wall may enable rational clinical planning for IIP treatment.

• The Journal of Advanced Prosthodontics
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• 제16권1호
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• pp.57-65
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• 2024

PURPOSE. The aim of this stuldy was to compare the clinical marginal fit of CAD-CAM inlays obtained from intraoral digital impression or addition silicone impression techniques. MATERIALS AND METHODS. The study included 31 inlays for prosthodontics purposes of 31 patients: 15 based on intraoral digital impressions (DI group); and 16 based on a conventional impression technique (CI group). Inlays included occlusal and a non-occlusal surface. Inlays were milled in ceramic. The inlay-teeth interface was replicated by placing each inlay in its corresponding uncemented clinical preparation and taking interface impressions with silicone material from occlusal and free surfaces. Interface analysis was made using white light confocal microscopy (WLCM) (scanning area: 694 × 510 ㎛²) from the impression samples. The gap size and the inlay overextension were measured from the microscopy topographies. For analytical purposes (i.e., 95-%-confidence intervals calculations and P-value calculations), the procedure REGRESS in SUDAAN was used to account for clustering (i.e., multiple measurements). For p-value calculation, the log transformation of the dependent variables was used to normalize the distributions. RESULTS. Marginal fit values for occlusal and free surfaces were affected by the type of impression. There were no differences between surfaces (occlusal vs. free). Gap obtained for DI group was 164 ± 84 ㎛ and that for CI group was 209 ± 104 ㎛, and there were statistical differences between them (p = .041). Mean overextension values were 60 ± 59 ㎛ for DI group and 67 ± 73 ㎛ for CI group, and there were no differences between then (p = .553). CONCLUSION. Digital impression achieved inlays with higher clinical marginal fit and performed better than the conventional silicone materials.

• The Journal of Advanced Prosthodontics
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• 제16권2호
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• pp.115-125
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• 2024

PURPOSE. The purpose of this in vitro study was to investigate the fracture resistance, surface hardness, and color stain of 3D printed, CAD-CAM milled, and conventional interim materials. MATERIALS AND METHODS. A total of 80 specimens were fabricated from auto polymerizing polymethyl methacrylate (PMMA), bis-acryl composite resin, CAD-CAM polymethyl methacrylate resin (milled), and 3D printed composite resin (printed) (n = 20). Forty of them were crown-shaped, on which fracture strength test was performed (n = 10). The others were disc-shaped specimens (10 mm × 2 mm) and divided into two groups for surface hardness and color stainability tests before and after thermal cycling in coffee solution (n = 10). Color parameters were measured with a spectrophotometer before and after each storage period, and color differences (CIEDE2000 [DE00]) were calculated. The distribution of variables was measured with the Kolmogorov Smirnov test, and one-way analysis of variance (ANOVA), Tukey HSD, Kruskal-Wallis, Mann-Whitney U tests were used in the analysis of quantitative independent data. Paired sample t-test was used in the analysis of dependent quantitative data (P < .05). RESULTS. The highest crown fracture resistance values were determined for the 3D printed composite resin (P < .05), and the lowest were observed in the bis-acryl composite resin (P < .05). Before and after thermal cycling, increase in mean hardness values were observed only in 3D printed composite resin (P < .05) and the highest ΔE₀₀ value were observed in PMMA resin for all materials (P < .05). CONCLUSION. 3D printing and CAD-CAM milled interim materials showed better fracture strength. After the coffee thermal cycle, the highest surface hardness value was again found in 3D printing and CAD-CAM milled interim samples and the color change of the bis-acryl resin-based samples and the additive production technique was higher than the PMMA resin and CAD-CAM milled resin samples.

• 대한소아치과학회지
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• 제34권2호
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• pp.234-246
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• 2007

소아치과에서 진정요법은 chloral hydrate와 hydroxyzine을 함께 경구투여하는 방법이 가장 보편적이고, 진정의 심도가 술자가 원하는 정도에 미치지 못할 때에는 midazolam이나 $N_2O/O_2$를 병용투여하는 경우가 종종 있다. 본 연구는 chloral hydrate와 hydroxyzine을 이용한 진정요법의 효과와 안전성을 평가하고, 경구투여만으로 적절한 진정수준을 얻지 못하여 $N_2O/O_2$를 병용투여한 경우 $N_2O/O_2$의 치료시간과 부작용에 대한 영향 그리고, 진정요법 효과에 영향을 줄 수 있는 변수들(연령, 성별, 체중, patient compliance, waiting time 등)을 확인할 목적으로 시행하였다. 2004년 12월부터 2005년 9월까지 단국대학교 치과병원 소아치과에서 chloral hydrate와 hydroxyzine을 이용하여 진정요법하에 치료받은 평균연령 $30{\pm}8$개월(12-51개월), 체중 $13{\pm}2kg(9.5-18kg)$의 총 94명(남아-46명, 여아-48명)의 환아들을 대상으로 조사하였다. 진정요법의 효과, 체중, 연령, 병용투여 방법에 따라 군을 분류하여 성별, 연령, 체중, patient compliance, waiting time, 치료시간, 치료양(RBVU), 부작용 등을 평가하였다. 진정요법 성공률은 85%였다. 진정요법에 성공한 그룹이 실패한 그룹보다 $N_2O/O_2$로 수면을 유도하여 사용하는 경우가 많았고, 치료시간이 길었다. 36개월, 14kg미만인 환아는 경구투여만으로 수면에 이를 수 있었고, waiting time이 짧았다. 36개월 이상인 환아는 $N_2O/O_2$를 사용하여 수면을 유도하는 경우가 많았다. 연령과 $N_2O/O_2$ 사용시간, $N_2O/O_2$사용과 치료시간사이에는 상관관계가 존재한 반면, 체중과 $N_2O/O_2$사용시간사이에는 상관관계가 없었다. 치료시간 연장, $N_2O/O_2$사용여부와 부작용 발생간에서 는 통계학적으로 유의한 차이는 확인되지 않았다.

• 치위생과학회지
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• 제16권3호
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• pp.217-224
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• 2016

본 연구는 2009년 국민건강영양조사 자료를 이용하여 우리나라 성인에서 다양한 혼란변수를 보정한 후 현존자연치아수와 COPD와의 연관성을 알아보고자 하였다. 40세 이상 성인 3,107명을 대상으로 구강검진과 폐기능검사를 시행하여 다음과 같은 결론을 얻었다. 첫째, 폐기능검사에 의한 COPD 유병률은 11%였다. 현존자연치아수를 0~19개군, 20~27개군, 28개군으로 나누었을 때, COPD의 분포는 현존자연치아수가 0~19개인 군에서 21.0%로 가장 높았다. 둘째, COPD는 65세 이상군, 남자, 교육수준이 낮을수록, 정상적인 BMI를 갖는 군, 고혈압군에서 높았다(p<0.001). 셋째, 인구사회학적 특성, 사회경제적 위치, 건강관련행태, 구강건강 및 행태, 전신건강상태를 보정한 다중로지스틱 회귀분석에서는 현존자연치아수 20~27개군(OR, 1.90)과 0~19개군(OR, 3.93)에서 COPD와 연관성을 보여, 현존자연치아수가 적을수록 COPD의 위험이 증가함을 확인하였다. 특히 치주질환과 COPD의 중요한 위험요인인 흡연상태에 따른 층화분석결과, 현재흡연군에서만 모든 치아를 가지고 있는 군에 비해 0~19개 치아를 가진 군에서 OR이 8.90배 높은 결과를 보여 강한 연관성을 보여주었다(OR, 8.90; 95% CI, 2.53~31.33). 본 연구 결과를 통해 현존자연치아수는 COPD와 연관성이 있음을 확인하였다.

• 치위생과학회지
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• 제17권2호
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• pp.134-141
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• 2017

연구는 2016년 5월부터 9월까지 경상북도에 소재한 산부인과에서 외래 진료를 받는 분만 전까지의 임신부에서 연구참여에 동의한 자 191명의 자기기입식 설문지를 이용하여 분석하였다. 임신부의 인구사회학적 특성, 임신관련 특성, 사회적 지지, 수면의 질 및 OHIP와 우울수준과의 관련성을 규명하기 위해 시도되었으며, 다음과 같은 결과를 얻었다. 임신부들의 우울수준 분포는 건강군이 25.1%, 우울군이 74.9%로 나타났다. 우울수준은 결혼생활만족에 불만족하는 군일수록, 직업이 없는 군일수록, 사회적 지지가 낮은 군일수록, 수면의 질이 좋지 않은 군일수록, OHIP가 높은 군일수록 우울군의 비율이 유의하게 높았다. 로지스틱 회귀분석 결과, 분만경험이 있는 군에 비해 없는 군에서 우울수준이 높은 군에 속할 위험비가 유의하게 증가한 반면, 사회적 지지가 낮은 군에 비해 높은 군에서 우울수준이 높은 군에 속할 위험비가 유의하게 감소하였다. 우울수준은 수면의 질 및 OHIP와는 유의한 양의 상관관계를 보인 반면, 사회적 지지와는 유의한 음의 상관관계를 보였다. 다중회귀분석 결과, 결혼생활만족도가 낮은 군일수록, 분만경험이 없는 군일수록, 사회적 지지가 낮은 군일수록, OHIP가 높은 군일수록 우울수준이 높았으며, 이들의 설명력은 22.3%였다. 이상의 연구결과를 종합하여 보면 임신부의 결혼생활만족도, 분만경험, 사회적 지지, OHIP 등이 우울과 관련이 있음을 알 수 있었다. 따라서 임신부의 우울을 감소시키기 위해서는 다양한 변수들을 충분히 고려한 입체적인 연구 모형을 구축하고 검증하여 긍정적인 사고를 형성할 수 있는 프로그램 개발 및 적용하는 방안을 모색하는 후속 연구가 계속되어야 할 것이다.

• 한국인구학
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• 제4권1호
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• pp.105-130
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• 1981

This study was conducted to compare the characteristics of high performane areas for family planning with that of low performance areas and to find factors which strongly affected contraceptive practice behavior. For the study, eight areas were selected from 274 rural family planning canvassing areas of Korean Population Policy and Program Evaluation Study, which was an action study operated in all areas of Cheju Island from July 1, 1976 until December 31,1979. As a first step of the action study, Cheju Island was devided up 318 family planning canvasser areas Each area was consisted of 200 households in rural district and 300 households in urhan one Duriog the period of project, each canvassing area had been managed by a female family planning canvasser, selected by director of health center considering several individual conditions needed for family planning activities Basic activities of canvassers were to counsell all the eligihie couples in own charged area about family planning methods and also to distribute contraceptives such as condoms and oral pills. In case couples desire to accept sterilization including vasectomy and tubal-ligation, the canvassers played a linking role connecting potential client with family planning field workers. Canvassng areas shows significant differentce in performance for family planning, nevertheless they are supposed to have almost the same conditions regarding family planning distribution channel. Because the purpose of the Cheju project was to eliminate all the problems that existed in governmental distribution system, that is to remove geographic, economic, cognitive and administrative barriers Accumulated performances of family planning methods accepted by residents in each area were calculated by eligible women aged 14-49. And then canvassing areas were ranked according to performance score. Consequently, 4 areas in extremely high and low family planning performance areas were selected respectively. Major results were obtained by comparing characteristics of high performance area with that of low performance areas, which are as follows: 1. The mean number of living children was about the same both in high and low performance areas for family planning. But respondents' mean age (38.5) in high performance areas was higher than that (37.0) in low performance areas 2. Respondents' perception in the expectant educational level of others' children in high performance areas was higher than that in low performance areas, although respondents educational level, monthly expenditure and ratio of children in high school and above was not different. 3. Ratio of ownerships of TV and newspaper in high performance areas was highen than that in low performance areas 4. The duration of canvasser' charge in high performance areas was longer than that of low performance areas, showing the fact that canvassers didn't move cut in high performance areas 5. In high performance areas, canvassers' houses were relatively located in the center part of the village. And so villagers resided in near distances from the anvasser's house 6. 4H clubs' activities in high performance areas were more active than those in low performance areas Therefore it was assumed that cohesiveness of community in high performance areas were stronger than that in low areas. 7. Canvassers' family planning practice rate was higher than that in low performance areas, and also canvassers' human relationship was more sociable than that of canvassers in low performance areas. 8. Fourteen variables which showed relatively high significance level in $X^2$ and F test were selected as independent variables for stepwise regression analysis. According to the results of regression analysis. five of 14 variables-distributors education level ($R^2$=.4439), duration of distributor's charge ($R^2$=.6166), 4H club activities ($R^2$=.6697), canvasser's contraceptive practice ($R^2$=.7377) and location of distributions house ($R^2$=.8010) explained 80.1 percent of total variance.

• 항공우주정책ㆍ법학회지
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• 제27권2호
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• pp.167-192
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• 2012

항공 산업은 고용창출 효과가 크고 고부가 가치인 선진국 형 지식기반 산업으로 평가되는 대표적 산업이다. 이러한 시대흐름에 따라 전 세계가 잠재적 경제력의 한축인 항공 산업에 눈을 돌리고 있는 것도 어찌 보면 당연한 일이 아닐 수 없다. 이와 같은 배경 하에 본 연구는 국토해양부에서 범정부적으로 추진 중인 항공인력양성사업의 중요성을 인식하고 급속히 발전하는 항공기술에 대처할 수 있는 항공우주기술 인력 및 잠재적 경제력의 한 축인 항공시장의 전문지식과 실무능력을 겸비한 국제항공 전문가를 석사급 인력을 국내 특성화 대학을 선정 지원하여 항공인력을 양성하는 사업의 평가지표를 개발하는 데 그 필요성을 인식하고, 항공전문가의 검토를 통한 타당성 검증 결과를 도출하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제35권6호
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• pp.360-367
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• 2013

Purpose: The purpose of this study was to perform three-dimensional (3D) assessment of facial soft tissue in patients with skeletal Class III and mandibular asymmetry after orthognathic surgery. Methods: Samples consisted of 3D facial images obtained from five patients with A point-nasion-B point angle less than 2 degrees, and more than 5 mm of menton deviation. All patients had been treated at Gangneung-Wonju National University Dental Hospital from 2009 to 2012. They had undergone orthognathic surgery of Lefort I, and sagittal split osteotomy for correction of skeletal deformity, and orthodontic treatment. Facial scanning was performed before treatment (T1) and post-surgical orthodontic treatment (T2). Linear and angle variables of soft tissue landmarks, antero-posterior facial depth, and facial volume were measured. Results: No significant differences in width of the alar base, mouth width, and nasal canting were observed between T1 and T2. However, lip deviation, menton deviation, alar canting, lip canting, and menton deviation angle were significantly reduced at T2. Antero-posterior facial depth on the axial plane parallel to the left cheilion was significantly reduced on the deviated side and significantly increased on the non-deviated side at T2. Volume of the lower lateral and lower medial parts of the face was reduced on the deviated side, and volume of upper lateral and lower lateral parts on the non-deviated side was significantly increased at T2. Conclusion: After orthognathic surgery, facial asymmetry of soft tissue was improved following skeletal changes, especially the mandibular region. Although the length of the alar base and mouth width did not change, lip and soft tissue menton were displaced to the medial side after treatment. Facial depth also became symmetric after treatment. Facial volume showed a decrease on the lower part of the deviated side and that on lateral parts of the non-deviated side showed an increase after treatment.