• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.1
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• pp.1-7
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• 2016

Mastication is the process to help digestion by chewing or grinding food. Masticatory system consists of maxilla, mandible, temporomandibular joints, ligaments, dentitions, and musculatures. Assessing the bite force can be one of the methods to estimate the masticatory system. Bite force is influenced by facial morphology, age, sex, periodontal status, temporomandibular joint disorder and dental condition, and so forth. In general, higher maximum bite force is seen in those who have a square-shaped face and in male rather than female. In addition, bite force tends to be increased by age 20, maintained constantly until age 40 - 50, and then decreased. Periodontal disease is known as a causative factor for decreased bite force while temporomandibular disorder (TMD) remains controversial as to whether it affects the force. The status of teeth is considered as an important factor to determine the maximum bite force.

• Journal of Broadcast Engineering
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• v.19 no.2
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• pp.240-249
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• 2014

According to the compressive sensing theory, it is possible to perfectly reconstruct a signal only with a fewer number of measurements than the Nyquist sampling rate if the signal is a sparse signal which satisfies a few related conditions. From practical viewpoint for image applications, it is important to reduce its computational complexity and memory burden required in reconstruction. In this regard, a Block-based Compressive Sensing (BCS) scheme with Smooth Projected Landweber (BCS-SPL) has been already introduced. However, it still has the computational complexity problem in reconstruction. In this paper, we propose a method which modifies its stopping criterion, tolerance, and convergence control to make it converge faster. Experimental results show that the proposed method requires less iterations but achieves better quality of reconstructed image than the conventional BCS-SPL.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.47-55
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• 2017

This study evaluated critical factors influencing the success of regenerative endodontic treatment for necrotic immature permanent teeth. The study enrolled patients who had regenerative endodontic treatment in a necrotic immature permanent tooth through 1-year follow-up. Possible explanatory variables related to the success rates for 46 teeth were age, gender, dental stage at the initial appointment, etiology, treatment information, and clinical and radiographic outcomes. The dental stage at the time of regenerative endodontic treatment did not influence the success rate. The success rate was significantly related to the etiology of the necrotic immature tooth. The success rate according to etiology decreased in the following order: dens evaginatus, caries, and trauma. There was also a significant difference according to the type of antimicrobial. The success rate was influenced by appropriate disinfection of the root canal system, provision of a scaffold, and coronal sealing. Above all, careful case selection is necessary for treating a necrotic immature permanent tooth, especially in cases of trauma.

• Journal of Yeungnam Medical Science
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• v.23 no.2
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• pp.152-161
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• 2006

Carcinoma of the gallbladder is an uncommon but highly malignant tumor with a poor five year survival rate. Early detection is very important for successful treatment because this tumor is very hard to cure in cases where it has advanced beyond the reach of surgical treatment. The purpose of this review was to evaluate risk factors for carcinoma of the gallbladder and determine the best management approach.. Solitary polys, more than one cm are considered to be predisposing factors for gallbladder carcinoma when they are found to be echopenic, sessile, and with a high cell density. Anomalous union of the pacreato-biliary duct(AUPBD) without a choledochal cyst is also considered to increase risk for gallbladder carcinoma. A polyps size of more than one cm and an AUPBD are indications for prophylactic cholecystectomy. The presence of gallstones is a well-established risk factor for the development of gallbladder carcinoma; risk appears to correlate with the stone size and the duration of chronic cholecystitis. Metaplastic changes of the gallbladder epithelium present with chronic cholecystitis and may indicate a premalignant lesion. Abnormal forms of cholecystitis such as xanthogranulomatous or a porcelain gallbladder also have malignant potential; cholecystoenteric fistula as well as bacterial infection of the gallbladder(typhoid, helicobacter species) also has malignant potential. In this review, the risk factors associated with carcinoma of the gallbladder are summarized with special attention to gallstones, polyps, AUPBD, and chronic inflammation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1641-1649
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• 2014

This study aimed to analyze the occurrence of colon polyps and also risk factors of colon polyps. Among health examination examinees, 508 people were included who underwent colonoscopy and abdominal ultrasonography at the same time. Physical measurements also performed such as height, weight, blood pressure, waist measurement and BMI. General characteristics including age, sex, smoking, drinking and exercise as a risk factors were checked. At the same time, we analyzed various blood tests and fasting blood sugar through blood-gathering. In the results, regarding risk factors of colon polyps, AST, ALT, TC, fatty liver, obesity and smoking were shown significantly high. As a dependent variable with colon polyps, the highest relation was fatty liver(3.4 times), and then T-C(2.3 times). Smoking factor showed 2.3 times higher relation than non-smokers.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.5
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• pp.683-700
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• 1998

치아경조직의 소실은 반드시 치아우식증이나 사고에 의해서만 일어나는 것이 아니라 마모에 의해서도 일어난다. 마모에 영향을 미치는 인자들은 시간/나이, 성별, 이갈이와 같은 과기능, 저작력, 위장관장애, 음식물, 환경적인 영향, 타액의 상태 그리고 교합적인 조건들이 있다. 한편 중심위와 최대교두감합위 불일치가 악구강계에 미치는 영향에 관해서는 아직도 논란이 분분하다. 본 연구의 목적은 중심위와 최대교두감합위의 불일치가 치아마모에 미치는 영향과 중심위에서 제일 먼저 닿는 치아와 나머지 치아의 마모에 있어서 차이에 대해서 알아 보는 것이다. 본 연구는 두개하악관절과 저작습관에 이상이 없으며, 식이습관에 문제가 없으며 치아우식증과 치주질환, 수복물, 교정 또는 교합치료의 경험이 없는 21세에서 25세 사이의 서울대학교 치과대학생을 대상으로 하였다. 교합기를 이용하여 중심위 교합-최대교두교두감합위 불일치를 조사하여, 중심위 교합-최대교두감합위가 불일치가 작은 군과 큰 군으로 나누었다. 각 군은 각각 10명의 피검자들로 구성되었다. 각 피검자의 인상채득 후 CR mounting을 시행하고 중심위교합-최대감합위 불일치를 측정한 다음 임상검사로 ordinal scale을 측정하고 모형을 통해 arbitrary scale을 측정하였다. 평균치아마모도 그리고 중심위에서 먼저 닿는 치아와 나머지 치아, 나머지 구치의 마모도를 각각 조사하여 통계처리하였다. 1. 평균치아마모도는 ordinal scale로 측정하였을 때 중심위 교합-최대교두감합위 불일치가 작은 군과 큰 군 사이에 통계적으로 유의할만한 차이가 없었다(p>0.05) 2. 평균치아마모도는 arbitrary scale로 측정하였을 때 중심위 교합-최대교두감합위 불일치가 작은 군과 큰 군 사이에 통계적으로 유의할만한 차이가 없었다(p>0.05). 3. CR에서 먼저 닿는 치아와 나머지 치아, 나머지 구치의 마모도는 ordinal scale로 측정하였을 때 통계적으로 유의한 차이가 없었다(p>0.05). 4. CR에서 먼저 닿는 치아와 나머지 치아, 나머지 구치의 마모도는 arbitrary scale로 측정하였을 때 먼저 닿는 치아에서 통계적으로 유의한 높은 수준의 마모도를 보였다(p<0.05).

• Radiation Oncology Journal
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• v.8 no.1
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• pp.29-34
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• 1990

Total of 154 patients of pathologically proven and previously untreated nasopharyngeal carcinoma who were treated in the Department of Therapeutic Radiology, Korea Cancer Center Hospital during the period from 1964 to 1984 were analyzed. Minimal follow-up period of survivors was 3 years. Thirteen percent of the patients had $T_4$ primary lesions and $65\%$ had stage IV disease. Total radiation dose to the primary site was $1550\~1750$ ret in 82 and above 1750 ret in 72 patients. Local control was obtained in $79\%$ of patients. Significant prognostic factors for the survival were tumor dose (above vs. below 1750 ret), age (below vs. above 30 years), stage (AJCC I-III vs. IV), T stage ($T_1\;vs.\;T_2-4$), and N stage (NO vs. $N^+$).

• Korean Journal of Community Nutrition
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• v.3 no.3
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• pp.380-388
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• 1998

This study was conducted to investigate the distribution of bone density according to age and the prevalence rate of osteoporosis I 613, middle-aged women who visited Saint Bundo Hospital in Pusan from June to December, 1997. Mean bone density of lumbar spine(L2L4), and femoral neck of 50-59 years of age was significantly lower than those of 40-49 years of age(p<0.05). At the 60years of age, mean bone density of two sites were less than those of 50-59 years of age. Mean bone density of lumbar spine tin the group of sixties were 20.7% lower than that of group aged under 40 ; For femoral neck, women in their sixties showed 22.6% lower density compared to the women aged under forty. Bone density of ward's triangle of sixties were the least, which was 34.2% lower than that of group aged under 40. Bone density in lumbar spine, femoral neck, trochanter and ward's triangle correlates strongly with each other(p<0.001). The proportion of osteoporosis was 3.6% in the group of forties, 10.9% in the group of fifties and 33.8% for the group aged over 60, which was assessed by bone density of lumbar spine. Bone density of lumbar spine, femoral neck and ward's triangle were positively correlated with height, weight and BMI(p<0.001∼p<0.01), and weight showed highest correlation with the bone density. Forty-four percent of variation in lumbar spine bone density was explained by age and weight.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.147-152
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• 2021

This study is a retrospective analysis of the results of tests at three general hospitals in Busan that perform mammography using digital mammography devices. There were 5,320 people in the study, and the results of their breast cancer screening were analyzed to verify the efficacy of breast cancer screening for digital mammography. The average age of patients who performed breast cancer screening was 57.7 years (range 30 to 87 years), and the cancer detection rate was 26, with 4.6 cases per 1,000 people. According to the cancer detection rate by risk factor in patients who conducted breast cancer screening, breast cancer was found in patients without underlying diseases more than in patients with underlying diseases. Additional ultrasound examinations show that the gastronomic rate identified is 3.6%, which is relatively very low compared to that of the Film-Screen system.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.430-437
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• 2007

The probability table of Moyers and prediction equation of Tanaka and Johnston that have been the most frequently used, cannot produce accurate prediction when used in Korean because they are based on the Caucasian popularity of the Northern European race. The method of Moyers or Tanaka and Johnston predicts sizes of the unerupted canine and premolars on the basis of the sizes of mandibular incisors. However, some of the recent papers raise a question as to whether the mandibular incisors are the best combination to predict the sizes of the unerupted canine and premolars. The purpose of this study is to determine which sum or combination of sums of permanent tooth widths present the best prediction for the unerupted canine and premolars in a Korean sample, to calculate a specific linear regression equation for this population, and to evaluate the clinical significance. A new linear regression equation was calculated based on the data of 178 Korean young adults(70 women, 108 men, mean age 21.63 years) with complete permanent dentitions. Fifty three more children(28 girls, 25 boys, mean age 14.22 years) were used as a validation sample for the application of the multiple linear regression equation. The conclusions were as follows: 1. The combination of the sums of permanent upper central incisors, lower lateral incisors and upper first molars was the best predictor for the unerupted canine and premolars in this sample($r=0.65{\sim}0.80$). 2. The multiple linear regression equation was calculated including sex and arch as additional predictor variables. male, upper: $Y\;=\;0.332{\times}X_0\;+\;6.195$ male, lower: $Y\;=\;0.332{\times}X_0\;+\;5.269$ female, upper: $Y\;=\;0.332{\times}X_0\;+\;5.929$ female, lower: $Y\;=\;0.332{\times}X_0\;+\;5.003$. The determination coefficient of the equation was 64% and a standard error of the estimate was 0.71mm. 3. In about 97% of the validation sample, the estimation of the tooth width sums of unerupted canine and premolars using the new multiple linear regression equation was smaller than 1mm compaired with the actual values.