• Journal of Oral Medicine and Pain
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• 제35권2호
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• pp.135-147
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• 2010

본 연구에서는 최근 Sato 등이 고안한 mixing ability index(MAI)를 이용하여 측두하악장애 환자 중 통증이 있는 군과 무통성 관절잡음이 있는 군을 대상으로 객관적인 저작 효율을 정상인으로 구성된 대조군과 비교하고, 주관적인 평가 방법인 설문조사법 중에서 음식섭취가능지수(Food Intake Ability Index, FIA)와 저작 능력에 대한 주관적 인식도 평가(Visual Analogue Scale, VAS)를 이용하여 저작 효율을 평가하고, 구강건강과 관련된 삶의 질을 평가하기 위해 Oral Health Impact Profile(OHIP)-49K 설문조사를 시행하였다. 각 평가 방법 간의 상관성을 알아보고, 또한 통증군에 있어서는 치료 후 통증이 감소함에 따라 저작 효율의 변화 양상을 조사하여 다음과 같은 결과를 얻었다. 1. MAI, FIA, VAS는 통증군이 정상군에 비해 통계학적으로 유의하게 감소하였으며, 관절잡음군보다도 감소하여 통증군이 정상군과 관절잡음군에 비해 저작 효율이 떨어지는 것으로 나타났다(P<0.05). 관절잡음군에서는 MAI, FIA, VAS에서 정상군과 유의한 차이를 보이지 않았다. 2. 구강건강관련 삶의 질에 대한 설문지인 OHIP-49K의 경우 정상군에 비해 통증군과 관절잡음군 모두 통계학적으로 유의하게 증가하여 구강건강과 관련한 삶의 질이 떨어지는 것으로 나타났다. 3. 전체 대상자(71명)에서 객관적 저작 능력 평가 방법인 MAI와 주관적 저작 능력 평가 방법인 FIA와 VAS간에는 서로 유의성 있는 상관관계를 보였다(P<0.01). OHIP-49K에서도 MAI를 제외하고 모두 통계학적으로 상관관계가 있는 것으로 나타났다. 4. 관절잡음군에서는 FIA와 VAS에서만 통계학적으로 상관관계가 있는 것으로 나타났으며(P<0.01), 이외의 모든 항목은 상관관계가 없는 것으로 나타났다. 5. 각 평가 방법 간의 상관성에서 FIA와 VAS는 전체 대상자, 통증군, 관절잡음군 모두에서 상관관계가 있는 것으로 나타났다. 6. 통증군에서 치료 전에 비해 치료 후 통증 감소와 함께 VAS에서는 통계학적으로 유의성 있게 증가 하였다(P<0.05). 반면에 MAI에 있어서는 저작 효율이 증가하는 경향을 보였으나 통계학적 유의성은 없었다. 또한 FIA, OHIP-49K에서도 치료 전과 후 통증 감소에 따른 변화는 없는 것으로 나타났다. 이번 연구를 통하여 측두하악장애 환자에서 저작 효율을 감소시키는 주요인은 통증이며, 관절잡음은 저작 효율을 감소시키는 요인은 아니지만 삶의 질을 저하시키는 한 요인으로 작용한다는 것을 알 수 있었다. 따라서 측두하악장애 환자에서 저작 효율을 개선시키기 위해서는 우선적으로 통증을 치료하는 것이 가장 중요하며, 삶의 질을 향상시키기 위해서는 통증뿐만 아니라 관절잡음에 대한 관리도 필요할 것으로 사료된다.

• 한국환경복원기술학회지
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• 제16권1호
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• pp.17-25
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• 2013

The mechanical properties appeared at the concrete mixed with Polypropylene fiber($1kg/m^3$, $3kg/m^3$, $5kg/m^3$) are compared with normal concrete and wire mesh one and evaluated. Achieved slump test to search effect that PP fiber gets to workability, even if the mixing amount of fiber increases, confirmed that slump value is no change almost. The no difference can be caused by hard mixture, but because of the big softness of fiber there is no effect greatly up to PP fiber mixing amount $5kg/m^3$ even with soft mixture. Compressive strengths and flexural strengths of the concretes with PP fiber and without the fiber are appeared almost alike. If examine load resistance ability by PP fiber mixing amount increase, it could know that the increase of fiber mixing amount improves load resistance ability and the toughness index is increased. While normal concrete is broken at the same time with crack, fiber mixed concrete stand in flexure load continuously after crack occurrence. In compare with wire mesh embeded concrete, wire mesh mixed concrete stands in some degree in flexure load by wire mesh crack occurrence and the test piece was broken at the same time. But, it could know that the PP fiber mixed concrete resist continuously to flexure load in bigger displacement.

• Journal of Korean Academy of Oral Health
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• 제42권4호
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• pp.216-223
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• 2018

Objectives: The purpose of the study was to investigate factors affecting the assessment of objective and subjective masticatory ability in the elderly, and to evaluate masticatory ability assessment more accurately. Methods: A total of 112 participants were recruited after oral examination in senior citizen welfare facilities. The participants' masticatory ability was evaluated objectively (Mixing ability index; MAI), and subjectively (Key food intake ability; KFIA). Participants' general characteristics and oral health-related variables were also recorded. Based on masticatory ability assessment, participants were classified as either high or low. IBM SPSS Statistics Ver.23.0 was used for all analyses, including descriptive statistics, Chi-square test, Mann-Whitney U test, Spearman rank correlation, and Logistic regression analysis. Results: Higher masticatory ability was positively correlated with higher scores on MAI and KFIA. Additionally, there was a significant positive correlation between MAI and KFIA. When analyzing factors affecting objective and subjective masticatory ability assessments, Functional tooth units (FTUs) were revealed as a related factor. In subjective masticatory ability assessment, oral moisture, difficulty in chewing, and the Geriatric Oral Health Assessment Index (GOHAI) were also influential factors. Conclusions: In order to accurately assess masticatory ability, it is necessary to use both objective and subjective measures. Additionally, to improve the masticatory ability in the elderly, treatment should be provided to improve overall oral health and satisfaction.

• 한국지반공학회논문집
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• 제33권11호
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• pp.97-104
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• 2017

벤토나이트와 현장토를 혼합하여 차수재료로 폐기물 매립장의 차수층에 많이 적용하고 있다. 차수층으로 사용되는 재료는 일반적으로 투수계수가 $1{\times}10^{-7}cm/s$ 이하인 재료를 사용한다. 벤토나이트를 현장에서 차수층 재료로 사용될 때 벤토나이트는 건조-수축 균열 발생 및 염수조건에서 팽창성 떨어지고 차수 기능을 상실하는 등의 문제점이 존재한다. 벤토나이트의 문제점을 극복하기 위해 본 연구에서는 균열 방지 및 해수조건에서 차수성을 확보할 수 있는 내염성 벤토나이트를 개발하였고, 건조수축균역 시험, 팽윤도 시험, 다짐시험 및 투수실험을 통해 내염성 벤토나이트의 혼합비 결정 및 성능을 평가하였다.

• Journal of Periodontal and Implant Science
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• 제45권6호
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• pp.205-209
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• 2015

Purpose: Dental implants present several advantages over other tooth replacement options. However, there has been little research on masticatory function in relation to implant treatment. Therefore, the aim of the present study was to evaluate the improvement of masticatory function two weeks after implant restoration. Methods: Masticatory ability was evaluated with the subjective food intake ability (FIA) and objective mixing ability index (MAI) methods. Fifty-four subjects with first and second missing molars completed the study. The subjects were asked to complete a self-reported questionnaire about 30 different food items, and to chew wax samples 10 times both before and two weeks after implant restoration. A total of 108 waxes were analyzed with an image analysis program. Results: Dental implant restoration for lost molar teeth on one side increased the FIA score by 9.0% (P<0.0001). The MAI score also increased, by 14.3% after implant restoration (P<0.0001). Comparison between the good and poor mastication groups, which were subdivided based on the median MAI score before implant restoration, showed that the FIA score of the poor group was enhanced 1.1-fold while its MAI score was enhanced 2.0-fold two weeks after an implant surgery. Conclusions: Using the FIA and MAI assessment methods, this study showed that masticatory function was improved two weeks after implant restoration. In particular, the enhancement of masticatory function by implant restoration was greater in patients with relatively poor initial mastication than in those with good initial mastication.

• Journal of Microbiology and Biotechnology
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• 제22권7호
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• pp.1005-1014
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• 2012

The understanding of the relationship between ammonia-oxidizing bacteria (AOB) communities in activated sludge and the operational treatment parameters supports the control of the treatment of ammonia-rich wastewater. The modifications of treatment parameters by alteration of the number and length of aerobic and anaerobic stages in the sequencing batch reactor (SBR) working cycle may influence the efficiency of ammonium oxidation and induce changes in the AOB community. Therefore, in the research, the impact of an SBR cycle mode with alternating aeration/mixing conditions (7 h/1 h vs. 4 h/5.5 h) and volumetric exchange rate (n) on AOB abundance and diversity in activated sludge during the treatment of anaerobic sludge digester supernatant at limited oxygen concentration in the aeration stage (0.7 mg $O_2/l$) was assessed. AOB diversity expressed by the Shannon-Wiener index (H') was determined by the cycle mode. At aeration/mixing stage lengths of 7 h/1 h, H' averaged $2.48{\pm}0.17$, while at 4 h/5.5 h it was $2.35{\pm}0.16$. At the given mode, AOB diversity decreased with increasing n. The cycle mode did not affect AOB abundance; however, a higher AOB abundance in activated sludge was promoted by decreasing the volumetric exchange rate. The sequences clustering with Nitrosospira sp. NpAV revealed the uniqueness of the AOB community and the simultaneously lower ability of adaptation of Nitrosospira sp. to the operational parameters applied in comparison with Nitrosomonas sp.

• Journal of Oral Medicine and Pain
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• 제38권1호
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• pp.53-67
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• 2013

보툴리눔 독소는 Clostridium botulinum이라는 박테리아가 만들어내는 독소를 의료용으로 희석, 정제한 약제로서 이 독소가 시냅스 전 신경말단에 부착되어 신경근접합부에서 아세틸콜린의 분비를 억제함으로써 근육의 수축을 차단하는 역할을 한다. 보툴리눔 독소 주사 요법은 구강안면 분야에서 저작근의 근경축, 근경련, 운동이상증, 측두하악관절질환, 근막통증, 이갈이, 특발성 교근비대증 또는 만성편두통을 비롯한 두통 등 다양한 질환에서 가역적, 보존적 치료법으로 활발히 사용되고 있다. 사용 범위가 넓어지면서 교근이나 측두근 같은 저작근 부위에 주사를 하는 경우가 많아지고 있으며 그러한 경우 약제자체의 약리학적 작용에 의해 일시적인 근마비 및 근위축에 따라 저작기능에 변화가 생기게 된다. 하지만 지금까지 보툴리눔 독소 주사치료의 효과나 활용에 대한 연구만이 주를 이루었고 부작용 중의 하나인 저작기능 변화에 대한 연구는 거의 이루어지지 않았다. 몇몇 저작기능과 관련한 연구 또한 근전도 등을 이용한 정적인 상태의 저작력 감소에 대한 연구로, 실제로 동적인 저작 환경을 반영하는 저작 효율에 대해서는 현재까지 전혀 연구가 이루어지지 않은 실정이다. 이에 본 연구에서는 총 40명의 건강한 성인환자를 대상으로 보툴리눔 A형 독소 주사 요법을 교근 부위에만 시술 받은 사람 과 교근과 측두근 부위 모두에 시술 받은 사람 각각 20명씩 두 군으로 나누어 주사를 시행하고, 주사 전과 주사 후 4주, 8주, 12주째의 저작 효율의 변화를 주관적 평가방법인 식품섭취능 (Food Intake Ability, 이하 FIA)과 저작 능력에 대한 주관적 인식도 (Visual Analogue Scale, 이하 VAS), 객관적 평가 방법인 Mixing Ability Test를 시행하여 알아보았다. 그 결과 보툴리눔 A형 독소 주사 후 4주 째에 저작효율의 뚜렷한 감소가 나타났으며 이후 서서히 회복되는 경향을 보였다. 주사부위를 달리하여 본 결과 교근과 측두근에 모두 주사를 시행하는 경우, 교근에만 주사를 시행하는 경우에 비해 주관적, 객관적인 값 모두 낮게 나타났다. 주관적인 값에 있어서 4주 째 유의하였으나 이후에는 유의하지 않았으며 객관적인 값은 전 기간에 걸쳐 유의하지 않았다. 실험에서 정한 주사 용량에 대해서는 측두근까지 주사가 이루어지더라도 교근만 주사를 시행한 사람과 비교하여 저작효율의 큰 차이가 없는 것으로 보인다. 또한 식품성상에 따라 저작 효율을 살펴본 결과 보툴리눔 A형 독소 주사가 단단하고 질긴 음식 섭취에 더 큰 영향을 미치는 것으로 보이며 무르고 약한 음식의 섭취 시에도 유의할만한 영향을 받는다는 사실을 확인 할 수 있었다.

• Journal of Oral Medicine and Pain
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• 제45권3호
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• pp.49-55
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• 2020

Purpose: This study investigated the association between the objective indicator of masticatory function assessment and the masseter muscle thickness (MMT) using ultrasound imaging. Methods: A total of 99 subjects (males: 24, females: 75, mean age: 76) were analyzed. The maximum bite force (MBF) was measured with a pressure-sensitive sheet and an image scanner. The mixing ability index (MAI) was calculated by image analysis after asking the subjects to chew a wax specimen. The MMT during rest and clenching were obtained with a diagnostic ultrasound system, and the difference in MMT during rest and MMT during clenching was defined as the difference in masseter muscle thickness (DMMT). Multiple regression analysis was performed to determine the independent variables affecting MBF and MAI. Results: The MBF showed correlation with the number of remaining teeth (β=0.346, p=0.002) and DMMT (β=0.251, p=0.011). The MAI correlated with only the number of remaining teeth (β=0.476, p<0.001). Conclusions: The DMMT reflects the state of masseter muscle contraction, and can be used as a predictor as well as the number of teeth when assessing masticatory function.

• 대한치과교정학회지
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• 제47권3호
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• pp.151-157
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• 2017

Objective: The objective of this study was to investigate the differences in masticatory efficiency among patients with different Angle's classes of malocclusion and to assess the correlation between masticatory efficiency and the occlusal contact area. Methods: The mixing ability index (MAI) was calculated for measuring masticatory efficiency of 61 adult patients according to Angle's classifications of malocclusion. The study included 25, 15, and 21 patients with Angle's Class I, II, and III malocclusions, respectively. Silicone interocclusal recording material was used to measure the occlusal contact area. Results: Both the MAI and occlusal contact area showed the highest average values in the Class I malocclusion group, followed by the Class II and Class III malocclusion groups. No significant difference was observed in the MAI values between the Class I and Class II malocclusion groups (p > 0.05), whereas a significant difference was observed between the Class I and Class III malocclusion groups (p < 0.01) and between the Class II and Class III malocclusion groups (p < 0.05). A weak positive correlation was also observed between the MAI and occlusal contact area (p < 0.01, $r^2=0.13$). Conclusions: The results of this study indicated that masticatory efficiency was the highest in patients with Angle's Class I malocclusion, followed by those with Angle's Class II and Angle's Class III malocclusions. Moreover, a weak positive correlation was observed between masticatory efficiency and the occlusal contact area.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권4호
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• pp.1-9
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• 2011

Bentonite has been generally used as vertical cutoff barrier material and reported to have several problems regarding its low workability, drying shrinkage cracking by particle cohesion, and ineffective waterproof ability under sea water condition. In this study, the particle sealant, the furnace slag coated by the mixture of bentonite, sepiolite and guargum, was developed to compensate these weak points and the hydraulic conductivity of the particle sealant was evaluated. Drying shrinkage cracking and swelling index was estimated to find the optimal mixing ratio of bentonite, sepiolite and guargum. The hydraulic conductivity of the particle sealants having different amount of sealant (bentonite-sepioliteguargum mixture) coating the furnace slag was estimated using the rigid wall permeameter and flexible wall permeameter. The results showed that drying shrinkage cracking was not found in the bentonite-sepiolite mixture with 20% sepiolite contents and the results from free swelling tests for the sealant having 1 : 0.025, 1 : 0.05 and 1 : 0.075 of weight ratios of bentonite-sepiolite mixture and guargum under simulated sea water condition were higher than those for the bentonitesepiolite mixture without guargum under tap water condition. These three sealants were coated on the furnace slag with 50% and 60% of sealant in the particle sealant and the hydraulic conductivity was estimated. In the cases of the particle sealants having 20% sepiolite in the bentonite-sepiolite mixture and 1 : 0.075 weight ratio of the bentonite-sepiolite mixture and guargum, the hydraulic conductivity from the rigid wall permeameter was below $1.0{\times}10^{-7}$ cm/sec under simulated sea water condition. The hydraulic conductivity of the particle sealant having $1.0{\times}10^{-6}$~$1.0{\times}10^{-7}$ cm/sec by the rigid wall permeameter was estimated using the flexible wall permeameter and found to be below $1.0{\times}10^{-7}$ cm/sec.