• Journal of Oral Medicine and Pain
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• v.35 no.2
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• pp.135-147
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• 2010

In this study, the objective masticatory efficiency of two groups of temporomandibular disorder patients, pain and sound groups, was compared with that in a normal group using the MAI (mixing ability Index). The subjective chewing ability was evaluated using questionnaires, such as the Food Intake Ability Index (FIA) and Visual Analogue Scale (VAS). The Oral Health Impact Profile (OHIP)-49K of the patients was also examined to measure the oral health-related quality of life. The results were as follows: 1. The MAI, FIA and VAS in the pain group were significantly lower than in the normal and sound groups. This shows that the chewing efficiency of the pain group was lower than the normal and sound groups (P<0.05). However, there was no significant difference between the sound and normal groups. 2. The OHIP-49K for the oral health-related quality of life showed a significant increase in both the pain and sound groups compared with normal group. This means that the oral health-related quality of life was lower in both the pain and sound groups. 3. There was a correlation between the MAI, FIA and VAS (P<0.01) in all subjects (71 persons). The OHIP-49K was associated with the FIA and VAS. 4. There was a correlation between the FIA and VAS (P<0.05) in the sound group but no correlation in the other groups. 5. There was a correlation between the FIA and VAS in all groups. 6. The VAS was increased significantly in the pain group according to the level of pain reduction after treatment (P<0.05). However, there was no significant increase in the MAI, even though there was an improvement in masticatory efficiency. In addition, there was no difference in the FIA and OHIP-49K according to the level of pain reduction after treatment. In this study, it is believed that pain is a main factor decreasing the masticatory efficiency in patients with temporomandibular disorders. Moreover, TMJ sounds decrease the quality of life but do not decrease the masticatory efficiency. Therefore, it is important to control the pain in order to improve the masticatory efficiency in temporomandibular disorder patients. Moreover, managing both pain and sound can improve the quality of life.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.1
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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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• v.42 no.4
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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.

• Journal of the Korean Geotechnical Society
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• v.33 no.11
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• pp.97-104
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• 2017

A bentonite mixing with local soil widely used as liner layer for landfill should have low permeability less than $1{\times}10^{-7}cm/s$. But there are several limitations of bentonite used as liner layer, such as drying shrinkage cracking, ineffective waterproof ability under salt water condition like flocculation under sea water. The purpose of this research is the development of a salt resistance bentonite by mixing sepiolite and guar gum to overcome the weak points of bentonite to get high water resistance capacity and permeability coefficient below $1{\times}10^{-7}cm/s$ under salt water condition. After having performed drying shrinkage cracking test, swelling index test, compaction test, and hydraulic conductivity test we confirmed the optimal mixing ratio of materials and evaluated the performance of materials.

• Journal of Periodontal and Implant Science
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• v.45 no.6
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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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• v.22 no.7
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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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• v.38 no.1
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• pp.53-67
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• 2013

This study was aimed to evaluate the masticatory efficiency after botulinum toxin type A (BTX-A) injection during 12 weeks using objective and subjective test. Also, we compared the difference of masticatory efficiency between group that injected into the masseter muscle only (M-group) and group that injected into the masseter and temporalis muscle (M-T group). The mixing ability index (MAI) was used as the objective indicator, and visual analogue scale (VAS) and food intake ability (FIA) index were used as the subjective indicators. It was concluded that masticatory efficiency was significantly lowered after a BTX-A injection into the masticatory muscle, but it gradually recovered in a predictable pattern by the 12 weeks. The disturbance of subjective masticatory efficiency was lasted longer than objective masticatory efficiency. The masticatory efficiency was lower in M-T group than M group. It was statistically significant in the VAS and FIA at 4 weeks, but the MAI showed no significancy. After 4weeks, there was rapid recovery of muscle function in M-T group, and the difference between two groups was not significant. It could be concluded that there will be no serious disturbance of mastication compared to injection is done only into the masseter muscle, even if injection is done into the masseter and temporalis muscle in dose of this study. According to the food properties, it was confirmed that people feel more discomfort on taking hard and tough foods after BTX-A injection and not only hard foods, but also intake of soft and runny foods were influenced by botulinum toxin injection.

• Journal of Oral Medicine and Pain
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• v.45 no.3
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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.

• The korean journal of orthodontics
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• v.47 no.3
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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.

• Journal of Soil and Groundwater Environment
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• v.16 no.4
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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.