• Journal of Periodontal and Implant Science
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• v.52 no.1
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• pp.3-27
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• 2022

Purpose: This study was conducted to evaluate and compare the effects of different graft materials used in alveolar ridge preservation on dimensional hard tissue changes of the alveolar ridge, assessed using cone-beam computed tomography (CBCT) scans. Methods: A systematic electronic search of MEDLINE and the Cochrane Central Register of Controlled Trials and a manual search were conducted from November 2019 until January 2020. Randomized controlled trials were included if they assessed at least 1 variable related to vertical or horizontal hard tissue changes measured using CBCT scans. After a qualitative analysis of the included studies, subgroups were formed according to the graft material used, and a quantitative analysis was performed for 5 outcome variables: changes in vertical alveolar bone height at 2 points (midbuccal and midpalatal/midlingual) and changes in horizontal (buccolingual) alveolar bone width at 3 different levels from the initial crest height (1, 3, and 5 mm). Results: The search resulted in 1,582 studies, and after an independent 3-stage screening, 16 studies were selected for qualitative analysis and 9 for quantitative analysis. The metaanalysis showed a significantly (P<0.05) lower reduction of alveolar ridge dimensions for the xenogenic subgroup than in the allogenic subgroup, both vertically at the midbuccal aspect (weighted mean difference [WMD]=-0.20; standard error [SE]=0.26 vs. WMD=-0.90; SE=0.22) as well as horizontally at 1 mm (WMD=-1.32; SE=0.07 vs. WMD=-2.99; SE=0.96) and 3 mm (WMD=-0.78; SE=0.11 vs. WMD=-1.63; SE=0.40) from the initial crest height. No statistical analysis could be performed for the autogenic subgroup because it was not reported in sufficient numbers. Conclusions: Less vertical and horizontal bone reduction was observed when xenogenic graft materials were used than when allogenic graft materials were used; however, the loss of alveolar ridge dimensions could not be completely prevented by any graft material.

• Journal of Korea Entertainment Industry Association
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• v.14 no.7
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• pp.519-528
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• 2020

Purpose of this study is to analyze the changes in state anxiety, heart rate, and fall efficacy of the elderly through the handle height of walking assistant vehicle (WAV). The subjects were 32 elderlies. WAV was in the form of strollers, and it's handle height was set as 48% of a subject's total height. Also, it's height was divided into 48, 43, 38%. To measure the state anxiety, Korean State-Trait Anxiety Inventory was used and to measure the heart rate, Fitbit Charge 2 wrist heart rate monitor was used. To measure the fall efficacy, Fall Efficacy Scale-Korea was used. As the results of state anxiety and heart rate, the statistically significant increase showed continuously through the decrease of the handle height of WAV. As the results of fall efficacy, the statistically significant decrease showed continuously through the decrease of the handle height of WAV. In all of the post hoc test, the results of the state anxiety and fall efficacy showed significant difference among the each handle height of WAV and the results of the heart rate showed significant difference between the 48, 43% and 38% handle height of WAV. Thus, to decrease the state anxiety and heart rate and increase the fall efficacy of the elderly, the handle height of WAV should be properly positioned and considered to adjust to 48% of the user's total height.

• Journal of International Academy of Physical Therapy Research
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• v.3 no.2
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• pp.469-474
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• 2012

The purpose of this study is to analyze the correlation between the stature and the muscle performance ratings and the subjective discomfort rations at performing lower arm's pronation and supination according to change sin the height of working table for more efficient performance at designing a working table and performing a work. For the purpose, this study conducted an experiment targeting 40 people in their 20s, who were classified into 4 groups each group composing 10 people at intervals of 5cm from the standard stature of 166.5cm. The experiment measured the maximum isometric pronation and the supination muscular power, and at measuring the factors, the heights of working tables were set as 800mm, 850mm, and 900mm. From the measurement results, it was found that the stature and the maximum muscular power was correlated. That is, as the experiment groups's average stature is higher, the maximum muscular power was higher. For the correlation between the motion patterns(pronation and supination) and the maximum muscular power, it was seen that the maximum muscular power was higher at performing the pronation than the supination. In the correlation between motion patterns and the subjective discomfort ratings, it was seen that the subjective discomfort rating was higher at performing the supination than the pronation. For the correlation between height adjustment and the subjective discomfort ratings, as the height of working table was lower, the subject discomfort rating was lower. Therefore there was no difference in the maximum muscular power according to the height changes of working table, but it was found that as the working table was higher, the user felt more comfortable.

• Interdisciplinary Bio Central
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• v.3 no.3
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• pp.11.1-11.5
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• 2011

The MRI (magnetic resonance imaging) volumetric analysis of the brain was performed in 59 healthy elderly Koreans (aged 62-76 years; 34 male, 25 female) to investigate whether the previously reported significant correlations between body height and brain volumes in the young aged Koreans (20's) still exist in the old aged Koreans (60's and 70's). Unlike previously reported significant correlations in the young aged Koreans, neither the correlation between whole brain volume and body height in male nor the correlation between cerebellar volume and body height in female show any significance in the old aged Koreans. The significant correlation between body height and whole brain volume was still observed when both male and female data were combined (r=0.27, P<0.05), but the correlation coef-ficient and the level of significance markedly decreased from those of previously reported Korean youth data (r=0.67, P<0.01). Simple linear regression analysis shows decrease of explanatory power of height (measured in $r^2$) from 44% in the youth group to 7% in the old age group on the variance of whole brain volume. Multiple linear regression analysis shows that age and sex, rather than height, are major explanatory variables for whole brain volume in the old aged Koreans. The loss of correlations in the aged group is suspected to be mainly due to age related brain volume changes.

• The Korean Journal of Malacology
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• v.29 no.1
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• pp.43-50
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• 2013

We investigated the growth performance of oysters (initial shell height $57.5{\pm}8.5$ mm) under differing conditions of tidal exposure time and culture rack height in an experiment that commenced in April, 2011. Significant differences were observed in shell height from June 2011, in total weight from August, and in meat weight from September. Fatness tended to decrease during the experimental period, but was not significantly different at the end of the experiment. Significant differences in survival rates were mainly observed from June to August. After September, further changes were not observed in any experimental treatment group. The greatest growth potential ($L_{\infty}$) and survival rate were observed at a sea level of approximately 116 cm. The results indicate that in the study area the use of oyster culture conditions involving 1 or 2 h of tidal exposure and 60 - 70 cm rack height could result in oysters reaching the favored commercial half shell size within 14 months, with > 80% survival.

• Journal of Periodontal and Implant Science
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• v.40 no.1
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• pp.25-32
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• 2010

Purpose: The performance of implant surgery in the posterior maxilla often poses a challenge due to insufficient available bone. Sinus floor elevation was developed to increase the needed vertical height to overcome this problem. However, grafting materials used for the sinus lift technique eventually show resorption. The present study radiographically compared and evaluated the changes in height of the grafting materials after carrying out maxillary sinus elevation with a window opening procedure. This study also evaluated the difference between two xenogenic bone materials when being used for the sinus lifting procedure. Methods: Twenty-one patients were recruited for this study and underwent a sinus lift procedure. All sites were treated with either bovine bone (Bio-$Oss^{(R)}$) with platelet-rich plasma (PRP) or bovine bone (OCS-$B^{(R)}$)/PRP. A total of 69 implants were placed equally 6-8 months after the sinus lift. All sites were clinically and radiographically evaluated right after the implant surgery, 7-12 months, 13-24 months, and 25-48 months after their prosthetic loading. Results: Changes of implant length/bone length with time showed a statistically significant decreasing tendency (P<0.05). There was no significant change in the Bio-$Oss^{(R)}$ group (P>0.05). In contrast, the OCS-$B^{(R)}$ group showed a significant decrease with time (P<0.05). However, no significant difference was observed between the two groups (P>0.05). Conclusions: The results showed that there was significant reduction in comparison with data right after placement, after 7 to 12 months, 13 to 24 months, and over 25 months; however, reduction rates between each period have shown to be without significance. No significant difference in height change was observed between the Bio-$Oss^{(R)}$ and the OCS-$B^{(R)}$ groups.

• Journal of Astronomy and Space Sciences
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• v.37 no.1
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• pp.69-75
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• 2020

We analyze the observations of temperature and ozone measured by the Microwave Limb Sounder (MLS) during the period of 2005-2016, to investigate the vertical structures of temperature and ozone in the stratosphere and mesosphere during stratospheric sudden warming (SSW). We compute the height profiles of the correlation coefficients between 55 height levels of MLS temperature anomalies and compare them with the results of Whole Atmosphere Community Climate Model simulations for three major SSWs. We also construct the temperature and ozone anomalies for the events to investigate the changes in the temperature and ozone distributions with height. There seems to always be a relatively weak but broad negative correlation between the temperature anomaly at 10 hPa and temperature anomalies over the entire mesosphere during the period before SSW events. However, this pattern gets stronger in the lower mesosphere but becomes a positive correlation in the upper mesosphere and lower thermosphere after the onset of SSW. We also found that the temperatures from the simulations show a similar trend to the observational results but with smaller variations and the transition height from negative to positive correlation in the mesosphere is much lower in the simulation than in the actual observations.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.4
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• pp.244-254
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• 2013

In this study, a method has been developed for estimating the change of nearshore random waves in response to sea-level rise, by extending the method proposed for regular waves by Townend in 1994. The relative changes in wavelength, refraction coefficient, shoaling coefficient, and wave height for random waves are presented as functions of relative change in water depth. The changes in wavelength and refraction coefficient are calculated by using the significant wave period and principal wave direction in the regular-wave formulas. On the other hand, the changes in shoaling coefficient and wave height are calculated by using the formulas proposed for shoaling and transformation of random waves in the nearshore area including surf zone. The results are proposed in the form of both formulas and graphs. In particular, the relative change in wave height is compared with the result for regular waves.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.4
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• pp.458-470
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• 2004

Statement of problem: Br${\aa}$nemark or ITI are two currently most widely used implant systems but with contrasting design, surgical and restoration methods. Purpose: The purpose of this study was to compare changes and its statistical significance in bone height and shape which may rise due to the differences between two implant systems. Also to analyse the effect of inter-implant distance on annual bone height changes. Material & Method: Those patients who were treated with two or more of either Br${\aa}$nemark or ITI implants at posterior mandibular area at Yonsei University Dental Hospital, Implant Clinic were selected. At annual examination appointments, standardised radiographs using parallel technique were taken. Marginal bone and inter-implant crestal bone changes were measured and following results were obtained. Results: 1) When ITI and Br${\aa}$nemark system were compared, both annual marginal and inter-implant crestal bone height changes in ITI system in the first two years were smaller than Br${\aa}$nemark and they were statistically significant. On the third year, however, there was no statistical difference between two implant systems on their annual bone level changes (p>0.05). 2) The Marginal and inter-implant crestal bone changes were compared when inter-implant distance was less than 4mm. Statistically significant bone level changes were noted on the first year only for ITI implants but in the first and second year for Br${\aa}$nemark implants (p>0.05). 3) When comparing angulation changes between marginal bone and implant fixture, ITI system had smaller angulation changes but the annual changes were not statistically significant (p>0.05). Conclusion: Within the limitation of this study, it could be concluded that Br${\aa}$nemark implant systems had more changes in marginal and inter-implant crestal bone level in the first and second year after loading with statistical significance. Further studies are recommended to see the effects of these bone loss during the first and second year after loading on the long term prognosis of Br${\aa}$nemark Implants.

• The korean journal of orthodontics
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• v.24 no.2
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• pp.275-294
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• 1994

The occlusal interference during adolescent period makes some effects on growth and development and morphological changes. And so, if we could predict the the timing and results of orthodontic treatment who have occlusal interference during adolescent period, it may be helpful for diagnosis and treatment planning of orthodontic treatment. For about those, the purpose of this study was to evaluate the effects of the posterolateral displacement by the metal casting crown with inclined pathway on the mandibular condyle and morphologic changes of mandible in the rat. The experimental animals were thirty six Sprague-Dawley male rats of 8 weeks old. Eight of them was used as control group, and experimental group 1 ( continuous appliance wearing group ) was composed of sixteen and experimental group 2 ( appliance removal group after worn the appliances during 3 months ) was composed of remaining twelve. The animals of experimental grouop 1 were sacrificed after 1, 2, 3, 6 months from beginning of the experiment and experimental group 2 were sacrificed 1, 2, 3 months after removal of the appliance from worn the appliance during 3 months. Both of mandible and temporomandibular joint were observed histologically and radiologically. The results were as follows : 1. In experimental group 1, the mandibular length and lower posterior height were decreased with experimental period, while the lower anterior height was increased, and the curvature of lower incisors and lingual inclination of anterior alveolar bone were profound as compared with control group. 2. In experimental group 1, both of the thickness of the condylar cartilage were thinned in the posterosuperior region, and this phenomenon was more prominent on right than left in 3-Mo experimental period and both sides were marked thinned in 6-Mo experimental period. 3. In experimental group 2, the lower anterior height was low and lower posterior height was high as compared with experimental group 1, and the curvature of lower incisors and lingual inclination of anterior alveolar bone were recovered to control group. 4. In experimental group 2, both of the thickness of the condylar cartilage were thickened in the posterosuperior region, and this phenomenon was more prominent with experimental period. 5. In experimental group 2, the mandibular length was short, lower anterior height was hight, the curvature of lower incisors were profound, and in histologically, both of the thickness of the condylar cartilage were thickened in the posterosuperior region as compared with control group. As shown above, the occlusal interfemce affected the condylar cartilage, curvature of lower incisor, inclination of anterior alveolar bone, mandibular length, and anterior and posterior height. When the interference was removed, significant recover was found in condylar cartilage, mandibular length, and posterior height. Although no significance was found, other items of measurement showed trends for recovery.