• The Journal of the Korean dental association
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• v.50 no.1
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• pp.6-12
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• 2012

As in all other parts in the body, oral tissue also undergoes dramatic changes with increasing age. Since these changes occasionally go beyond physiological scope, which may result in pathological changes, it is essential for dentist to understand changes caused by normal aging process. With increasing age, tooth morphology and occlusion also varies, especially loss of hard tissue, which is taking place in lifelong time, occurs as a result of tooth wear. When this loss of hard tissue is presented rapidly or excessively, functional and esthetical problems are raised, resulting in lowering quality of life of patient as well as making dental treatment for oral rehabilitation even more complex. Therefore, based on understanding of change in occlusion with increasing age, strategic approaches for maintenance of oral health in both functional and esthetic aspect are required as appropriate restoration and maintenance for progressive tooth wear enables desirable occlusal relationship. Carefully planned-restorative treatment in accordance with changed occlusal relationship is also required in the same context. Instead of taking changes in oral tissue as only a consequence of ageing, it is vital to educate patient and his or her guardian, assuring maintenance of oral hygiene and regular dental check-up are of utmost importance for improved oral health.

• Journal of Korean Medicine Rehabilitation
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• v.19 no.1
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• pp.11-21
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• 2009

Objectives : This study was performed to investigate the effects of Semen Persicae(SP) on muscle type change and vascularization effect by measuring expression of Myosin heavy chain (MHC) and Vascular endothelial growth factor (VEGF) protein in the Middle cerebral artery occlusion(MCAo) rats. Methods : The middle cerebral artery was occluded, SP extraction was administrated for 4 days. The effects of SP on muscle type change and vascularization were measured. Results : 1. VEGF protein expressions in the Semen Persicae oral administration group of MCAo group were increased compared to the control group. 2. There were no significant difference between the Semen Persicae oral administration of MCAo group and the control group in MHC isoform (Type I, Type IIa) expression change. Conclusions : The present study demonstrates the effect of Semen Persicae in the vascularizing after ischemia, but has no significant effect in musle type change and the improvement of musle atrophy.

• The korean journal of orthodontics
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• v.8 no.1
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• pp.27-37
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• 1978

In order to know the variation of the associated craniofacial skeletal angle and linear distance according to the change of gonial angle, the roentgenographic cephalo metric study was undertaken in Korean normal cephalometric analysis and eletric computer. The fallowing results were optained. 1) The size of gonial angle is mainly depend on the lower gonial angle. The mean of upper gonial gngle is almost same in normal occlusion group$^*$ and malocclusion group. 2) It was resulted on normal group and malocclusion group by F test that the number of parameters that were significant at 5% level of confidence were 14 parameters in normal occlusion group and 22 parameters in malocclusion group. 3) Ramus height and mandibular body length increased and facial ratio is decreased as gonial angle decreased. 4) MP-T, overbite depth and Y-axis angle is not related to gonial angle in normal occlusion group, but in moloclusion group, as gonial angle decreased, MP-T and overbite depth is increased and Y-axis angle is decreased. 5) SN-MP, OP-MP, PP-MP is increased as gonial anglel increased, it was mainly depend on the lower gonial angle.

• The KIPS Transactions:PartB
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• v.13B no.1 s.104
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• pp.35-46
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• 2006

The dynamic change of background and moving objects is an important factor which causes the problem of occlusion in tracking moving objects. The tracking accuracy is also remarkably decreased in the presence of occlusion. We therefore propose an active fusion model which is robust against partial occlusions that are occurred by background and other objects. The active fusion model is consisted of contour-based md region-based snake. The former is a conventional snake model using contour features of a moving object and the latter is a regional snake model which considers region features inside its boundary. First, this model classifies total occlusion into contour and region occlusion. And then it adjusts the confidence of each model based on calculating the location and amount of occlusion, so it can overcome the problem of occlusion. Experimental results show that the proposed method can successfully track a moving object but the previous methods fail to track it under partial occlusion.

• Journal of TMJ Balancing Medicine
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• v.9 no.1
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• pp.4-11
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• 2019

Objectives: Although intraoral balancing appliance therapy has been used effective to several diseases, verification studies through cerebral diseases are poorly reported so far. Thus we investigated the effect of tooth-cut induced dental malocclusion against mouse model of ischemic stroke. Methods: Tooth-cut and 90 min middle cerebral artery occlusion (MCAO) were loaded to C57BL/6 male mice, and total infarct area, neurological deficit scores (NDS), histological change of hippocampal region were observed. Production levels of reactive oxygen species (ROS) and inducible nitric oxide synthase (iNOS) in cerebral tissue were also measured. Results: The longer the tooth-cut period, the greater the area of cerebral infarction caused by MCAO, and NDS began to increase as the tooth was cut, and the results were more negative when MCAO was loaded. Histological change of hippocampal cells was significant when tooth-cut was maintained for 7 days. Those damages were thought to depend on the generation of ROS and iNOS in brain tissue. Conclusions: Since tooth-cut increased total area of cerebral infarction due to MCAO in mice, it is able to be confirmed that anomaly of the temporomandibular occlusion can affect neurological diseases.

• The korean journal of orthodontics
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• v.5 no.1
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• pp.51-56
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• 1975

In orthodontic field, the study on gnathostatic model is very important to the diagnosis and analysis of malocclusion. The purpose of this study is to observe that relation of orbital plane and upper canine in Koreans. We selected 230 cases with normal occlusion, 124 male and 106 female cases aged from 12 years to 25 years, to prepare 230 gnathostatic models, and measured the distance from midpoint of mesio-distal distance of upper canine to orbital plane in gnathostatic model. The results obtained were as follows: 1) The mean value of the distance from upper canine to orbital plane showed no significant change with age. 2) The mean value of the distance from the upper canine to orbital plane was -3.11mm in male and -3.84mm in female. 3) The orbital plane passed through the upper canine in normal occlusion of Koreans.

• Journal of Biomedical Engineering Research
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• v.24 no.5
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• pp.421-425
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• 2003

In this study the occlusion of dural-sac. the outer membrane of spinal cord in the lumbar region. was quantitatively analyzed using one motion segment finite element model. Occlusion was quantified by calculating cross sectional area change of dural-sac for different compressive impact duration (loading rate) due to bony fragment at the posterior wall of the cortical shell in vertebral body. Dural-sac was occluded most highly in the range of 8∼12 msec impact duration by the bony fragment intruding into the spinal canal. $\Delta$t = 400 msec case 4 % cross sectional area change was calculated. which is the same as the cross sectional area change under 6 kN of static compressive loading.

• Journal of Oral Medicine and Pain
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• v.48 no.4
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• pp.152-158
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• 2023

Purpose: This pilot study aimed to evaluate changes in joint space (JS) using cone-beam computed tomography (CBCT) images of patients diagnosed with temporomandibular joint (TMJ) osteoarthritis (OA) and to determine the association between occlusal changes and JS. Methods: CBCT images were used to measure the anterior, superior, and posterior JSs of the sagittal plane. The differences in JS values over time and between groups were compared. The percentage change in the anteroposterior position of the mandibular condyle between groups was also analyzed. Results: Thirty-four subjects (mean age=43.91±20.13), comprising eight males (23.5%) and 26 females (76.5%), were divided into 18 patients with no change in occlusion (NCO) and 16 patients with a change in occlusion (CO) during TMJ OA. The JS measurements of the study subjects showed a decrease in anterior joint space (AJS) values over time. There was no difference in JS measurements between the groups at T1 and T2. AJS values measured at T1 were lower in the CO group than in the NCO group, but the difference was not statistically significant. In both groups, a posterior position of the mandibular condyle was initially observed with high frequency. However, there is a statistically significant difference in CBCT images taken after occlusal changes, with an increased frequency of condyles observed in the anterior or central positions. Conclusions: In conclusion, AJS decreased over time in TMJ OA, and the mandibular condyle became more anteriorly positioned with occlusal changes. Therefore, clinicians should diligently monitor mandibular condyle morphology and JS using CBCT, along with the patient's clinical symptoms, to treat and control TMJ OA effectively.

• The KIPS Transactions:PartA
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• v.17A no.4
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• pp.189-196
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• 2010

This paper presents an improved marker detection algorithm using hybrid features such as corner, line segment, region, and adaptive threshold values, etc. In usual augmented reality environments, there are often marker occlusion and poor illumination. However, existing ARToolkit fails to recognize the marker in these situations, especially, partial concealment of marker by user, large change of illumination and dim circumstances. In order to solve these problems, the adaptive threshold technique is adopted to extract a marker region and a corner extraction method based on line segments is presented against marker occlusions. In addition, a compensating method, corresponding the marker size and center between registered and extracted one, is proposed to increase the template matching efficiency, because the inside marker size of warped images is slightly distorted due to the movement of corner and warping. Therefore, experimental results showed that the proposed algorithm can robustly detect the marker in severe illumination change and occlusion environment and use similar markers because the matching efficiency was increased almost 30%.

• The korean journal of orthodontics
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• v.13 no.1
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• pp.73-82
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• 1983

The author studied on the dental arch widths and lengths and height of palates at 3 groups of dentition: mixed dentition, early permanent dentition, young adult, having normal occlusion and dentition. The models of the 336 maxillary and mandibular case, made from alginate-base hydrocolloid impressions were measured and analyzed statistically. The result as follows; 1. The upper intercanine width increased between the mixed dentition group and early permanent dentition group but there was no change in the young adult group in both sexes. The lower intercanine width increased between the mixed dentition group and early permanent dention group in the male. 2. The upper and lower 1st bimolar width increased slightly with age in the male but there was no change in the female. 3, The sex difference found in this study was one of absolute size, the female being slightly smaller than the male in the early permanent dentition group and young adult. 4. The arch length had no notable sexual differences and decreased between the mixed dentition group and early permanent dentition group. There was no change in the arch length in the young adult. 5. The height of palate increased gradually with age.