• The Journal of Korean Academy of Prosthodontics
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• v.54 no.1
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• pp.49-56
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• 2016

Excessive occlusal wear can result in unacceptable damage to the residual teeth structure, anterior guidance and masticatory function. An 86-year-old man presented with worn dentition and anterior deep bite due to loss of the posterior support. Two implants covered by Korean national health insurance, fixed partial denture and direct composite resin were used to restore the dentition, instead of removable prosthesis. The occlusal vertical dimension was increased by 2 mm in the premolar area and shortened dental arch concept was applied. This treatment was a less expensive alternative to full-mouth rehabilitation with positive esthetic and functional outcomes after 7 months of follow-up.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.115-126
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• 2000

Dental arch expansion is one of the method used to solve the dental crowding problem by non-extraction. Many formulae using tooth size have been suggested to predict ideal inter-premolar and inter-molar width. The purpose of this study was to evaluate the adequacy of some upper dental arch width prediction methods, namely Pont's method, Schmuth's method and Cha's method. The sample consisted of the casts of 119 Korean young adults who had no muscular abnormality, no skeletal discrepancy, and Angle's Class I molar relationships. Measurements were obtained directly from plaster casts; they Included mesiodistal crown diameters of the four maxillary incisors, as well as maxillary inter-first-premolar and inter-first-molar arch widths as specified by Pont. The correlation coefficients between the sum of incisors(SI) and upper dental arch width were calculated. The differences between predicted width and actual width were classified as overestimated, properestimated, and underestimated. The data obtained from each group were analyzed for statistical differences. The results were as follows : 1. Upper dental arch width indices were calculated from SI in normal occlusion (81.96 : premolar index, 62.55 : molar index). 2. Low correlations between SI and arch width were noted in normal occlusion (0.50 in the inter-premolar width, 0.39 in the inter-molar width). 3. Pont's formula and Schmuth's formula tended to overestimate the inter-premolar width. A more even distribution of estimates was noted in Cha's fomula. 4. Cases within $\pm$1 mm range of observed inter-premolar width were $45\%$ in the Cha's formula, $40\%$ in the Pont's formula, and $39\%$ in the Schmuth's formula. 5. All formulae had a tendency to underestimate the inter-molar width, but Cha's formula had better predictability than others. 6. Cases within $\pm$1 mm range of observed inter-molar width were $40\%$ in the Cha's formula, $29\%$ in the Pont's formula, and $13\%$ of Schmuth's formula. The data presented in this study does not support the clinical usefulness of ideal arch width prediction methods using the mesiodistal width of maxillary incisors.

• The Journal of the Korean dental association
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• v.55 no.12
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• pp.842-849
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• 2017

The term, 'crossed occlusion' implies clinical situation in which the residual teeth in one arch have no contact with those in the antagonistic arch, resulting in the collapse of occlusal vertical dimension. The treatment goal of this pathologic condition is restoration of the collapsed vertical dimension and stabilization of abnormal mandibular position. Previously, konus removable prostheses or tooth supported overdentures were suggested to solve crossed occlusion. Nowadays, dental implants have been used for definitive support to solve this problem. In this case report, a 65 years old female patient had a crossed occlusion, in which the maxillary posterior residual teeth and mandibular anterior residual teeth cross. Interim removable and fixed dental prostheses were used to confirm the proper vertical and horizontal jaw relation. After that, the mandibular posterior edentulous region was restored with implant-supported fixed dental prostheses. Computer tomography guided implant surgery was performed according to the concept of the restoration-driven implant placement. The maxillary anterior edentulous region was restored with Kennedy class IV removable prosthesis, considering the patient's economic status. The patient's jaw position and prostheses have been well maintained at the follow-up after 6 months of definitive restoration. The antero-posterior crossed occlusion problems appeared to be effectively solved with the combination of removable in one arch and implant-supported fixed prostheses in the other.

• Journal of Korean Association for Spatial Structures
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• v.10 no.3
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• pp.81-90
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• 2010

Large spatial structures have the different dynamic characteristics from general rahmen structures and many studies on dynamic behavior of it is conducted. But most studies was conducted about the particular shape of large spatial structures and, directly, the usable results of studies are very limited for seismic design of large spatial structures with the lower structure. So, this study is conducted about the truss arch structure that the basic dynamic characteristics of large spatial structure is inherent in, and the change of its seismic response is analyzed when columns have different length on both ends of it. According to the difference of column's length on both ends, the vertical acceleration response of truss arch structure is affected more than the horizontal acceleration response of it. Therefore, when the stiffness of lower structures that support the upper structure is different, the consideration of the vertical response is significantly required for the seismic design of large spatial structures.

• Journal of Chest Surgery
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• v.39 no.4 s.261
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• pp.317-319
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• 2006

Under median sternotomy and left thoracotomy, extra-anatomic aorta bypass between ascending aorta and descending thoracic aorta without cardiopulmonary bypass support has been done effectively and easily without complications for a selected case of atypical coarctation associated with hypoplasia of aortic arch. It should be considered as an alternative operative technique for complex aortic arch reconstruction.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.1
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• pp.41-56
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• 2017

Recently, the necessity of deep and double-deck tunnels has been grown day by day due to the increase of traffic volume at metropolitans and thus the study on the divergence of those tunnels becomes required. Therefore sensitivity analyses were conducted with FLAC 2D program by selecting ground condition, coefficient of lateral pressure, support pattern, and depth of rock cover as parameters. Ultimately, this study is to find the optimal shape and support method of a diverged section. As the results of this study, it turned out that the box type gave higher stability of the section than arch type unlike the general thought. It can be explained that the arch type has about 30% bigger excavation area than the box type. When the ground conditions are poor, steel pipe grouting reinforcement gives higher stability than rockbolt reinforcement, but its thickness and range do not give a great influence on the stability of the enlarged section.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.9
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• pp.1557-1563
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• 2016

According to recent studies, poor sitting posture of the spine has been shown to lead to a variety of spinal disorders. For this reason, it is important to measure the sitting posture. We proposed a strategy for classification of sitting posture using machine learning. We retrieved acceleration data from single tri-axial accelerometer attached on the back of the subject's neck in 5-types of sitting posture. 6 subjects without any spinal disorder were participated in this experiment. Acceleration data were transformed to the feature vectors of principle component analysis. Support vector machine (SVM) and K-means clustering were used to classify sitting posture with the transformed feature vectors. To evaluate performance, we calculated the correct rate for each classification strategy. Although the correct rate of SVM in sitting back arch was lower than that of K-means clustering by 2.0%, SVM's correct rate was higher by 1.3%, 5.2%, 16.6%, 7.1% in a normal posture, sitting front arch, sitting cross-legged, sitting leaning right, respectively. In conclusion, the overall correction rates were 94.5% and 88.84% in SVM and K-means clustering respectively, which means that SVM have more advantage than K-means method for classification of sitting posture.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.4
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• pp.423-436
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• 2011

Trauma from occlusion (TFO) is a pathologic alterations which develop in the periodontium as a result of undue masticatory force. The purpose of this article is to review the controversies about TFO. There are evidences that TFO is a risk factor in the progression of periodontitis. Tooth mobility should be reduced by selective occlusal adjustment. TFO can be developed dependent on the masticatory pattern, occlusion and anterior overbite in sound periodontal conditions. Secondary TFO may aggravate unstable occlusion. If "loss of posterior support" was occur, the problems were worsen. Extrusion, migration, rotation and pathologic deviation can be resulted. Opposite contention is the "shortened dental arch" concept. However, these two concepts persue the occlusal stability together. To treat TFO adequately, exact diagnosis and multi-disciplinary treatment should be needed.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.2
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• pp.176-183
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• 2014

Severely absorbed edentulous ridge cannot bear mechanical stress, causes undesired transformation of oral environment and makes patients difficult to adapt to dentures. Nowadays implant overdenture can be a treatment of choice in order to relieve patients' discomfort and improve stability and retention of the denture. Placement of implant on maxilla is difficult because of its bone quality and anatomic structure. It also has wide supportive tissue and convenience of border sealing, which provides sufficient support and stabilization with conventional complete denture. Mandible, on the other hand, is difficult to obtain sufficient support, retention and stabilization with conventional complete denture. Therefore, implant overdenture is recommended on mandible. Locator attachment has been improved for convenience of use and male parts of various retention enabled it to replace ball type attachment clinically. In this study, we restored maxillary arch with conventional denture, and mandibular arch with implant and tissue-supported overdenture and Locator attachment system.

• Physical Therapy Korea
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• v.29 no.3
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• pp.208-214
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• 2022

Background: Pronated foot posture (PFP) contributes to excessive dynamic knee valgus (DKV). Although foot orthoses such as medial arch support (MAS) are widely and easily used in clinical practice and sports, few studies have investigated the effect of MAS on the improvement of DKV during stair descent in individuals with a PFP. Moreover, no studies reported the degree of improvement in DKV according to the severity of PFP when MAS was applied. Objects: This study aimed to examine the immediate effect of MAS on DKV during stair descent and determine the correlation between navicular drop distance and changes in DKV when MAS is applied. Methods: Twenty individuals with a PFP (15 males and five females) participated in this study. The navicular drop test was used to measure PFP severity. The frontal plane projection angle (FPPA) was calculated under two conditions, with and without MAS application, using 2-dimensional video analysis. Results: During stair descent, the FPPA with MAS (173.1° ± 4.7°) was significantly greater than that without MAS (164.8° ± 5.8°) (p < 0.05). There was also a significant correlation between the navicular drop distance and improvement in the FPPA when MAS was applied (r = 0.453, p = 0.045). Conclusion: MAS application can affect the decrease in DKV during stair descent. In addition, MAS application should be considered to improve the knee alignment for individuals with greater navicular drop distance.