• Title/Summary/Keyword: Retainer

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DOUBLE CROWN RETAINED REMOVABLE PARTIAL DENTURE - 4 YEARS IN RETROSPECT (Double crown retained RPD의 4년 임상 관찰)

  • Lee Seok-Hyung
    • The Journal of Korean Academy of Prosthodontics
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    • v.42 no.1
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    • pp.73-82
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    • 2004
  • Statment of problem : Little in known about the importance of selection of various double crowns as retainer in determining the outcome of treatment with double crown retained removable partial denture. Purpose : To obtain information about the effects and the results of this treatment modality. Material and methods : This study describes 61 double crown retained removable partial dentures worn by 51 patients from Samsung Medical Center, Seoul a time ranging between 6 and 48 months and evaluate occlusal contacts on the denture teeth, denture movement, incidence of denture relining, denture retention, fracture of dentures and abutments, hygiene, residual ridge inflammatory changes, number of lost abutment,. interruption of denture use. Results : One tenth of all the restorations were relined. Restorations in 21 arches fractured repeatedly for various reasons . There was no apparent interrelationship between fractures and the five groups. Conclusion : Good prognoses of removable partial dentures were shown in all groups(Kennedy Classes I, II, III, combination and few remaining abutment).

Applications of Fiber Reinfored Composite in Dental Practice (Fiber Reinforced Composite를 이용한 치료 증례)

  • Cho, Jin-Hyoung
    • Journal of Dental Rehabilitation and Applied Science
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    • v.22 no.1
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    • pp.23-27
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    • 2006
  • This case reports describe a new approach to the use of polymers in orthodontics, using a fiber reinforced composite(FRC). FRC was successfully used in a periodontal splints, fiber post for endodontic use, orthodontic retainer and space maintainers, implant prosthesis, large span bridge, management of cracked tooth, anchorage reinforcement in orthodontics. FRC has highly favorable mechanical properties, and its strength-to-weight ratios is superior to those of most alloys. FRC has potential for use in many applications in dentistry and is expected to gain increasing application and popularity in dentistry. These case reports show that FRC is a promising anchorage reinforcement material for use in orthodontic practice.

A CLINICAL STUDY ON THE DISTRIBUTION AND THE BOND FAILURE OF ETCHED (MARYLAND) BRIDGE: A PRELIMINARY REPORT OF 135 CASES (MARYLAND BRIDGE의 적용분포 및 결합실패에 관한 임상적 연구(I))

  • Yang, Jae-Ho
    • The Journal of Korean Academy of Prosthodontics
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    • v.24 no.1
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    • pp.7-16
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    • 1986
  • The purpose of this study was to examine the distribution and the bond failure of the acid-etched ceramometal retainer (Maryland Bridge). 126 subjects who treated by faculty and residents of Department of Prosthodontics, Seoul National University Hospital from Dec. 1982 to Dec. 1986 were selected for this study. From the foregoing study author obtained the following conclusions. 1. A total of 135 restorations were placed in the mouths of patients ranging in age from 11 to 10 years (man 62, woman 64). 2. Most restorations were applied to replace anterior teeth. 3. It was found that of the total number of bridges constructed 59.3 percent were the three-unit type. 4. Replacing one tooth mining was the most frequent cases (74.1 percent). 5. Of the total number of cases, 10.4 percent stowed bond failure. 6. The bond failure, author suggest, be due to one or more of mis-fit of framework, occlusion, material in itself, faulty case selection and lack of technique.

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A CASE REPORT OF SEPTOTOMY OPERATED AFTER TREATMENT OF ROTATED TEETH (Septotomy를 행한 염전치의 교정치험예)

  • Yang, Won-Sik;Kim, Yung-Bok;Kim, Jong-Tae
    • The Journal of the Korean dental association
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    • v.16 no.11 s.114
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    • pp.849-856
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    • 1978
  • Relapse following rotational movement of the tooth is a common problem in orthodontic practice. To overcome such relapse, many procedures have been advocated: prolonged retention, permanent retention, over-rotation, rotation of teeth at an early age, surgical procedures such as gingivectomy, redressement force, septotomy, et cetra. A 23-year-old woman presented with Angle's Class I malocclusion and extreme rotation of maxillary central incisors. After 15 months' active therapy, septotomy was performed on maxillary central incisors and Howley retainer was applicated for the purpose of overcoming rotational relapse. During the 1 year post-operative observation, negligible, if any, rotational relapse occurred.

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Transient Thermoelastic Analysis and 3 Dimensional Stress Analysis of Carbon/Carbon Brake Disks (탄소/탄소 브레이크 디스크의 과도기 열탄성 해석과 3차원 응력해석)

  • 오세희;유재석;김천곤;홍창선;김광수
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.11a
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    • pp.147-152
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    • 2000
  • This paper presents the thermoelastic analysis and 3-D failure analysis of the carbon/carbon brake disk. The mechanical properties of the carbon/carbon brake disk were measured for both in-plane and out of plane directions. The mechanical properties were used as the input of the thermoelastic analysis and 3-D stress analysis for the brake disk. The gap between rotor clip and clip retainer was an important parameter in the loading transfer mechanism of the rotor. The change of gap was considered separating the mechanical deformation and thermal deformation. Because the rotor clip and clip retainers were not contacted, the clip retainers and rivets were excluded from the rotor analysis model. The disk was modeled by using the cyclic symmetry condition and the contact problem between the rotor disk and rotor clip was considered. From the results of the 3-D stress analysis, the stress concentration at the key hole of the brake disk was confirmed.

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Structural Analysis considering Electromagnetic Force on Motor/Generator for Flywheel Energy Storage System (전자기력을 고려한 플라이휠 에너지 저장시스템용 전동발전기 구조해석)

  • Ko, W.S.;Ryu, D.W.;Oh, S.D.;Seong, Tae-Hyeon;Han, Sang-Cheol;Han, Yeong-Hui
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.485-490
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    • 2004
  • Flywheel Energy Storage System(FESS) consists of a high speed flywheel with an integral motor/generator suspended on non contact bearings and in an evacuated housing. Permanent magnet machines as the FESS motor/generator are a popular choice, since there are no excitation losses which means substantial increase in the efficiency. In this paper, the structural design method of rotor retainer for a high speed motor/generator are presented.

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Some Instances of Manchurian Naturalization and Settlement in Choson Dynasty (향화인의 조선 정착 사례 연구 - 여진 향화인을 중심으로 -)

  • Won, Chang-Ae
    • (The)Study of the Eastern Classic
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    • no.37
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    • pp.33-61
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    • 2009
  • In the late Koryo period, until 14th century, there had been at least two groups of Manchurians who were conferred citizenships; one group was living as an original inhabitant in the coastal area of north­eastern part of Korean peninsular, long time ago, and they were over one thousand households. The other was coming down from inland, eastern part of Yoha River, to the area of Tuman River to settle down and they were at least around one hundred and sixty households, including such tribes as Al-tha-ry, Ol-lyang-hap, Ol-jok-hap and others. They were treated courteously, from the early days of Choson dynasty, with governmental policies in an economic, political, and social ways. They were given, for instance, a house, a land, household furniture, and clothes. They were allowed to get marry with a native Korean to settle down. They were educated how to cultivate their lands. It was also possible for them to be given an official position politically or allowed to take a National Civil Official Examination. The fact they could take such an Examination, in particular, means they were treated fairly and equally, because they also had a privilege to improve their social positions through the formal system as much as common people. Two typical families were scrutinized, in this paper, family Chong-hae Lee and family Chon-ju Ju. All of them were successful to settle down with different backgrounds each other. The former were from a headman, Lee Jee-ran, who controlled his tribe, over five hundred households. He was given three titles of a meritorious retainer at the founding of Chosun dynasty, at the retrieval of armies, and an enshrined retainer. His son, Lee Wha-yong, was also given a vassal of merit who kept a close tie successfully with the king's family through a marriage. Upon the foundation of their ancestors, their grandsons, family Lee Hyo-yang and family Lee Hyo-gang, each, had taken solid root as an aristocratic Yang-ban class. The former became a high officer family, generation by generation, while the latter changed into a civil official family through Civil Official Examinations. They lived mainly around Seoul, Kyong-gi Province and some lived in their original places, Ham-kyong Province. Chu-man, the first ancestor, was given a meritorious retainer at the founding of the dynasty and Chu-in was also given a high officer position from the government. They kept living at the original place, Ham-heung, Ham-kyong Province, and then became an outstanding local family there. They began to pass the Civil Official Examinations. After 17th century on the passers were 17 in Civil Official Examinations and 40 were passed in lower civil examinations. The positions in government they attained usually were remonstrance which position was prohibited particularly to North­Western people at that time. The Chosun dynasty was open to Machurians widely through the system of envoy, convoy, and naturalization. It was intended to build up an enclosure policy through a friendly diplomatic relation with them against any possible invasion from outside. This is one reason why they were supported fully that much in a various way.

Effect of New Mattress System with Vegetation Base Materials on the Vegetation Coverage of Stream bank (계안 복원을 위한 매트리스형 식생기반재 돌망태 공법의 계안사면 피복효과)

  • Choi, Hyung Tae;Jeong, Yong-Ho;Park, Jae-Hyeon
    • Journal of Korean Society of Forest Science
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    • v.101 no.2
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    • pp.175-184
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    • 2012
  • This study was conducted to develop new mattress systems with vegetation base materials for protecting stream bank and rapid rehabilitation. Vegetation base materials are primarily compounded with fine soil, organic composts and peat moss as plant fibers, a water retainer and a soil improver. Peat moss can usually provide necessary natural fibers and organic materials in soil. Especially, peat moss can absorb up to 25 times its own weight in water and is therefore valued as a water retainer to prevent drying effect of vegetation base materials which can harm the growth of vegetation in mattresses. Normally mattress systems resist the lateral earth pressures or stream power by their own weight. Therefore, filled materials must have suitable weight, compressive strength and durability to resist the loading, as well as the effects of water and weathering. In this project, 100 to 200-mm clean, hard stones were basically specified, and about 50-mm rubbles were also used. Test application of new mattress system carried out in the stream bank of a small stream in the Gwangreung experimental forest, belonging to Korea Forest Research Institute (KFRI) in December 16th, 2006. As a result of the monitoring of vegetation coverage of test application plots (each plot size is 4 by 2 m), the coverage of all plots reached 100% in the end of May, 2007 (approximately 50 days passed after the first gemination of vegetation). The coverage of the plots using big hard stones and organic composts and the plots containing peat moss increased more rapidly. The results show that peat moss is effective to retain soil moisture and establish more sound environment for vegetation gemination.

TREATMENT OF IMPACTED MANDIBULAR FIRST MOLAR BY SURGICAL EXPOSURE : A CASE REPORT (매복된 하악 제1대구치의 외과적 노출술을 이용한 치험례)

  • Cho, Yun-Jung;Park, Young-Ok;Kim, Tae-Wan;Kim, Hyun-Jung;Kim, Young-Jin;Nam, Soon-Hyeun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.34 no.2
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    • pp.322-328
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    • 2007
  • The first molar is important for mastication and also it plays roles to formation of vertical occlusion and growth of jaw bone after mixed dentition. Impaction of mandibular first molar can result in a short lower facial height, formation of a follicular cyst, pericoronal inflammation, resorption of the roots of neighboring teeth and malocclusion. The options of treatment plans are as follows; observation, surgical exposure, orthodontic traction, surgical relocation and extraction. Surgical exposure could be considered as a basic treatment plan. For surgical exposure it is important to maintain patent channel between the crown and the normal eruptive path into the oral cavity, many techniques including cementation of a celluloid crown, packing with zinc oxide-eugenol surgical pack are used. In these cases, we could observe spontaneous eruption of mandibular first molar using surgical exposure with or without removal of odontoma. Also we could obtain the main patency effectively and conveniently by using surgical pack and translucent retainer.

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A STUDY ON THE STRESS DISTRIBUTION OF ABUTMENT TEETH AND RESIDUAL RIDGE AREA BETWEEN TELESCOPIC AND CLASP TYPE RPD BY FEM METHOD (telescope형 및 Clasp형 유지장치를 이용한 국소의치 지지조직의 응력분포에 관한 삼차원 유한요소법적 연구)

  • Koak, Jai-Young;Kim, Kwang-Nam;Chang, Ik-Tae;Heo, Seong-Joo
    • The Journal of Korean Academy of Prosthodontics
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    • v.37 no.1
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    • pp.104-126
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    • 1999
  • The purpose of this study was to compare and evaluate the stress distribution and displacement developed in the abutment teeth and residual ridge area by madibular unilateral distal extension removable partial denture with 2 different retainer designs. The retainers on right and left canine and right 2nd molar were Alters clasp in one model and telescopic crown in the other model. The stress distribution of abutment teeth and residual ridge area on two model were compared and analyzed with 3-dimensional finite element method. 150N and 400N forces were applied vertically, 30 degree and horizontally on the central fossa area of left 1st molar of the removable partial denture, and then stress distribution patterns were analyzed and compared. The results were as follows 1. As the magnitude and angulation of applied force were increased, the magnitude of stress on the right and central residual ridge area and the right canine of the telescopic type increased and comparing to those of the Alters clasp type. 2. As the magnitude and angulation of applied force were increased, the mesial direction of displacement on the right residual ridge area and the right tooth of the telescopic type increased and the distal direction of displacement on left residual ridge area and the left canine increased comparing to those of Akers clasp type. 3. As the vertical force was applied, the distal direction of the displacement of the right tooth were greater and that of the left canine was smaller and the upward displacement of the right canine was greater in telescopic partial denture than those of Akers clasp type. 4. As the 30 degree force was applied, the mesial direction of the displacement of the right tooth were greater and the distal direction of the displacement of the left canine was smaller and the upward displacement of the right canine was greater in telescopic partial denture than those of Akers clasp type. In the horizontal force the results were same in right area tooth but the distal direction of displacement was greater in left canine. 5. In both removable partial dentures, as the magnitude and degree of force were increased, the stress and displacement were increased. The compressive force was dominative than the ten sile force. 6. In both removable partial dentures, the magnitude of stress was greater on mucosal tissue area than that of the alveolar bone area on distal extension residual ridge area but the result was reversed on anterior residual ridge area. The displacement was always greater on mucosal tissue area than that of alveolar bone area.

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