• Title/Summary/Keyword: Partial denture

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SUPERELASTICITY OF CAST SHAPE MEMORY Ni-Ti ALLOY (주조 형상기억 니켈-티타늄 합금의 초탄성)

  • Choi, Dong-Ik;Choie, Mok-Kyun
    • Journal of the Korean Academy of Esthetic Dentistry
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    • v.3 no.1
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    • pp.32-43
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    • 1995
  • Ni-Ti alloy has excellent corrosion resistance, biocompatibility, shape memory effect and superelasticity, so it has been used widely in biomedical fields. But it has difficulty in casting due to its high melting temperature and oxygen affinity at high temperature. Recently it has been attempted to cast Ni-Ti alloy using new casting machine and investment. The purpose of this study was to examine the superelastic behavior of cast shape memory Ni-Ti alloy and to compare the mechanical properties of the cast shape memory alloy with those of commercial alloys for removable partial denture framework. Ni-Ti alloy(Ni 50.25%, Ti 49.75% : atomic ratio) was cast with dental argon-arc pressure casting machine and Type IV gold alloy, Co-Cr alloy, Ni-Cr alloy, pure titanium were cast as reference. Experimental cast Ni-Ti alloy was treated with heat($500{\pm}2^{\circ}C$) in muffle furnace for 1 hour. Transformation temperature range of cast Ni-Ti alloy was measured with differential scanning calorimetry. The superelastic behavior and mechanical properties of cat Ni-Ti alloy were observed and evaluated by three point bending test, ultimate tensile test, Vickers microhardness test and scanning electron microscope. The results were as follows : 1. Cast Ni-Ti alloy(Ni 50.25%, Ti 49.75% : atomic ratio) was found to have superelastic behavior. 2. Stiffness of cast Ni-Ti alloy was considerably lesser than that of commercial alloys for removable partial denture. 3. Permanent deformation was observed in commercial alloys for removable partial denture framework at three point bending test over proportional limit(1.5mm deflection), but was not nearly observed in cast Ni-Ti alloy. 4. On the mechanical properties of ultimate tensile strength, elongation and Vickers microhardness number, cast Ni-Ti alloy was similiar to Type IV gold alloy, Co-Cr alloy, Ni-Cr alloy and pure titanium. With these results, cast Ni-Ti alloy had superelastic behavior and low stiffness. Therefore, it is suggested that cast Ni-Ti alloy may be applicated to base metal alloy for removable partial denture framework.

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FINITE ELEMENT ANALYSIS OF STRESS PATTERNS ON PERIODONTIUM OF SPLINTED ABUTMENTSFOR DISTAL EXTENSION REMOVABLE PARTIAL DENTURE (후방연장 국소의치에서 지대치의 splinting에 따른 치주조직의 응력 변화에 관한 유한요소법적 연구)

  • Hwang, Jae-Woong;Chang, Ik-Tae;Kim, Kwang-Nam
    • The Journal of Korean Academy of Prosthodontics
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    • v.33 no.2
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    • pp.241-268
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    • 1995
  • Splint therapy, the immobilization of teeth, has been done for patient's masticatory comforts and an adjunctive aid in periodontal therapy. Mandibular premolars are frequently splinted in many distal extension removable partial denture cases. But splinting is an extensive restoration that may not be conservative of tooth structure and may prove to be quite costly to the patient. The two dimensional finite element analysis method was used to determine the magnitude and mode of distribution of the stresses of the periodontal ligament and supporting alveolar bone when abutments with different periodontal supports were splinted and distal-extension removable partial denture was subjected to different loading schemes. The results were as follows : 1. When abutments were splinted, stresses moved from apico-distal to apico-mesial of terminal abutment on a vertical force and from disto-alveolar crest to apex on a distally directed force. But stresses were generally diminished on a mesially directed force. 2. As vertical bone loss was proceeding, most of stresses were transmitted to residual ridge and the rest of stresses were concentrated on apex of distal abutment. But these apical stresses were minimized when abutments were splinted. 3. As mesially inclined bone loss was proceeding, it seemed to be dangerous that many stresses were concentrated on the distal alveolar crest, especially in the distally directed load case. Abutments splinting decreased the alveolar crestal stresses but not enough. 4. For all vertical stresses were effectively decreased on splinting, stresses were concentrated as highly on apico-mesial area of distal abutment in distally directed load cases as the distal inclination of bone level was severe. 5. The directions and magnitudes of abutment movements were decreased with teeth splinting.

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RPD framework fabrication using computer-aided design (CAD) and rapid prototyping (Computer-aided design (CAD) 및 쾌속조형술을 이용한 가철성 국소의치 수복 증례)

  • Park, Seon-Ah;Koak, Jai-Young;Heo, Seong-Joo;Kim, Seong-Kyun;Park, Ji-Man
    • The Journal of Korean Academy of Prosthodontics
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    • v.55 no.1
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    • pp.94-99
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    • 2017
  • Nowadays, digital dentistry is generally applied to prosthodontics with fabrication of inlays or any other fixed prostheses by utilizing CAD/CAM (computer-aided design/computer-aided manufacturing) technology and intraoral scanner. However, in fabricating removable prosthesis, there are some limitations for digital technology to substitute conventional casting method. Therefore, approaching removable prostheses fabrication with CAD/CAM technology would be a meaningful trial. In this case report, Kennedy class III mandibular edentulous patient who was in need of increasing the vertical dimension of occlusion was treated with removable partial denture using CAD and rapid prototyping technique. Surveying and designing the metal framework of the partial denture was performed with CAD, and sacrificial plastic pattern was fabricated with rapid prototyping technique. During the follow up period of nine months, the removable partial denture has provided satisfactory results in esthetics and function.

A case of removable dentures using digital method (디지털 방식을 이용하여 제작한 양악 가철성 의치 수복 증례)

  • Lee, Ji-Soo;Ahn, Su-Jin;Leesungbok, Richard;Lee, Suk-Won
    • The Journal of Korean Academy of Prosthodontics
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    • v.56 no.3
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    • pp.250-257
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    • 2018
  • Generally dentures are manufactured by conventional method, however the frequency of fabricating denture using digital method is increasing due to the recent development of digital technology in dentistry. The digital method of manufacturing denture is classified into two systems; 3D scan of the impression to arrange the artificial teeth on the CAD (Computer-aided design) and 3D printing to produce the resin-based complete denture, or 3D scan of the model to design of the framework using CAD, resin pattern formation by 3D printing and casting of metal framework of complete denture or removable partial denture. In this case report, electronic surveying and design the metal framework of the dentures were performed using CAD program, and plastic resin patterns fabricated by 3D printing were casted for upper full denture and lower removable partial denture. During follow-up periods, dentures using digital method have provided satisfactory results esthetically and functionally.

Esthetic removable partial denture with implants and resin clasp: Case report (임플란트와 레진 클래스프를 이용한 심미 가철성 국소의치 증례)

  • Kim, Su-Min;Jeon, Young-Chan;Jeong, Chang-Mo;Yun, Mi-Jung;Huh, Jung-Bo
    • The Journal of Korean Academy of Prosthodontics
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    • v.53 no.1
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    • pp.58-65
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    • 2015
  • For the rehabilitation of fully edentulous patients, implant-supported removable partial dentures can be considered as one of the treatment options with complete dentures or implant-supported overdentures. If removable partial dentures are used in combination with a small number of implants placed in strategically important positions, it can offer additional stability, retention and support through implants and reduce a burden of surgical procedures compared with fixed implant-supported prostheses with extensive implant placement. Moreover, the economical benefit can be expected as well. The purpose of this case report is to present a treatment in which an implant-supported removable partial denture was fabricated considering residual alveolar bone status and demands after teeth loss in a patient who had been using a distal extension removable partial denture for a long period of time. In anterior area, fixed prostheses were fabricated with implant placement and in posterior area, short implants provide only support for the removable partial denture. In addition, denture base and clasp were made of thermoplastic acrylic resin. Finally, functionally and aesthetically satisfying treatment results can be achieved.

Implant-assisted removable partial denture using freely removable abutment in a fully edentulous patient: A case report (완전 무치악 환자에서 자유 착탈가능 임플란트 지대주를 이용한 임플란트 융합 국소의치 수복증례)

  • Oh, You-Kyoung;Jeong, Chang-Mo;Yun, Mi-Jung;Lee, So-Hyoun;Lee, Hyeon-Jong;Huh, Jung-Bo
    • The Journal of Korean Academy of Prosthodontics
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    • v.58 no.1
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    • pp.58-66
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    • 2020
  • Implant-Assisted Removable Partial Dentures (IARPDs) treatment is being performed in a fully edentulous patient using implant surveyed prosthesis as an abutment. Implant-supported prosthesis as an abutment of IARPDs is classified into screw-retained and cement-retained type according to the retention type, and each has advantages and disadvantages. The EZ crown system (Samwon DMP, Yangsan, Korea) has a cylinder combined with abutment, and the nickel-titanium spring in this cylinder provides a constant force on the zirconia ball to obtain retention in EZ crown system. In this patient, the natural abutment teeth of the mandibular overdenture was hopeless. We planned implant assisted removable partial denture using anterior implant surveyed prosthesis considering functional and esthetical rehabilitation, cost and patient's needs. When fabricating IARPDs using implant as abutment, we could compensate for the shortcomings of existing implant-supported prosthesis retention type and made the design of removable partial denture easy due to using EZ crown system.

Complication and management of implant-assisted removable partial denture with distal extension: a clinical report (양측성 후방연장 임플란트 보조 국소의치의 합병증과 관리: 증례보고)

  • Choi, Jung-Yun;Lee, Jung-Jin;Song, Kwang-Yeob;Park, Ju-Mi;Kim, Kyoung-A;Seo, Jae-Min
    • Journal of Dental Rehabilitation and Applied Science
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    • v.32 no.4
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    • pp.338-344
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    • 2016
  • Implant supported removable partial denture (ISRPD) using the implants enables favorable rehabilitation by complementing biomechanical limitations of the conventional removable partial denture (RPD). However, continuous recall check is necessary for evaluation of the mechanical and biological complications to ensure good long-term prognosis of ISRPD. This clinical report describes the complication and management in patient of Kennedy class I edentulism with ISRPD using healing abutment. The wear and fracture of healing abutment occurred at 36 months after delivery. So, healing abutment was replaced by connecting $Locator^{(R)}$ abutment for altering into the implant retained partial overdenture.