• Title/Summary/Keyword: RPD

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The path of placement of a removable partial denture: a microscope based approach to survey and design

  • Mamoun, John Sami
    • The Journal of Advanced Prosthodontics
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    • v.7 no.1
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    • pp.76-84
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    • 2015
  • This article reviews the topic of how to identify and develop a removable partial denture (RPD) path of placement, and provides a literature review of the concept of the RPD path of placement, also known as the path of insertion. An optimal RPD path of placement, guided by mutually parallel guide planes, ensures that the RPD flanges fit intimately over edentulous ridge structures and that the framework fits intimately with guide plane surfaces, which prevents food collecting empty spaces between the intaglio surface of the framework and intraoral surfaces, and ensures that RPD clasps engage adequate numbers of tooth undercuts to ensure RPD retention. The article covers topics such as the causes of obstructions to RPD intra-oral seating, the causes of food collecting empty spaces that may exist around an RPD, and how to identify if a guide plane is parallel with the projected RPD path of placement. The article presents a method of using a surgical operating microscope, or high magnification (6-8x or greater) binocular surgical loupes telescopes, combined with co-axial illumination, to identify a preliminary path of placement for an arch. This preliminary path of placement concept may help to guide a dentist or a dental laboratory technician when surveying a master cast of the arch to develop an RPD path of placement, or in verifying that intra-oral contouring has aligned teeth surfaces optimally with the RPD path of placement. In dentistry, a well-fitting RPD reduces long-term periodontal or structural damage to abutment teeth.

Accuracy of CAD-CAM RPD framework according to manufacturing method: A literature review (국소의치 구조물(framework)의 CAD-CAM 제조방식에 따른 정확도: 문헌고찰)

  • Yi, Yuseung
    • The Journal of Korean Academy of Prosthodontics
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    • v.59 no.3
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    • pp.370-378
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    • 2021
  • Purpose. The purpose of this study was to evaluate the currently published literatures investigating the accuracy of computer-aided design and computer-aided manufacturing removable partial denture (CAD-CAM RPD) framework with different manufacturing techniques and methods. Materials and methods. A comprehensive search for literatures was conducted in PubMed database using specific keywords with the patient, intervention, comparison, and outcome (PICO) question, "Is there a difference in accuracy of RPD frameworks manufactured using digital workflow according to the manufacturing process and methods?" Results. A total of 7 articles were selected. Two studies compared intraoral scanning and laboratory scanning for RPD frameworks and had heterogenous results. In the studies using different manufacturing process, RPD frameworks had clinically acceptable accuracy in both subtractive and additive manufacturing. Polyetheretherketone (PEEK)-milled RPD frameworks showed higher fit accuracy than traditionally casted or 3D printed RPDs. Direct milling method showed a higher accuracy than indirect milling method. However, in rapid prototyping, indirect method showed higher accuracy than direct method. Conclusion. The RPD frameworks fabricated using CAD-CAM technology showed a clinically acceptable level of accuracy regardless of manufacturing process or techniques. Consistent results have not been reported regarding the digital impression methods, which were intra oral scanning or laboratory scanning, and further studies are needed.

A literature review on RSM-based robust parameter design (RPD): Experimental design, estimation modeling, and optimization methods (반응표면법기반 강건파라미터설계에 대한 문헌연구: 실험설계, 추정 모형, 최적화 방법)

  • Le, Tuan-Ho;Shin, Sangmun
    • Journal of Korean Society for Quality Management
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    • v.46 no.1
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    • pp.39-74
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    • 2018
  • Purpose: For more than 30 years, robust parameter design (RPD), which attempts to minimize the process bias (i.e., deviation between the mean and the target) and its variability simultaneously, has received consistent attention from researchers in academia and industry. Based on Taguchi's philosophy, a number of RPD methodologies have been developed to improve the quality of products and processes. The primary purpose of this paper is to review and discuss existing RPD methodologies in terms of the three sequential RPD procedures of experimental design, parameter estimation, and optimization. Methods: This literature study composes three review aspects including experimental design, estimation modeling, and optimization methods. Results: To analyze the benefits and weaknesses of conventional RPD methods and investigate the requirements of future research, we first analyze a variety of experimental formats associated with input control and noise factors, output responses and replication, and estimation approaches. Secondly, existing estimation methods are categorized according to their implementation of least-squares, maximum likelihood estimation, generalized linear models, Bayesian techniques, or the response surface methodology. Thirdly, optimization models for single and multiple responses problems are analyzed within their historical and functional framework. Conclusion: This study identifies the current RPD foundations and unresolved problems, including ample discussion of further directions of study.

A Comparative Study of Periodontal Conditions Following insertion of Distally Extending Cantilever Bridges or Removable Partial Dentures (후방연장 계속가공의치와 가철성 국소의치 지대치의 치주조직 상태에 관한 비교)

  • Kim, Chung-Chan;Choi, Kwang-Choon;Han, Soo-Boo
    • Journal of Periodontal and Implant Science
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    • v.23 no.2
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    • pp.352-357
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    • 1993
  • The purpose of the present study was to evaluate and compare the periodontal conditions of distally extending cantilever bridges(CB) and removable patial dentures(RPD). 78 patients treated with removable partial dentures were divided into 2 groups; bilateral free-ending (type 1) and unilateral free-ending(type 2). 43 patients treated with distally extending cantilever bridges were divided into 4 groups according to position of missing molars and number of including abutment tooth (or teeth) (type 1-4). Prosthodontic status of the abutment teeth were assessed; overcontoured crown, overhanged margin, embrasure closure, and others. Their Periodonted status were assessed with Plaque Index Gingial Index(GI) Sulcus bleedy Index (SBI), Tooth mobility(TM) & Posher depth(PPD). 35.9% of RPD group and 38.1 of CB grouphad disconfort on mastication with prosthetics. 16.7% of RPD group and 6.1% of CB group showed on opposing sites. Overhanged margins were 58.3% for RPD group and 86.6% for GB group. 45.5% of RPD group and 72% of CB group had embrasure closure on the abutment teeth. 30.5% of GB group had oversized pontic. Gb group showed much higher clinical parameters than RPD groups, but statistically not significant. Type 2 of RPD group showed lower GI and SBI, but statistically not significant. Type 3 of CB group showed the highest GI and SBI and type 2 showed the highest tooth mobility, but there is no differences between the same type of groups. In conclusion, only minor differences in periodontal conditions were recorded in RPD and CB group.

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Prosthetic treatment for patient with anterior overbite and partial edentulism using maxillary hybrid telescopic double crown RPD and mandibular fixed prostheses: A 11-yr follow-up (전치부 과개교합을 가진 상하악 부분 무치악 환자에서의 상악 하이브리드 텔레스코픽 이중관 국소의치와 하악 고정성 보철물을 이용한 치료의 11년 경과관찰 증례)

  • Choi, Hyunsuk;Cho, Jin-Hyun
    • The Journal of Korean Academy of Prosthodontics
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    • v.59 no.4
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    • pp.415-421
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    • 2021
  • The biomechanical prognosis of conventional removable partial denture is questionable in case of patient with few remaining teeth or periodontally compromised teeth. In this case, hybrid telescopic double crown RPD may be a successful treatment alternative. Hybrid telescopic double crown RPD has following advantages over conventional RPD: secondary splinting effect between abutments, more vertical stress direction and more convenient in repairing the denture after extraction of abutment tooth. In this clinical case, patient had deep overbite in anteriors and partially edentulous. The maxilla was restored with hybrid telescopic double crown RPD and the mandible was restored with implants and fixed prostheses. Long-term follow-up and supportive periodontal treatment were performed, and satisfactory results were achieved in terms of function and aesthetics.

Quality Characteristics of Sikhe Prepared with the Roots Powder of Doraji (Platycodon grandiflorum A. DE. Candolle) (도라지 분말을 첨가한 식혜의 품질 특성)

  • Jeong, Seung-Il;Yu, Hyeon Hee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.5
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    • pp.759-765
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    • 2013
  • In this study, we investigated the quality characteristics of Sikhye, a traditional Korean drink, made with various amounts (0.5, 1, 2, and 3%) of powder from the roots of Doraji (RPD), for different storage periods (1, 3, 5, 7, 10, 13, or 15 days). The pH and Hunter's L value of Sikhye decreased with higher amounts of added RPD, while saccharinity as well as "a" and b values increased. During storage, pH and Hunter's L value of Sikhye tended to decrease while "a" and b values increased. The saccharinity of Sikhye with 0.5% and 1% RPD reached its maximum values on the tenth storage day and continuously decreased during the storage period. In contrast, the saccharinity of Sikhye with 2% and 3% RPD increased during the storage period, and had its maximum saccharinity on the fifteenth storage day. During the storage of Sikhye the total microbial cell count, typically $3.19{\sim}0.35{\times}10^2$ CFU/mL on the third storage day, was undetected in Sikhye with 3% RPD. The total microbial cell count of Sikhye without RPD increased to $1.91{\times}10^9$ CFU/mL by the fifteenth storage day, while Sikhye with 0.5, 1, 2, and 3% RPD added contained $8.43{\times}10^8$, $9.77{\times}10^7$, $2.10{\times}10^7$, and $7.21{\times}10^6$ CFU/mL, respectively. Thus, the total cell count was lower with higher additions of RPD. In sensory tests, the Sikhye control, or with 0.5% and 1% RPD added, didn't show significant differences in the texture of rice granules, plumpness of rice granules, floating of rice granules, taste, flavor, and sweetness values. The overall preference was highest (5.38) for Sikhye with 0.5% RPD, followed by the control, 1% RPD, 2% RPD and 3% RPD. In conclusion, according to preference tests, we recommended the addition of 0.5% or 1% RPD in Sikhye.

Development of a STEP-compliant Web RPD Environment (STEP표준과 Web을 이용한 RPD환경 구축)

  • 강석호;김민수;김영호
    • Korean Journal of Computational Design and Engineering
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    • v.5 no.1
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    • pp.23-32
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    • 2000
  • In this paper, we present a Web-enabled product data sharing system for the support of RPD (Rapid Product Development) process by incorporating STEP (STandard for the Exchange of Product model data) with Web technology such as VRML (Virtual Reality Markup Language), SGML (Structured Generalized Markup Language) and Java. Extreme competition makes product life cycle short by incessantly deprecating current products with a brand-new one, and thus urges enterprises to devise a new product faster than ever. In this environment, an RPD process with effective product data sharing system is essential to outstrip competitors by speeding up the development process. However, the diversity of product data schema and heterogeneous systems make it difficult to exchange the product data. We chose STEP as a neutral product data schema and Web as an independent exchange environment to overcome these problems. While implementing our system, we focused on the support of STEP AP 203 UoF (Units of Functionality) views to efficiently employ STEP data models that are maximally normalized, and therefore very cumbersome to handle. Our functionality-oriented UoF view approach can increase users'appreciation since it facilitates the modular usage of STEP data models. This can also enhance the accuracy of product data. We demonstrate that our view approach is applicable to the configuration control of mechanical assemblies.

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Fine-tuning of gene expression dynamics by the Set2-Rpd3S pathway

  • Lee, Bo Bae;Kim, Ji Hyun;Kim, TaeSoo
    • BMB Reports
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    • v.50 no.4
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    • pp.162-163
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    • 2017
  • RNA polymerase II-interacting the Set2 methyltransferase co-transcriptionally methylates histone H3 at lysine 36 within the body of genes. This modification facilitates histone deacetylation by Rpd3S HDAC in 3' transcribed regions to suppress cryptic initiation and slow elongation. Although this pathway is important for global deacetylation, no strong effects have been seen on genome-wide transcription under optimized laboratory conditions. In contrast, this pathway slows the kinetics of mRNA induction when target genes are induced upon environmental changes. Interestingly, a majority of Set2-repressed genes are overlapped by a lncRNA transcription that targets H3K36 methylation and deacetylation by Rpd3S HDAC to mRNA promoters. Furthermore, this pathway delays the induction of many cryptic transcripts upon environmental changes. Therefore, the Set2-Rpd3S HDAC pathway functions to fine-tune expression dynamics of mRNAs and ncRNAs.

Research Trend of an International IMS RPD Project (국제 IMS RPD 프로젝트의 연구 동향)

  • 최병욱
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.3
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    • pp.15-21
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    • 2000
  • The Intelligent Manufacturing Systems (IMS) Rapid Product Development (RPD) Project is an international partnership formed to build a pre-competitive research and development program that will address the integration of new technologies in manufacturing and provide an infrastructure for industry to cooperate much more closely in the product development cycle. In this explanatory paper, a research trend of the RPD project is briefly presented, together with its background and state-of-the-art, focusing on objectives and target results of its sub-projects which include rapid development of functional parts and tools, validation and reverse engineering, and information logistic system.

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