• The Journal of Korean Academy of Prosthodontics
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• v.56 no.4
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• pp.375-383
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• 2018

Clinicians are faced with many difficulties when planning prosthodontic restorations with implants in a complete edentulous patient. When planning fixed implant prosthetics, it is often necessary to have additional surgery due to highly reduced alveolar bone, as well as high treatment costs and long-term treatment durations can be required. In addition, lack of interocclusal space can be a problem when planning implant supported overdentures. In this study, we planned to place a small number of implants on the anterior maxilla and used them as the abutments for distal-extension removable partial dentures on the posterior side in a maxillary fully edentulous patient. This would reduce the possibility of additional invasive operations such as alveolar bone graft, shorten the treatment time, and be relatively easy for elderly patients to burden. In this case, the patient was provided with a distal-extension removable partial denture and anterior implant fixed prostheses, which was similar to the previous one, and showed good adaptation, and chewing efficiency and esthetics was recovered.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.5
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• pp.429-440
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• 2002

Current dental restorations present a relatively weak resistance to fracture. Owing to their unique mechanical properties, fibre-reinforced polymers are now being considered. Unidirectional or woven continuous fibres, made of glass, polyethylene, carbon or Kevlar, have been evaluated. This study focused on the use of glass fibre knitted fabrics to reinforce acrylate resins, in order to investigate the possibility to construct single crowns as well as three unit bridges. Some points affecting the final composite system were tested ; 1) static strength, with focus on the stress transfer under a occlusal contact point ; 2) modelling of a three nit bridge ; 3) fatigue strength as a posterior three unit bridge material. The study demonstrated that knitted fabric reinforcements are showing an interesting compromise between stiffness, static strength for single crown. For three unit bridge applications in the posterior arch, however knitted glass fabric reinforcements were not strong enough in fatigue An additional reinforcement in the posterior arch fixed partial denture design was recommended.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.2
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• pp.146-156
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• 2024

Implant assisted removable partial denture (IARPD) has been practiced in various forms for a long time, and among them, implant surveyed crown RPD is gaining predictability as well as being considered as a treatment option for patients with anatomical and financial disadvantages. The position of implant could be divided as posterior placement or anterior placement according to the purpose of the treatment and should be planned in consider to the alveolar ridge of patient, anticipated prognosis of remaining teeth, and opposing dentition. This case report describes a treatment for mandibular Kennedy class I partial edentulous patient with two implant-supported surveyed crown and implant assisted removable partial denture. Given the difficulty of posterior placement in this patient and the prognosis of the residual teeth, the plan was to place two implants in close proximity to the residual teeth, which were placed in the planned position, angle, and depth using guided surgery. The process of fabricating the fixed prosthesis was carried out in parallel with the maxillary edentulous tooth arrangement process to increase predictability, and when fabricating the localized tooth, the implant was designed in a form that allows the patient to perform functional movements by preventing excessive loading as the last supporting tooth, and was fabricated through a secondary impression process. Each treatment procedure was proceeded as planned, with aesthetically and functionally satisfactory results for both patient and operator.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.4
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• pp.437-447
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• 2011

In patients who used removable partial dentures for a long period of time, gradual alveolar bone resorption occurs in edentulous area. However, in residual teeth area, alveolar bone is maintained sound. This causes an imbalance in intermaxillary distance between a maxillae and a mandible which is intensified due to expansion in vertical and horizontal bone amount difference between the two area as time passes. As the result, this shows a substantial difference in vertical position according to the period of teeth loss even after residual teeth loss. As in this situation, a patient with bilaterally and anterio-posteriorly different intermaxillary distance, various prosthodontic problems can be caused in fixed implant prosthodontics and implant overdenture. This study shows a case in which implant-supported removable partial denture was fabricated considering residual alveolar bone height 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 with short intermaxillary distance, fixed prosthodontics were fabricated with implant placement and in posterior area with long intermaxillary distance, a removable partial denture was fabricated. Finally, a small number of implants were placed without additional surgery and economical and comfortable treatment results were shown.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.2
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• pp.166-179
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• 2008

Excessive concentration of stress which is occurred in occlusion around the implant in case of the implant supported fixed partial denture has been known to be the main cause of the crestal bone destruction. Therefore, it is essential to evaluate the stress analysis on supporting tissue to get higher success rates of implant. The purpose of this study was to evaluate the effects of stress distribution and deformation in 3 different types of three-unit fixed partial denture sup-ported by two implants, using a three dimensional finite element analysis in a three dimensional model of a whole mandible. A mechanical model of an edentulous mandible was generated from 3D scan, assuming two implants were placed in the left premolars area. According to the position of pontic, the experiments groups were divided into three types. Type I had a pontic in the middle position between two implants, type II in the anterior posi-tion, and type III in the posterior position. A 100-N axial load was applied to sites such as the central fossa of anterior and posterior implant abutment, central fossa of pontic, the connector of pontic or the connector between two implants, the mandibular boundary conditions were modeled considering the real geometry of its four-masticatory muscular supporting system. The results obtained from this study were as follows; 1. The mandible deformed in a way that the condyles converged medially in all types under muscular actions. In comparison with types, the deformations in the type II and type III were greater by 2-2.5 times than in the type I regardless of the loading location. 2. The values of von Mises stresses in cortical and cancellous bone were relatively stable in all types, but slightly increased as the loading position was changed more posteriorly. 3. In comparison with type I, the values of von Mises stress in the implant increased by 73% in Type II and by 77% in Type III when the load was applied anterior and posterior respectively, but when the load was applied to the middle, the values were similar in all types. 4. When the load was applied to the centric fossa of pontic, the values of von Mises stress were nearly $30{\sim}35%$ higher in the type III than type I or II in the cortical and cancellous bone. Also, in the implant, the values of von Mises stress of the type II or III were $160{\sim}170%$ higher than in the type I. 5. When the load was applied to the centric fossa of implant abutment, the values of von Mises stress in the cortical and cancellous bone were relatively $20{\sim}25%$ higher in the type III than in the other types, but in the implant they were 40-45% higher in the type I or II than in the type III. According to the results of this study, musculature modeling is important to the finite element analysis for stress distribution and deformation as the muscular action causes stress concentration. And the type I model is the most stable from a view of biomechanics. Type II is also a clinically accept-able design when the implant is stiff sufficiently and mandibular deformation is considered. Considering the high values of von Mises stress in the cortical bone, type III is not thought as an useful design.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.228-238
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• 2020

In order to deliver fixed partial denture to a patient successfully, dentist must take into many considerations beforehand. Patient's occlusal pattern should be fully understood before delivering any type of prosthesis, whether it's canine guidance or group function occlusion. In order to do so, movement of mandible should be recorded precisely. Introduced by Meyers in 1933, functionally generated path technique (FGP) has been successfully used to record mandibular movement with various materials, such as wax, and utilize it in fabricating precise prosthesis. In the following cases, patients showed secondary caries or endodontic-periodontic lesion on maxillary molars. Root canal treatment and subgingival curettage were done for each patient. Since the long term prognosis of each tooth was questionable, lateral force should be minimized. In order to do so, FGP technique was used to record mandibular movements precisely. Instead of using conventional plaster impression, intra-oral scanning of wax tracing was done to fabricate prosthesis efficiently. After delivery of fixed partial denture, favorable outcome was obtained.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.2
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• pp.113-118
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• 2002

Conventional radiograph, computed tomograph (CT), magnetic resonance image (MRI) are commonly used methods for diagnosis of oro-maxillofacial cancer. MRI is an effective tool to verify soft tissue lesion however, metal produces black artifacts in the image. Therefore, metal structure should be removed before taking MRI to diagnose head and neck cancer patients. A 52-year-old female patient with adenocarcinoma in the posterior right soft palate was referred to take a MRI before surgery. She has 7-unit porcelain fused to metal bridge in the maxilla. Eight-unit Tagis-Vectris fixed partial denture was fabricated to replace her existing PFM bridge to take a MRI without any artifact before and after surgery. The patient satisfied with her restorations in terms of esthetics, function after 11 months. Even though minor staining was detected, Tagis-Vectris restoration fixed partial denture was intact during observation period.

• The Journal of Advanced Prosthodontics
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• v.4 no.2
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• pp.76-83
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• 2012

PURPOSE. Zirconia has been used in clinical dentistry for approximately a decade, and there have been several reports regarding the clinical performance and survival rates of zirconia-based restorations. The aim of this article was to review the literatures published from 2000 to 2010 regarding the clinical performance and the causes of failure of zirconia fixed partial dentures (FPDs). MATERIALS AND METHODS. An electronic search of English peer-reviewed dental literatures was performed through PubMed to obtain all the clinical studies focused on the performance of the zirconia FPDs. The electronic search was supplemented by manual searching through the references of the selected articles for possible inclusion of some articles. Randomized controlled clinical trials, longitudinal prospective and retrospective cohort studies were the focuses of this review. Articles that did not focus on the restoration of teeth using zirconia-based restorations were excluded from this review. RESULTS. There have been three studies for the study of zirconia single crowns. The clinical outcome was satisfactory (acceptable) according to the CDA evaluation. There have been 14 studies for the study of zirconia FPDs. The survival rates of zirconia anterior and posterior FPDs ranged between 73.9% - 100% after 2 - 5 years. The causes of failure were veneer fracture, ceramic core fracture, abutment tooth fracture, secondary caries, and restoration dislodgment. CONCLUSION. The overall performance of zirconia FPDs was satisfactory according to either USPHS criteria or CDA evaluations. Fracture resistance of core and veneering ceramics, bonding between core and veneering materials, and marginal discrepancy of zirconia-based restorations were discussed as the causes of failure. Because of its repeated occurrence in many studies, future researches are essentially required to clarify this problem and to reduce the fracture incident.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.2
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• pp.358-394
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• 1995

The author studied the actual conditions on the production of dental prosthesis made in laboratories, and also studied interrelationships between dentists and laboratory technicians in both personal and technical aspects. Two hundred-eighty four technicians, work in dental laboratories presently, were surveyed via mail and direct contact during the period from June 1 to June 30 and August 27 to August 28 in 1994 respectively. The obtained results were as follows : 1. Among the respondents, 90.5% we re working in commercial dental laboratories and their laboratories were mainly located in the Seoul area(40.9%, P<0.05). The numbers of employees in these laboratories were less than 10 persons(70.0%, P<0.01), and 75.9% of these laboratories have been in operation less than 15 years. 2. Most laboratory procedures were accomplished according to established disciplines. However, procedures such as die trimming in fixed restorations and the qualifications of the people designing removable partial dentures were not. Other problem areas were boxing of the working cast, the person determining the posterior palatal seal area, selection and arrangement of artificial teeth, occlusion rim correction and laboratory remounting of the processed denture in complete denture restorations. 3. Only half of the requesting dentists could send work authorizations to the laboratories with their work and even so, its contents were quite lacking. Consequently, there must be some standards in writing work authorization. 4. Technicians most desired clean and accurate impressions in fixed and removable dentures, and enough tooth reduction in porcelain fused to metal restorations. 5. For the establishment of better relationships between dentist and dental technician, the respondents desired the establishment of equal footing first(33.5%), and frequent conversations and muture understanding second(25.9%).

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.175-186
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• 2022

A crossed occlusion resulting from the presence of posterior teeth in one arch but no opposing teeth in the opposite arch results in collapse of the vertical dimension. In this case, the patient has a class III malocclusion with crossed occlusion and anterior crossbite. In order to evaluate the proper vertical dimension, provisional denture was used to stabilize the vertical occlusal dimension for 3 months. After, provisional fixed restoration was used for the stabilizing occlusal relationship and aesthetic improvement for lip support. Definitive prosthesis in implants in the mandible and abutments in the maxillary were using Porcelain-fused-to-metal crown (PFM) crown and the maxillary unilateral edentulous area was treated with removable partial dentures. Through this, proper support of the posterior region and normal anterior occlusal relationship were formed, and the patient was able to obtain aesthetically and functionally satisfactory treatment results.