• Journal of the Korean Academy of Esthetic Dentistry
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• v.27 no.2
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• pp.97-104
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• 2018

Mandibular anterior region has high implant survival rates and better accessibility compared with any other region. Even if there are possibilities for perforation on lingual cortical bone due to improper drilling and bleeding caused by lingual artery damage, mandibular anterior region is a safe region because less amount of major anatomical structures exist compared with other regions. However, because of narrow bucco-lingual width of alveolar ridge, it is challengeable to obtain esthetic implant prosthesis. Although patients are less sensitive subjectively, mandibular anterior region is as difficult as maxillary anterior region in that implant placement location plays a critical role on the prognosis of implant prosthesis. One-piece implant is a very useful option for mandibular anterior region. Considering the narrow roots and thin alveolar bone of mandible, it is clinically difficult for implant diameter to be greater than 3mm In this case, we could approach the esthetic restoration in mandibular anterior region with one-piece implant and immediate loading.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.1
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• pp.98-129
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• 1995

The purpose of this study was to evaluate how mandibular implant-supported fixed complete prosthesis, implant and mandible responded mechanically, according to curvature of arch, number and location of fixture, and amounts of load. The shape of mandibular arch was tapered or square form and, 4 or 6 fixtures were implanted in each arch model. A vertical load of 10kg was applied at the center of prosthesis and a vertical load of 20kg was applied at the location of the 10mm or 20mm cantilever posterior to the most distal implant. Three-dimensional finite element analysis was performed for stress distribution and deflection using commercial software(ABAQUS program) for Sun-SPARC Workstation. The results were as follows : 1. The case square arch form was more stable to compare with that of tapered arch form in respect of stress distribution and displacement under vertical load on the center of prosthesis. 2. 6-implants cases were more stable than 4-implants cases for decreasing bending torque under vertical load on the center of prosthesis. 3. Under vertical load on cantilever extension, the case of 10mm long cantilever was more stable than that of 20mm long cantilever in respect of stress distribution and displacement. 4. Under vertical load on cantilever extension, 6-implants cases had a tendency to reduce displacement and to increase the reaction force of supporting point due to increasing of the bending stiffness of the prosthesis than 4-implant case. 5. When the ends of 10mm or 20mm long cantilever were loaded, the most distal implant was under compressive stress but the second most distal implant was under the highest tensile stress and the remaining implants were under varying tensile stress. 6. Because 6-implants cases had smaller displacement than 4-implants cases, 6-implants cases were more favorable in respect of prevention of screw loosening under repeated loadings.

• The Journal of Korean Academy of Prosthodontics
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• v.14 no.1
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• pp.66-71
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• 1976

The purpose of this investigation was to evaluate the mouth preparation and design of removable partial dentures. A total of 187cases for the prefabricated partial denture frameworks in both maxillary and mandibular semi-dentulous situations (66 cases and 203 cases) was selected from this study. The evaluations of mouth preparation and design observed here involved the classification of edentulous spaces, status of abutment splinting with location, design of direct retainer and structure of maxillary major connector according to the incidence of both dental arches, ages, sexes and segment of semidentulousness. The analyzed results were as follows: 1) The order of frequency rate in removable partial denture construction was Class II (50.27%), Class I (36. 90%), Class III (10.69%), and Class IV (2.14 %). 2) The distribution on design of maxillary removable partial denture prosthesis was 33.22% and 64.11% in mandibular removable partial denture prosthesis. 3) The age distribution of removable partial denture prosthesis was prominent after40 years (41.71%). 4) The design pattern of maxillary major connectors was in order of anteroposterior bar, single palatal bar, palatal strap, U-shape connector. 5) The design pattern of direct retainer was in order of Aker's clasp, I-bar clasp, backaction clasp, cuspid universal clasp. 6) The abutment for partial denture clasp splinted between premolar and premolar and its frequency rate revealed 53.44%. 7) It seemed that the location and design of the indirect retainer showed accepatble limit.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.1
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• pp.25-30
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• 2018

In edentulous patients, the advantages of prosthodontic therapy using oral implants include both stability and comfort. Advantages suggested for this approach include the prevention of mandibular bone resorption and increased masticatory function. Implant hybrid prostheses place 4 to 6 implants between the mental foramens, and cantilevers are used to replace the posterior teeth at both ends. The 85 - year - old female patient visited our clinic with complete edentulism in the maxilla and mandible. This article reports a satisfactory clinical and esthetic outcome of full mouth rehabilitation using removable complete denture in the maxilla and implant hybrid prosthesis in the mandible.

• Journal of Technologic Dentistry
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• v.43 no.1
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• pp.19-28
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• 2021

Purpose: This study aimed to obtain basic data on oral health improvement by investigating the EQ-5D index according to the oral prosthesis status of elderly persons aged 65 years or older in Korea using the Seventh Korea National Health and Nutrition Examination Survey. Methods: In this study, 3,426 elderly persons aged 65 years or older were included to analyze the relationship between the dental prostheses status and EQ-5D index in the collected data. Results: Compared to the "complete denture" in oral prosthesis, EQ in case of no dental prostheses or fixed dental prostheses is comparable to removable prosthetics such as "no dental prostheses," "one fixed bridge," and "two or more fixed bridges." Removable partial denture and complete denture required for the maxillary and mandibular EQ-5D index were significantly higher in "not necessary" than in "complete denture necessary" in all the elderly persons. Conclusion: The condition of the dental prosthesis and the need for a removable partial denture and complete denture for the elderly's EQ-5D index were confirmed, and it was found that the fixed dental prostheses were more effective than the removable dental prostheses. Therefore, oral health education programs for the elderly should be developed to promote dental function and oral health maintenance.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.4
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• pp.780-806
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• 1995

The purpose of this study was to describe the application of 3D finite element analysis to determine resultant stresses on the bone anchored fixed prosthesis, implants and supporting bone of the mandible according to fixture numbers and load conditions. 4 or 6 fixtures and the bone anchored fixed prosthesis were placed in 3D finite element mandibular arch model which represents an actual mandibular skull. A $45^{\circ}$ diagonal load of 10㎏ was labiolingually applied in the center of the prosthesis(P1). A $45^{\circ}$ diagonal load of 20㎏ was buccolingually applied at the location of the 10mm or 20mm cantilever posterior to the most distal implant(P2 or P3). The vertical distribution loads were applied to the superior surfaces of both the right and the left 20mm cantilevers(P4). In order that the boundary conditions of the structure were located to the mandibular ramus and angle, the distal bone plane was to totally fixed to prevent rigid body motion of the entire model. 3D finite element analysis was perfomed for stress distribution and deflection on implants and supporting bone using commercial software(ABAQUS program. for Sun-SPARC Workstation. The results were as follows : 1. In all conditions of load, the hightest tensile stresses were observed at the metal lates of prostheses. 2. The higher tensile stresses were observed at the diagonal loads rather than the vertical loads 3. 6-implants cases were more stable than 4-implants cases for decreasing bending and torque under diagonal load on the anterior of prosthesis. 4. From a biomechanical perspective, high stress developed at the metal plate of cantilever-to-the most distal implant junctions as a consequence of loads applied to the cantilever extension. 5. Under diagonal load on cantilever extension, the 6-implants cases had a tendency to reduce displacement and to increase the reaction force of supporting point due to increasing the bendign stiffness of the prosthesis than 4-implants cases. 6. Under diagonal load on cantilever extension, the case of 10mm long cantilever was more stable than that of 20mm long cnatilever in respect of stress distribution and displacement. 7. When the ends of 10mm or 20mm long cantilever were loaded, the higher tensile stress was observed at the second most distal implant rather than the first most distal implant. 8. The 6-implants cases were more favorable about prevention of screw loosening under repeated loadings because 6-implants cases had smaller deformation and 4-implants cases had larger deformation.

• Journal of Korean Dental Science
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• v.13 no.2
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• pp.67-72
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• 2020

Purpose: This clinical study presented the effectiveness of 2-stage posterior maxillary segmental osteotomy (PMSO) under local anesthesia in gaining interarch space to restore the posterior mandibular segment with dental implants. Materials and Methods: Nine patients who received two-stage PMSO for mandibular implant placement from 2003 to 2011 were included in the study. Of the 9 patients, 7 were female and 2 were male. Ages ranged form 28 to 72 (mean 46.6). Potential complications were investigated such as sinus infection, survival of bone segment, inflammatory root resorption of adjacent teeth, relapse of bone segment and timing of implant placement, delivery of implant prosthesis and stability of bone segment. Result: None of the patients showed relapse or complication. Bone segments were stabilized by opposed implant prosthesis. Conclusion: Office-based 2-stage PMSO under local anesthesia can be considered a stable and predictable procedure. Also pedicle damage can be avoided by allowing favor of blood supply to the bone segments. From these advantages, it can be concluded that this surgical procedure can decrease post-operative complications.

• Journal of Technologic Dentistry
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• v.41 no.2
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• pp.149-156
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• 2019

Purpose: Prosthodontics for edentulous patients is a treatment technique using implant, which has impactful results in retention and support effects. Methods: As a retention technique, SCRP (screw and cement retained implant prosthesis) has reported in many studies as a beneficial method for both patients and curers, which can reduce errors in process of making abutment and top implant. Results: Prosthesis manufacturing, as polymerization method of hardened resin teeth with thermoplastic resin, is helpful for patients with aesthetic and financial situations regarding residual ridge and interocclusal relationship, also indicates reliable results in both retention and care. Conclusion: Using SCRP technique, we notably obtained a clinical and aesthetic outcome from five implants in anterior tooth, which are half fixable and detachable implants on screw of implant abutment by the technicians at anytime.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.1
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• pp.28-37
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• 2024

Severe cases of mandibular prognathism can be treated with orthodontic therapy or surgical correction, but there are situations where only prosthetic improvement is possible. An understanding of class III patients is needed, including a vertical chewing pattern and the absence of anterior guidance. Additionally, it is relatively easy to increase occlusal vertical dimension to correct the anterior crossbite, but this approach can sometimes lead to unfavorable results, necessitating careful diagnosis and treatment planning. In this case report, oral rehabilitation was conducted in a patient with mandibular prognathism and asymmetry, utilizing implants and fixed dental prosthesis. Through a step-by-step treatment approach, the existing occlusal vertical dimension was maintained, and the final fixed dental prosthesis restoration was completed. Accordingly, it shows functional and aesthetically appropriate results, and reports on the patient's diagnosis and treatment process.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.3
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• pp.193-200
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• 2024

In patients with severe alveolar bone resorption on mandibular anterior edentulous areas, it can be difficult to place implants in the location for crowns, and to create the fixed prosthesis having an adequate emergence profile or embrasure, which makes maintenance difficult. Fabricating a removable zirconia prosthesis with a milled bar on poorly positioned implants can be a good option because of easy maintenance. In this case, the patient had severe bone resorption on mandibular anterior region, and large vertical space. We report on the aesthetical and easy-to-maintain results by placing two implants and fabricating a zirconia prosthesis using milled bar.