• The Journal of Korean Academy of Prosthodontics
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• v.37 no.3
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• pp.375-382
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• 1999

The purpose of this article is to present the clinical and laboratory procedures for single tooth restoration using 'Combination Implant Crown'. It is cemented on implant abutment and that abutment is screw-retained over implant body. This type of implant restorations has the advantages of cement-retained restoration while being antirotational and retrievable. And, more esthetic and functional result can be achieved by minimizing the size of access hole. The results were as follows : 1. Preparation of abutment below the cuff line should be avoided 2. Axial reduction of implant abutment should not be excessive because it may weaken the abutment 3. More esthetical and functional occlusal surface was achieved with a minimal access hole which is slightly larger than the diameter of hex driver to enable future total retrievability. 4. Combination Implant Crown has the advantages of both the cement-retained and screw-retained type implant restoration. 5. Cementation between implant crown and abutment reduces screw loosening through even force distribution

• The Journal of Advanced Prosthodontics
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• v.11 no.2
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• pp.112-119
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• 2019

PURPOSE. Zirconia materials have been used for implant-retained restorations, but the stress distribution of zirconia is not entirely clear. The aim of this study is to evaluate the stress distribution and risky areas caused by the different design of zirconia restorations on the atrophic bone of the posterior maxilla. MATERIALS AND METHODS. An edentulous D4-type bone model was prepared from radiography of an atrophic posterior maxilla. Monolithic zirconia and zirconia-fused porcelain implant-retained restorations were designed as splinted or non-splinted. 300-N occlusal forces were applied obliquely. Stress analyses were performed using a 3D FEA program. RESULTS. According to stress analysis, the bone between the 1) molar implant and the 2) premolar in the non-splinted monolithic zirconia restoration model was stated as the riskiest area. Similarly, the maximum von Mises stress value was detected on the bone of the non-splinted monolithic zirconia models. CONCLUSION. Splinting of implant-retained restorations can be more critical for monolithic zirconia than zirconia fused to porcelain for the longevity of the bone.

• Journal of Korean Dental Science
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• v.15 no.1
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• pp.84-91
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• 2022

An all-on-4 restoration allows edentulous patients to use a fixed prosthesis with a minimum number of implants. These implant-supported fixed complete dentures have traditionally been fabricated as screw-retained or cement-retained prostheses. However, it is difficult to passively fit the long-span full-arch prosthesis using the screw-retained type restoration, and predictable retrievability is not obtained with the cement-retained type. This case report describes a prosthesis fabricated using a combination of the two retention types. The screwmentable method allows the implant-supported fixed complete denture to achieve a passive fit at the connection with retrievability. In addition, a framework with an optimized size was designed by using digital dental technology.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.312-318
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• 2013

PURPOSE. The aim of this study was to compare the passivity of implant superstructures by assessing the strain development around the internal tapered connection implants with strain gauges. MATERIALS AND METHODS. A polyurethane resin block in which two implants were embedded served as a measurement model. Two groups of implant restorations utilized cement-retained design and internal surface of the first group was adjusted until premature contact between the restoration and the abutment completely disappeared. In the second group, only nodules detectable to the naked eye were removed. The third group employed screw-retained design and specimens were generated by computer-aided design/computer-aided manufacturing system (n=10). Four strain gauges were fixed on the measurement model mesially and distally to the implants. The strains developed in each strain gauge were recorded during fixation of specimens. To compare the difference among groups, repeated measures 2-factor analysis was performed at a level of significance of ${\alpha}$=.05. RESULTS. The absolute strain values were measured to analyze the magnitude of strain. The mean absolute strain value ranged from 29.53 to 412.94 ${\mu}m/m$ at the different strain gauge locations. According to the result of overall comparison, the cement-retained prosthesis groups exhibited significant difference. No significant difference was detected between milled screw-retained prostheses group and cement-retained prosthesis groups. CONCLUSION. Within the limitations of the study, it was concluded that the cement-retained designs do not always exhibit lower levels of stress than screw-retained designs. The internal adjustment of a cement-retained implant restoration is essential to achieve passive fit.

• The Journal of the Korean dental association
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• v.42 no.2 s.417
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• pp.138-149
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• 2004

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.365-375
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• 2009

Statement of problems: Stress analysis on implant components of the combined screw- and cement-retained implant prosthesis has not investigated yet. Purpose: The purpose of this study was to assess the load distribution characteristics of implant prostheses with the different prosthodontic retention types, such as cement-type, screw-type and combined type by using 3-dimensional finite element analysis. Material and methods: A 3-dimensional finite element model was created in which two SS II implants (Osstem Co. Ltd.) were placed in the areas of the first premolar and the first molar in the mandible, and three-unit fixed partial dentures with four different retention types were fabricated on the two SS II implants. Model 1 was a cement-retained implant restoration made on two cement-retained type abutments (Comocta abutment; Osstem Co. Ltd.), and Model 2 was a screw-retained implant restoration made on the screw-retained type abutments (Octa abutment; Osstem Co. Ltd.). Model 3 was a combined type implant restoration made on the cement-retained type abutment (Comocta abutment) for the first molar and the screw-retained type abutment (Octa abutment) for the first premolar. Lastly, Model 4 was a combined type implant restoration made on the screw-retained type abutment (Octa abutment) for the first molar and the cement-retained type abutment (Comocta abutment) for the first premolar. Average masticatory force was applied on the central fossa in a vertical direction, and on the buccal cusp in a vertical and oblique direction for each model. Von-Mises stress patterns on alveolar bone, implant body, abutment, abutment screw, and prosthetic screw around implant prostheses were evaluated through 3-dimensional finite element analysis. Results: Model 2 showed the lowest von Mises stress. In all models, the von Mises stress distribution of cortical bone, cancellous bone and implant body showed the similar pattern. Regardless of loading conditions and type of abutment system, the stress of bone was concentrated on the cortical bone. The von-Mises stress on abutment, abutment screw, and prosthetic screw showed the lower values for the screw-retained type abutment than for the cement-retained type abutment regardless of the model type. There was little reciprocal effect of the abutment system between the molar and the premolar position. For all models, buccal cusp oblique loading caused the largest stress, followed by buccal cusp vertical loading and center vertical loading. Conclusion: Within the limitation of the FEA study, the combined type implant prosthesis did not demonstrate more stress around implant components than the cement type implant prosthesis. Under the assumption of ideal passive fit, the screw-type implant prosthesis showed the east stress around implant components.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.4
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• pp.356-362
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• 2020

All the faculties at the prosthodontic department in Kyung Hee University Dental Hospital at Gangdong, have been implementing the Top-Down concept of treatment approach since 2006 in which the outcomes of the last prosthetic treatment are predicted in advance during the treatment planning stage of patients with dental tissue defects. Based on the Top-Down concept, this report is also an example of how the final prosthetic treatment was performed in advance before going into implant surgery for the missing teeth. Among the various methods of connecting implant fixture and restoration, the cement-retained method is relatively simple to manufacture restoration without being constrained by the angle of the implants placed, but difficult to remove remaining subgingival excess cement completely, and to detach it being when necessary. In the report, SB-locking method will be introduced which enables an aesthetic implant restoration without either a screw hole or residual excess cement.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.423-430
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• 2016

The implant prosthesis can be divided into the screw retained prosthesis and cement retained prosthesis. Each type has advantages as well as disadvantages which is unfavorable to maintain the implants. To overcome these drawbacks, T-screw system was developed. T-screw system which utilizes a lingual direction of the screw to retain the implant prosthesis, has advantages of retrievability of the prosthesis, passive fit, and possibility to form esthetic and functional occlusal surface. The prior prosthesis which utilized horizontal screws had difficulty in fabrication especially in the case of multiple units, and also limited use with all-ceramic prosthesis. In this case, fabricating the implant prosthesis by using the T-screw system showed superior results in easy maintenance, esthetics, and also functions. In addition, we are to report the method of using the T-screw system in implant prosthesis, such as multiple units of implant prosthesis and all ceramic prosthesis.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.1
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• pp.71-78
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• 2017

The retaining methods of implant prosthesis were classified into a screw-retained and a cement-retained type. A screw-retained prosthesis has many advantages, such as retrievability, preventing residual cement, while their disadvantages include the possibility of screw loosening and fracture, on the contrary advantages of cement-retained prosthesis are relatively low cost, but they are difficult to retrieve. To combine the advantages of both type, screw-cement retained prosthesis (SCRP) type have been introduced. But they still require ideal implant placement. So we introduce fiber post retained prosthesis without residual cement for preventing soft tissue trouble due to excessive cement.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.3
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• pp.147-156
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• 2021

There are various treatment options such as conventional complete denture, hybrid prosthesis and implant-supported fixed prosthesis for fully edentulous patients. In case of implant-supported fixed prosthesis, compared to removable prosthesis, it is difficult to place the implant in the correct position considering the anatomical contours of the final prosthesis. In this case, a full mouth rehabilitation with implant-supported fixed prosthesis was performed for a patient who required extraction of all remaining teeth due to dental caries and chronic periodontitis. In the implant placement stage, the implant was placed in the desired position using a surgical guide fabricated considering the anatomical contours of the final prosthesis, and the function and esthetics were evaluated through correction and re-fabrication of the fixed provisional restoration. A final restoration of porcelain fused to gold prosthesis was delivered to the patient based on the provisional restoration. To cope with complications such as loosening of screws and fracture of porcelain, a screw-retained type prosthesis was fabricated for the posterior part and a screw-cement-retained type prosthesis for the anterior part. As a result, the patient showed an improved prognosis in terms of functional and esthetics after the final prosthesis was delivered.