• 대한치과보철학회:학술대회논문집
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• 2003.04a
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• pp.98-98
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• 2003

• 대한치주과학회:학술대회논문집
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• 2003.11a
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• pp.63-63
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• 2003

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.3
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• pp.360-365
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• 2000

The completely edentulous patient has few treatment options in conventional dentistry. When implants are considered, treatment plans range from a 2-implant overdenture to a completely implant-supported prosthesis. Fixed prosthesis is often the preferred selection of the edentulous patient. fixed full-arch cert amo-metal restorations can be a predictable implant treatment modality for the edentulous patient. Implant-supported fixed prosthesis has several advantages: predictability, fixedness, retrievability, improved function, lower maintenance of prosthesis, long-term published success. Edentulous patients with a severely resorbed mandible often experience problems with their dentures. Treatment concepts involving two to four implants for the support of an overdenture have been proposed. There seems to be no need to insert more than two endosteal implants to support an overdenture, however, long-term prospective studies are needed to support this notion. Using short endosseous implants and an overdenture in the extremely resorbed mandible is a justified treatment option because of the relative simplicity and low morbidity of this treatment strategy. Implant-supported overdenture has several advantages: Cost, retrievability, hygiene access, profile and contour control, increased retention and stability, implant installed in a predicted region(ant. mandible).

• Journal of Korean Dental Science
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• v.6 no.1
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• pp.27-33
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• 2013

The introduction of osseointegrated dental implants in dentistry brought about a new era in everyday dental practice. For the past 50 years, prosthetic restoration with implant-supported prosthesis has developed into a viable and predictable treatment option. Alongside the increasing use of dental implants is the occurrence of many complications during implant placement (surgery), in the mechanical or prosthetic problem, and in the biological aspect. In particular, abutment or screw fracture as one of the mechanical complications can put the dentist in a tight spot in a clinical situation. It is hard to remove the fractured abutment and screw to restore it properly. Therefore, it is very important that clinicians consider possible complications in advance and make an appropriate treatment plan. We discuss cases of abutment fracture and mechanical/prosthetic complications together with the causes and solutions.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.207-214
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• 2008

Purpose: The aim of augmentation of the alveolar ridge is to restore absorbed alveolar ridges for future implant site or esthetic prosthodontic restoration. The present clinical report describes the anterior maxillary augmentation cases using a soft tissue rotated palatal flap, and considers various problems of before and after surgery. Method: First & second patients were treated by vascularized interpositional periosteal-connective tissue(VIP-CT) flap for horizontal soft tissue augmentation. Especially second patient was progressed with bone grafting at the same time. Third patient was treated by the same flap with bone graft and implant placement in single tooth missing premaxillary area. Result: The obtained horizontal augmentation width measured $0.5{\sim}2.7\;mm$. Conclusion: This technique constitutes a viable approach for augmentation the anterior sector of alveolar ridge with the placement of dental implants. But it needs correct diagnosis preparation and careful surgery skill.

• The Journal of Advanced Prosthodontics
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• v.8 no.4
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• pp.304-312
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• 2016

PURPOSE. The aim of this study was to investigate the stress distribution of 2-short implants (2SIs) installed in a severely atrophic maxillary molar site. MATERIALS AND METHODS. Three different diameters of internal connection implants were modeled: narrow platform (NP), regular platform (RP), and wide platform (WP). The maxillary first molars were restored with one implant or two short implants. Three 2SI models (NP-oblique, NP-vertical, and NP-horizontal) and four single implant models (RP and WP in a centered or cantilevered position) were used. Axial and oblique loadings were applied on the occlusal surface of the crown. The von Mises stress values were measured at the bone-implant, peri-implant bone, and implant/abutment complex. RESULTS. The highest stress distribution at the bone-implant interface and the peri-implant bone was noticed in the RP group, and the lowest stress distribution was observed in the 2SI groups. Cantilevered position showed unfavorable stress distribution with axial loading. 2SI types did not affect the stress distribution in oblique loading. The number and installation positions of the implant, rather than the bone level, influenced the stress distribution of 2SIs. The implant/abutment complex of WP presented the highest stress concentration while that of 2SIs showed the lowest stress concentration. CONCLUSION. 2SIs may be useful for achieving stable stress distribution on the surrounding bone and implant-abutment complex in the atrophic posterior maxilla.

• 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.59 no.4
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• pp.478-486
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• 2021

This report demonstrates a method of generating a chair-side and computer-aided template for implant surgery based on the Top-Down and restoration-driven concept. Compared to the traditional CAD-CAM process which requires multiple steps to be taken between dental clinic and laboratory, this alternative procedure, VARO guide system (VARO Guide, CAD, Pre-Guide, VARO-mill, NeoBiotech, Seoul, South Korea) enables accurate and patient-friendly implant surgery as well as immediate provisional restoration in a single visit. First, bite-registration at centric jaw relation and CBCT were taken using the Pre-Guide. The CBCT data was then reorganized directly through the chair-side CAD, and we could determine the most appropriate 3-dimensional position of implant. The STL file was extracted and put into the chair-side CAM (VARO-mill) to fabricate a VARO. This surgical guide allowed the implants to be accurately positioned into the planned sites within an hour.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.32 no.1
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• pp.16-22
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• 2023

Esthetic factors are very important in the success of maxillary anterior implant restoration. However, achieving esthetic results is difficult, especially in cases where periodontitis has resulted in severe alveolar bone loss. In the case of maxillary anterior teeth, the alveolar ridge resorption that begins immediately after tooth extraction interferes with the esthetic implant restoration. Therefore immediate implant placement can be performed to minimize the alveolar ridge resorption. However, in severe bone loss cases, immediate implant placement could result in esthetic failure, and this result might cause irreparable problems. We can also perform alveolar ridge preservation and then place implants later. On JCP published in 2019, there is the consensus of European academy of periodontology on the extraction socket management and the timing of implant placement. This consensus states that alveolar ridge preservation should be considered when there is severe labial bone loss in an esthetically important area such as maxillary anterior region. On performing the alveolar ridge preservation, we cannot obtain the primary wound closure, so secondary wound healing is induced with open membrane technique or soft tissue grafting should be performed for primary wound closure. However, the secondary wound healing can have a negative impact on bone regeneration, and soft tissue grafting such as FGG or CT graft can be burdensome for both patients and dentists. On the other hand, by using the granulation tissue in the extraction socket, primary closure can be achieved without soft tissue grafting. Also some studies have shown that granulation tissue in periodontal defects contains stem cells that may help in tissue regeneration. Based on this, implant restorations were performed on maxillary anterior teeth with severe alveolar bone loss by alveolar ridge preservation using granulation tissue. In spite of the severe bone defect of the extraction socket, relatively esthetic results could be obtained in implant restorations.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.3
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• pp.253-267
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• 2008

The purpose of this study was to evaluate the pattern and the magnitude of stress distribution in the supporting tissues surrounding implant fixture with different diameter of implant fixtures(3i implant, Ø4.0, Ø5.0, Ø6.0mm and UCLA abutments(Ø4.1, Ø5.0, Ø6.0mm using photoelastic stress analysis. Photoelastic model was made with PL-2 resin(Measurements Group, Raleigh, USA) and three implants of each diameter were placed in the mandibular posterior edentulous area distal to the canine. Individual crowns were fabricated using UCLA abutments. Photoelastic stress analysis was carried out to measure the fringe order around the implant supporting structure under simulated loading conditions(15 lb, 30 lb). The results were as follows; 1. The more the diameter of implant fixture was increased, the less the stress concentration on cervical area of fixture was observed under loading. 2. Increasing mesiodistal diameter of implant superstructure had no much influence on stress distribution around implant fixture. 3. The use of smaller abutment had no influence on stress distribution around implant fixture. The use of smaller abutment diameter than that of implant fixture had no favorable effect on implant supporting tissue at biomechanical consideration.