• Journal of Periodontal and Implant Science
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• 제35권2호
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• pp.437-448
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• 2005

This study is an analysis of distribution of patients who installed Xive implant in Yonsei University Hospital and types of implant site for about 2 years recall check and cumulative survival rate. 41 implant were used in this study. It shows the conclusion below. 1. Patients at the age of 40s and 50s were 60% of all implant cases and average number of implant was 2.4(man), and 1.9(woman). All cases were operated on mandible, 3 implants on anterior region and 38 implants on posterior region. 2. The major cause of tooth loss is dental caries(48.8%), followed by periodontal disease. 3. Most distribution of bone qaulity for mandibular implant site was type II(65.8%) and bone quantity was type B(75.6%). 4. The majority of implants were those of 11, 13mm in length(95%) and regular diameter in width (64%). 5. The 41(19 persons) Xive implants that were placed in the mandibular anterior and posterior region were all survival and showed a 100% 2 year cumulative survival rate. The results provided us with basic data on patient type, implant distribution, bone condition, and survival rate. We wish that our results coupled with other research data helps assist in the further study for better implant success rates, etc.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권4호
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• pp.331-338
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• 2004

Stress transfer to the surrounding tissues is one of the factors involved in the design of dental implants. Unfortunately, insufficient data are available for stress transfer within the regenerated bone surrounding dental implants. The purpose of this study was to investigate the concentration of stresses within the regenerated bone surrounding the implant using three-dimensional finite element stress analysis method. Stress magnitude and contours within the regenerated bone were calculated. The $3.75{\times}10-mm$ implant (3i, USA) was used for this study and was assumed to be 100% osseointegrated, and was placed in mandibular bone and restored with a cast gold crown. Using ANSYS software revision 6.0, a program was written to generate a model simulating a cylindrical block section of the mandible 20 mm in height and 10 mm in diameter. The present study used a fine grid model incorporating elements between 165,148 and 253,604 and nodal points between 31,616 and 48,877. This study was simulated loads of 200N at the central fossa (A), at the outside point of the central fossa with resin filling into screw hole (B), and at the buccal cusp (C), in a vertical and $30^{\circ}$ lateral loading, respectively. The results were as follows; 1. In case the regenerated bone (bone quality type IV) was surrounded by bone quality type I and II, stresses were increased from loading point A to C in vertical loading. And stresses according to the depth of regenerated bone were distributed along the implant evenly in loading point A, concentrated on the top of the cylindrical collar loading point B and C in vertical loading. And, In case the regenerated bone (bone quality type IV) was surrounded by bone quality type III, stresses were increase from loading point A to C in vertical loading. And stresses according to the depth of regenerated bone were distributed along the implant evenly in loading point A, B and C in vertical loading. 2. In case the regenerated bone (bone quality type IV) was surrounded by bone quality type I and II, stresses were decreased from loading point A to C in lateral loading. Stresses according to the depth of regenerated bone were concentrated on the top of the cylindrical collar in loading point A and B, distributed along the implant evenly in loading point C in lateral loading. And, In case the regenerated bone (bone quality type IV) was surrounded by bone quality type III, stresses were decreased from loading point A to C in lateral loading. And stresses according to the depth of regenerated bone were distributed along the implant evenly in loading point A, B and C in lateral loading. In summary, these data indicate that both bone quality surrounding the regenerated bone adjacent to implant fixture and load direction applied on the prosthesis could influence concentration of stress within the regenerated bone surrounding the cylindrical type implant fixture.

• 대한치과보철학회지
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• 제42권5호
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• pp.597-607
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• 2004

Purpose: This study was peformed to investigate the retrievability of the cemented crown from the cementation type implant abutment. Material and method: The cementation type implant abutments (NEOBIOTECH implant abutment regular, 3 degree taper, 10mm length, 4mm diameter, Ti grade III, machined surface. Hwasung, Kyunggi-do) and cemented crowns were divided into 3 groups, depending on their hole angles formed in the crowns for their retrievability. The abutments and crowns were luted with 4 kinds of cements and separation test using metal wedge was executed with Instron 4465 Universal Testing Machine and the maximum impact force of the modified crown ejector was measured. Results and conclusion : 1. All of the cementation type implant abutments and cemented crowns were separated with relatively small force by metal wedge. 2. The retrieving force was minimum when the metal wedge was applied perpendicular to the axis of abutment. 3. The force for retrieving crowns from abutments was maximum in resin cement group, and reduced in orders of zinc phosphate cement, glass ionomer cement and zinc oxide eugenol cement. 4. The maximum force obtained by the crown ejector was higher than the retrieval force in ZOE and GI cement and lower than that in ZPC and resin cement. 5. If it has similar conditions clinically, the cemented crowns luted with 2 types of cements (ZOE, GI cement) can be safely retrieved from the cementation type implant abutments by the modified crown ejector.

• The Journal of Advanced Prosthodontics
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• 제12권1호
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• pp.33-37
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• 2020

PURPOSE. The purpose of this study is to evaluate the effects of type of magnet attachment and implant angulation in two implant overdenture models. MATERIALS AND METHODS. Magnet attachments used in this study were flat and dome types (MGT5515, MGT5520D, Dentium Co., Seoul, Korea). Two implants with keepers were inserted in the resin blocks at a distance of 24 mm. For the first model, the implants were parallel to the vertical and perpendicular to the horizontal; for the second model, both were angulated 5 degrees to the mesial; for the third model, both were angulated 10 degrees toward the mesial. The retentive force was measured in both vertical and lateral directions. Statistical analyses were performed using SPSS software version 22.0 (α=.05). RESULTS. The flat type magnet attachment showed the highest lateral retentive force in the 20° divergent group (P<.05) and the dome type magnet attachment showed the highest lateral retentive force in the parallel group (P<.05). The vertical and lateral retentive force of the dome type magnet attachment was greater than that of the flat type magnet attachment in every direction (P<.05). CONCLUSION. Within the limitations of this study, the dome shape magnet attachment can resist vertical and lateral retentive force more superiorly than the flat type magnet attachment, regardless of angle, in the mandibular two implant model.

• 대한치과보철학회지
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• 제47권4호
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• pp.365-375
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• 2009

연구목적: 임플란트 보철물의 유지형태 중 나사 및 시멘트 혼합 유지형의 경우 나사 풀림력 등에 영향을 주는 임플란트 구성 성분의 응력에 관한 연구가 부족하였다. 임플란트 상부 보철물의 유지형태, 즉, 시멘트 유지와 나사 유지, 그리고 이 두 가지 유지형태가 서로 연결된 혼합형의 임플란트 보철물의 응력분산의 특징들을 3차원 유한요소분석법을 이용하여 비교하고자 하였다. 연구재료 및 방법: 하악골에서 제1소구치 부위와 제1대구치 부위에 2개의 임플란트 (SS II, Osstem Co. Ltd., Seoul, Korea)를 식립한 가상의 3본 계속가공의치를 모델화하였다. 지대주 종류와 그 위치에 따라, 4가지 모형 군으로 나누어 실험하였다. 모형 1은제1대구치와 제1소구치 각각의 고정체에 모두 동일한 시멘트 유지형 지대주인 Comocta abutment (Osstem Co. Ltd) 를 장착하여 3본 계속가공의치를 합착시킨 경우이고, 모형 2는 제1대구치와 제1소구치 각각의 고정체에 모두 나사 유지형 지대주인 Octa abutment (Osstem Co. Ltd) 를 장착하여 3본 계속가공의치를 나사로 고정시킨 경우이며, 모형 3은 제1대구치의 고정체에는 시멘트 유지형 지대주인 Comocta abutment를 장착하고, 제1소구치에는 나사 유지형 지대주인 Octa abutment를 장착한 후 3본 계속가공의치를 각각 시멘트 합착 및 나사로 고정시킨 경우이다. 그리고 모형 4는 모형 3에서 각각 제1대구치 및 제1소구치의 지대주를 맞바꾼 후 3본 계속가공의치를 나사 및 시멘트로 고정시킨 경우로 나누었다. 평균저작압인 하중을 대구치 565 N과 소구치 288 N의 힘으로 설정하고 수직방향으로 중심와와 협측 교두정에, 그리고 $30^{\circ}$ 경사 하중을 협측 교두정 부위에 준 다음 골, 고정체, 지대주, 그리고 지대주 나사 등에 나타나는 von-Mises stress 양상을 평가하였다. 결과: 네 가지 모형 중 나사 유지형 지대주인 Octa abutment를 제1대구치와 제1소구치 부위에 사용한 모형 2가 전반적으로 가장 낮은 안정적인 응력 분포를 보였다. 네 가지 모형 모두 피질골 및 고정체에 미치는 응력 크기 및 분포는 거의 유사하며, 치조골에 작용하는 응력은 하중의 종류와 상관없이 주로 피질골에 집중되었다. 지대주, 지대주 나사, 그리고 보철물 나사 등에 미치는 응력 크기나 분포는 모형에 관계없이 나사 유지형인 경우가 시멘트 유지형인 경우에 비해 낮은 안정적인 값을 보였다. 제1대구치와 제1소구치의 상부 구조물의 차이에 의한 교호작용 (reciprocal action)은 상대적으로 약하였다. 모든 부위에서 중앙 수 직하중, 교두정 수직하중, 그리고 교두정 경사하중의 순으로 응력값이 증가하였다. 결론: 본 유한 요소실험의 한계내에서 나사 및 시멘트 혼합 유지형의 임플란트 보철물은 시멘트 유지형만 사용하는 경우와 비교하여 주위에 더 큰 응력을 나타내지는 않았다. 이상적인 passive fit의 가정하에서 나사 유지형의 임플란트 보철물이 본체와 주위에 가장 작은 응력을 나타내었다.

• 대한치과보철학회지
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• 제37권3호
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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

• Journal of Periodontal and Implant Science
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• 제29권4호
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• pp.929-942
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• 1999

Three beagle dogs aged over one and half years were used in this study. All mandibular premolars were carefully extracted. Two AVANA implants(Sumin, Korea) and two 3i implants(Implant Innovation, USA) were installed at each right and left side respectively. Each dog was sacrificed at 4, 8. 12 weeks. Non-decalcified specimens were made and stained for a light microscopic study. The results were as follows ; 1. Inflammation was not observed in the area of bone tissue adjacent to the implant body. 2. With time, quantity of osseointe-gration increased in each type of den-dental implant. There was no difference between AVANA implant and 3i implant. 3. Maturation of the bone around each type of the dental implant increased with time. 12 weeks after implant installation, the bone around dental implant represented compact bone-like appreance. 4. In case implants were located adjacent to a root, newly-formed periodontal ligament tissue was observed around the implant. And the direction of the periodontal ligament fiber was parallel to the surface of the implant . Within the results of this study, AVANA implants represented similar osseointegra-tion in comparision with 3i implants.

• 대한치과보철학회지
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• 제38권5호
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• pp.724-743
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• 2000

One of the biggest clinical problems of osseointegrated implant prosthesis is the excessive stress caused by bite forces which are transfered directly into the bone through the osseointegrated implant fixtures. So several biodynamic problems occur when there is an excessive fatigue stress. The factors of stress distribution are the number, kind, position, arrangement of the implants, and the distance between the implants, and the kind, quality of superstructure prosthesis and connection type between the rest implant and the superstructure. Recently, a distal short additional implant, socalled rest implant, is employed to reduced the stresses in conventional cantilevered prostheses. This study was undertaken to analyze the stresses transfered by osseointegrated implant cantilevered prostheses depending upon the number and the position of implants, the presence of rest implant, and the type of their connection. Three dimensional finite element analysis was attempted using ANSIS ver. 5.3 program under IBM INDIGO computer. The results were as follows : 1. The rest implant influenced on the pattern of stress distribution on the anterior area of the mandible and the superstructure. 2. In the group employing the rest implants, the fixed type of connection between the rest implant and the superstructure was more stable than the ball attachment type on the stress distribution. 3. In the group employing the ball attachment between the rest implant and the superstructure, the case with 4-implants(on canine, premolar) was little more stable than the case with 6-implants and the case with 4-implants(on incisor, premolar) on the stress distribution. 4. In the cantilevered group, the case with 4-implants(on incisor, premolar) and the case with 6-implants were more stable than the case with 4-implants(on canine, premolar) on the stress distribution. 5. In all of the group, the case with 6-implants and the fixed type of connection was the most stable and the case with 4-implants (on canine, premolar) was the most unstable on the stress distribution.

• 대한치과보철학회지
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• 제35권4호
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• pp.627-646
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• 1997

In order to find the degree of osseointegration at bone-implant interface of clinically successful implants, models including the 3.75mm wide, 10mm long screw type $Br{\aa}nemark$ implant as a standard and cylinder, 15mm long, 5.0mm wide, two splinted implants, and implants installed in various cancellous bone density were designed. Also, the amount of load and material of prostheses were changed. The stress and minimum contact fraction were analyzed on each model using three-dimensional finite element method(I-DEAS and ABAQUS version 5.5). The results of this study were as follows. 1. 10mm long, 3.75mm diameter-screw type implant had $36.5{\sim}43.7%$ of minimum contact fraction. 2. Cylinder type implant showed inferior stress distribution and higher minimum contact fraction than screw type. 3. As implant length was increased, minimum contact fraction was increased a little, however, maximum principal stress was decreased. 4. Implants with a large diameter had lower stress value with slightly higher minimum contact fraction than standard screw type. 5. Two splinted implants showed no change of minimum contact fraction. 6. The higher bone density, the lower stress value. 7. The material of occlusal surface had no effect on the stress of the bone-implant interface.

• Journal of Periodontal and Implant Science
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• 제35권4호
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• pp.907-919
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• 2005

Porphyromonas gingivalis is a gram negative. black-pigmented anaerobe, associated with periodontitis & peri-implantitis. Fimbriae(fimA) of P. gingivalis are filamentous components on the cell surface and important in the colonization and invasion of periodontal tissue. But all P. gnigivalis strains don't have equal pathogenicity, inequality among strains originates from different fimA genotype. P. gnigivalis fimA gene encoding fimbrillin(structural subunit of fimbriae) has been classified into 5 genotypes(types I to V) based on the nucleotide sequences. In the present study, we examined the prevalence of these fimA genotypes in patients with dental implant and the relationship between prevalence of these genotypes and a condition of peri-implant tissue. Dental plaque specimens obtained from 189 peri-implant sulci of 97 patients with dental implants were analyzed by 16S rRNA fimA gene-directed PCR assay. P. gingivalis were detected in 86.2% of the alll samples. Among the P. gingivalis-positive samples, a significant difference in the occurrence of typeII was observed between test and the two control groups. In two control groups, typeII fimA were detected in 6.3%(PD<5mm/BOP-). 18.7%(PD<5mm/BOP+). In the test $group(PD{\geqq}5mm/BOP+)$, type II fimA genotype were detected most frequently in 50.0% . And a correlation between specific fimA types and peri-implantitis was found in $typeII(R^2=l.105)$. These results suggest that P. gingivalis strains that possess typeII fimA are gradually increased, as a condition of peri-implant tissue is getting complicated and are closely associated with peri-implant health status. We speculate that these organisms be involved in peri-implantitis