• 구강회복응용과학지
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• 제18권4호
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• pp.277-288
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• 2002

Seven finite element models were constructed in mandible having single screw-type implant fixture connected to the premolar superstructure, in order to evaluate how the length, diameter and platform shape of a screw-type fixture influence the stress in the supporting tissue around fixtures. Each finite element model was varied in terms of length, diameter, and platform shape of the fixture. In each model, 250N of vertical load was placed on the central pit of an occlusal plane and 250N of oblique load placed on the buccal cusp. The stress distribution in the supporting tissue and the other components was analysed using 2-dimensional finite element analysis and the maximum von Mises stress in each reference area was compared. Under lateral loading, the stress was larger at the abutment/fixture interface, and in the crestal bone, compared to the stress pattern under vertical loading. The amount of stress at the superstructure was similar regardless of the length, diameter and platform shape of a fixture. Around the longer fixture, the stress was decreased at the bone crest and subjacent cancellous bone and increased in the cancellous bone area apical to the fixture. Around the wider fixture, the stress was decreased at the abutment/fixture interface, and the bone crest and increased in the cancellous bone area apical to the fixture. Around the fixture having wider platform, less stress was produced at the abutment/fixture interface and the upper part of the cortical bone, compared to the fixture having standard platform. In conclusion, the stress distribution of the supporting tissue was affected by length, diameter, and platform shape of a fixture, and the fixture which was larger in diameter and length could reduce the stress in the supporting tissues at the bone-fixture interface and bone crest area.

• 대한치과기공학회지
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• 제38권3호
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• pp.151-156
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• 2016

Purpose: The dental implant should be enough to endure chewing load and it's required to have efficient design and use of implant to disperse the stress into bones properly. This study was to evaluate the stress distribution on a supporting bone by lengths and diameters of the implant fixture. Methods: The modeling and analysis of stress distribution was used for the simple molar porcelain crown model by Solidworks as FEM program. It was designed on applying with tightening torque of 20 Ncm of a abutment screw between a cement retained crown abutment and a fixture. The fixtures of experimental model used 10, 13mm by length and 4, 5mm by diameter. A external vertical loading on the two buccal cusps of crown and performed finite element analysis by 100 N. Results: The maximum von Mises stress(VMS) of all supporting bone models by fixture length and diameter were concentrated on the upper side of supporting compact bone. The maximum stress of each model under vertical load were 164.9 MPa of M410 model, and 141.2 MPa of M413 model, 54.3 MPa of M510 model, 53.6 MPa of M513 model. Conclusion: The stress reduction was increase of fixture's diameter than it's length. So it's effective to use the wider fixture as possible to the conditions of supporting bone.

• 대한치과기공학회지
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• 제28권2호
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• pp.347-353
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• 2006

The Purpose of this study was to compare the distribution of implant fixtures according to length and diameter between screw-retained and cement-retained implant-supported fixed prosthesis and to asses whether prosthesis retained types affected the selection of size of implant fixtures. This study presents a follow-up 2,416 implant-supported fixed type prosthesis that have been screw retained or cemented retained for about 10 years in 14 dental clinics. Included in the study were 458 men and 397 women and implant fixtures used in this study were screw retained type 1,057 and 1,359 of cemented retained type. The statistical results among the diameter types of fixture by prosthesis retained type was no significant difference noted (P= 0.809) and there was significant differences was enough to among the lengths of fixture by prosthesis retained type (P= 0.020). However there were no significant difference among the fixture diameter types and length by prosthesis retained type (P= 0.486). So there was not affected to prostheis fixation mechanism for the size of implant fixtures.

• The Journal of Advanced Prosthodontics
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• 제1권2호
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• pp.97-101
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• 2009

STATEMENT OF PROBLEM. Unlike screw-retention type, fixture-abutment retention in Locking taper connection depends on frictional force so it has possibility of abutment to sink. PURPOSE. In this study, Bicon$^{(R)}$ Implant System, one of the conical internal connection implant system, was used with applying loading force to the abutments connected to the fixture. Then the amount of sinking was measured. MATERIAL AND METHODS. 10 Bicon$^{(R)}$ implant fixtures were used. First, the abutment was connected to the fixture with finger force. Then it was tapped with a mallet for 3 times and loads of 20 kg corresponding to masticatory force using loading application instrument were applied successively. The abutment state, slightly connected to the fixture without pressure was considered as a reference length, and every new abutment length was measured after each load's step was added. The amount of abutment sinking (mm) was gained by subtracting the length of abutment-fixture under each loading condition from reference length. RESULTS. It was evident, that the amount of abutment sinking in Bicon$^{(R)}$ Implant System increased as loads were added. When loads of 20 kg were applied more than 5 - 7 times, sinking stopped at $0.45{\pm}0.09\;mm$. CONCLUSION. Even though locking taper connection type implant shows good adaption to occlusal force, it has potential for abutment sinking as loads are given. When locking taper connection type implant is used, satisfactory loads are recommended for precise abutment location.

• 대한치과기공학회지
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• 제26권1호
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• pp.69-76
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• 2004

The objective of this finite element method study was to analyze the stress distribution induced on a supporting bone by 3.75mm, 4.0mm, 5.0mm diameter of dental implant fixture(13mm length). 3-dimensional finite element models of simplified gold alloy crown(7mm height) and dental implant structures(gold cylinder screw, gold cylinder, abutment screw, abutment, fixture and supporting bone(cortical bone, cancellous bone) designs were subjected to a simulated biting force of 100 N which was forced over occlusal plane of gold alloy crown vertically. Maximum von Mises stresses(MPa) under vertical loading were 9.693(3.75mm diameter of fixture), 8.885(4.0mm diameter of fixture), 6.301(5.0mm diameter of fixture) and the highest von Mises stresses of all models were concentrated in the surrounding crestal cortical bone. The wide diameter implant was the good choice for minimizing cortical bone-fixture interface stress.

• 대한치과보철학회지
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• 제54권2호
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• pp.110-119
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• 2016

목적: 본 연구는 임플란트 지대주의 체결부 길이와 골정에 대한 고정체 상단의 위치에 따라서, 하중 적용 시 고정체, 지대주, 나사 및 골에서의 응력 분포에 어떤 변화가 나타나는지 평가해 보고자 하였다. 재료 및 방법: 원추형 사면과 육각 기둥 형태의 회전저항구조를 갖는 내측 연결형 임플란트에서 지대주의 체결부 길이가 2.5 mm, 3.5 mm, 4.5 mm인 경우와 각 경우에서 고정체 상단이 골정과 같거나 골정보다 2 mm 상방에 위치할 때를 상정하여, 유한요소분석을 위한 모델을 총 6개 형성하였다. 각 경우에서 170 N의 30도 경사하중을 적용하였다. 결과: 6개의 유한요소분석 모델 모두에서, 임플란트는 고정체와 지대주의 체결 상단 부위에서, 주위 골에서는 골정 부근에서 최대 응력 값을 나타냈다. 지대주의 체결부 길이가 길어질수록, 주어진 하중에서 발생되는 고정체, 지대주, 나사 및 골에서의 최대 응력 값은 줄어들었다. 고정체 상단이 골정과 동일한 높이에 있는 경우보다 골정 2 mm 상방에 위치하는 경우에서 지대주의 체결부 길이가 길어질수록 모든 부위에서 더 큰 비율로 최대 응력 값의 감소를 나타내었다. 결론: 지대주의 체결부 길이가 길어질수록 모든 부위에서 주어진 하중에 따른 최대 응력 값이 줄어드는 것을 알 수 있었고, 임플란트의 기계적 및 생물학적 합병증 예방에 도움이 될 수 있을 것으로 판단된다.

• 구강회복응용과학지
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• 제24권1호
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• pp.77-89
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• 2008

이 연구의 목적은 원추형 내측 연결 임플랜트 시스템에서 하중조건에 따른 지대주의 침하 및 적합도를 평가하는 것이다. 본 연구에서는 내부 원추형 연결방식의 Alloden implant system (Nei Corp. Korea)의 고정체와 2종류(conventional, FDI)의 지대주를 사용하였다. 임상에서 Alloden 임플랜트는 지대주와 고정체 연결시 처음에 손으로 지긋이 눌러 고정시킨 후 mallet을 이용하여 약 3회정도 타격을 가하여 고정한다. 이때 타격시의 정확한 힘을 측정하여 각 실험군에 적용시켰다. 적용 횟수는 손가락으로 누르는 힘을 1회, mallet으로 타격하는 힘을 3회, 저작력으로 가정한 20kg의 힘을 지대주의 침하가 생기지 않을때까지 각각의 표본에 적용하였다. 그 후 각 단계에 대한 지대주의 침하량을 Vernier caliper를 이용하여 측정하였다. 임플랜트는 불포화 폴리에스터(Epovia, Cray Valley Inc. Korea)에 매몰하여 중합시켰고 모든 표본을 절삭한 후 연마하여 주사전자현미경을 통하여 분석, 평가하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제39권
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• pp.2.1-2.6
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• 2017

Background: All clinicians are aware of the difficulty of installing a dental implant in posterior maxilla because of proximate position of maxillary sinus, insufficient bone width, and lower bone density. This study is to examine which factors will make the implantation in the posterior maxilla more difficult, and which factors will affect the postoperative implant stability in this region. Methods: Five hundred seventy-three fixtures on the maxilla posterior were included for this study from all the patients who underwent an installation of the dental implant fixture from January 2010 to December 2014 at the Department of Oral and Maxillofacial Surgery in Pusan National University Dental Hospital (Yangsan, Korea). The postoperative implant stability quotient (ISQ) value, fixture diameter and length, presence of either bone graft or sinus lift, and graft material were included in the reviewed factors. The width and height of the bone bed was assessed via preoperative cone beam CT image analysis. The postoperative ISQ value was taken just before loading by using the OsstellTM $mentor^{(R)}$ (Integration Diagnostics AB, Gothenburg, Sweden). The t test and ANOVA methods were used in the statistical analysis of the data. Results: Mean ISQ of all the included data was 79.22. Higher initial bone height, larger fixture diameter, and longer fixture length were factors that influence the implant stability on the posterior edentulous maxilla. On the other hand, the initial bone width, bone graft and sinus elevation procedure, graft material, and approach method for sinus elevation showed no significant impact associated with the implant stability on the posterior edentulous maxilla. Conclusions: It is recommended to install the fixtures accurately in a larger diameter and longer length by performing bone graft and sinus elevation.

• 대한치과보철학회지
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• 제41권5호
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• pp.674-688
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• 2003

Statement of Problem : With increasing demand of the implant-supported prosthesis, it is advantageous to use the different platform width of the fixture according to bone quantity and quality of the patients. Purpose : The purpose of this study was to assess the loading distributing characteristics of two implant designs according to each platform width of fixture, under vertical and inclined loading using finite element analysis. Material and method : The two kinds of finite element models were designed according to each platform width of future (4.1mm restorative component x 11.5mm length, 5.0mm wide-diameter restorative component x 11.5mm length). The crown for mandibular first molar was made using UCLA abutment. Each three-dimensional finite element model was created with the physical properties of the implant and surrounding bone. This study simulated loads of 200N at the central fossa in a vertical direction, 200N at the outside point of the central fossa with resin filling into screw hole in a vertical direction and 200N at the buccal cusp in a 300 transverse direction individually Von Mises stresses were recorded and compared in the supporting bone, fixture, and abutment screw. Results : The stresses were concentrated mainly at the cortex in both vertical and oblique load ing but the stresses in the cancellous bone were low in both vertical and oblique loading. Bending moments resulting from non-axial loading of dental implants caused stress concentrations on cortical bone. The magnitude of the stress was greater with the oblique loading. Increasing the platform width of the implant fixture decreased the stress in the supporting bone, future and abutment screw. Increased the platform width of fixture decreased the stress in the crown and platform. Conclusion : Conclusively, this investigation provides evidence that the platform width of the implant fixture directly affects periimplant stress. By increasing the platform width of the implant fixture, it showed tendency to decreased the supporting bone, future and screw. But, further clinical studies are necessary to determine the ideal protocol for the successful placement of wide platform implants.

• 대한치과보철학회지
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• 제40권4호
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• pp.374-385
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• 2002

A total of 605 implant fixture prosthesis delivered by 3 clinics and 2 laboratories were examined in this study, The object of this study was to determine the proper length of screw head. The depth of access hole were measured and compared to the type of fixture, abutment, gold screw and prosthesis. The results were as follows : 1 The average number of fixtures per patient were 2.97. 2. The number of fixture installed in the upper posterior area are 327(55.56 %), the upper posterior area 171 (28.25%). 3. The depth of access hole is 4.23 mm in shallow area, and 5.46 mm in deep area and the differences were 1.23 mm. 4. The average depth of the aceess hole of the UCLA abutment were 5.02 mm. 5. The number of 4-5 mm access hole depth were 60(22.39%) in abutment screw level and the number of 4-5 mm depth in fixture level were 101 (29.19%). 6. In the shape of screw head, hexed type were 576(95.21%), slotted type were 29(4.79%).