• The Journal of Advanced Prosthodontics
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• 제6권1호
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• pp.35-38
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• 2014

PURPOSE. This study aimed to evaluate the correlation between microleakage and screw loosening at different types of implant-abutment connections and/or geometries measuring the torque values before and after the leakage tests. MATERIALS AND METHODS. Three different abutment types (Intenal hex titanium, internal hex zirconium, morse tapered titanium) with different geometries were connected to its own implant fixture. All the abutments were tightened with a standard torque value then the composition was connected to the modified fluid filtration system. After the measurements of leakage removal torque values were re-measured. Kruskal-wallis test was performed for non-parametric and one-way ANOVA was performed for parametric data. The correlation was evaluated using Spearman Correlation Test (${\alpha}=0.05$). RESULTS. Significantly higher microleakage was found at the connection of implant-internal hex zirconium abutment. Observed mean torque value loss was also significantly higher than other connection geometries. Spearman tests revealed a significant correlation between microleakage and screw loosening. CONCLUSION. Microleakage may provoke screw loosening. Removing torque values rationally decrease with the increase of microleakage.

• 대한치과보철학회지
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• 제44권2호
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• pp.207-216
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• 2006

Statement of Problem: To conduct a successful function of implant prosthesis in oral cavity for a long time, it is important that not only structure materials must have the biocompatibility, but also the prosthesis must be designed for the stress, which is occurred in occlusion, to scatter adequately within the limitation of alveolar bone around implant and bio-capacity of load support. Now implant which is used in clinical part has a very various shapes, recently the fixture that has tapered form of internal connection is often selected. However the stress analysis of fixtures still requires more studies. Purpose: The purpose of this study is to stress analysis of the implant prosthesis according to the different implant systems using finite element method. Material and methods: This study we make the finite element models that three type implant fixture ; $Br{\aa}nemark$, Camlog, Frialit-2 were placed in the area of mandibular first premolar and prosthesis fabricated, which we compared with stress distribution using the finite element analysis under two loading condition. Conclusion: The conclusions were as follows: 1. In all implant system, oblique loading of maximum Von mises stress of implant, alveolar bone and crown is higher than vertical loading of those. 2. Regardless of loading conditions and the type of system. cortical bone which contacts with implant fixture top area has high stress, and cancellous bone has a little stress. 3. Under the vertical loading, maximum Von mises stress of $Br{\aa}nemark$ system with external connection type and tapered form is lower than Camlog and Frialit-2 system with internal connection type and tapered form, but under oblique loading Camlog and Frialit-2 system is lower than $Br{\aa}nemark$ system.

• The Journal of Advanced Prosthodontics
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• 제8권5호
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• pp.388-395
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• 2016

PURPOSE. The purpose of this study was to evaluate the resistance to deformation under static overloading by measuring yield and fracture strength, and to analyze the failure characteristics of implant assemblies made of different titanium grades and connections. MATERIALS AND METHODS. Six groups of implant assemblies were fabricated according to ISO 14801 (n=10). These consisted of the combinations of 3 platform connections (external, internal, and morse tapered) and 2 materials (titanium grade 2 and titanium grade 4). Yield strength and fracture strength were evaluated with a computer-controlled Universal Testing Machine, and failed implant assemblies were classified and analyzed by optical microscopy. The data were analyzed using the One-way analysis of variance (ANOVA) and Student's t-test with the level of significance at P=.05. RESULTS. The group $IT4_S$ had the significantly highest values and group IT2 the lowest, for both yield strength and fracture strength. Groups $IT4_N$ and ET4 had similar yield and fracture strengths despite having different connection designs. Group MT2 and group IT2 had significant differences in yield and fracture strength although they were made by the same material as titanium grade 2. The implant system of the similar fixture-abutment interfaces and the same materials showed the similar characteristics of deformation. CONCLUSION. A longer internal connection and titanium grade 4 of the implant system is advantageous for static overloading condition. However, it is not only the connection design that affects the stability. The strength of the titanium grade as material is also important since it affects the implant stability. When using the implant system made of titanium grade 2, a larger diameter fixture should be selected in order to provide enough strength to withstand overloading.

• 구강회복응용과학지
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• 제24권1호
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• pp.57-65
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• 2008

연구목적 : 본 연구에서는 rotational freedom을 측정할 수 있는 기구를 개발하여 시중에서 유통되고 있는 국산 임플란트 및 다양한 국적의 임플란트들의 기계적인 가공오차들을 측정하여 다양한 임플란트 시스템의 component간의 기계적인 안정성을 평가하고자 한다. 또한 본 연구에서는 더 나아가 최근에 임플란트 abutment로 각광을 받고 있는 각종 ceramic abutment의 절삭 가공오차에 관한 항목을 측정하여 임플란트 제조사 및 임상의들에게 올바른 정보를 제공하고자 한다. 연구재료 및 방법 : 국내에서 유통되는 외부연결구조의 외국산 임플란트 시스템(Nobel Biocare, Anthorgyr)과 국산 시스템(Neobiotec)과 내부연결구조의 임플란트 시스템(외국산:Nobel Biocare, Anthorgyr, Straumann, Frident Dentsply, 국산:Dentium) 별로 임플란트 fixture, abutment, analog를 서로 교차 연결하여 회전각도측정기(rotational angle measuring device)로 freedom of rotational angle을 측정하였다. 국산 외부연결구조의 지르코니아 abutment(ZirAce)를 외부연결구조의 임플란트 시스템(Neobiotec, Nobel Biocare, Anthorgyr)의 fixture와 analog와 교차연결하여 freedom of rotational angle을 측정하였다. 연구결과 : 국산 외부연결구조의 임플란트 시스템은 약 2.67도(fixture와 abutment 연결시), 내부연결구조의 임플란트는 약 4.3도(fixture와 abutment 연결시)의 rotational freedom을 보였다. 국산 지르코니아 abutment는 외국산 및 국산 외부연결구조 임플란트 시스템과 상관없이 3도 이하(fixture와 연결시)의 결과를 보였다. 결 론 : 시제품으로 제작된 디지털 회전각도측정기는 높은 분해능을 갖고 있었으며, 국산 임플란트의 기계적 가공오차는 외국산 임플란트와 거의 유사했다. 국산 세라믹 abutment의 기계적 가공오차는 fixture 제조회사별로 다르게 나타났지만 같은 회사의 절삭가공된 금속 abutment와 비교시 가공오차가 더 적었다.

• 대한치과보철학회지
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• 제55권3호
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• pp.251-257
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• 2017

목적:본 연구에서는 long internal connection 형태의 임플란트 지대주를 내부 연결 길이에 변화를 주어 임플란트-지대주 결합부의 안정성을 비교 평가해 보고자 하였다. 재료 및 방법: Long internal connection의 임플란트(Replus system, $4.7{\times}11.5mm$)를 각각 지대주의 길이에 따라 4개의 군(1, 2, 3, 4 mm 군)으로 나누었고 총 20개의 시편을 사용하였다. 시편을 레진에 매몰하여 고정시키고 100 N의 힘으로 임플란트 장축에 대해 30도의 각도에서 $1.0{\times}10^6$ 번의 반복하중을 가한 후 하중 전 후의 풀림회전력의 차이를 계산하여 95% 유의수준에서 Kruskal-Wallis 검정 방법을 통해 통계 분석하였다. 결과:지대주 내부 길이에 따른 풀림 회전력의 통계적 유의성은 나타나지 않았으며 (P > .05) 어떤 시편에서도 완전한 나사 풀림이나 나사 파절은 관찰되지 않았다. 결론: 내측 연결 임플란트에서 지대주 내부길이에 따른 나사 풀림의 정도는 차이가 나지 않았다.

• 대한치과보철학회지
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• 제43권4호
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• pp.544-561
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• 2005

Purpose : This study was to assess the loading distributing characteristics of implant systems with internal connection or external connection under vertical and inclined loading using finite element analysis. Materials and methods : Two finite element models were designed according to type of internal connection or external connection The crown for mandibular first molar was made using cemented 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 (loading condition A), 200N at the centric cusp tip in a 15$^{\circ}$ inward inclined direction (loading condition B), or 200N at the centric cusp tip in a 30$^{\circ}$ outward inclined direction (loading condition C) respectively. Von Mises stresses were recorded and compared in the supporting bone, fixture, abutment and abutment screw. Results : 1. In comparison with the whole stress or the model 1 and model 2, the stress pattern was shown through th contact of the abutment and the implant fixture in the model 1, while the stress pattern was shown through the abutment screw mainly in the model 2. 2. Without regard to the loading condition, greater stress was taken at the cortical bone, and lower stress was taken at the cancellous bone. The stress taken at the cortical bone was greater at the model 1 than at the model 2, but the stress taken at the cortical bone was much less than the stress taken at the abutment, the implant fixture, and the abutment screw in case of both model 1 and model 2. 3. Without regard to the loading condition, the stress pattern of the abutment was greater at the model 1 than at the model 2. 4. In comparison with the stress distribution of model 1 and model 2, the maximum stress was taken at the abutment in the model 1. while the maximum stress was taken at the abutment screw in the model 2. 5. The magnitude of the maximum stress taken at the supporting bone, the implant fixture, the abutment, and the abutment screw was greater in the order of loading condition A, B and C. Conclusion : The stress distribution pattern of the internal connection system was mostly distributed widely to the lower part along the inner surface of the implant fixture contacting the abutment core through its contact portion because of the intimate contact of the abutment and the implant fixture and so the less stress was taken at the abutment screw, while the abutment screw can be the weakest portion clinically because the greater stress was taken at the abutment screw in case of the external connection system, and therefore the further clinical study about this problem is needed.

• The Journal of Advanced Prosthodontics
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• 제6권2호
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• pp.126-132
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• 2014

PURPOSE. This study was conducted to evaluate the influence of the implant-abutment connection design and diameter on the screw joint stability. MATERIALS AND METHODS. Regular and wide-diameter implant systems with three different joint connection designs: an external butt joint, a one-stage internal cone, and a two-stage internal cone were divided into seven groups (n=5, in each group). The initial removal torque values of the abutment screw were measured with a digital torque gauge. The postload removal torque values were measured after 100,000 cycles of a 150 N and a 10 Hz cyclic load had been applied. Subsequently, the rates of the initial and postload removal torque losses were calculated to evaluate the effect of the joint connection design and diameter on the screw joint stability. Each group was compared using Kruskal-Wallis test and Mann-Whitney U test as post-hoc test (${\alpha}$=0.05). RESULTS. The postload removal torque value was high in the following order with regard to magnitude: two-stage internal cone, one-stage internal cone, and external butt joint systems. In the regular-diameter group, the external butt joint and one-stage internal cone systems showed lower postload removal torque loss rates than the two-stage internal cone system. In the wide-diameter group, the external butt joint system showed a lower loss rate than the one-stage internal cone and two-stage internal cone systems. In the two-stage internal cone system, the wide-diameter group showed a significantly lower loss rate than the regular-diameter group (P<.05). CONCLUSION. The results of this study showed that the external butt joint was more advantageous than the internal cone in terms of the postload removal torque loss. For the difference in the implant diameter, a wide diameter was more advantageous in terms of the torque loss rate.

• 대한치과보철학회지
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• 제44권4호
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• pp.421-431
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• 2006

Statement of problem : Accurate impression is essential to success of implant prostheses. But there have been few studies about the accuracy of fixture-level impression technique in internal connection implant system. Purpose: This study evaluated the accuracy of splinted fixture-level impression technique using clinical methods and the effect of internal hex on fit of superstructure in internal connection implant system (Astra Tech). Material and method : Two metal master frameworks made from two abutments (Cast-to Abutment ST) each for parallel and divergent conditions and a corresponding. passively fitting, dental stone master cast with four future replicas (Fixture Replica ST) were fabricated. Ten dental stone casts were made with vinyl polysiloxane impressions from the master cast by acrylic resin splinted fixture-level impression technique. To evaluate the accuracy of impression technique, the fit of master frameworks for test models was evaluated using screw resistance test (SRT) and one-screw test. The results of SRT were recorded as SRT values from grade 1 to grade 5 by 1/4 turn. And to evaluate the effect of hex on fit of superstructure, the same tests were performed after removing hexes of master frameworks. Results: 1. There was only one case (2.5%) showing SRT value of test model below ade 2 in total before and after removing hexes of master frameworks. And, by removing hexes. SRT values decreased in only one test model (5%) and did not change in 17 test models (85%). 2. SRT values of the 1$^{st}$ screws were grade 2 in 80% of cases before, and grade 1 in 80% of cases after removing hexes. And, by removing hexes, SRT values decreased in 72.5% of cases. 3. SRT values of the 2$^{nd}$ screws were grade 3 in 85% of cases before, and grade 3 in 95% of cases after removing hexes. And, by removing hexes, SRT values did not change in 85% of cases. 4. There were only 2 cases regarded as acceptable fit by one-screw test, and SRT values of 2$^{nd}$ screws of both cases were grade 2. Conclusion. Within the limitations of this study, future-level impression of internal connection implant system is considered to obtain inaccurate working cast, even using acrylic resin splinted impression technique. And, it is considered to be unable improve the fit to remove the hexes of implant restoration.

• The Journal of Advanced Prosthodontics
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• 제13권6호
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• pp.343-350
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• 2021

PURPOSE. The success of an implant-prosthetic rehabilitation is influenced by good implant health and an excellent implant-prosthetic coupling. The stability of implant-prosthetic connection is influenced by the rotational tolerance between anti-rotational features on the implant and those on the prosthetic component. The aim of this study is to investigate the rotational tolerance of a conical connection implant system and its titanium abutment counterpart, in various conditions. MATERIAL AND METHODS. 10 preparable titanium abutments, having zero-degree angulation (MegaGen, Daegu, Korea) with an internal 5-degree conical connection, and 10 implants (MegaGen, Daegu, Korea) were used. Rotational tolerance between the connection of implant and titanium abutments was measured through the use of a tridimensional optics measuring system (Quick Scope QS250Z, Mitutoyo, Kawasaki, Japan) in the as-received condition (Time 0), after securing with a titanium screw tightening at 35 Ncm (Time 1), after tightening 4 times at 35 Ncm (Time 2), after tightening one more time at 45 Ncm (Time 3), and after tightening another 4 times at 45 Ncm (Time 4). RESULTS. The group "Time 0" had the lowest values of rotational freedom (0.22 ± 0.76 degrees), followed by the group Time 1 (0.46 ± 0.83 degrees), the group Time 2 (1.01 ± 0.20 degrees), the group Time 3 (1.30 ± 0.85 degrees), and the group Time 4 (1.49 ± 0.17 degrees). CONCLUSION. The rotational tolerance of a conical connection is low in the "as received" condition but increases with repetitive tightening and with application of a torque greater than 35 Ncm.

• 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.