• 대한치과의사협회지
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• 제54권3호
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• pp.184-190
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• 2016

The osseointegration of titanium implants has been examined over the past 50 years. Many implant systems have been introduced and have become popular to the implant dentistry. The designs of the connection between implant fixture and abutment are divided into external vs internal connection. From beginning, the $Br{\aa}nemark$ system was characterized by an external hexagon. Internal connection has been developed to reduce stress transferred to the bone. These differences may have impact on the clinical procedures and protocols, laboratory and components costs, and incidence of complications. Therefore, the clinician has to know the different biomechanical features and understand their implications to produce successful implant-supported prosthesis with an external or an internal connection system.

• 대한치과의사협회지
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• 제54권3호
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• pp.198-205
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• 2016

The purpose of this paper was to investigate the significance of splinted and non-splinted implant-supported restorations with an internal connection for multiple consecutively missing teeth. Upon examination of the effects of fixture-abutment connection, the distribution of occlusal load was favorable in splinted implant-prosthesis with an external connection, but effect of strain distribution was not significant in splinted implant-prosthesis with an internal connection. In splinted implant-prostheses for short implants, strain distribution was not affected by the method of retention. For cement-retained prostheses, the effect of strain distribution due to splinting was not significant. In clinical studies, non-splinted prostheses with an internal connection for multiple consecutively missing teeth showed high survival rate, mild marginal bone loss, and stable periodontal condition. However, failure to achieve optimal proximal contact between single-unit prostheses may lead to food impaction, and veneer fracture may be inevitable when the framework provides inadequate support in the proximal region. In conclusion, splinted implant-prosthesis is not an indication in all cases, and clinical consideration of its use should be based on the patient's oral condition, such as location and number of implants, formation of proximal contact, canine guidance, existence of parafunctional habit, and oral hygiene, when multiple consecutively missing teeth are replaced by internal connection type implant.

• 대한치과보철학회지
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• 제44권2호
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• pp.174-184
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• 2006

Purpose: Current trend in implant dentistry is changing from external connection to internal connection. To evaluate the splinting of external and internal connection implant on screw loosening, 2-units prosthesis was fabricated with BioPlant $System^(R)$ of external connection type and Lifecore STAGE-1 Single Stage Implant $System^(R)$ of internal connection type. Material and Method: Experimental group is classified into three groups. 1) $G_1-EE$: 2-units prosthesis was fabricated with two Bioplant $System^(R)$ of external connection type. 2) $G_1-EI$: 2-units prosthesis was fabricated with one BioPlant $System^(R)$ of external connection type and one Lifecore STAGE-1 Single Stage Implant $System^(R)$ of internal connection type. 3) $G_1-II$: 2-units prosthesis was fabricated with two Lifecore STAGE-1 Single Stage Implant $System^(R)$ of internal connection type. In fabricating 2-units prosthesis, two hexed abutments are recommended when two implants are installed parallel, otherwise one hexed abutment is used on major occlusal force area and one nonhexed abutment is used on the other area. Since it is rare to find two implants being parallel, it is hard to fabricate prosthesis with passive adaptation using two hexed abutments. It is much more difficult to acquire passive adaptation when using hex abutment compared to nonhex abutment. To evaluate the influence of hexed and nonhexed abutment on screw loosening, 2-units prosthesis was fabricated with hexed and nonhexed abutment. Experimental group is classified into three groups. 1) $G_2-HH$: 2-units prosthesis was fabricated with two hexed abutments. 2) $G_2-HN$: 2-units prosthesis was fabricated with one hexed abutment and one nonhexed abutment. 3) $G_2-NN$: 2-units prosthesis was fabricated with two nonhexed abutments. Result: The results of comparing the detorque value after loading on a each prosthesis periodically are as follows. 1. In splinting group of external and internal connection implant, $G_1-II$ group demonstrated the biggest detorque value, followed by $G_1-EI$ group and $G_1-EE$ group. 2. There is no notable significance between external connection implant of $G_1-EI$ group and $G_1-EE$ group and also no significance between internal connection implant of $G_1-EI$ group and $G_1-II$ group. 3. $G_2-HH$ group showed higher detorque value than $G_2-HN\;and\;G_2-NN$ group. From the results, we can concluded that using both external connection and internal connection implant together is clinically acceptable and in order to acquire a good passive adaptation in fabricating 2-units implant prosthesis we can use two nonhexed abutments.

• The Journal of Advanced Prosthodontics
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• 제9권4호
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• pp.271-277
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• 2017

PURPOSE. This in vitro study aimed to evaluate the effect of implant connection design (external vs. internal) on the fit discrepancy and torque loss of zirconia and titanium abutments. MATERIALS AND METHODS. Two regular platform dental implants, one with external connection ($Br{\aa}nemark$, Nobel Biocare AB) and the other with internal connection (Noble Replace, Nobel Biocare AB), were selected. Seven titanium and seven customized zirconia abutments were used for each connection design. Measurements of geometry, marginal discrepancy, and rotational freedom were done using video measuring machine. To measure the torque loss, each abutment was torqued to 35 Ncm and then opened by means of a digital torque wrench. Data were analyzed with two-way ANOVA and t-test at ${\alpha}=0.05$ of significance. RESULTS. There were significant differences in the geometrical measurements and rotational freedom between abutments of two connection groups (P<.001). Also, the results showed significant differences between titanium abutments of internal and external connection implants in terms of rotational freedom (P<.001). Not only customized internal abutments but also customized external abutments did not have the exact geometry of prefabricated abutments (P<.001). However, neither connection type (P=.15) nor abutment material (P=.38) affected torque loss. CONCLUSION. Abutments with internal connection showed less rotational freedom. However, better marginal fit was observed in externally connected abutments. Also, customized abutments with either connection could not duplicate the exact geometry of their corresponding prefabricated abutment. However, neither abutment connection nor material affected torque loss values.

• 대한치과보철학회지
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• 제43권3호
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• pp.338-351
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• 2005

Statement of problem. Accurate fit between the implant components is important because the misfit of the implant components results in frequent screw loosening, irreversible screw fracture, plaque accumulation, poor soft tissue reaction, and destruction of osseointegration. Purpose. This study is to evaluate the machining accuracy and consistency of the implant fixture/ abutment/screw interfaces of the internal connection system by using a Stereoscopic Zoom microscope and FE-SEM(field emission scanning electron microscope) Materials and methods. The implant systems selected in this study were internal connection type implants from AVANA(Osstem^{\circledR}), Bioplant(Cowell-Medi^{\circledR}), Dio(DIO^{\circledR}), Neoplant(Neobiotech 􀋓), Implantium(Dentium􀋓)systems. Each group was acquired 2 fixtures at random. Two piece type abutment and one piece type abutment for use with each implant system were acquired. Screw were respectively used to hold a two piece type abutment to a implant fixture. The implant fixtures were perpendiculary mounted in acrylic resin block. Each two piece abutment was secured to the implant fixture by screw and one piece abutment also secured to the implant fixture. Abutment/fixture assembly were mounted in liquid unsaturated polyester. All samples were cross-sectioned with grinder-polisher unit. Finally all specimens were analysed the fit between implant fixture/abutment/screw interfaces Results and conclusions. 1. Implant fixture/abutment/screw connection interfaces of internal connection systems made in Korea were in good condition. 2. The results of the above study showed that materials and mechanical properties and quality of milling differed depending on their manufacturing companies.

• 대한치과보철학회지
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• 제42권4호
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• pp.356-372
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• 2004

Statement of problom: In the internal connection system the loading transfer mechanism within the inner surface of the implant and also the stress distribution occuring to the mandible can be changed according to the abutment form. Therefore it is thought to be imperative to study the difference of the stress distribution occuring at the mandible according to the abutment form. Purpose: The purpose of this study was to assess the loading distributing characteristics of 3 implant systems with internal connection under vertical and inclined loading using finite element analysis. Material and method: Three finite element models were designed according to the type of internal connection of ITI(model 1), Friadent(model 2), and Bicon(model 3) respectively. This study simulated loads of 200N in a vertical direction (A), a $15^{\circ}$ inward inclined direction (B), and a $30^{\circ}$ outward inclined direction (C). Result: The following results have been made based on this numeric simulations. 1. The greatest stress showed in the loading condition C of the inclined load with outside point from the centric cusp tip. 2. Without regard to the loading condition, the magnitudes of the stresses taken at the supporting bone, the implant fixture, and the abutment were greater in the order of model 2, model 1, and model 3. 3. Without regard to the loading condition, greater stress was concentrated at the cortical bone contacting the upper part of the implant fixture, and lower stress was taken at the cancellous bone. 4. The stress of the implant fixture was usually widely distributed along the inner surface of the implant fixture contacting the abutment post. 5. The stress distribution pattern of the abutment showed that the great stress was usually concentrated at the neck of the abutment and the abutment post, and the stress was also distributed toward the lower part of the abutment post in case of the loading condition B, C of the inclined load. 6. In case of the loading condition B, C of the inclined load, the maximum von Misess stress at the whole was taken at the implant fixture both in the model 1 and model 2, and at the abutment in the model 3. 7. The stress was inclined to be distributed from abutment post to fixture in case of the internal connection system. Conclusion: The internal connection system of the implant and the abutment connection methods, the stress-induced pattern at the supporting bone, the implant fixture, and the abutment according to the abutment connection form had differenence among them, and the stress distribution pattern usually had a widely distributed tendency along the inner surface of the implant fixture contacting the a butment post.

• 대한치과의사협회지
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• 제56권11호
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• pp.605-614
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• 2018

PURPOSE. The purpose of this study is to determine the efficacy of the DENTIS submerged-type implant with an internal hex connection and to build corresponding abutment-selection criteria. MATERIAL AND METHODS. A total of 204 patients received submerged implant fixtures with an internal hex connection at the Dong-A University Hospital Dental clinic in Busan from January 2013 and May 2016. Three specific abutments, UCLA abutments, customized abutments, ready-made abutments, were randomly selected. Implant success was defined as the basis of the International Congress of Oral Implantologists(ICOI, 2007) criteria. The relationship between the implant success rate and the abutment factor was analyzed using the Kruskal-Wallis test(P<.05). RESULTS. A total of 508 implants were placed in 204 patients. After a mean observation period of 38.6 months, 493 out of 508 implants were in normal function, yielding an overall success rate of 97.05%. A total of 15 implants failed: 10 in the maxillary molar area, 4 in the mandibular molar area, and 1 in the mandibular incisal area. All of the implant failures occurred in a single-implant prosthesis, especially high in the maxillary molar area. The Kruskal-Wallis analysis showed that abutment selection has no significant correlation with implant failure(P>.05). CONCLUSION. DENTIS submerged implants with an internal hex connection showed predictable results with a success rate of 97.05%. It is no influence on the success rate in the selection of submerged implant abutment with an internal hex connection.

• The Journal of Advanced Prosthodontics
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• 제11권3호
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• pp.147-154
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• 2019

PURPOSE. This study aimed to evaluate the effect of two different implant-abutment connection structures with identical implant design on peri-implant bone level. MATERIALS AND METHODS. This clinical study was a patient-blind randomized controlled trial following the CONSORT 2010 checklists. This trial was conducted in 24 patients recruited between March 2013 and July 2015. Implants with internal friction connection were compared to those with external hex connection. One implant for each patient was installed, replacing the second molar. Implant-supported crowns were delivered at four months after implant insertion. Standardized periapical radiographs were taken at prosthesis delivery (baseline), and one year after delivery. On the radiographs, distance from implant shoulder to first bone-to-implant contact (DIB) and peri-implant area were measured, which were the primary and secondary outcome, respectively. RESULTS. Eleven external and eleven internal implants were analyzed. Mean changes of DIB from baseline to 1-year postloading were 0.59 (0.95) mm for the external and 0.01 (0.68) mm for the internal connection. Although no significant differences were found between the two groups, medium effect size was found in DIB between the connections (Cohen's d = 0.67). CONCLUSION. Considering the effect size in DIB, this study suggested the possibility of the internal friction connection structure for more effective preservation of marginal bone.

• 대한치과보철학회지
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• 제49권4호
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• pp.346-353
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• 2011

연구 목적: 임플란트 식립 후 변연골 흡수에 따라 임플란트 주위 연조직이 재구성되며, 이에 따라 치료의 예후 및 심미성 등에 영향을 주게 된다. 그러므로 임플란트 경부 주위 골조직 보존을 위한 임플란트 경부에 다양한 디자인이 연구되고 있다. 본 고찰의 목적은 초기 변연골 흡수의 원인과 이에 따른 임플란트 주위의 연조직 변화에 대해 고찰하고, 어떠한 임플란트 경부 디자인이 임플란트 주위 조직의 보존에 유리한 지 알아보고자 한다. 연구 재료 및 방법: Pubmed database에서 임플란트 초기 변연골 흡수의 원인과 관련된 논문과 임플란트 경부의 여러 디자인에 관한 논문을 검색하여 분석하였다. 임플란트 경부 디자인은 one piece implant, two piece implant, internal hex abutment, external hex abutment, taper joint connection, butt joint connection, scalloped design abutment, platform switching concept에 관해 검토하였다. 결과: 초기의 임플란트 주위 조직 보존에 대하여 one piece implant가 two piece implant보다 유리한 것으로 여러 임상적, 실험적 연구가 있다. Two piece implant에서는 internal hex abutment가 external hex abutment보다, taper joint connection가 butt joint connection보다 유리할 것으로 보여진다. Scalloped design abutment에 대해서는 논쟁의 여지가 있어 더 많은 연구가 필요할 것으로 판단된다. Platform switching concept은 그 원인이 명확히 밝혀지지는 않았으나 임상적, 실험적으로 초기 임플란트 주위 조직 보존에 대해 유리한 것으로 판단된다. 결론: 임플란트 경부의 디자인마다 각각의 장단점이 있고 추가적인 연구가 더 필요한 제한이 있지만 현재까지의 선행 연구들을 분석 종합해 보면 초기 임플란트 주위 조직 보존을 고려한다면 가능한 경우 one piece implant가 유리할 것으로 판단되며, 보철적인 문제나 다른 이유로 인하여 two piece implant를 고려할 경우 platform switching concept, internal connection abutment, taper joint connection을 이용하는 것이 임플란트 주위 조직 보존에 좀더 유리할 것으로 사료된다.

• 대한치과보철학회지
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• 제42권2호
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• pp.226-237
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• 2004

Purpose: Four finite element models were constructed in the mandible having a single implant fixture connected to the first premolar-shaped superstructure, in order to evaluate how the shape of the fixture and the implant-abutment connection would influence the stress level of the supporting tissues fixtures, and prosthethic components. Material and methods : The superstructures were constructed using UCLA type abutment, ADA type III gold alloy was used to fabricate a crown and then connected to the fixture with an abutment screw. The models BRA, END , FRI, ITI were constructed from the mandible implanted with Branemark, Endopore, Frialit-2, I.T.I. systems respectively. In each model, 150 N of vertical load was placed on the central pit of an occlusal plane and 150 N of $40^{\circ}$ oblique load was placed on the buccal cusp. The displacement and stress distribution in the supporting tissues and the other components were analysed using a 2-dimensional finite element analysis . The maximum stress in each reference area was compared. Results : 1. Under $40^{\circ}$ oblique loading, the maximum stress was larger in the implant, superstructure and supporting tissue, compared to the stress pattern under vertical loading. 2. In the implant, prosthesis and supporting tissue, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 3. In the superstructure and implant/abutment interface, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 4. In the implant fixture, the maximum stress was smaller with the internal connection type (FRI) and the morse taper type (ITI) when compared to that of the external connection type (BRA & END). 5 The stress was more evenly distributed in the bone/implant interface through the FRI of trapezoidal step design. Especially Under $40^{\circ}$ oblique loading, The maximum stress was smallest in the bone/implant interface. 6. In the implant and superstructure and supporting tissue, the maximum stress occured at the crown loading point through the ITI. Conclusion: The stress distribution of the supporting tissue was affected by shape of a fixture and implant-abutment connection. The magnitude of maximum stress was reduced with the internal connection type (FRI) and the morse taper type (ITI) in the implant, prosthesis and supporting tissue. Trapezoidal step design of FRI showed evenly distributed the stress at the bone/implant interface.