• The Journal of Korean Academy of Prosthodontics
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• v.43 no.2
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• pp.258-263
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• 2005

Statement of problem. Implant screw loosening has been remained a problem in implant prosthodontics. The time needed to insert screw driver into abutment screw head should be shortened for the purpose of decreasing the chair time. Purpose. The purpose of this study was to investigate the effects of the design of abutment screw driver on the amount of time for insertion of screw driver into abutment screw head. Material and methods. Hexagonal and rectangular types of abutment screw drivers were used. The original abutment screw drivers were modified by grinding acute angle of the screw driver tip (modified drivers). Group 1 : hexagonal type abutment screw and original driver Group 2 : hexagonal type abutment screw and modified driver Group 3 : rectangular type abutment screw and original driver Group 4 : rectangular type abutment screw and modified driver UCLA lab analogues were located in acrylic resin block. The angulations of them were 0 and 20 degrees. The times needed for insertion were measured. Group 1 and 3 were used as controls. Results. 1. Group 2 showed shorter insertion time than group 1, regardless of implant angulations (p<.05). 2. Group 4 showed shorter insertion time than group 3, regardless of implant angulations (p<.05). Conclusion. Modified abutment screw drivers required less amount of time to insert screw driver into abutment screw head. Modification of abutment screw driver was beneficial.

• The Journal of Advanced Prosthodontics
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• v.1 no.1
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• pp.37-40
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• 2009

STATEMENT OF PROBLEM. Implant drivers are getting popular in clinical dentistry. Unlike to implant systems with external hex connection, implant drivers directly engage the implant/abutment interface. The deformation of the implant/abutment interface can be introduced while placing an implant with its implant driver in clinical situations. PURPOSE. This study evaluated the change of rotational freedom between an implant and its abutment after application of different insertion torques. MATERIAL AND METHODS. Three kinds of internal connection implants were utilized for the current study($4.5{\times}12\;mm$ Xive, $4.3{\times}11.5\;mm$ Inplant Magicgrip, $4.3{\times}12\;mm$ Implantium MF). An EstheticBase, a 2-piece top, a Dual abutment was used for its corresponding implant system. The rotational freedom between an implant and its abutment were measured before and after applying 45, 100 Ncm insertion torque. Repeated measures ANOVA was used for statistical analysis. RESULTS. Under 45 Ncm insertion torque, the rotational freedom between an implant and its abutment was significantly increased in Xive(P = .003). However, no significant change was noted in Inplant Magicgrip and Implantium MF. Under 100 Ncm torque, both in Xive(P = .0005) and Implatium MF(P = .03) resulted in significantly increased rotational freedom between the implant and its abutment. DISCUSSION. The design of the implant/implant driver interface effectively prevented the deformation of implant/abutment interface. Little change was noted in the rotational freedom between an implant and its abutment, even though the insertion torque was far beyond clinical application. CONCLUSIONS. The implant/abutment joint of internally connecting implants were quite stable under insertion torque in clinical situation.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.4
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• pp.346-353
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• 2011

Purpose: The peri-implant soft tissue is remodeled by the initial marginal bone resorption affecting the prognosis and esthetic result of treatment. Thus various designs on implant neck design are studied to preserve peri-implant bone. The purpose of this study is to review on the causes of initial marginal bone resorption, the configuration of peri-implant soft tissue, and the implant crestal module favorable in preserving peri-implant tissue. Materials and methods: The studies on the causes of initial marginal bone resorption and the implant crestal modules are researched and reviewed using Pubmed database. The implant crestal modules including one piece and two-piece implant, internal and external hex abutment, taper and butt joint connection, scalloped design abutment, and platform switching concept are reviewed. Results: A number of clinical and experimental studies preferred one piece implant to two-piece in preserving initial peri-implant tissue. For two piece implants, internal hex abutment and taper joint connection appear more favorable than external hex abutment and butt joint connection relatively. Controversial issues still exist on scalloped design requiring more studies on it. Although the rationale is not certain, the concept of platform switching seems favorable in preserving initial peri-implant tissue based on clinical and experimental studies. Conclusion: Each implant crestal module contains its own advantages and disadvantages with various controversial issues. In the aspect of preservation of initial peri-implant tissue, however, one-piece implant seems beneficial. In cases when two-piece implant is more appropriate due to prosthodontic concerns or any other problems, the application of platform switching concept, internal connection abutment, and taper joint connection may be favorable for the preservation of peri-implant tissues.

• The Journal of Advanced Prosthodontics
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• v.13 no.1
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• pp.46-54
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• 2021

Purpose. The design of the implant-abutment complex is thought to be responsible for marginal bone loss (MBL) and might affect the condition of the peri-implant tissues. This the present study aimed to evaluate the influence of the implant-abutment complex on MBL and the peri-implant tissues in partially edentulous patients treated with dental implants and determine the most advantageous design. Materials and Methods. A total of ninety-one endosseous implants with different designs of implant-abutment complex [tissue level-TL (n = 30), platform switch-PS (n = 18), and platform match-PM (n = 43)] were reviewed for MBL, Probing Pocket Depth (PPD) and Bleeding on Probing (BoP). MBL was calculated for first year of the insertion and the following years. Results. The median MBL for the PM implants (2.66 ± 1.67 mm; n = 43) in the first year was significantly higher than those for the other types (P=.033). The lowest rate of MBL (0.61 ± 0.44 mm; n = 18) was observed with PS implants (P=.000). The position of the crown-abutment border showed a statistically significant influence (P=.019) and a negative correlation (r=-0.395) on MBL. BoP was found significantly higher in PM implants (P=.006). The lowest BoP scores were detected in PS implants, but the difference was not significant (P=.523). The relation between PPD and connection type revealed no statistically significant influence (P>.05). Conclusion. Within the limitations of the present study, it may be concluded that PS implants seem to show better peri-implant soft tissue conditions and cause less MBL.

• The Journal of the Korean dental association
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• v.50 no.3
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• pp.118-125
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• 2012

CAD/CAM systems (computer-aided design / computer-aided manufacturing) used for decades in restorative dentistry have its application to implant dentistry. This study aimed to overview CAD/CAM systems used implant dentistry, especially emphasizing custom implant abutments manufacturing. CAD/CAM custom abutments present the advantages of being specific to each patient and providing a better fit than the stock and cast custom abutments. This cutting edge technology of virtual-designed and computer-milled implant abutments will likely replace traditional implant restorative protocols and become the standard for implant dentistry in the foreseeable future.

• The Journal of Advanced Prosthodontics
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• v.12 no.5
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• pp.316-321
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• 2020

PURPOSE. The stress distribution and microgap formation on an implant abutment structure was evaluated to determine the relationship between the direction of the load and the stress value. MATERIALS AND METHODS. Two types of three-dimensional models for the mandibular first molar were designed: bone-level implant and tissue-level implant. Each group consisted of an implant, surrounding bone, abutment, screw, and crown. Static finite element analysis was simulated through 200 N of occlusal load and preload at five different load directions: 0, 15, 30, 45, and 60°. The von Mises stress of the abutment and implant was evaluated. Microgap formation on the implant-abutment interface was also analyzed. RESULTS. The stress values in the implant were as follows: 525, 322, 561, 778, and 1150 MPa in a bone level implant, and 254, 182, 259, 364, and 436 MPa in a tissue level implant at a load direction of 0, 15, 30, 45, and 60°, respectively. For microgap formation between the implant and abutment interface, three to seven-micron gaps were observed in the bone level implant under a load at 45 and 60°. In contrast, a three-micron gap was observed in the tissue level implant under a load at only 60°. CONCLUSION. The mean stress of bone-level implant showed 2.2 times higher than that of tissue-level implant. When considering the loading point of occlusal surface and the direction of load, higher stress was noted when the vector was from the center of rotation in the implant prostheses.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.2
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• pp.192-209
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• 2004

Purpose : The purpose of this study was to evaluate the machining accuracy and consistency of implant/abutment/screw combination or internal connection type. Material and methods: In this study, each two randomly selected internal implant fixtures from ITI, 3i, Avana, Bicon, Friadent, Astra, and Paragon system were used. Each abutment was connected to the implant with 32Ncm torque value using a digital torque controller or tapping. All samples were cross-sectioned with grinder-polisher unit (Omnilap 2000 SBT Inc) after embeded in liquid unsaturated polyester (Epovia, Cray Valley Inc). Then optical microscopic and scanning electron microscopic(SEM) evaluations of the implant-abutment interfaces were conducted to assess quality of fit between the mating components. Results : 1) Generally, the geometry of the internal connection system provided for a precision fit of the implant/abutment into interface. 2) The most precision fit of the implant/abutment interface was provided in the case of Bicon System which has not screw. 3) The fit of the implant/abutment interface was usually good in the case of ITI, 3I and Avana system and the amount of fit of the implant/abutment interface was similar to each other. 4) The fit of the implant/abutment interface was usually good in the case of Friadent, Astra and Paragon system. The case of Astra system with the inclined contacting surface had the most Intimate contact among them. 5) Amount of intimate contact in the abutment screw thread to the mating fixture was larger in assembly with two-piece type which is separated screw from abutment such as Friadent, Astra and Paragon system than in that with one-piece type which is not seperated screw from abutment such as ITI, 3I and Avana system. 6) Amount of contact in the screw and the screw seat of abutment was larger in assembly of Friadent system than in asembly of Astra system of Paragon system. Conclusion: Although a little variation in machining accuracy and consistency was noted in the samples, important features of all internal connection systems were the deep, internal implant-abutment connections which provides intimate contact with the implant walls to resist micro-movement, resulting in a strong stable interface. From the results of this study, further research of the stress distribution according to the design of internal connection system will be required.

• The Journal of Advanced Prosthodontics
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• v.9 no.4
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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.

• The Journal of the Korean dental association
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• v.56 no.11
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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.

• Journal of Technologic Dentistry
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• v.32 no.4
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• pp.317-325
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• 2010

Purpose: The aim of this study is to make some basic materials to find retention force difference based on the total height of CAD/CAM zirconia abutment used for implant, retention force difference based on how to regulate the height of the abutment, retention force difference based on the size and retention force difference based on the design group. Methods: The retention force was measured by being pulled at the speed of 1mm/min after being combined with zirconia block and abutment using Temp-BOND of Kerr. The experiment was done at the research lab of OSTEM in Busan by useing UNIVERSAL TESTING MACHINE on March 3rd, 2010. Results: After analysing the total height and the retention force, p-value had minor difference by 0.01 statistically. Namely, 3mm, 4mm, 5mm had the retention force difference and we could see retention force difference on 3mm and 5mm at the post test. After analyzing how to regulate the height and retention force, p-value had minor difference by 0.000 statistically. Namely, 1mm and 2mm had the retention difference and we could see that 1mm and 2mm with the total height had retention difference. After analyzing the retention force based on the size, p-value had minor retention force difference by 0.000 statistically. Namely, 7 different size had retention force difference and we could see the size 21.9mm, 32.9mm, 32.9mm, 38.4mm, 48.9mm and 54.9mm had retention force difference. Conclusion: Namely 9 different design group had retention difference and we could see that 9 design group with 5.6.7.8 design group and 9 design group with 1.2.3.4. design group had retention force.