• The Journal of Korean Academy of Prosthodontics
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• v.53 no.4
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• pp.345-351
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• 2015

Purpose: The purpose of this study was to evaluate the proper axial thickness of zirconia abutment applied to implant in the anterior region. Materials and methods: Zirconia abutments were prepared at different axial wall thickness by processing pre-sintered zirconia blocks via CAD/CAM to obtain equal specimens. The abutments were each produced with a thickness of 0.5 mm (Group 1), 0.8 mm (Group 2), 1.2 mm (Group 3), or 1.5 mm (Group 4). The implant used in this study was a external connection type one (US, Osstem, Pussan, Korea) product and the zirconia abutment was prepared via replication of a cemented abutment. The crowns were prepared via CAM/CAM with a thickness of 1.5 mm and were cemented to the abutments using $RelyX^{TM}$ UniCem cement. A universal testing machine was used to apply load at 30 degrees and measure fracture strength of the zirconia abutment. Results: Fracture strength of the abutments for Group 1, Group 2, Group 3, and Group 4 were $236.00{\pm}67.55N$, $599.00{\pm}15.80N$, $588.20{\pm}33.18N$, and $97.83{\pm}98.13N$, respectively. Group 1 showed a significantly lower value, as compared to the other groups (independent Mann-Whitney U-test. P<.05). No significant differences were detected among Group 2, Group 3, and Group 4 (independent Mann-Whitney U-test. P>.05). Conclusion: Zirconia abutment requires optimal thickness for fracture resistance. Within the limitation of this study, > 0.8 mm thickness is recommended for zirconia abutment in anterior implants.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.2
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• pp.179-190
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• 2012

The installation of an implant in the distal extension area to assist a partial dentrue (IARPD) was used carefully in clinical situations. The purpose of this review on the IARPD is describing the concept, clinical results and guidelines of IARPD. For the review, a literature search was performed using the PubMed. The data from the literature suggest that the placement of the implants could improve function and patient satisfaction. In addition, IARPD reduced the residual ridge resorption. Longer and wider implant should be placed. Less than $15^{\circ}$ angulation may be not harmful. To prevent the loosening of the abutment, modified abutment or resilient attachment should be used. However, the connection method between the clasp retention and IARPD should be considered for long time success. Moreover, longitudinal clinical studies are required for evaluation of IARPD.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.4
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• pp.250-259
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• 2023

The use of digital technology in fixed prosthetic treatment using implants enables predictive treatment through diagnosis and virtual surgery by integrating clinical and radiological information of patients. Existing digital scanning methods require several components to be removed, such as removing the healing abutment and connecting the scan body. In the scannable healing abutment developed in consideration of this point, scanning is performed directly on the healing abutment, maintaining soft tissue sealing and simplifying scanning. Digital technology can also be used when obtaining the intermaxillary relationship. Recently, various digital technologies have been reported to acquire the intermaxillary relationship of edentulous patients using surgical guides, patient-specific scanning devices, or scans of the inside of temporary dentures. In this case, the implant-supported fixed prosthesis treatment was performed through scanning the scannable healing abutment and the inner side of the temporary denture to obtain the intermaxillary relationship, thereby simplifying the treatment process and obtaining aesthetically and functionally excellent clinical results.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.3
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• pp.189-198
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• 2017

Purpose: This study aims to analyze the stress distribution of mandibular molar restoration supported by the implants with external hex and internal taper abutment connection design. Materials and Methods: Models of external connection (EXHEX) and internal connection (INCON) implants, corresponding abutment/crowns, and screws were developed. Supporting edentulous mandibular bony structures were designed. All the components were assembled and a finite element analysis was performed to predict the magnitude and pattern of stresses generated by occlusal loading. A total of 120 N static force was applied both by axial (L1) and oblique (L2) direction. Results: Peak von Mises stresses produced in the implants by L2 load produced 6 - 15 times greater than those by L1 load. The INCON model showed 2.2 times greater total amount of crown cusp deflection than the EXHEX model. Fastening screw in EXHEX model and upside margin of implant fixture in INCON model generated the peak von Mises stresses by oblique occlusal force. EXHEX model and INCON model showed the similar opening gap between abutment and fixture, but intimate sealing inside the contact interface was maintained in INCON model. Conclusion: Oblique force produced grater magnitudes of deflection and stress than those by axial force. The maximum stress area at the implant was different between the INCON and EXHEX models.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.4
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• pp.301-309
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• 2015

Purpose: The aim of this study was to evaluate the clinical performance of screw- and cement-retained implant prosthesis (SCP) design in terms of retained preload of abutment screws and cement washout. Materials and methods: Patients with the partial posterior edentulous areas comprised the study group. Implants were placed, and SCPs were delivered after 3 to 6 months healing. Follow-up examinations were performed. The implant survival rate and the prosthetic success rate were evaluated. The retained preload ratio of abutment screws and the prosthetic decementation ratio were measured. Results: Twenty one SCPs (forty three implants)in twenty patients were followed up to 64 months. All of the implants survived during the follow-up period (mean follow-up: 34 months). The prosthetic success rate was 100 % considering no abutment, screw, porcelain or metal frame fractures, as well as no screw loosening. The retained preload ratio of SCPs at the end of follow-up period was 97.61% (${\pm}16.29$) and the decementation ratio was 9.5 %. Conclusion: Within the limitations of this clinical study, SCP design showed favorable short-term clinical performances in respect of screw loosening and cement washout.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.3
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• pp.259-267
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• 2014

Fatigue tests were performed in various simulated body environments reflecting various factors (such as body fluids, artificial saliva) relevant within a living body. First, the fatigue limit under a simulated body environment (artificial saliva) was evaluated and the governing factors of implant fatigue strength were looked into by observing the fracture mode. The fatigue life of an implant decreased in the artificial saliva environment compared with that in the ringer environment. Furthermore, in the artificial saliva environment, the implant fracture mode was fatigue failure of fixture as opposed to the abutment screw mode in the ringer environment. In the fatigue test, corrosion products were observed on the implant in the simulated body environment. A larger amount of corrosion products were generated on the artificial saliva specimen than on the ringer specimen. It is thought that the stronger corrosion activity on the artificial saliva specimen as compared with that on the ringer specimen led to an overall decrease of fatigue life of the former specimen. In the case of the implant with a nitrided abutment screw eliminated hardened layer (TixN), a several times increase in fatigue life is achieved in comparison with tungsten carbide-coated implants.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.4
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• pp.299-306
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• 2017

In this case report, immediate loading of an implant-supported single-tooth prosthesis through complete digital workflow. A patient presented for restoration of missing a single tooth in the mandibular first molar. The digital impression was made with intraoral scanner and implant was placed using surgical guide pre-fabricated with pre-operative computed tomography (CT) and scan data. After 1 week later, prefabricated customized abutment and provisional restoration were connected for immediate loading. After 8 weeks later, abutment level impression was taken by intraoral scanner. At 3 months later from implant installation, monolithic zirconia crown were fabricated. This clinical report presents satisfying result in accuracy and patient satisfaction. A completely modeless digital procedure met expectations regarding precision, esthetics, and functionality.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.2
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• pp.119-126
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• 2012

State of problem: Cement-retained implant-supported prostheses are routinely used in dentistry. The use of high strength cements has become more popular with the increasing confidence in the stability of the implant-abutment screw connection and the high survival rates of osseointegrated implants. No clinical data on retention of metal copings using CAD/CAM. To evaluate retention of metal copings using CAD/CAM system bonded to short titanium abutment with four different cements and compare retentive strength of metal copings with sandblasting or without sandblasting before cementation. Forty titanium abutment blocks were fabricated and divided into 4 groups of 10 samples each. Forty metal copings with occlusal hole to allow for retention testing were fabricated using CAD/CAM technology. The four cements were Fujicem(Fuji, Japan), Maxcem Elite(Kerr, USA), Panavia F2.0(Kurarary, Japan) and Superbond C&B(Sunmedical, Japan). The copings were cemented on the titanium abutment according to manufacture's recommendation. All samples were stored for 24h at 37oC in 100% humidity and tested for retention using universal testing machine(Instron) at a crosshead speed of 1.0mm/min. Force at retentive failure was recorded in Newton. The mode of failure was also recorded. Means and standard deviations of loads at failure were analyzed using ANOVA and Paired t-test. Statistical significance was set at P<0.05. Panavia F2.0 provided significantly higher retentive strength than Fujicem, Maxcem Elite(P<0.05). Sandblasting significantly increased bond strength(P<0.05). The mode of failure was cement remaining principally on metal copings. Within the limitation of this study, Panavia F2.0 showed significantly stronger retentive strength than Fujicem, Maxcem Elite(p<0.05). The Ranking order of the cements to retain the copings was Panavia F2.0, Fujicem = Maxcem Elite. Sandblasting significantly increased bond strength(P<0.05). The retentive strength of metal copings on implant abutment were influenced by surface roughness and type of cements.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.3
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• pp.245-256
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• 2023

When restoring with a dental digital system for implant-supported prosthesis, a double digital scanning technique is required: an intraoral scan of the three-dimensional implant location and intraoral scan after placement of temporary denture or provisional prosthesis. During the intraoral scan, the use of scan body as a stable landmark can improve the accuracy of digital impression and simplify laboratory process. In this case, a full-digital system was used to plan and fabricate a custom abutment, provisional prosthesis, and definitive prosthesis. After implant placement, the scan area of the intraoral scan body connected with implant and the intraoral scan body marked on the inside of temporary denture were superimposed. Out of the superimposed files, a custom abutment and provisional prosthesis were fabricated which match the vertical dimension of temporary denture, and definitive prosthesis was fabricated based on provisional prosthesis. We report this case because result has been functionally and esthetically satisfactory by using vertical dimension and central relation set during the fabrication of temporary denture to the definitive prosthesis.

• 대한치주과학회:학술대회논문집
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• 2005.11a
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• pp.212-212
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• 2005