• The Journal of the Korean dental association
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• v.47 no.4
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• pp.184-190
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• 2009

OBJECTIVE The purpose of clinical study was to evaluate the survival of dental implants used in restoring patients with implant supported removable partial dentures (ISRPDs) of different configurations. MATERIALS AND METHODS The sample consisted of 20 consecutively treated partially edentulous patients, who, between 2003 and 2008, had a total of 84implants placed in different arch sites and who were treated with ISRPDs. The mean age was 57 years. Mean follow up time from delivery of ISRPDs was 3 years 2 months (range, 1 to 6 years). Osseointegration failure, postoperative complication of dental prosthesis, and the success rate of ISRPDs were retrospectively evaluated using clinical and radiographic examination. RESULT The overall implant survival rate was 100%. During follow up, the one clasp of removable partial denture was broken in 1 year11 months after prosthesis delivery. All patients were satisfied with their prosthesis. CONCLUSIONS Implant supported removable partial dentures could serve as favorable prognosis. Careful patient selection, with an appropriate maintenance and recall system, is recommended to obtain satisfactory results.

• Journal of Korean Dental Science
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• v.16 no.1
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• pp.1-8
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• 2023

Dental treatment for the disabled should be a customized that considers the characteristics and degree of cooperation of each disabled patient. There are additional considerations during implant treatment and tooth extraction in disabled patients. Since some brain lesion disorder or cardiac disease patients may be taking antiplatelet or anticoagulant medications, it is necessary to evaluate whether these medications should be discontinued before an invasive procedure. Precautions should be taken for patients with heart valve disease considering the risk of infective endocarditis, especially during invasive dental procedures. Moreover, disabled patients may have difficulty in following instructions and cautions. There are specific considerations for each stage of implant treatment in disabled patients. In the case of patients who are in the pre- or post-transplant state, it is necessary to assess their general condition and oral disease due to the risk of infection. Since disabled patients with various systemic diseases may visit the dental clinic, it is important to understand their characteristics and treatment process in order to flexibly adjust the dental treatment plan accordingly.

• Korean Journal of Computational Design and Engineering
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• v.20 no.4
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• pp.348-356
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• 2015

It is important to devise methods for assisting dentists to consistently determine implant positions and directions and to accurately perform drilling tasks during dental implant surgery. In this paper, we propose a novel approach to tooth implant placement planning which deals with the determination of the positions and directions of multiple implant fixtures for a set of missing mandibular teeth and suggests the selection of the sizes and types of the implant fixtures. We combine Korean standard data in the sizes and positions of human teeth with the patient specific 3D models of mandibular jawbones, nerve curves, and neighboring teeth around the missing teeth in order to determine the positions and directions of the implant fixtures for the missing teeth. Using the geometric and spatial information of the jawbones, the teeth and the implant fixtures, we can construct the 3D models of surgical guide stents which are crucial to perform drilling tasks with ease and accuracy. Adopted in 3D simulation of dental implant placement, the approach can provide surgeon students with good educational contents. We also expect that, with further work, the approach can be used as a useful tool to plan for dental implant surgery.

• The Journal of Advanced Prosthodontics
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• v.13 no.2
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• pp.79-88
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• 2021

Purpose. To assess peri-implant stress distribution using finite element analysis in implant supported fixed partial denture with occlusal schemes of cuspally loaded occlusion and implant protected occlusion. Materials and methods. A 3-D finite element model of mandible with D2 bone with partially edentulism with unilateral distal extension was made. Two Ti alloy identical implants with 4.2 mm diameter and 10 mm length were placed in the mandibular second premolar and the mandibular second molar region and prosthesis was given with the mandibular first molar pontic. Vertical load of 100 N and and oblique load of 70 N was applied on occlusal surface of prosthesis. Group 1 was cuspally loaded occlusion with total 8 contact points and Group 2 was implant protected occlusion with 3 contact points. Results. In Group 1 for vertical load, maximum stress was generated over implant having 14.3552 Mpa. While for oblique load, overall stress generated was 28.0732 Mpa. In Group 2 for vertical load, maximum stress was generated over crown and overall stress was 16.7682 Mpa. But for oblique load, crown stress and overall stress was maximum 22.7561 Mpa. When Group 1 is compared to Group 2, harmful oblique load caused maximum overall stress 28.0732 Mpa in Group 1. Conclusion. In Group 1, vertical load generated high implant stress, and oblique load generated high overall stresses, cortical stresses and crown stresses compared to vertical load. In Group 2, oblique load generated more overall stresses, cortical stresses, and crown stresses compared to vertical load. Implant protected occlusion generated lesser harmful oblique implant, crown, bone and overall stresses compared to cuspally loaded occlusion.

• The Journal of Advanced Prosthodontics
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• v.14 no.4
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• pp.223-235
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• 2022

PURPOSE. To compare the clinical outcomes of two types of implant restoration for posterior edentulous area, 3-unit bridge supported by 2 implants and 3 implant-supported splinted crowns. MATERIALS AND METHODS. The data included 127 implant-supported fixed restorations in 85 patients: 37 restorations of 3-unit bridge supported by 2 implants (2-IB), 37 restorations of 3 implant-supported splinted crowns (3-IC), and 53 single restorations (S) as controls. Peri-implantitis and mechanical complications that occurred for 14 years were analyzed by multivariable Cox regression model. Kaplan-Meier curves and the multivariable Cox regression model were used to analyze the success and survival of implants. RESULTS. Peri-implantitis occurred in 28.4% of 2-IB group, 37.8% of 3-IC group, and 28.3% of S control group with no significant difference. According to the implant position, middle implants (P2) of the 3-IC group had the highest risk of peri-implantitis. The 3-IC group showed a lower mechanical complication rate (7.2%) than the 2-IB (16.2%) and S control group (20.8%). The cumulative success rate was 52.8% in S (control) group, 62.2% in 2-IB group, and 60.4% in 3-IC group. The cumulative survival rate was 98.1% in S (control) group, 98.6% in 2-IB group, and 95.5% in 3-IC group. There was no significant difference in the success and survival rate according to the restoration type. CONCLUSION. The restoration type was not associated with the success and survival of implants. The risk of mechanical complications was reduced in 3 implant-supported splinted crowns. However, the middle implants of the 3 implant-supported splinted crowns had a higher risk of peri-implantitis.

• Journal of Technologic Dentistry
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• v.40 no.1
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• pp.41-47
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• 2018

Purpose: The purpose of this study was to analyze the biomechanical properties of the dental implants on the supporting bone using three-dimensional finite element method when three different abutment materials were applied to the implant system. Methods: Three different dental implant models were fabricated by applying Ti, PEEK, and CRE-PEEK (60% carbon-reinforced PEEK) to abutment material. The abutment and connecting screw from the fixture was applied with a tightening torque of 20 Ncm. And then, total loads of 150 N were applied in an $30^{\circ}oblique$ direction (to the vertical). The structural stability of dental implants on the supporting bone was analyzed using Von Mises stress and principal stress values. Results: The maximum tensile stress of the cortical bone was highest at 12.6 MPa in the PEEK abutment (Model-B). Ti abutment (Model-A) and CRE-PEEK abutment (Model-C) showed similar stress distributions (10.6 and 10.3 MPa, respectively). And the maximum compressive principal stress was similar in all models. The Von Mises stress value delivered to the bone around the implant was highest at 16.5 MPa in Model-B. On the other hand, Model-A and C showed similar stress distributions (14.0 and 13.8 MPa, respectively). In addition, the maximum equivalent stress applied to the abutment was highest at 629.8 MPa in Model-A. The stress distribution in Model-C was 573.9 MPa. Whereas, Model-B showed the lowest value at 165.6 MPa. Conclusion : The dental implant supporting bone system using PEEK material seems to have the possibility of supporting bone fracture. It was found that the CRE-PEEK abutment can reduce the elastic deformation and reduce the stress value of the interfacial bone.

• The Journal of the Korean dental association
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• v.48 no.3
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• pp.205-217
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• 2010

Purpose The aim of this study is to evaluate the survival rates and analyze the stability of lateral approach and trans-crestal approach for maxillary sinus floor elevation of simultaneous implant placement. Materials and method 407 patients who have been treated in LivingWell dental hospital between 2003 to 2009 were selected. Lateral window technique, osteotome technique and sinus drill technique were used for sinus floor elevation procedure. A total of 714 implants-MP-1 HA coated implant(Tapered Screw $Vent^{TM}$, $Spline^{TM}$, Zimmer, USA), FBR surfaced implant(Pitt-$Easy^{TM}$, Oraltronics, Germany)-were placed in grafted maxillary sinus simultaneously. The autogenous bone or a combination with the allograft or alloplast was grafted into sinus. Sinus floor elevation was combined with vertical/horizontal onlay bone grafts to reconstruct the defect of alveolar ridge. Results The average preoperative height of the maxillary alveolar bone was 5.78mm(range: 0.4mm~12.5mm). 14 implants failed during the healing period(lateral approach: 4, trans-crestal approach: 10) and 3 implant failed after prosthetic loading(lateral approach: 2, trans-crestal approach: 1). The cumulative survival rate of implants after 6 years was 97.6%. Trans-crestal approach(97.4%) and lateral approach(97.9%) had similar survival rates. Conclusion The results indicate that the trans-crestal approach and lateral approach for maxillary sinus elevation is a acceptable method at atrophic maxillary posterior area.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.5
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• pp.260-266
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• 2019

Objectives: Dental implants shorter than 8 mm, called short dental implants (SDIs), have been considered to have a lower success rate than standard length implants. But recent studies have shown that SDIs have a comparable success rate, and implant diameter was more important for implant survival than implant length. Also, SDIs have many advantages, such as no need for sinus lifting or vertical bone grafting, which may limit use in medically compromised patients. Materials and Methods: In this study, 33 patients with 47 implants 7-mm long were examined over the last four years. All patients had special medical history and were categorized into 3 groups: systemic disorders, such as diabetes mellitus (controlled or uncontrolled), mental disability, and uncontrolled hypertension; oral cancer ablation with reconstruction, with or without radiotherapy; diverse osteomyelitis, such as osteoradionecrosis and bisphosphonate-related osteonecrosis of the jaw. Most of these patients have insufficient residual bone quality due to mandible atrophy or sinus pneumatization. Results: The implant diameters were 4.0 (n=38), 4.5 (n=8), and 5.0 mm (n=1). Among the 47 implants placed, 2 implants failed before the last followup. The survival rate of 7-mm SDIs was 95.74% from stage I surgery to the last follow-up. Survival rates did not differ according to implant diameter. The mean marginal bone loss (MBL) at 3 months, 1 and 2 years was significantly higher than at implant installation, and the MBL at 1 year was also significantly higher than at 3 months. MBL at 1 and 2 years did not differ significantly. Conclusion: Within the limitations of the present study, the results indicate that SDIs provide a reliable treatment, especially for medically compromised patients, to avoid sinus lifting or vertical bone grafting. Further, long-term follow-up is needed.

• The Journal of Advanced Prosthodontics
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• v.4 no.3
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• pp.158-161
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• 2012

PURPOSE. The aim of the present study was to evaluate if a smaller morse taper abutment has a negative effect on the fracture resistance of implant-abutment connections under oblique compressive loads compared to a conventional abutment. MATERIALS AND METHODS. Twenty morse taper conventional abutments (4.8 mm diameter) and smaller abutments (3.8 mm diameter) were tightened (20 Ncm) to their respective implants ($3.5{\times}11$ mm) and after a 10 minute interval, implant/abutment assemblies were subjected to static compressive test, performed in a universal test machine with 1 mm/min displacement, at $45^{\circ}$ inclination. The maximum deformation force was determined. Data were statistically analyzed by student t test. RESULTS. Maximum deformation force of 4.8 mm and 3.8 mm abutments was approximately 95.33 kgf and 95.25 kgf, respectively, but no fractures were noted after mechanical test. Statistical analysis demonstrated that the evaluated abutments were statistically similar (P=.230). CONCLUSION. Abutment measuring 3.8 mm in diameter (reduced) presented mechanical properties similar to 4.8 mm (conventional) abutments, enabling its clinical use as indicated.

• Journal of Technologic Dentistry
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• v.44 no.3
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• pp.67-75
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• 2022

Purpose: This study aimed to comparatively evaluate the stress distribution of bones surrounding the implant system to which both titanium and polyetheretherketone (PEEK) abutments are applied using a three-dimensional finite element analysis. Methods: The three-dimensional implant system was designed by the computer-aided design program (CATIA; Dassault Systemes). The discretization process for setting nodes and elements was conducted using the HyperMesh program (Altair), after finishing the design of each structure for the customized abutment implant system. The results of the stress analysis were drawn from the Abaqus program (Dassault Systèmes). This study applied 200 N of vertical load and 100 N of oblique load to the occlusal surface of a mandibular first molar. Results: Under external load application, the PEEK-modeled dental implant showed the highest von Mises stress (VMS). The lowest VMS was observed in the Ti-modeled abutment screws. In all groups, the VMS was observed in the crestal regions or necks of implants. Conclusion: The bones surrounding the implant system to which the PEEK abutment was applied, such as the cortical and trabecular bones, showed stress distribution similar to that of the titanium implant system. This finding suggests that the difference in the abutment materials had no effect on the stress distribution of the bones surrounding implants. However, the PEEK abutments require mechanical and physical properties improved for clinical application, and the clinical application is thought to be limited.