• The Journal of Korean Academy of Prosthodontics
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• v.46 no.6
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• pp.634-638
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• 2008

PURPOSE: The application of computer-aided technology to implant dentistry has created new opportunities for treatment planning, surgery and prosthodontic treatment, but the correct selection and combination of available methods may be challenging in times. Hence, the purpose of this case report is to present a combination of several computer-aided tools as approaches to manage complicated implant case. MATERIAL AND METHODS: A 47 year-old female patient with severe dental anxiety, high expectations, financial restrictions and poor compliance presented for a fixed rehabilitation. A CT scan with a radiographic template obtained with software (SimPlant, Materialize, Leuven, Belgium) was used for treatment planning. The surgical plan was created and converted into a stereolithographic model of the maxilla with bone-supported surgical templates (SurgiGuide, Materialise, Leuven, Belgium), that allowed for the precise placement of 7 implants in a severely resorbed edentulous maxilla. After successful osseointegration, an accurate scan model served as the basis for the fabrication of a one-piece milled titanium framework using the Procera (Nobel Biocare, Gothenburg, Sweden) technology. The final rehabilitation of the edentulous maxilla was rendered in the form of a screw-retained maxillary metal-reinforced resin-based complete prosthesis. RESULTS: Despite challenging circumstances, 7 implants could be placed without bone augmentation in a severely resorbed maxilla using the SimPlant software for pre-implant analysis and the SurgiGuide-system as the surgical template. The patient was successfully restored with a fixed full arch restoration, utilizing the Procera system for the fabrication of a milled titanium framework.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.8
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• pp.984-991
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• 2011

The aim of this study is to develop a humeral Intramedullary fixation nail (HIFN) suitable for Korean people. In this study, CT images were obtained from 72 Korean cadaveric humeral bones and 3D Korean humeral bone models were reconstructed based on the CT images to investigate anatomical characteristics. Major design parameters of HIFN were selected using the morphological measurement information of the Korean humeral bone models. Through finite element analysis and mechanical tests, the developed HIFN prototype was compared with the Polarus HIFN ($ACUMED^{(R)}$, USA), and it was found that the HIFN prototype showed similar and/or superior mechanical performance compared to the Polarus HIFN. Also, clinical validation for the HIFN prototype was carried out to check predictable troubles in surgical operations. Finally, optimal design modification was proposed to prevent the possible axillary nerve injury due to the locking screw system of the HIFN prototype.

• Journal of Korean Neurosurgical Society
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• v.52 no.1
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• pp.21-26
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• 2012

Objective : To evaluate a new posterior atlantoaxial fixation technique using a nitinol shape memory loop as a simple method that avoids the risk of vertebral artery or nerve injury. Methods : We retrospectively evaluated 14 patients with atlantoaxial instability who had undergone posterior C1-2 fusion using a nitinol shape memory loop. The success of fusion was determined clinically and radiologically. We reviewed patients' neurologic outcomes, neck disability index (NDI), solid bone fusion on cervical spine films, changes in posterior atlantodental interval (PADI), and surgical complications. Results : Solid bone fusion was documented radiologically in all cases, and PADI increased after surgery (p<0.05). All patients remained neurologically intact and showed improvement in NDI score (p<0.05). There were no surgical complications such as neural tissue or vertebral artery injury or instrument failure in the follow-up period. Conclusion : Posterior C1-2 fixation with a nitinol shape memory loop is a simple, less technically demanding method compared to the conventional technique and may avoid the instrument-related complications of posterior C1-2 screw and rod fixation. We introduce this technique as one of the treatment options for atlantoaxial instability.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.3
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• pp.100-106
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• 2021

Typical implants are not specified the screw structure and the surface process according to the bone quality of the human body. The purpose of this study is to complement the shortcomings of the existing implant surface processing method. It is to propose a surface processing method that increases the adhesion between the implant and bone tissue by increasing the surface area per unit area of the implant. It is very important to establish precise and systematic process parameters when surface treatment of implants using lasers. Therefore, we intend to develop a process so that the implant can be a biocompatible structure using a Q-switching Nd:YAG laser with a wavelength of 1.06um. Implant surface treatment technology through this study will be used in the industry.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.31 no.2
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• pp.56-63
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• 2022

The mandibular 4 anterior incisor restoration has small teeth and a small space, so the choice of abutment is always a concern. The mandibular 4 anterior incisor extraction is caused by periodontal disease, interdental embrasure greatly open is advantageous of oral hygiene management. Try to make it small diameter with custom abutment, it is limited to the space for the screw. Rather than setting the post site of one body implant to a horizontal cross-section, it is advantageous to set it to a longitudinal cross-section, for interdental embrasure formation. When using an internal bone level implant, rather than using a two-piece abutment, using a one-piece abutment can more effectively secure space for interdental embrasure.

• Journal of Veterinary Clinics
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• v.23 no.3
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• pp.291-299
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• 2006

During long bone lengthening, there are many disadvantages including axial deviation, malalignment and re-fracture which are commonly encountered inspite of its proven abilities. To study the effects of intramedullary K-wire application on the lengthening of long bone, ten skeletally mature mongrel dogs were separated into two groups(Group I, II). Right femurs of group I(5 dogs) were fixed with only monolateral external fixator after subperiosteal osteotomy. Right femurs of group II(5 dogs) were fixed with mono lateral external fixator and intramedullary K-wire after subperiosteal osteotomy. Lengthening was started at 7 days after the surgery with the rate of 0.5 mm per day for 5 weeks and the dogs were sacrificed after 15 weeks postoperatively to examine histologic differences and evaluate bone mineral density. Radiographic examination at an interval of two weeks was done to evaluate the type of callus formed and to analyze complications including instability of external skeletal fixation and axial deviation. Bone mineral density at the lengthened area and contralateral nonlengthened area were measured using quantitative computerized tomography. Histological examination of regenerated bone was performed using Masson's trichrome stain method. The radiographs demonstrated poor callus formation, higher incidence of axial deviation and screw loosening in the group I compared to the group II. The bone mineral density at the lengthened area in the group II was higher than that of the group I(P<0.05). Histological examination showed that the new bone trabeculae in the group II were greater than that of the group I. In conclusion, the combination of monolateral external fixator and intramedullary K-wire can prevent pin loosening, axial deviation and reduce healing period in dogs.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.611-619
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• 2017

Objective : In addition to bone bridging inside a cage or graft (intragraft bone bridging, InGBB), extragraft bone bridging (ExGBB) is commonly observed after anterior cervical discectomy and fusion (ACDF) with a stand-alone cage. However, solid bony fusion without the formation of ExGBB might be a desirable condition. We hypothesized that an insufficient contact area for InGBB might be a causative factor for ExGBB. The objective was to determine the minimal area of InGBB by finite element analysis. Methods : A validated 3-dimensional, nonlinear ligamentous cervical segment (C3-7) finite element model was used. This study simulated a single-level ACDF at C5-6 with a cylindroid interbody graft. The variables were the properties of the incorporated interbody graft (cancellous bone [Young's modulus of 100 or 300 MPa] to cortical bone [10000 MPa]) and the contact area between the vertebra and interbody graft (Graft-area, from 10 to $200mm^2$). Interspinous motion between the flexion and extension models of less than 2 mm was considered solid fusion. Results : The minimal Graft-areas for solid fusion were $190mm^2$, $140mm^2$, and $100mm^2$ with graft properties of 100, 300, and 10000 MPa, respectively. The minimal Graft-areas were generally unobtainable with only the formation of InGBB after the use of a commercial stand-alone cage. Conclusion : ExGBB may be formed to compensate for insufficient InGBB. Although various factors may be involved, solid fusion with less formation of ExGBB may be achieved with refinements in biomaterials, such as the use of osteoinductive cage materials; changes in cage design, such as increasing the area of polyetheretherketone or the inside cage area for bone grafts; or surgical techniques, such as the use of plate/screw systems.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.5
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• pp.386-395
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• 2011

Introduction: Osteoporosis is a major health problem in the elderly that involves changes in the properties of bone as well as impaired bone healing around a titanium implant in both humans and animals. This study examined effect of low intensity pulsed ultrasound (LIPUS) on the bone healing process around a titanium implant in osteoporosis-induced rats. Materials and Methods: Sixteen rats were divided into two groups. A control group with osteoporosis induced by removing both ovaries and an experimental group of rats that were applied with LIPUS after osteoporosis had been induced. A screw type titanium implant (diameter, 2.0 mm: length, 3.5 mm, Cowell-Medi, KOREA) was placed into the tibias of 16 rats. The control and experimental group contained 8 rats each. The rats were sacrificed at 1, 2, 4, and 8 weeks after implantation to examine the histopathology and immunochemistry. Results: The histopathology examination revealed earlier new bone formation in the experimental group than the control group. In particular, at 1 week after implantation, more new bone matrix and collagen were observed around the implant of the experimental group compared to the control group. Immunochemistry analysis showed that the level of OPG expression of the experimental group was higher in the early stages than in the control group. After 8 weeks, the levels of OPG expression were similar in both groups. The expression level of receptor activator of nuclear factor kB ligand (RANKL) was stronger in the experimental group than the control group. After 4 weeks, the level of RANKL expression was similar in both groups. Conclusion: These results suggest that the application of LIPUS to implantation can promote bone healing around titanium in osteoporosis animals.

• Journal of Korean Orthopaedic Sports Medicine
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• v.5 no.1
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• pp.75-80
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• 2006

Purpose: To evaluate the efficiency of Acutrak screw fixation for radial head fracture (Mason type 2) without considering the safe Bone of radial head. Materials and Methods: Consecutive seven radial head fracture of Mason type II underwent internal fixation with Acutrak screws from May 2001 to February 2003. The mean follow-up period was 1.2years (ranged, $6 months{\sim}2.5 years$). The mean age of patients was 47 years old (ranged, $36{\sim}60years$ old). The cause of injury were fall down -4 cases and traffic accident -3 cases. The results were evaluated by Mayo Clinic results scoring system. Results: Functional Rating Index of Mayo Clinic was excellent- 2 cases and good- 5 cases. There were no nonunion, loosening, heterotopic ossification, infection or degenerative changes. The postoperative range of motion in elbow joint is nearly full for flexion, extension, pronation and supination in this study Conclusion: Consideration of safe zone is not necessary when Acutrak screws are used for radial head fracture. It seems to be a useful method that Acutrak screw fixation for radial head fracture (Mason type II) could achieve good radiologic and clinical results without influencing proximal radio-ulnar joint and has powerful fixation.

• The korean journal of orthodontics
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• v.36 no.5
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• pp.324-330
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• 2006

Objective: The purposes of this study were to evaluate the differences between sand blasted, large grit and acid-etched (SLA) treated mini-implants and smooth surface orthodontic mini-implants in relation to the removal torque as well as the histologic analysis. Methods: Custom-made, screw-shaped, titanium implants with a length of 9.5 mm and an outer diameter of 1.8 mm were divided into 2 groups; the SLA group (20 SLA treated orthodontic mini-implants) and the smooth surface group (20 smooth surface mini-implants), and placed In the tibia metaphysis of 10 rabbits. Each rabbit had 4 mini-implants placed, 2 in each tibia. The right tibia were implanted with the SLA group mini-implants and the left tibia had the smooth group mini-implants placed. Each mini-implant group were immediately applied with a continuous traction force of 150 g using a Ni-Ti coil spring. The rabbits were sacrificed 6 weeks post-surgically. Subsequently, the legs were stabilized, the Ni-Ti coil springs were removed and the mini-implants were removed under reverse torque rotation with a digital torque gauge. Results: 6 weeks after placement, the SIA group presented a higher mean removal torque value (8.29 Ncm) than the smooth group (3.34 Ncm) and histologic analysis revealed a higher new bone formation aspect along the screw in the SLA group. Conclusion: Results of this study indicates that SLA treated mini-implants may endure higher orthodontic forces without loosening.