• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.348-354
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• 2020

Purpose: Zirconia is differentiated from other ceramics because of its high resistance to corrosion and wear, excellent flexural strength (900~1400 MPa), and high hardness. Dental zirconia with proven mechanical/biological stability is suitable for the manufacture of implants. However, there are limited in vivo studies evaluating stress distribution in zirconia compared with that in titanium implants and studies analyzing finite elements. This study was conducted to evaluate the stress distribution of the supporting bone surrounding zirconia and titanium implants using the finite element analysis method. Methods: For finite element analysis, a single implant-supported restoration was designed. Using a universal analysis program, eight occlusal points were set in the direction of the occlusal long axis. The occlusal load was simulated at 700 N. Results: The zirconia implant (47.7 MPa) von Mises stress decreased by 5.3% in the upper cortical bone compared with the titanium implant (50.2 MPa) von Mises stress. Similarly, the zirconia implant (20.8 MPa) von Mises stress decreased by almost 4% in the cancellous bone compared with the titanium implant (21.7 MPa) von Mises stress. The principal stress in the cortical and cancellous bone exhibited a similar propensity to von Mises stress. Conclusion: In the supporting bone, the zirconia implant is able to reduce bone resorption caused by mechanically transferred stress. It is believed that the zirconia implant can be a potential substitute for the titanium implant by reinforcing aesthetic characteristics and improving stress distribution.

• Journal of Korean Foot and Ankle Society
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• v.21 no.1
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• pp.7-11
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• 2017

Purpose: We retrospectively analyzed the radiographic and clinical results after the first ray of forefoot osteotomy using low profile wedge plate without additional cancellous bone grafting for pes planus correction. Materials and Methods: Twenty-four patients were enrolled in this study. Medial cuneiform opening wedge osteotomy was performed in 12 patients (Cotton osteotomy, group C) and first metatarsal base osteotomy was performed in 12 patients (group MT). Results: On average, the wedge size was 5.61 mm (5~6 mm). The mean time to radiographic union was 3.18 and 3.27 months in groups C and MT, respectively. Postoperative talonavicular coverage angle, talo-first metatarsal angle (anteroposterior), talo-first metatarsal angle (lateral), talo-calcaneal angle (lateral), medial cuneiform height, and American orthopaedic foot, as well as ankle society midfoot scale were significantly improved in both groups. Nonunion, delayed union or fixation failure was not presented in our series. Conclusion: We have shown that low profile wedge plate was effective in the case of first ray forefoot osteotomy for pes planus correction without any additional cancellous bone grafting.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.373-376
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• 2002

Most previous studies using ultrasound for osteoporosis diagnosis have employed ultrasound in a frequency range of 0.2-1 MHz. In this study, acoustic properties of the 12 defatted bovine cancellous bone specimens were investigated in vitro. Speed of sound (SOS) and broadband ultrasonic attenuation (BUA) were measured using three matched pairs of transducers with the center frequencies of 1, 2.25, and 3.5 MHz, respectively, in order to cover a broad frequency range of 0.5-2 MHz. The relative orientation between ultrasonic beam and bone specimens was the mediolateral (ML) direction of the bovine tibia. SOS showed significant linear positive correlations with apparent density for all three pairs of transducers of 1 MHz, 2.25 MHz, and 3.5 MHz, respectively. BUA showed relatively weak correlations with apparent density for the pairs of transducers of 1 MHz and 2.25 MHz. Furthermore, in the measurement with the pair of 3.5 MHz transducers, BUA was independent of apparent density. SOS and BUA were only weakly correlated with each other. The linear combination of SOS and BUA showed significant correlations with apparent density. These results suggest that the frequency range up to 1.5 MHz may be also useful in the osteoporosis diagnosis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.7
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• pp.1103-1109
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• 2003

An adaptive bone remodeling is simulated by using the cellular automata (CA) method. It is assumed that bone tissue consist of bone marrow, osteoclast, osteoblast cell or osteoprogenitor cell. Two types of local rule are adopted; those are the metabolism rule and adaptive bone formation rule. The metabolism rule is based on the interactions of cells and the bone formation rule is based on the adaptation against the mechanical stimulus. The history of load and memory of mechanical stimulus are also considered in the local rules. As a result, the pattern of distribution of the bone tissue is dynamically adequate and it is similar to intact cancellous bone.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2197-2202
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• 2011

In this study, we propose a new short dental implant and investigate its bio-mechanical characteristics by using three dimensional finite element analyses. The proposed dental implant has the central cavity which can be integrated with the core of cancellous bone remained by trepanning drill. We take the Bicon short implant as a reference model for studying the effects according to the shape of cavity. The parametric finite element model using ANSYS APDL has been built to determine which length, diameter and thread of central cavity would be effective to dissipate stress. The reduction of undesirable stress in adjacent bone which can suppress bone defects and the eventual failure of implants. The numerical results shows that the cavity of well-determined shape has the beneficial effects on reducing the bone absorption in cancellous bone.

• The Journal of Korean Obstetrics and Gynecology
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• v.15 no.4
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• pp.17-31
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• 2002

Objective : This study was carried out to investigate the effects of the hormones and cytokines associated with bone metabolism in ovariectomized rats. Method : Twenty-four Female-Sprague-Dawley rats were divided into sham operated(normal) group, ovariectomized(control)group, ovariectomized and treated with extract Caraganae Sinicae Radix(treated) group. Each group was investigated the changes of body weight at 3,5,7weeks after treatment, and femur weight, femur/body weight, thickness of compact bone of body of femur, area of cancellous bone of distal epiphysis of femur, serum estrogen, serum calcitonin, serum parathormone, serum Tumor Necrosis $Factor-{\alpha}$, serum $lnterleukin-1{\beta}$ at 7weeks after treatment. The results were summerized as follows; 1. The treated group showed significant change in body weight compared with the control group at 5,7weeks after treatment. 2. The treated group revealed significant increases in femur/body weight compared with the control group. 3. The treated group showed a little thicker compact bone of body of femur than the control group. 4. The area of cancellous bone of distal epiphysis of femur in treated group was increased significantly compared with control group. 5. The level of serum estrogen showed no change compared with control group. 6. The level of serum calcitonin showed no change compared with control group. 7. The level of serum parathormone was decreased in treated group significantly compared with control group. 8. The level of serum $TNF-{\alpha}$ was decreased in treated group significantly compared with control group. 9. The level of serum $interleukin-1{\beta}$ showed no change compared with control group. The results indicate that Caraganae Sinicae Radix inhibits bones resorption in ovariectomized rats by it's lowering effects on serum parathormone and $TNF-{\alpha}$.

• Journal of Veterinary Clinics
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• v.30 no.2
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• pp.127-130
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• 2013

A 13-year-old, 4.2 kg female poodle was referred for failure of first bilateral mandibular surgery at a local animal hospital after pathologic fracture. Surgery was performed with 2.0-mm miniplates/screws and porcine cancellous bone grafts. In addition, because of the large size of the right segmental defect, a barrier absorbable membrane was employed for guide bone regeneration on right mandible. After surgery, follow-ups performed at 1 day, 1, 4, 8, and 12 weeks; there were no signs of dental malocclusion, nonunion or soft tissue infection. However, a 1-year long-term follow-up showed nonunion in the left mandibular fracture site for which a collagen membrane had not been used. It is considered that use of porcine bone graft with barrier absorbable membrane may be effective for the repair of mandibular nonunion in a geriatric dog.

• The Journal of the Korean bone and joint tumor society
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• v.10 no.1
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• pp.13-21
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• 2004

Purpose: We analyzed the result of autologous bone marrow stromal cell transplantation with or without cancellous chip bone allograft for benign long bone lesions. Materials and methods: Since July 1996, eight benign bone lesions treated by curettage, cancellous chip bone allograft and bone marrow or marrow stromal cell transplantation were observed for resolution of clinical symptoms, new bone formation and consolidation. There were 6 males and 2 females. Average age was 24 (range 8 to 47) years old. Histologic diagnoses were 5 fibrous dysplasia, 2 simple bone cysts and one chondroblastoma and fibrous cortical defect each. Mean follow-up period was 16.3 (range 3 to 84) months. Results: In all four symptomatic patients, the pain was subsided in two weeks after surgery. New bone formation in the lesion was observed at 4 weeks, which incorporated into surrounding normal bone around 8 weeks. There were one pathologic fracture through the lesion at 3 weeks and one recurrence of simple bone cyst at 5 months postoperatively. Conclusion: Bone marrow or marrow stromal cell transplantation for bone defects from curettage of benign bone lesions, with or without cancellous chip bone allograft revealed rapid healing. Though it was the result of short-term follow up, it supports that bone marrow stromal cell transplantation will be very useful for the treatment of benign long bone cysts or other lesions. The complete curettage of inner cystic wall is important to prevent later recurrence, and the rigid internal fixation is also needed in selected high risk lesions of fracture.

• Clinics in Shoulder and Elbow
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• v.20 no.1
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• pp.42-45
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• 2017

One of the most important factors leading to a successful healing of rotator cuff tear is good bone quality to secure the suture anchor in the bone for a stable fixation. However, rotator cuff tear are commonly found in elderly patients, and their proximal humerus often shows osteoporosis or cystic lesions. Especially when the transosseous repair prevails for a torn rotator cuff, a weak metaphyseal cancellous bone is often the case, which associated with difficulty in stable fixation of the lateral row suture anchor. In this situation, we were able to augment the lateral row fixation with polymethylmethacrylate bone cement. Although there is a concern of disturbance in the blood flow and healing potential, our case showed good clinical results with respect to healing. If we suspect a weak fixation of the lateral row suture anchor, bone cement seems to be a good option for augmentation.

• Archives of Plastic Surgery
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• v.38 no.3
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• pp.222-227
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• 2011

Purpose: Autogenous particulate bone grafting is a type of autogenous bone graft that consists of small particles of cortical and cancellous bone. Autogenous particulate bone grafting has been used for calvarial bone defect after calvarial defect of craniosynostosis and prevention of temporal depression after fronto-orbital advancement. The results were followed up and studied for effectiveness of autogenous calvarial particulate bone grafting. Methods: Cranial vault remodeling and fronto-orbital advancement was performed for six craniosynostosis patient from August 2005 to October 2007. Autogenous particulate bone grafting was harvested from endocortex of separated cranial vault and if insufficient, from extocortex of occipital region using Hudson brace & D'Errico craniotomy bit and was grafted on the calvarial bone defect of cranial vault and temporal hollow. Fibrin glues were added to the harvested particulated bone for adherence and shaping of paticles. Results: Autogenous particulate bone grafting was followed-up at least longer than I year. The calvarial bony defects following primary cranial remodeling were successfully covered and postoperative temporal depressions after fronto-orbital advancement were also well prevented by grafted particulated bone. Conclusion: Autogenous calvarial particulate bone graft can be harvested in infants and young children with minimal donor site morbidity. It effectively heals cranial defects in children and during fronto-orbital advancement reduces the prevalence of osseous defects independent of patient age. It's easy and effective method of reconstruction of calvarial defect.