• Korean Journal of Metals and Materials
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• v.49 no.12
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• pp.983-988
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• 2011

Failure analyses of the screws in spinal fixation devices were carried out. The fractured screws were retrieved from a patient who had spinal surgery in the thoracic vertebrae from number 10 to 15. The failure occurred one month after the removal of the braces. Microstructures and fracture surfaces were examined by optical and scanning electron microscopy. The microstructures of the screws corresponded to annealed Ti-6Al-4V bar. However, in the vicinity of the screw surface, there was an insufficient number of fine precipitates. Fracture surfaces showed typical fatigue failure modes. Regarding the fact that no machining defects were detected, fatigue crack initiation might have been caused by the lack of precipitates near the screw surfaces. Only the fourth of five fixed screws was severely stress-concentrated by the action of the spinal bones, while the stress of the 4th screw was decreased to half of its acceptable level when the screw was supplemented by one more, which might have been fixed in the 6th vertebra under the 5th position by the switching of its position. The stress simulation was conducted by ANSYS with 3D CAD of PRO/E in order to understand the stress concentration behavior and to provide an effective spinal surgery guide.

• Journal of the Korean Orthopaedic Association
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• v.56 no.4
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• pp.361-365
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• 2021

Pelvic fractures are high-energy injuries, often accompanied by damage to the adjacent tissues and organs. For patients with pelvic trauma, active treatment is required early in the injury, because mortality can increase if appropriate treatment is not provided. In most cases, however, minimally invasive surgery is considered because extensive surgery cannot be performed due to the patient's condition. Percutaneous fixation of the pubis has been introduced because it can be applied easily to achieve the stability of the anterior part of the pelvis. Although many studies introduced percutaneous fixation of pubic bone fractures, most describe screw fixation for nondisplaced fractures. When treating displaced fractures with percutaneous screw fixation, it is difficult for the guide pin or drill bit to avoid the joint surface. Using a bent guide pin could allow easy insertion of the cannulated screw while avoiding the articular surface.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.4
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• pp.329-340
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• 2006

Statement of problem: Damping of the peak force transmitted to implants has been reported by in vitro studies using impact forces on resin-veneered superstructures. Theoretical assumptions suggest that use of acrylic resin for the occlusal surfaces of a prosthesis would protect the connection between implant and bone. Therefore, the relationship between prosthesis materials and the force transmitted through the implant system also needs to be investigated under conditions that resemble the intraoral mechanical environment. Purpose: The purpose of this study was to analyze the fracture strength and modes of temporary prosthesis when a flange or occlusally extended structure were connected on the top of the abutment. Material and method: Modified abutments of winged and bulk design were made by casting the desired wax pattern which is made on the UCLA type plastic cylinder. Temporary crowns were made using templates on the modified abutments, and its fracture toughness and strain were compared to the traditional temporary prosthesis. To evaluate the effect of aging, 5.000 times of thermocycling were performed, and their result was compared to the 24hours specimen result. Results: The following conclusions were drawn from this study: 1. In the fracture toughness test, temporary crown's fracture line located next to the screw hole while modified designs with metal support showed fracture line on the metal and its propagation along the metal-resin interface. 2. Wing and bulk structure didn't show significant difference in the fracture toughness (p>0.05), but wing structure showed stress concentration on the screw hole area compared to bulk structure which showed even stress distribution. 3. In the fracture toughness test after thermocycling, wing and bulk structure showed increased or similar results in metal supported area while off-metal area and temporary crown showed decreased results. 4. In the strain measurement after thermocycling, its value increased in the temporary and bulk structure. However, wing structure showed decreased value in the loading point while increased value in the screw hole area. Conclusion: Wing type design showed compatible result to the bulk type that its application with composite resin prosthesis to the implant dentistry is considered promising.

• Archives of Plastic Surgery
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• v.35 no.3
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• pp.345-348
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• 2008

Purpose: Fracture of the frontal sinus accounts for 5-15% of all facial fractures. Only anterior table fracture occupies one third of the frontal sinus fracture. Conventional coronal approach is the standard treatment, but this method is very aggressive, especially in patient with simple, depressed, anterior frontal sinus wall fracture. We introduce new, simple technique for these patients, using small incision and Dual-top screws. Methods: A 27-year-old male patient was introduced to our department under the impression of fracture of frontal sinus, involving only anterior table. Under general anesthesia, 1.5 cm-sized, small incision was made on the suprabrow area. We reduced fractured fragment with two dual-top screws and 25G wires. Fixation was not necessary Results: The operation took about forty minutes, and the patient discharged 2 days after the operation. Postoperative 2 months follow up CT shows maintenance of reduction site. Gross depression of the forehead and visible scar was not observed. Conclusion: Although the indication of this procedure is limited, less aggressive, simple and very effective to the patient with simple. depressed, anterior frontal sinus fracture.

• Journal of Korean Foot and Ankle Society
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• v.19 no.1
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• pp.11-17
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• 2015

Purpose: To report the radiographic and clinical results of 6.5 mm cancellous full threaded buttress screw or Steinmann pin fixation to maintain a reduction of calcaneal posterior facet depression fracture. Materials and Methods: From June 2009 to June 2012, 50 consecutive cases with calcaneal joint depression fracture that underwent open reduction and screw or pin fixation were enrolled in this study. A 6.5 mm cancellous full threaded screw was inserted from the posteroinferior aspect of the calcaneal tuberosity to the posterior facet (group A) or Steinman pin was inserted from the posterosuperior aspect of the calcaneal tuberosity to the calcaneocuboidal joint (group B). Both preoperative and postoperative Bohler and Gissane angles were measured radiographically, and American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale on the final follow-up were assessed. Results: The mean age of patients was 44.1 years, and the mean follow-up period was 27.2 months. According to the Sanders classification, 28 cases were type II and 22 cases were type III. In Sanders type II, Bohler and Gissane angles improved significantly from $10.1^{\circ}$ and $126.2^{\circ}$ preoperatively to $27.2^{\circ}$ and $117.1^{\circ}$, respectively, in the immediate postoperative radiograph, and at the final follow-up, $26.6^{\circ}$ and $118.6^{\circ}$, respectively. In Sanders type III, Bohler and Gissane angles improved significantly from $5.0^{\circ}$ and $129.8^{\circ}$ to $29.9^{\circ}$ and $119.3^{\circ}$, respectively, in the immediate postoperative radiograph, and $26.9^{\circ}$ and $120.2^{\circ}$ at the final follow-up. All cases achieved bony union, and the average period until complete union was 13.3 weeks. AOFAS ankle-hindfoot scale was 82.6 in Sanders type II and 77.3 in Sanders type III at the final follow-up. Conclusion: A 6.5 mm cancellous full threaded buttress screw or Steinman pin fixation is a noninvasive treatment method with a merit of being able to maintain the bearing capacity of the posterior facet comparable to plate fixation.

• Clinics in Shoulder and Elbow
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• v.10 no.2
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• pp.212-219
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• 2007

Purpose: To determine the causes of the surgical treatment results in glenoid fracture by a retrospective analysis. Materials and methods: From March 1999 to February 2004, 9 patients who underwent an open reduction due to a glenoid fracture were reviewed. The modified Ideberg classification was used. There were 1, 3, 2, 1 and 2 cases of modified Ideberg type I, II, III, V, and VI, respectively. The internal fixators were a reconstruction plate, a small plate, a one-third tubular plate, a small screw, and a cannulated screw in 6, 1, 3, 3 and 1 case, respectively. The constant score and Adam's functional assessment method were used to evaluate the postoperative shoulder function. Results: The average time for fracture union was 7 weeks. The functional assessment was excellent in 4 cases, good in 3 cases, and fair in 2 cases. There were two complications related to surgery; articular screw encroachment, and inferior glenoid bone resorption without instability. Conclusion: A glenoid fracture with glenohumeral instability or displaced that was treated by open surgery showed good clinical results. Moreover, the more comminuted fracture had a lower functional score.

• Proceedings of the Korean Society of Veterinary Clinics Conference
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• 2009.10a
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• pp.248-248
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• 2009

• Imaging Science in Dentistry
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• v.43 no.3
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• pp.171-177
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• 2013

Purpose: The purpose of this study was to compare the efficacy of two imaging modes in a cone beam computed tomography (CBCT) system in detecting root fracture in endodontically-treated teeth with fiber posts or screw posts by selecting two fields of view. Materials and Methods: In this study, 78 endodontically-treated single canal premolars were included. A post space was created in all of them. Then the teeth were randomly set in one of 6 artificial dental arches. In 39 of the 78 teeth set in the 6 dental arches, a root fracture was intentionally created. Next, a fiber post and a screw post were cemented into 26 teeth having equal the root fractures. High resolution (HiRes) and standard zoom images were provided by a CBCT device. Upon considering the reconstructed images, two observers in agreement with each other confirmed the presence or absence of root fracture. A McNemar test was used for comparing the results of the two modes. Results: The frequency of making a correct diagnosis using the HiRes zoom imaging mode was 71.8% and in standard zoom was 59%. The overall sensitivity and specificity in diagnosing root fracture in the HiRes mode were 71.79% and 46.15% and in the standard zoom modes were 58.97% and 33.33%, respectively. Conclusion: There were no significant differences between the diagnostic values of the two imaging modes used in the diagnosis of root fracture or in the presence of root canal restorations. In both modes, the most true-positive results were reported in the post space group.

• Journal of the Korea Society of Computer and Information
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• v.12 no.5
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• pp.285-292
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• 2007

This study was developed the metallic plate for fixation in the femur fracture for the orthopedic region and rigid fixation with plates has a firm place in fracture treatment. Most plates can be used for rigid as well as biological and dynamical fracture fixation. The device's designation and sizing has a specific with bending structural stiffness and strength, known meaning that is reliable regardless of the plate by the short type and long type. Short plate have a wrapping of femur and long plate have to preserve a pole of femur. The bending strength of the curved metallic long plate has to evaluate a 11,000N and The bending strength of the curved metallic short plate has to evaluate a 6,525N. The tensile stress through to press a plate is $1573N/m^2\;and\;1539N/m^2$. The device can be used to support Revision case of Hip Implant and to use a case of Hip screw compression of Hip Neck Fracture.

• Journal of Korean Orthopaedic Sports Medicine
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• v.2 no.2
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• pp.176-180
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• 2003

We describe in this report the accurate reduction of a transverse displaced glenoid fracture through arthroscopic control . We used the lateral and superior (Neviaser portal) portal of the arthroscopic surgery in the shoulder joint for the U 4.0-mm titanium cannulated cancellous screw fixation. The advantages of this treatment are excellent intra-articular visualiBation, decreased soft tissue dissection ,less blood loss, shortened postoperative recovery and early ROM exercise. There(ore, we report the method of operation and the cases .