• Journal of Technologic Dentistry
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• v.30 no.1
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• pp.25-31
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• 2008

Cp-Ti and Ti-6Al-4V alloys commonly used dental implant materials, particularly for orthopaedic and osteosynthesis because of its suitable mechanical properties and excellent biocompatibility. This alloys have excellent corrosion behavior in the clinical environment. The first factor to decide the success of dental implantation is sufficient osseointegration and high corrosion resistance between on implant fixture and its surrounding bone tissue. In this study, in order to increase corrosion resistance and biocompatibility of Cp-Ti and Ti-6Al-4V alloy that surface of manufactured alloy was coated with TiN by RF-magnetron sputtering method. The electrochemical behavior of TiN coated Cp-Ti and Ti-6Al-4V alloy were investigated using potentiodynamic (EG&G Co, PARSTAT 2273. USA) and potentiostatic test (250mV) in 0.9% NaCl solution at 36.5 $\pm$ 1$^{\circ}C$. These results are as follows : 1. From the microstructure analysis, Cp-Ti showed the acicular structure of $\alpha$-phase and Ti-6Al-4V showed the micro-acicular structure of ${\alpha}+{\beta}$ phase. 2. From the potentiodynamic test, Ecorr value of Cp-Ti and Ti-6Al-4V alloys showed -702.48mV and -319.87mV, respectively. Ti-6Al-4V alloy value was higher than Cp-Ti alloy. 3. From the analysis of TiN and coated layer, TIN coated surface showed columnar structure with 800 nm thickness. 4. The corrosion resistance of TiN coated Cp-Ti and Ti-6Al-4V alloys were higher than those of the non-coated Ti alloys in 0.9% NaCl solution from potentiodynamic test, indicating better protective effect. 5. The passivation current density of TiN coated Cp-Ti and Ti-6Al-4V alloys were smaller than that of the noncoated implant fixture in 0.9% NaCl solution, indicating the good protective effect resulting from more compact and homogeneous layer formation.

• Clinics in Shoulder and Elbow
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• v.21 no.3
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• pp.151-157
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• 2018

Background: Nonunion of lateral humeral condyle fracture causes cubitus valgus deformity. Although corrective osteotomy or osteosynthesis can be considered, there are controversies regarding its treatment. To evaluate elbow joint biomechanics in non-united lateral humeral condyle fractures, we analyzed the motion of elbow joint and pseudo-joint via in vivo three-dimensional (3D) kinematics, using 3D images obtained by computed tomography (CT) scan. Methods: Eight non-united lateral humeral condyle fractures with cubitus valgus and 8 normal elbows were evaluated in this study. CT scan was performed at 3 different elbow positions (full flexion, $90^{\circ}$ flexion and full extension). With bone surface model, 3D elbow motion was reconstructed. We calculated the axis of rotation in both the normal and non-united joints, as well as the rotational movement of the ulno-humeral joint and pseudo-joint of non-united lateral condyle in 3D space from full extension to full flexion. Results: Ulno-humeral joint moved to the varus on the coronal plane during flexion, $25.45^{\circ}$ in the non-united cubitus valgus group and $-2.03^{\circ}$ in normal group, with statistically significant difference. Moreover, it moved to rotate externally on the axial plane $-26.75^{\circ}$ in the non-united cubitus valgus group and $-3.09^{\circ}$ in the normal group, with statistical significance. Movement of the pseudo-joint of fragment of lateral condyle showed irregular pattern. Conclusions: The non-united cubitus valgus group moved to the varus with external rotation during elbow flexion. The pseudo-joint showed a diverse and irregular motion. In vivo 3D motion analysis for the non-united cubitus valgus could be helpful to evaluate its kinematics.

• Clinics in Shoulder and Elbow
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• v.18 no.2
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• pp.68-74
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• 2015

Background: The purpose of our study was to evaluate the functional and radiologic outcomes of additive augmentation sutures through rotator cuff for proximal humeral fractures stabilized locking plate in elderly patients. Methods: We enrolled 74 patients over the age of 60 years who received internal fixation using locking plates for proximal humeral fractures. Of these, 50 patients had additive augmentation sutures through rotator cuff. The mean age at the time of surgery was 72.1 years (range, 60-89 years), and the mean follow-up period was 17.5 months (range, 12-62 months). The humeral neck-shaft angle and humeral head height were used as radiological markers to assess the effect of additive augmentation sutures through rotator cuff. We allocated the patients who received additive augmentation sutures into group A and those who did not into group B. Results: At the final follow-up, the mean Korean Showlder Society score and Constant scores were $88.96{\pm}12.1$ and $86.6{\pm}11.9$, respectively, in group A and $86.21{\pm}11.8$ and $85.3{\pm}11.7$, respectively, in group B (p=0.368, 0.271). At the final follow-up, the mean loss in humeral neck-shaft angle from the time of immediate postoperative measurement was $1.6^{\circ}$ in group A and $4.8^{\circ}$ in group B, whereas the mean loss in humeral head height was 0.82 mm in group A and 0.52 mm in group B (p=0.029, 0.178). Conclusions: The surgical outcomes of internal fixation using locking plates for proximal humeral fractures were clinically and radiologically good in elderly patients over the age of 60 years without any observable complications. Further, the loss of humeral head shaft angle at the final follow-up from its initial postoperative measurement was significantly smaller in patients who received an additive augmentation suture than in those who did not. Thus, we conclude that augmentation sutures are a beneficial option for elderly patients that clinicians can consider at the time of surgical decision making.

• Journal of Trauma and Injury
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• v.26 no.3
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• pp.111-124
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• 2013

Purpose: We should prepare proper medical service for disaster control as South Korea is not free from terrorism and war, as we experienced through the two naval battles of the Yeonpyeong, one in 1999 and the other in 2002, the sinking of Cheonan in 2010, and the attack against the border island of Yeonpyeong in 2010. Moreover, North Korea's increasingly bellicose rhetoric and mounting military threats against the world demand instant action to address the issue. The aim of this article is to describe our experience with three patients with combat-related gunshot and explosive injuries to their extremities and to establish useful methods for the management of patients with combat-related injuries. Methods: Three personnel who had been injured by gunshot or explosion during either the second naval battle of the Yeonpyeong in 2002 or the attack against the border island of Yeonpyeong in 2010 were included in our retrospective analysis. There were one case of gunshot injury and two cases of explosive injuries to the extremities, and the injured regions were the left hand, the right foot, and the right humerus. In one case, the patient had accompanying abdominal injuries, and his vital signs were unstable. He recovered after early initial management and appropriate emergency surgery. Results: All patients underwent emergent surgical debridement and temporary fixation surgery in the same military hospital immediately after their evacuations from the combat area. After that, continuous administration of antibiotics and wound care were performed, and definite reconstructions were carried out in a delayed manner. In the two cases in which flap operations for soft tissue coverage were required, one operation was performed 5 weeks after the injury, and the other operation was performed 7 weeks after the injury. Definite procedures for osteosynthesis were performed at 3 months in all cases. Complete union and adequate functional recovery were achieved in all cases. Conclusion: The patient should be stabilized and any life-threatening injuries must first be evaluated and treated with damage control surgery. Staged treatment and strict adherence to traditional principles for open fractures are recommended for combat-related gunshot and explosive injuries to the extremities.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.497-503
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• 2014

Minimally invasive intramedullary nail insertion or plate osteosynthesis has shown good results for the treatment of long bone fractures. However, directly seeing the fracture site is impossible; surgeons can only confirm bone fragments through a fluoroscopic imaging system. The narrow field of view of the equipment causes malalignment of the fracture reduction, and radiation exposure to medical staff is inevitable. This paper suggests two methods to solve these problems: surgical navigation using 3D models reconstructed from computed tomography (CT) images to show the real positions of bone fragments and estimating the rotational angle of proximal bone fragments from 2D fluoroscopic images. The suggested methods were implemented using open-source code or software and evaluated using a model bone. The registration error was about 2 mm with surgical navigation, and the rotation estimation software could discern differences of $2.5^{\circ}$ within a range of $15^{\circ}$ through a comparison with the image of a normal bone.

• Archives of Plastic Surgery
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• v.38 no.2
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• pp.155-160
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• 2011

Purpose: Fibrillar collagens like type I collagen, are the major constituent of the extracellular matrix and structural protein of bone. Also, it can be a scaffold for osteoblast migration. The purpose of this study is to estimate the effects of absorbable atelo-collagen sponge (Teruplug$^{(R)}$, Terumo biomaterials Co., Tokyo, Japan) insertion in tooth extraction sites on periodontal healing of the second molar, healing of the fractured mandibular bone and new bone formation of third molar socket after the extraction of the impacted third molar with mandibular angle fracture. Methods: In our study of six cases of mandibular angle fractures, all of them underwent the extraction of the third molar tooth & absorbable atelo-collagen sponge insertion in tooth extraction site. Three of them had a intraoral infection & oral opening to fracture site, two of the six had dental caries, and only one had reduction problem due to third molar position. Six consecutive patients with noncomminuted fractures of the mandibular angle were treated by open reduction and internal fixation using one noncompression miniplates and screws placed through a transoral incision. Results: All of the patients have showed good postoperative functions and have not experienced complications requiring second surgical intervention. There was well healing of the mandibular bone and the most new bone formation of third molar socket after the extraction of the impacted third molar with mandibular angle fracture. Conclusion: The results of this study suggest that absorbable atelo-collagen sponge is relatively favorable bone void filler with prevention of tissue collapse, food packing, and enhance periodontal healing. Thus, the use of atelo-collagen sponge and one noncompression miniplate seems to be relatively easy, safe, and effective for the treatment of fractures of the mandibular angle and third molar extraction.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.2
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• pp.77-82
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• 2017

Objectives: The aim of this study was to compare the mechanical resistance of four different osteosyntheses modeled in two different sagittal split ramus osteotomy (SSRO) designs and to determine the linear loading in a universal testing machine. Materials and Methods: An in vitro experiment was conducted with 40 polyurethane hemimandibles. The samples were divided into two groups based on osteotomy design; Group I, right angles between osteotomies and Group II, no right angles between osteotomies. In each group, the hemimandibles were distributed into four subgroups according to the osteosynthesis method, using one 4-hole 2.0 mm conventional or locking plate, with or without one bicortical screw with a length of 12.0 mm (hybrid technique). Each subgroup contained five samples and was subjected to a linear loading test in a universal testing machine. Results: The peak load and peak displacement were compared for statistical significance using PASW Statistics 18.0 (IBM Co., USA). In general, there was no difference between the peak load and peak displacement related to osteotomy design. However, when the subgroups were compared, the osteotomy without right angles offered higher mechanical resistance when one conventional or locking 2.0 mm plate was used. One locking plate with one bicortical screw showed higher mechanical resistance ($162.72{\pm}42.55N$), and these results were statistically significantly compared to one conventional plate with monocortical screws (P=0.016) and one locking plate with monocortical screws (P=0.012). The difference in peak displacement was not statistically significant based on osteotomy design or internal fixation system configuration. Conclusion: The placement of one bicortical screw in the distal region promoted better stabilization of SSRO. The osteotomy design did not influence the mechanical behavior of SSRO when the hybrid technique was applied.

• The korean journal of orthodontics
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• v.29 no.4 s.75
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• pp.457-466
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• 1999

It has been reported that skeletal relapse and dental change after mandibular setback do occur not only after intermaxillary fixation(IMF) removal but also during IMF The side effects of skeletal relapse during IMF have clinical importance because they can cause many Postoperative orthodontic Problems. Generally, the Prevention of solid union between segments, compensatory tooth movement, anterior openbite, etc. have been cited as the side effects of jaw displacement. The purpose of this study was to evaluate the skeletal relapse and dental change during IMF. The material consisted of 28 patients who were treated by BSSRO(bilateral sagittal split ramus osteotomy), wire osteosynthesis, IMF for correction of mandibular prognathism. Through cephalometric analysis, the amount and direction of surgical movement, skeletal relapse and dental change during IMF were measured. The correlation between surgical movement and skeletal relapse, between skeletal relapse and dental changes were evaluated. The following conclusions were obtained; 1. Distal segment was repositioned backward and upward, proximal segment showed clockwise rotation during surgery. 2. During ]m, anterior portion of distal segment was displaced backward and posterior portion was displaced upward. Proximal segment was displaced upward with forward movement of p-Go(gonion of proximal segment). Backward surgical movement of p-GO was significantly correlated with forward displacement of p-Go. 3. Overjet and overbite were not changed during IMF. The compensatory tooth movements during IMF were characterized by retroclination of upper incisors md retroclination, extrusion of lower incisors. These compensatory tooth movements had statistically significant correlation with upward displacement of d-Go (gonion of distal segment).

• Journal of the Korean Orthopaedic Association
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• v.56 no.1
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• pp.26-33
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• 2021

Purpose: This study evaluated the results of dual plate fixation for periprosthetic femur fracture after total knee arthroplasty (TKA). Materials and Methods: From October 2007 to February 2013, 23 cases of periprosthetic femur fracture after TKA were treated at the author's hospital. There were 13 cases of fixation using a medial and lateral dual plate when the stability of the fracture site could not be achieved by one side fixation with a follow-up of more than one year. The cases included no loosening of the femoral component in fractures that were categorized as Lewis-Rorabeck classification II and supracondylar comminuted fractures and elongation of the fracture line to the lateral epicondyle of the femur or stem in the medullary canal. The mean age was 72 years (65-82 years), and 11 cases were female. Three cases had a stem due to revision. The mean bone marrow density was -3.2 (-1.7 to -4.4), and the mean period from primary TKA to periprosthetic fractures was 28 months (1-108 months). The mean follow-up period was 23 months (12-65 months). The medial fracture site was first exposed via the subvastus approach. Second, the supplementary plate was fixed on the lateral side of the fracture using a minimally invasive plate osteosynthesis technique. The average union time, complications, and Hospital for Special Surgery Knee Score (HSS) at the last follow-up were evaluated. Results: The mean union time was 17.4 weeks (7-40 weeks). Two cases showed delayed bone union and nonunion occurred in one case, in whom bone union was achieved three months later after re-fixation using a dual plate with an autogenous bone graft. The mean varusvalgus angulation was 1.67 degrees (-1.2-4.9 degrees), and the mean anterior-posterior angulation was 2.86 degrees (0-4.9 degrees) at the last follow-up. The mean knee range of motion was 90 degrees, and the HSS score was 85 points (70-95 points) at the last follow-up. Conclusion: Dual plate fixation for periprosthetic femur fractures that had not achieved stability by one side plate fixation after TKA showed a good clinical result that allowed early rehabilitation.