• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.4
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• pp.320-324
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• 2010

Introduction: The placement of a single miniplate is not sufficient to achieve rigid fixation in mandibular angle fractures. It often causes difficulties in reducing the intermaxillary fixation (IMF) period. Consequently, the placement of 2 miniplates is preferable. The intraoral approach in an open reduction and internal fixation (ORIF) of a mandibular angle fracture with 2 miniplates is often challenging. Accordingly, an alternative of transbuccal approach is performed. However, this method leaves a scar on the face and can result in facial nerve injury. This clinical study suggests a protocol that can maintain rigid fixation without a transbuccal approach in mandibular angle fractures. Materials and Methods: The subjects were 7 patients who sustained fractures of the mandibular angle and treated at Department of Oral and maxillofacial surgery, Sacred Heart Hospital, Hallym University. ORIF under general anesthesia was done using the intraoral approach. One miniplate was inserted on external oblique ridge of the mandible, and the other was placed on lateral surface of the mandibular body with contra-angle drill and driver. A radiographic assessment and occlusal contact point examination was carried out before surgery, and 2, 4 and 6 weeks after surgery. Results: The mean operation time was 80 minutes. Regarding the occlusion state, the number of contact points increased after surgery. Paresthesia and infection were reported to be complications before surgery. Conclusion: The placement of 2 miniplates using contra-angle drill for ORIF of mandibular angle fractures allows early movement of the mandible without IMF. We propose this approach to reduce the patients’discomfort and simplify the surgical procedure.

• Archives of Plastic Surgery
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• v.34 no.3
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• pp.365-370
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• 2007

Purpose: There are many reports about facial bone fractures, but limited to retrospective data of a single hospital. Etiology and severity of the facial bone fracture have been changed and treatment method and materials have been advanced. In order to reflect those changes and provide up-to-date data of the facial bone fractures in Daegu, we gathered the data and analyzed the epidemiologic study. Methods: The medical records of 1058 fractures in 895 patients were gathered from 5 general hospitals in Daegu during last year and these data were analyzed by following parameters: age, sex, place of residence, occupation, cause of injury, time of injury, location of fracture, length of in-hospital stay, time of operation, treatment method, associated injury, complication. Statistical analysis was performed using the Chi-square test. Results: Most commonly involved age group was 20s(26%) and the sex ratio was 3.4:1(male predominance). Fractures were occurred more in unban and white-color workers. Among variable etiology of injury, traffic accident was the most common cause. Time of injury was heighest at 6 to 7 P.M., on Sunday, in July. Locations of fractures were following sequence: nasal, zygoma, mandible, orbit, maxilla. Mean length of in-hospital stay and time of operation after injury were 6.3 and 3.2 days, respectively. In treatment methods, operative methods were dominant than conservative management and general anesthesia were favored than local anesthesia. Associated injuries were noticed in 188 cases(21.2%) and complications were in 94 cases(8.9%) and among them, ocular problem were common. Conclusion: Compared to previous studies, mean age of occurrence was lowered and the etiologies showed age-specific pattern and reflected the change of lifestyle. In young age groups, sports injury, violence were more dominant and the other hand, traffic accident and fall were dominant in older groups.

• Membrane Journal
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• v.28 no.3
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• pp.214-219
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• 2018

In the present study, superflux nickel capillary supports for gas and vapor separation membranes were prepared by a combined process of NIPS and sintering. Nickel capillary precursors were prepared by NIPS process from PSf-Ni-DMAC-PEG400 dope solution and was sintered at various temperatures in $H_2$ atmosphere to reliably produce Ni capillary support. The optimized Ni capillary support has an outer and inner diameters of 722 and $550{\mu}m$, and its thickness was $94{\mu}m$. It has 3-dimensional pore channel network and its porosity and mean pore diameter was 26% and $4{\mu}m$, respectively. Also, its mechanical strength was tested in tensile mode: its fracture load was 2.84 kgf and the fracture elongation was 13%. Finally, its single gas permeance was measured: He, $N_2$, $O_2$, and $CO_2$ permeance was 432,327, 281,119, 264,259, and 193,143 GPU, respectively. The superflux behavior could be explained from viscous flow through the macropores having a diameter of $4{\mu}m$ and narrow thickness. It could be concluded that the superflux behavior of the Ni capillary support was from the 3-D pore channel network and the small thickness.

• Bulletin of the Society of Naval Architects of Korea
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• v.27 no.4
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• pp.58-66
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• 1990

A series of test was performed measuring the failure strength and failure mode of Gr/Pi, $[0^{\circ}/45^{\circ}/90^{\circ}/-45^{\circ}]_s$ laminate containing a single pin loaded hole. The finite element method is applied to calculate the stress distribution in the laminates, then the failure load and the failure mode were predicted by means of the characteristic length. 12 different geometric variations were developed to analyze the effects of the ratio of specimen width to hole diameter (W/d) and ratio of edge distance to hole diameter (L/d). X-Ray of NDE methods were utilized in finding out the initial defects, damage and the fracture mechanism, and SEM(Scanning Electron Microscopes) was used the evaluation of the fracture mechanism and crack propagation around hole under tension pin loading. $[0^{\circ}/45^{\circ}/90^{\circ}/-45^{\circ}]_s$ laminate are found to be most sensitive to W/d but not so influenced by L/d. The failure mode and tensile strength predicted by the model show agreement with experiment data for pin loading bolted jointed test except range of $L/d{\leqq}3$.

• Journal of Korean Neurosurgical Society
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• v.62 no.1
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• pp.96-105
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• 2019

Objective : The aims in the management of thoracolumbar spinal fractures are not only to restore vertebral column stability, but also to obtain acceptable alignment of the thoracolumbar junction (T-L junction) to prevent complications. However, insufficient surgical correction of the thoracolumbar spine would be likely to cause late progression of abnormal kyphosis. Therefore, we identified the surgical factors that affected unfavorable radiologic outcomes of the thoracolumbar spine after surgery. Methods : This study was conducted in a single institution from January 2007 to December 2013. A total of 98 patients with unstable thoracolumbar spine fracture were included. In these patients, fixation was done through transpedicular screws with rods by three surgical patterns. We reviewed digital radiographs and analyzed the images preoperatively and postoperatively during follow-up visits to compare the change of the thoracolumbar Cobb angle with radiologic parameters and clinical outcomes. The unfavorable radiologic group was defined as the patients who were measured as having greater than 20 degrees of thoracolumbar Cobb angle on the last follow-up, or who underwent kyphotic progression of thoracolumbar Cobb angle greater than 10 degrees from the immediate postoperative state to final follow-up, or who had overt instrument failure with/without additional surgery. We assessed the risk factors that affected the unfavorable radiologic outcomes. Results : We had 43 patients with unfavorable radiologic outcomes, including 35 abnormal thoracolumbar alignments and 14 instrumental failures with/without additional surgery. The multivariate logistic regression test showed that immediate postoperative T-L junction Cobb angle less than 10.5 degrees was a statistically significant risk factor, as well as the presence of osteoporosis (p=0.017 and 0.049, respectively). Conclusion : Insufficient correction of thoracolumbar kyphosis was considered to be a major factor of an unfavorable radiological outcome. The spinal surgeon should consider that having a T-L junction Cobb angle larger than 10.5 degrees immediately after surgery could result in an unfavorable radiological outcome, which is related to a poor clinical outcome.

• Composites Research
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• v.33 no.6
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• pp.371-376
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• 2020

The adhesive strength can be improved through surface treatment. The most common method is to improve physical bonding by varying the surface conditions. This study presents the effect of laser surface treatment on the adhesive strength of CFRP. The surface roughness was patterned using a 1064 nm laser. The effects of the number of laser shots and the direction and length of the pattern on the adhesion of the CFRP/CFRP single joint were investigated through tensile tests. Tests according to ASTM D5868 were performed, and the bonding mechanism was determined by analyzing the damaged surface after a fracture. The optimized number of the laser shots and the optimized depth of the roughness should be required to increase the bonding strength on the CFRP surface. When considering the shear stress in the tensile direction, the roughness pattern in the direction of 45° that increases the length of the fracture path in the adhesive layer resulted in an increase of the adhesive strength. The surface treatment of the bonding surface using a laser is a suitable method to acquire a mechanical bonding mechanism and improve the bonding strength of the CFRP bonding joint. The study on the optimized laser process parameters is required for utilizing the benefits of laser surface processing.

• Archives of Plastic Surgery
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• v.49 no.2
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• pp.195-199
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• 2022

Nasolacrimal duct (NLD) damage is associated in the majority of type II and III naso-orbito-ethmoid (NOE) fractures. Our study aims to investigate the efficacy and safety of prophylactic NLD intubation in the setting of facial fractures, by comparing incidence of postoperative epiphora and wound infection. A retrospective matched control study was conducted on all patients with surgically treated facial fractures from 2008 to 2013 (n=280) (IRB ref number: DSRB 2013/01198). Patients with the following fracture types were included: NOE (n=16), frontal sinus (n=2), Le Fort II/III (n=8), and > 1 type (n=48). All patients in this study were included with the intention to treat. The study group comprised patients who were intubated, while the control group patients were not intubated. Each group had 37 patients matched for age, gender, fracture type, and injury type. A single oculoplastic surgeon skilled in lacrimal surgery performed the procedure for all intubated patients. Patients with more severe and complex facial fractures were intubated with bicanalicular Crawford stents. Postoperative epiphora and infective complications (both facial wound and dacryocystitis) were assessed at 1, 3, 6, and 12 months. There was no significant difference in incidence of either postoperative epiphora (p=0.152) or wound infection (p=0.556) comparing both groups. Reduced incidence of postoperative epiphora in the study group is statistically not significant and does not support the need for prophylactic intubation. If radiographic evidence of NLD disruption or regurgitation seen on syringing on the NLD intraoperatively is present, intubation is safe and efficacious only if performed by an expert.

• The Journal of Korean Medicine
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• v.44 no.2
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• pp.149-169
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• 2023

Objectives: This study was designed to statistically analyze patients hospitalized for thoracolumbar compression fractures at Daejeon University Daejeon Korean Medicine Hospital from January 1, 2017 to December 31, 2021. Methods: A total of 62 patients were analyzed through electronic medical records in this study. The extracted data was analyzed using IBM SPSS ver.27.0. Results: 1. Traffic accident patients were more likely to reduce pain by more than half compared to falls and other patients. Patients without spinal disease were more likely to reduce pain by more than half compared to those without. The shorter the absolute bed rest and the longer the hospital stay, the higher the probability of pain reduction by more than half. 2. The duration of pain half-reduction was longer in patients with diabetes than in patients without diabetes. 3. The longer the hospitalization period and the shorter the absolute bed rest period, the less pain was reported upon discharge. Males complained of less pain at discharge than females, and patients without spinal disease complained less than those without. Patients who did not receive absolute bed rest complained of less pain upon discharge than those who did not. Conclusions: This study included patients hospitalized for thoracolumbar compression fractures and showed that etiology, absolute bed rest period, hospitalization period, gender, spinal disease, diabetes statistically affected the degree of pain reduction.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.420-429
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• 2007

The purpose of this study was to compare the micro ensile bond strength to bovine dentin of several adhesives (SM, Scotch $Bond^{TM}$ Multipurpose; SB, $Adper^{TM}$ Single Bond 2; SE, $Clearfil^{(R)}$ SE Bond; AQ, AQ $Bond^{TM}$; TS, $Clearfil^{(R)}$ tri-S Bond). Except SM and SB, they have a simplified one- or two-step application protocols in compare with the dentin adhesives conventional three-step protocols. For the microtensile bond strength test, the labial surfaces of bovine incisors were used. Following exposure of dentin layer, according to their manufacturer's directions, each dentin adhesives were applied and composite resin blocks were constructed. The teeth were sectioned for specimen and tested microtensile bond strength. Also observed the fracture mode of interface. The obtained results were as follows : 1. The microtensile bond strength values ranged from 51.34 to 24.04 MPa on dentin(in decreasing order, SE, SM, SB, AQ and TS). 2. The highest microtensile bond strength was by SE and SM on bovine dentin, and the lowest by AQ and TS. 3. SM, SB and SE showed cohesive failures and adhesive failure but AQ, TS presented almost adhesive failures. In summary, microtensile bond strengths of single-step adhesives (AQ and TS) on bovine dentin were significantly lower than those of multi-step adhesives (SM, SB and SE) (p<0.05).

• Restorative Dentistry and Endodontics
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• v.32 no.3
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• pp.222-235
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• 2007

The objectives of this study was to evaluate the effect of thermocycling on the ${\mu}TBS$ (microtensile bond strength) to dentin with four different adhesive systems to examine the bonding durability. Freshly extracted $3^{rd}$ molar teeth were exposed occlusal dentin surfaces, and randomly distributed into 8 adhesive groups 3-steps total-etching (Scotchbond Multi-Purpose Plus; SM, All Bond-2; AB), 2-steps total-etching (Single Bond; SB, One Step plus; OS), 2-steps self-etching (Clearfil SE Bond; SE, AdheSE AD) and single-step self-etching systems (Promp L-Pop; PL, Xeno III; XE) Each adhesive system in 8 adhesives groups was applied on prepared dentin surface as an instruction and resin composite (Z250) was placed incrementally and light-cured. The bonded specimens were sectioned with low-speed diamond saw to obtain $1\times1mm$ sticks after 24 hours of storage at $37^{\circ}C$ distilled water and proceeded thermocycling at the pre-determined cycles of 0, 1,000 and 2,000. The ${\mu}TBS$ test was carried out with EZ-tester at 1mm/min. The results of bond strength test were statistically analyzed using one-way ANOVA/ Duncan's test at the a < 0.05 confidence level. Also, the fracture mode of debonded surface and the interface were examined under SEM. The results of this study were as follows ; 1. 3-step total etching adhesives showed stable, but bond strength of 2-step adhesives were decreased as thermocycling stress. 2. SE showed the highest bond strength, but single step adhesives (PL, XE) had the lowest value both before and after thermocycling. 3 Most of adhesives showed adhesive failure. The total-etching systems were prone to adhesive failure and the single-step systems were mixed failure after thermocycling. Within limited results of this study, the bond strength of adhesive system was material specific and the bonding durability was affected by the bonding step/ procedure of adhesive Simplified bonding procedures do not necessarily imply improved bonding performance.