• The Journal of Advanced Prosthodontics
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• v.8 no.3
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• pp.194-200
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• 2016

PURPOSE. The prospective follow-up aimed to assess the performance of lithium disilicate crowns and clinical reasons of adverse events compromising survival and quality. MATERIALS AND METHODS. 58 patients were treated with 375 heat-pressed monolithic crowns, which were bonded with resin cement. Annual recalls up to five years included a complete dental examination as well as quality assessment using CDA-criteria. Any need for clinical intervention led to higher complication rate and any failure compromised the survival rate. Kaplan-Meier-method was applied to all crowns and a dataset containing one randomly selected crown from each patient. RESULTS. Due to drop-outs, 45 patients (31 females, 14 males) with the average age of 43 years (range = 17-73) who had 327 crowns (176 anterior, 151 posterior; 203 upper jaw, 124 lower jaw) were observed and evaluated for between 4 and 51 months (median = 28). Observation revealed 4 chippings, 3 losses of retention, 3 fractures, 3 secondary caries, 1 endodontic problem, and 1 tooth fracture. Four crowns had to be removed. Survival and complication rate was estimated 98.2% and 5.4% at 24 months, and 96.8% and 7.1% at 48 months. The complication rate was significantly higher for root canal treated teeth (12%, P<.01) at 24 months. At the last observation, over 90% of all crowns showed excellent ratings (CDA-rating Alfa) for color, marginal fit, and caries. CONCLUSION. Heat pressed lithium disilicate crowns showed an excellent performance. Besides a careful luting, dentists should be aware of patients' biological prerequisites (grade of caries, oral hygiene) to reach full success with these crowns.

• Journal of Korean Society of Steel Construction
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• v.24 no.4
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• pp.479-490
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• 2012

Flexural tests on full-scale H-shaped beams, built up from high-strength steels (HSB800 and HSA800) with a nominal tensile strength of 800 MPa, was carried out to study the effect of flange slenderness of high-strength steel on flexural strength and rotation capacity. The primary objective was to investigate the appropriateness of extrapolating current stability criteria (originally developed for ordinary steel) to high-strength steel. The performance of high-strength steel specimens was very satisfactory from the strength, but not from the rotation capacity, perspective. The inferior rotation capacity of high-strength steel beams was shown to be directly attributable to the absence of a distinct yield plateau and the high yield ratio of the material. Residual stress measurements reconfirmed that the magnitude of the residual stress is almost independent of the yield stress of the base metal.

• The Korean Journal of Pain
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• v.21 no.3
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• pp.202-205
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• 2008

Background: Lumbar radicular pain is a frequent and often debilitating event. Although many treatment methods have been described in several studies, the available evidences regarding efficacy is not sufficient enough to draw definitive conclusions on an optimal therapy regime. Pulsed radiofrequency (RF) treatment was found to exert a beneficial effect on intractable radicular pain in individuals. The purpose of this study was to assess the efficacy of pulsed RF of the dorsal root ganglion for chronic lumbar radicular pain. Methods: Twenty five patients with chronic lumbar radicular pain that was refractory to selective nerve root blockage met the inclusion criteria of our study and received pulsed RF treatment. The average numeric rating scale (NRS) for leg pain during usual activities and the Oswestry disability index (ODI) were measured at 1 and 3 months after the procedure. Results: Of the 25 patients accepted for pulsed RF treatment, one dropped out due to a vertebral compression fracture during this study. ODI and NRS showed a positive trend in favor of the pulsed RF treatment. No significant complications were observed during the study period. Conclusions: It appears that pulsed RF treatment of the lumbar spinal dorsal root ganglion may be an effective treatment method for patients suffering from lumbar radicular pain, and who were not responsive to selective nerve root blockage.

• Clinics in Shoulder and Elbow
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• v.19 no.4
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• pp.229-236
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• 2016

Background: Cubitus varus and cubitus valgus deformities are common complications of distal humeral fractures in children. We evaluated the usefulness of supracondylar dome osteotomy as a treatment option for adults with cubitus varus or valgus deformity developed during childhood. Methods: Ten patients who had received supracondylar dome osteotomy and stabilization with plates to treat cubitus varus or valgus deformity between July 2006 and August 2013 were included in this study. Their mean age at the time of surgery was $36.50{\pm}10.22years$. The mean follow-up duration was $54.80{\pm}32.50months$. We evaluated humerus-elbow-wrist angles (HEWA), improvements in the lateral prominence index (LPI) or medial prominence index (MPI), Mayo elbow performance scores (MEPS), and overall results in accordance with the Banerjee criteria. Results: For the six patients with cubitus varus, the mean postoperative HEWA, mean correction angle, and mean improvement in LPI were $9.72^{\circ}{\pm}3.95^{\circ}$, $27.67^{\circ}{\pm}10.75^{\circ}$, and $6.92%{\pm}3.40%$, respectively. For the four patients with cubitus valgus, the mean postoperative HEWA, mean correction angle, and mean improvement in MPI were $14.73^{\circ}{\pm}2.97^{\circ}$, $11.55^{\circ}{\pm}3.26^{\circ}$, and $11.33%{\pm}6.39%$, respectively. There was no significant difference between postoperative and preoperative mean MEPS. The subjective ulnar nerve symptoms were alleviated in all patients. The overall results were excellent in six and good in four patients. Conclusions: This study suggests that supracondylar dome osteotomy with secure fixation using double plates may be useful in correcting cubitus varus or cubitus valgus deformity, yielding good functional outcomes in adults.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.2
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• pp.140-144
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• 2003

Ameloblastoma is cytologically a benign tumor, but is clinically characterized by infiltrative growth and high recurrency. The criteria for surgical treatment of ameloblastoma has not yet established and it is generally accepted that ameloblastoma be treated differently based on clinical types. The purpose of this paper is to consider effectiveness of enucleation in large-sized intraosseous ameloblastoma that has treated more frequently by radical treatment. 39 cases of the intraosseous ameloblastomas were treated by enucleation in the department of oral and maxillofacial surgery of Yonsei University, dental college from February 1990 to January 2001. 25 cases were selected because they were large in size that could produce facial disfigurement or pathologic fracture of jaws. They were radiographically characterized by the cortical bone that was expanded or eroded locally and histopathologically by 19 solid ameloblastomas and 6 intramural type of unicystic ameloblastomas. Among the 25 cases, 4 cases - 3 solid ameloblastomas and 1 intramural type of ameloblastoma - recurred. Recurrence rate was 16%. The compact bone which is not invaded by ameloblastoma was used as surgical margin of enucleation with accompanying chemical cauterization for killing the residual tumor cells. This may have been the reason for the low recurrence rate. So, it is considered that enucleation and long-term follow-up enable the large-sized intraosseous ameloblastomas that were characterized by almost destroyed cancellous bone and expanded or discontinued cortical bone to treat minimizing facial disfigurement and masticatory dysfunction and sociopsychological impact produced by radical treatment. I recommend that the large-sized intraosseous ameloblastomas without involvement to the surrounding soft tissues be first treated by enucleation.

• Journal of the Korea Concrete Institute
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• v.20 no.3
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• pp.345-356
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• 2008

In the previous study, direct inelastic strut-and-tie model (DISTM) was developed to perform inelastic design of reinforced concrete members by using linear analysis for their secant stiffness. In the present study, for convenience in design practice, the DISTM was further simplified so that inelastic design of reinforced concrete members can be performed by a run of linear analysis, without using iterative calculations. In the simplified direct inelastic strut-and-tie model (S-DISTM), a reinforced concrete member is idealized with compression strut of concrete and tension tie of reinforcing bars. For the strut and tie elements, elastic stiffness or secant stiffness is used according to the design strategy intended by engineer. To define the failure criteria of the strut and tie elements, concrete crushing and reinforcing bar fracture were considered. The proposed method was applied to inelastic design of various reinforced concrete members including deep beam, coupling beam, and shear wall. The design results were compared with the properties and the deformation capacities of the test specimens.

• Journal of Korean Foot and Ankle Society
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• v.21 no.4
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• pp.128-134
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• 2017

Purpose: To introduce reliable and newly developed radiographic measures based on a lateral ankle radiograph to assess a syndesmotic reduction after screw fixation and to compare with the radiographic measures based on the anteroposterior (AP) and mortise radiographs. Materials and Methods: The postoperative ankle radiographs of 34 ankle fracture cases after screw fixation for concurrent syndesmosis injury were reviewed. Two radiographic parameters were measured on each AP and mortise radiograph; tibiofibular clear space (TFCS) and tibiofibular overlap (TFO). Five radiographic parameters were measured on the true lateral radiographs; the anteroposterior tibiofibular (APTF) ratio, anterior tibiofibular ratio (ATFR), posterior tibiofibular ratio (PTFR), distances of intersection of the anterior fibular border and the tibial plafond to anterior cortex of the tibia (AA'), and the intersection of posterior fibular border and tibial plafond to the tip of the posterior malleolus (BB'). In addition, the distance (XP) between the fibular posterior margin (X) crossing tibial plafond or the posterior malleolus and posterior articular margin (P) of the tibial plafond was measured on the lateral view. Results: Using TFCS and TFO in the AP and mortise radiographs, malreductions of syndesmosis were estimated in 17 of 34 cases (50.0%). Using the introduced and developed radiographic measures in the lateral radiographs, syndesmotic malreductions were estimated in 16 out of 34 cases (47.1%). Seventeen cases (50.0%) showed no evidence of postoperative diastasis using the radiographic criteria on the AP and mortise view, 10 cases (58.8%) of whom showed evidence of a malreduction on the lateral radiograph. The newly developed measurements, XP, were measured 0 in 11 out of 34 cases (32.4%). Conclusion: The reduction of syndemosis after screw fixation can be accurately assessed intraoperatively with a combination of several reliable radiographic measurements of the lateral radiograph and traditional radiographic measurements of the AP and mortise radiograph.

• Journal of Trauma and Injury
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• v.20 no.2
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• pp.72-76
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• 2007

Purpose: The purpose of this clinical trial was to evaluate the fixation method for treating alveolar fractures in an emergency department. Methods: The efficiency of using the fixation method was judged on the basis of clinical criteria. Stability, occlusion state, bleeding amount after fixation, operation time, and difficulties during procedural operation were recorded. Results: Eight patients were enrolled in this study. In all instances, the fixation method was effective in bleeding control. Each patient had a noticeable decrement in bleeding. A wire was used for four of the eight patients, and nylon strings was used for the others. The average operation time was 6.3 minutes for the wire patients and 2.8 minutes for the Nylon string patients. No specific problem was identified during the procedural operation. However, the difference in the fixation material influenced the effectiveness of the procedure, the operation time, and the satisfaction of the doctor. Conclusion: In the emergency department, the fixation method using wire or nylon string in the treatment of alveolar fractures is effective in bleeding control

• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.35-46
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• 2000

In this paper, an analytical model is proposed to predict the shear strenth of RC beams strengthened by FRP. This predictional model is composed of two basic models-the upper bound theorem for shear failure (shear tension or shear compression criteria) and a truss model based on the lower bound theorem for diagonal tension creteria. Also, a simple flexural theory based on USD is used to explain flexural failure. The major cause of destruction of RC beams shear strengthened by FRP does not lie in FRP fracture but in the loss of load capacity incurred by rip-off failure of shear strengthening material. Since interfacial shear stree between base concrete and the FRP is a major variable in rip-off failure mode, it is carefully analyzed to derive the shear strengthening effect of FRP. The ultimate shear strength and failure mode of RC beams, using different strengthening methods, estimated in this predictional model is then compared with the result derived from destruction experiment of RC beams shear strengthened using FRP. To verify the accuracy and consistency of the analysis, the estimated results using the predictional model are compared with various other experimental results and data from previous publications. The result of this comparative analysis showed that the estimates from the predictional model are in consistency with the experimental results. Therefore, the proposed shear strength predictional model is found to predict with relative accuracy the shear strength and failure mode of RC beams shear strengthened by FRP regardless of strengthening method variable.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.1
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• pp.54-61
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• 2011

Introduction: Bisphosphonates is used widely for the treatment of the Paget's disease, multiple myeloma, bone metastases of malignant tumors with the prevention of pain and their pathological fracture. However, it was recently suggested that bisphosphonates related osteonecrosis of the jaw (BRONJ) is a side effect of bisphosphonate use. Materials and Methods: Twenty-four individuals, who were referred to the Department of Oral and Maxillofacial surgery, Dankook University Dental Hospital, were selected from those who had exposed bone associated with bisphosphonates from January, 2005 to December, 2009 according to the criteria of American Association of Oral and Maxillofacial Surgeons (AAOMS) for BRONJ. The patients group consisted of 7 males and 17 females between the age of 46 to 78 years (average 61.8 years). Each patient had panoramic imaging, computed tomography (CT), whole body bone scanning performed for a diagnosis and biopsy sampling from the necrotizing tissue. C-terminal cross-linking telopeptide of type I collagen (CTX) level of patients who had undergone surgical intervention was measured 7 days before surgery. Results: The main cause of bone exposure was post-extraction (15), chronic periodontitis (4), persistent irritation of the denture (3). Twenty people had undergone BRONJ treatment for two to eight months except for 4 people who had to maintain the bisphosphonates treatment to prevent a metastasis and bone trabecular pain with medical treatment. When the bisphosphonate treatment was suspended at least for 3 months and followed up according to the AAOMS protocols, the exposed necrotizing bones were found to be covered by soft tissue. Conclusion: Prevention therapy, interruption of bisphophonates for at least 3 months and cooperation with the physician for conservative treatment are the essential for treating BRONJ patient with high risk factors. The CTX level of BRONJ patients should be checked before undergoing surgical intervention. Surgical treatments should be delayed in the case of a CTX level <150 pg/mL.