• Journal of Life Science
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• v.29 no.12
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• pp.1337-1344
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• 2019

Osteoporosis is characterized by a reduction in bone mass and typically manifests as an increase in fractures. Because this disease is common in elderly populations and lifespans are rapidly increasing, the incidence of osteoporosis has also grown. Most drugs currently used for osteoporosis treatment target osteoclasts in the bone tissue to prevent absorption. However, these medications also cause certain side effects and, furthermore, cannot increase bone mass. Thus, in order to control osteoporosis, regenerative medicine that utilizes adult stem cells and osteoblasts has been extensively studied. Statins, also known as 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, are cholesterol-lowering drugs that have been widely prescribed for cardiovascular diseases. Interestingly, recent studies have reported the beneficial effects of various statins on bone formation via the activation of osteoblasts. Thus, the current study investigated the effects of seven statin-family drugs on osteoblast activity during osteogenic differentiation using adult stem cells from human periosteal tissue. Specifically, statin effects on alkaline phosphatase activity, an early marker of bone cell differentiation, and on calcium deposit, a late marker of bone cell differentiation, were assessed. The results demonstrate that some statins (for example, pitavastatin and pravastatin) have a weak but positive effect on bone formation, and the findings therefore suggest that statin treatments can be a novel modulator for osteogenic differentiation and regenerative medicine using periosteal stem cells.

• Journal of the Korean Orthopaedic Association
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• v.52 no.1
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• pp.25-32
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• 2017

Purpose: The purpose of this study was to analyze the radiological and clinical outcomes in elderly patients with unstable intertrochanteric femur fractures in accordance with the length of intramedullary nail. Materials and Methods: Between August 2009 and December 2014, a total of 139 patients-older than 65 years of age with AO/OTA classification of 31-A2 unstable intertrochanteric femur fracture-who has been followed-up for at least 1 year after the treatment with internal fixation by using an intramedullary nail were enrolled for this retrospective control study. The subjects were classified into two groups according to the length of intramedullary nail: 106 patients in the short group (group I) and 33 patients in the long group (group II). For radiological assessments, the reduction state, time to union, and implant related complications were examined. The clinical outcomes were assessed by preoperative hemoglobin, operating time, intraoperative bleeding amount, blood transfusion rate, hospitalization period, and Charnley hip pain scoring system at the final follow-up. Results: The postoperative radiographs showed good or acceptable reduction in all cases. The mean time of radiologic bone union was 4.8 months, and there was no difference between the two groups. With respect to surgical time, the group II was found to take longer (57.87 minutes) than the group I (45.65 minutes) (p=0.003). The bleeding amount during surgery of the group II was greater (288.78 ml) than that of the group I (209.90 ml) (p=0.046). The clinical results at the final follow-up were found to be satisfactory in both groups. Conclusion: In cases of good reduction of the fracture from the treatment of unstable intertrochanteric femur fracture accompanying the posteromedial fragment in elderly patients, both groups-long and short intramedullary nails-showed satisfactory radiological and clinical outcomes.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.156-163
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• 2009

Statement of problem: Recently, there have been increased esthetic needs for posterior dental restorations. The failure of posterior dental ceramic restoration are possible not only by the characters of the component materials but also by the type of food. Purpose: The research aim was to compare the in vitro fracture resistance of simulated first molar crowns fabricated using 4 dental ceramic systems, full-porcelain-occlusal-surfaced PFG, half-porcelain-occlusal-surfaced PFG, Empress 2, Ice Zirkon and selected Korean foods. Material and methods: Eighty axisymmetric crowns of each system were fabricated to fit a preparation with 1.5- to 2.0-mm occlusal reduction. The center of the occlusal surface on each of 15 specimens per ceramic system was axially loaded to fracture in a Instron 4465, and the maximum load(N) was recorded. Afterwards, selected Korean foods specimens(boiled crab, boiled chicken with bone, boiled beef rib, dried squid, dried anchovy, round candy, walnut shell) were prepared. 15 specimens per each food were placed under the Instron and the maximum fracture loads for them were recorded. The 95% confidence intervals of the characteristic failure load were compared between dental ceramic systems and Korean foods. Afterwards, on the basis of previous results, 14Hz cyclic load was applied on the 4 systems of dental ceramic restorations in MTS. The reults were analyzed by analysis of variance and Post Hoc tests. Results: 95% confidence intervals for mean of fracture load 1. full porcelain occlusal surfaced PFG Crown: 2599.3 to 2809.1 N 2. half porcelain occlusal surfaced PFG Crown: 3689.4 to 3819.8 N 3. Ice Zirkon Crown: 1501.2 to 1867.9 N 4. Empress 2 Crown: 803.2 to 1188.5 N 5. boiled crab: 294.1 to 367.9 N 6. boiled chicken with bone: 357.1 to 408.6 N 7. boiled beef rib: 4077.7 to 4356.0 N 8. dried squid: 147.5 to 190.5 N 9. dried anchovy: 35.6 to 46.5 N 10. round candy: 1900.5 to 2615.8 N 11. walnut shell: 85.7 to 373.1 N under cyclic load(14Hz) in MTS, fracture load and masticatory cycles are: 1. full porcelain occlusal surfaced PFG Crown fractured at 95% confidence intervals of 4796.8-9321.2 cycles under 2224.8 N(round candy)load, no fracture under smaller loads. 2. half porcelain occlusal surfaced PFG Crown fractured at 95% confidence intervals of 881705.1-1143565.7 cycles under 2224.8 N(round candy). no fracture under smaller loads. 3. Ice Zirkon Crown fractured at 95% confidence intervlas of 979993.0-1145773.4 cycles under 382.9 N(boiled chicken with bone). no fracture under smaller loads. 4. Empress 2 Crown fractured at 95% confidence intervals of 564.1-954.7 cycles under 382.9 N(boiled chicken with bone). no fracture under smaller loads. Conclusion: There was a significant difference in fracture resistance between experimental groups. Under single load, Korean foods than can cause fracture to the dental ceramic restorations are boiled beef rib and round candy. Even if there is no fracture under single load, cyclic dynamic load can fracture dental posterior ceramic crowns. Experimental data with 14 Hz dynamic cyclic load are obtained as follows. 1. PFG crown(full porcelain occlusion) was failed after mean 0.03 years under fracture load for round candy(2224.8 N). 2. PFG crown(half porcelain occlusion) was failed after mean 4.1 years under fracture load for round candy(2224.8 N). 3. Ice Zirkon crown was failed after mean 4.3 years under fracture load for boiled chicken with bone(382.9 N). 4. Empress 2 crown was failed after mean 0.003 years under fracture load for boiled chicken with bone(382.9 N).

• Journal of Korean Foot and Ankle Society
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• v.20 no.2
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• pp.67-72
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• 2016

Purpose: The purpose of this study was to assess the 2-year follow-up results of patients with a trimalleolar fracture, who had undergone an anterior incision cannulated screw fixation of the posterior malleolar fragment, which had more than 25% of articular involvement or had no cortical continuity with the distal tibia. Materials and Methods: Among 28 patients with a trimalleolar fracture who had undergone fixation of the posterior malleolar fragment between February 2005 and February 2010, 14 patients, who underwent an anterior incision cannulated screw fixation of posterior malleolar fragment and were followed-up for more than 2 years, were selected. The postoperative clinical and radiological findings immediately and at the 1- and 2-year follow-up were compared. The clinical findings were evaluated as American Orthopaedic Foot and Ankle Society (AOFAS) score. The radiological assessment was evaluated as the maintenance of reduction, period to bone union, and the presence of nonunion, malunion, and complications. Results: The clinical outcome by mean AOFAS score revealed 83.0 points in the group with preoperative displacement below 2 mm and 80.7 points in the group with preoperative displacement above 2 mm postoperatively. The mean AOFAS score was 91.7 and 93.1 points in the group with preoperative displacement below 2 mm on 1- and 2-year follow-up, respectively, and 89.8 and 91.7 points in group with the preoperative displacement above 2 mm on 1- and 2-year follow-up, respectively. After a 2-year follow-up among 14 cases selected for this study, 13 cases showed an excellent reduction state and only 1 case (7.1%) showed a displacement of more than 2 mm. No complication were encountered in the group with preoperative displacement below 2 mm. On the other hand, among 8 patients in the group with preoperative displacement above 2 mm, there were 3 with limitations of the range of motion of the ankle joint (37.5%) and 1 post-traumatic arthritis (12.5%) at the 2-year follow-up. Conclusion: Anterior incision cannulated screw fixation of the posterior malleolar fragment could be a valuable method for the treatment of trimalleolar fractures that provides satisfactory results.

• Clinics in Shoulder and Elbow
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• v.15 no.1
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• pp.25-31
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• 2012

Purpose: The clinical and radiographic outcomes of the internal fixation, which were executed on patients over the age of 65 with proximal humerus fracture by using a polyaxial angular stable locking compression plate (Non-Contact-Bridging proximal humerus plate, Zimmer, Switzerland, NCB), were evaluated. Materials and Methods: Thirty two patients over the age of 65 among the proximal humerus fracture treated with NCB plate, between August 2007 and January 2011, were chosen as the subjects. The average age of patients was 71 years, and the average postoperative follow-up period was 11.5 months. The fractures included 14 two-part and 18 three-part fractures. The clinical results were evaluated, using the visual analog scale (VAS) score and the Constant score. The radiological results were evaluated by time to union and Paavolainen method, which measures the neck shaft angle. Results: At the last follow-up examination, the mean VAS score was 3 points and the mean Constant score was 64.5 points, with bone union achieved after the average of 16.2 weeks following the surgery in all the cases. The mean neck shaft angle was 125.9 and 24 cases had good results, while 8 cases had fair results by Paavolainen method, at the last follow-up. There were 1 case of delayed union and cerclage wire failure, and 3 cases of subacromial impingement. There were no complications, such as loss of reduction, nonunion, screw loosening, or avascular necrosis of the humeral head. Conclusion: Internal fixation, using a NCB plate, was considered to be an effective surgical method in treating proximal humerus fracture in the elderly patients, on whom the fixation of the fracture and maintenance of reduction are difficult.

• Restorative Dentistry and Endodontics
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• v.19 no.2
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• pp.345-371
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• 1994

Restorative procedures can lead to weakening tooth due to reduction and alteraton of tooth structure. It is essential to prevent fractures to conserve tooth. Among the several parameters in cavity designs, cavity isthmus and depth are very important. In this study, MO amalgam cavity was prepared on maxillary first premolar. Three dimensional. finite element models were made by serial photographic method and cavity depth(1.7mm, 2.4mm) and isthmus (11 4, 1/3, 1/2 of intercuspal distance) were varied. linear, eight and six-nodal, isoparametric brick elements were used for the three dimensional finite element model. The periodontal ligament and alveolar bone surrounding the tooth were excluded in these models. Three types model(B, G and R model) were developed. B model was assumed perfect bonding between the restoration and cavity wall. Both compressive and tensile forces were distributed directly to the adjacent regions. G model(Gap Distance: 0.000001mm) was assumed the possibility of play at the interface simulated the lack of real bonding between the amalgam and cavity wall (enamel and dentin). When compression occurred along the interface, the forces were transferred to the adjacent regions. However, tensile forces perpendicular to the interface were excluded. R model was assumed non-connection between the restoration and cavity wall. No force was transferred to the adjacent regions. A load of 500N was applied vertically at the first node from the lingual slope of the buccal cusp tip. This study analysed the displacement, von Mises stress, 1 and 2 direction normal stress and strain with FEM software ABAQUS Version 5.2 and hardware IRIS 4D/310 VGX Work-station. The results were as follows: 1. G model showed stress and strain patterns between Band R model. 2. B model and G model showed the bending phenomenon in the displacement. 3. R model showed the greatest amount of the displacement of the buccal cusp followed by G and B model in descending order. G model showed the greatest amount of the displacement of the lingual cusp followed by B and R model in descending order. 4. B model showed no change of the displacement as increasing depth and width of the cavity. G and R model showed greater displacement of the buccal cusp as increasing depth and width of the cavity, but no change in the displacement of the lingual cusp. 5. As increasing of the width of the cavity, stress and strain were not changed in B model. Stress and strain were increased on the distal marginal ridge and buccopulpal line angle in G and R model. The possibility of the tooth fracture was increased. 6. As increasing of the depth of the cavity, stress and strain were not changed in B and G model. Stress and strain were increased on the distal marginal ridge and buccopulpal line angle in R model. The possibility of the tooth fracture was increased.

• Journal of Trauma and Injury
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• v.36 no.4
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• pp.441-446
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• 2023

Inferior vena cava (IVC) injuries, while accounting for fewer than 0.5% of blunt abdominal trauma cases, are among the most difficult to manage. Despite advancements in prehospital care, transportation, operative techniques, and perioperative management, the mortality rate for IVC injuries has remained at 20% to 66% for several decades. Furthermore, 30% to 50% of patients with IVC injuries succumb during the prehospital phase. A 65-year-old male patient, who had been struck in the back by a 500-kg excavator shovel at a construction site, was transported to a regional trauma center. Injuries to the right side of the infrarenal IVC and the right external iliac vein (EIV) were suspected, along with fractures to the right iliac bone and sacrum. The injury to the right side of the infrarenal IVC wall was repaired, and the right internal iliac artery was ligated. However, persistent bleeding around the right EIV was observed, and we were unable to achieve proximal and distal control of the right EIV. Attempts at prolonged manual compression were unsuccessful. To decrease venous return, we ligated the right superficial femoral vein. This reduced the amount of bleeding, enabling us to secure the surgical field. We ultimately controlled the bleeding, and approximately 5 L of blood products were infused intraoperatively. A second-look operation was performed 2 days later, by which time most of the bleeding sites had ceased. Orthopedic surgeons then took over the operation, performing closed reduction and external fixation. Five days later, the patient underwent definitive fixation and was transferred for rehabilitation on postoperative day 22.

• Clinics in Shoulder and Elbow
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• v.14 no.1
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• pp.59-66
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• 2011

Purpose: We wanted to evaluate the clinical and radiological outcomes and the prognosis of various surgical treatments for the distal clavicle fracture with an acromioclavicular joint injury. Materials and Methods: A retrospective study of 21 patients with a minimum of 12 months follow up was done. We classified acromioclavicular (AC) injury into type I (only intra-articular fracture (IAF), 5 cases), type II (IAF with widening of the AC joint > 7 mm, 9 cases) and type III (IAF with AC joint superior subluxation > 50%, 7 cases). The distal clavicle fractures were fixed using plate (9 cases), mini screws (1 case), K wire and tension band wiring (10 cases) and transarticular pinning (1 case). Acromioclavicular or coracoacromial ligament reconstruction was not done in all the cases. Results: In 20 of 21 cases, bone union was achieved at an average of 8.4 weeks. Traumatic arthritis (5 cases), AC joint widening (4 cases) and AC joint subluxation (2 cases) were noted at the last follow up. The average UCLA score was 32.6 in the type I AC joint injuries, 34 in type II and 34.1 in type III. There was no relationship between the clinical outcomes and the preoperative AC joint injury pattern, postoperative traumatic arthritis, AC joint widening or AC joint subluxation (p>0.05). Conclusion: Satisfactory results were achieved by acute reduction and firm fixation of the distal clavicle fracture with AC joint injury. There was no relationship between the pattern of AC joint injury, the residual radiologic findings and the functional outcome.