• Clinics in Shoulder and Elbow
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• 제16권2호
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• pp.107-114
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• 2013

목적: 상완골 간부 골절에서 골수강 내 금속정 고정을 시행한 후 잔존한 전위에 대해 임상적, 방사선학적 결과를 분석하였다. 대상 및 방법: 2004년 7월부터 2011년 8월까지 상완골 간부 골절에 대해서 골수강 내 금속정 고정 후 잔존한 전위가 10 mm 이상, 20 mm 미만인 8예를 대상으로 하였다. 평균 연령은 54.1세(43~70세), 남자 3예, 여자 5예였다. 수술 직후 단순 방사선 사진으로 전위와 각형성의 정도를 측정하였으며, 추시 방사선 사진으로 이의 호전 정도와 골유합, 합병증 여부를 확인하였다. 술 후 견관절 및 주관절의 운동 범위와 통증에 대해서 조사하였다. 결과: 모든 예에서 골유합을 얻을 수 있었고, 평균 골유합 기간은 16.1주였다. 최종 추시 견관절 및 주관절의 운동범위는 대부분 정상 범위로 돌아왔다. 1예에서 견관절 강직으로 인하여 관절경적 관절낭 이완술 및 도수 조작술 후 운동범위를 회복하였으며, 일시적인 견관절 통증 1예, 주관절 통증 1예가 있었다. 2예에서 근위 나사못의 빠짐이 있었으나 모두 골유합을 얻었다. 결론: 상완골 간부 골절에서 골수강 내 금속정 고정 후 잔존한 전위에도 불구하고 골유합을 얻을 수 있었으며 우수한 임상적 결과를 보였기 때문에, 관혈적 정복 또는 추가 고정은 필요하지 않았다.

• The Korean Journal of Ceramics
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• 제7권2호
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• pp.74-79
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• 2001

Alumina composite reinforced by chopped alumina fiber was fabricated by filter-pressing the fiber slurry followed by the infiltration of alumina slurry. The chopped fiber was coated with nickel by electroless plating method. The green samples were densified by hot-pressing. Microstructures were studied by SEM and the mechanical properties such as bending strength and fracture toughness were measured. The resulting mechanical properties were analyzed in relation with processing parameters such as preform density and resulting microstructures. The load-displacement curve of the specimen with Ni interlayer but without Ni inclusion showed brittle fracture mode due to the direct contact between matrix and fiber. The load-displacement curve of the specimen with Ni interlayer and Ni inclusion in the matrix which is introduced by high applied pressure during specimen preparation showed non-brittle fracture mode due to the fiber pull-out and dutile phases in the matrix.

• Restorative Dentistry and Endodontics
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• 제19권2호
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• pp.384-408
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• 1994

The purpose of this study was to evaluate the fracture resistance of tooth restored with gold inlay. A profound understanding of the isthmus width factor, which is one of the several parameters of cavity designs, would facilitate the appropriate cavity preparation in a specific clinical situation. In this study, the cavities for gold inlay were prepared in maxillary left first premolar. A three-dimensional model was designed using I-DEAS program. The model was composed of 2515- nodes and 2172 isoparametric brick elements. In the model isthmus width was varied into 1/4, 1/3 and 1/2 of intercuspal width respectively, and numeric values of the material properties of enamel, dentin and gold was set. Three types of load : concentrated load, divided load and distributed load was 500N. The empty cavities in the model were also examined using divided load and distributed load. The three - dimensional Finite Element Method was used to analysis the displacement and stress distribution. The results were as follows : 1. All of the experimental models which were filled with gold inlay revealed similar direction of displacement to that of the natural tooth model under the same load type. But in the models with empty cavities, as the isthmus width increased, the degree of displacement increased in the case of divided load type. 2. All experimental models which were filled with gold inlay showed stress concentration at load points, but in the models with empty cavities at divided load type, as isthmus width increased, stress was concentrated at the comer of the pulpal floor. 3. In the models with empty cavities at divided load type, tooth fracture was expected regardless of isthmus width, but all experimental models which were filled with gold inlay after cavity preparation were not susceptible to fracture. 4. In all experimental models which were filled with gold inlay after cavity preparation, displacement patterns were similar under both concentrated and divided load types. In the models with empty cavities, a divided load resulted in a bucco-lingual cuspal displacemenat in both sides, but a distributed load resulted in a lingual displacement of the tooth.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제48권5호
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• pp.303-308
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• 2022

Objectives: Selection of treatment methods for mandibular condylar fractures remains controversial. In this study, we investigated treatment methods for condylar fractures to determine the indications for open or closed reduction. Patients and Methods: Patients >12 years of age treated for mandibular condylar fractures with a follow-up period of ≥3 months were included in this study. The medical records of enrolled patients were reviewed for sex, age, fracture site, treatment method (open or closed reconstruction), postoperative intermaxillary fixation period, operation time, and complications. Radiological analysis of fracture fragment displacement and changes in ramal height difference was performed using computed tomography and panoramic radiography. Results: A total of 198 patients was investigated, 48.0% (n=95) of whom underwent closed reduction and 52.0% (n=103) underwent open reduction. There was no significant correlation between reduction method and patient sex, age, or follow-up period. No statistically significant difference between the incidence of complications and treatment method was observed. None of the patients underwent open reduction of condylar head fracture. Binary logistic regression analysis showed that open reduction was significantly more frequent in patients with subcondylar fracture compared to in those with a fracture in the condylar head area. There was no statistically significant correlation between the groups and fracture fragment displacement. However, there was a significant difference between the treatment groups in amount of change in ramal height difference between the fractured and the non-fractured sides during treatment. Conclusion: No significant clinical differences were found between the open and closed reduction methods in patients with mandibular condylar fractures. According to fracture site, closed reduction was preferred for condyle head fractures. There was no significant relationship between fracture fragment displacement and treatment method.

• Restorative Dentistry and Endodontics
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• 제19권2호
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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.

• Structural Engineering and Mechanics
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• 제28권6호
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• pp.749-765
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• 2008

Free axisymmetric vibrations of layered cylindrical shells of variable thickness are studied using spline function approximation techniques. Three different types of thickness variations are considered namely linear, exponential and sinusoidal. The equations of axisymmetric motion of layered cylindrical shells, on the longitudinal and transverse displacement components are obtained using Love's first approximation theory. A system of coupled differential equations on displacement functions are obtained by assuming the displacements in a separable form. Then the displacements are approximated using Bickley-spline approximation. The vibrations of two-layered cylindrical shells, made up of several types of layered materials and different boundary conditions are considered. Parametric studies have been made on the variation of frequency parameter with respect to the relative layer thickness, length ratio and type of thickness variation parameter.

• Clinics in Shoulder and Elbow
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• 제20권1호
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• pp.49-56
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• 2017

Since the olecranon fractures are caused by relatively low-energy injuries, such as a fall from standing height, they are usually found without comminution. Less commonly they can be developed by high-energy injuries and have severe concomitant comminution or injuries to surrounding structures of the elbow. Because the fracture by nature is intra-articular with the exception of some avulsion-type fracture, a majority of olecranon fractures are usually indicated for surgical treatment. Even if there is minimal displacement, surgical treatment is recommended because there is a possibility of further displacement by the traction force of triceps tendon. The most common type of olecranon fracture is displaced, simple non-comminuted fracture (that is, Mayo type IIA fractures). Although tension band wiring was the most widespread treatment method for these fractures previously, there is some trends toward fixation using locking plates. Primary goal of the surgery is to restore a congruent joint and extensor mechanisms by accurate reduction and stable fixation so that range of motion exercises can be performed. The literature has shown that good clinical outcomes are achieved irrespective of surgical fixation technique. However, since the soft tissue envelope around the elbow is poor and the implants are located at the subcutaneous layer, implant irritation is still the most common complication associated with surgical treatment.

• The Journal of Advanced Prosthodontics
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• 제3권1호
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• pp.51-55
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• 2011

BACKGROUND. Mandibular displacement is a common complication of condylar fracture. In the mandibular displacement due to condylar fracture, it is difficult to restore both esthetics and function without using orthognathic surgery. CASE DESCRIPTION. This clinical report described a full mouth rehabilitation in the patient with bilateral condylar fractures and displaced mandible using bilateral sagittal split ramus osteotomy (BSSRO) and simultaneous dental implant surgery. Mandibular position was determined by model surgery through the diagnostic wax up and restoration of fractured teeth. The precise amount of the mandibular shift can be obtained from the ideal intercuspation of remaining teeth. CLINICAL IMPLICATION. Mandibular displacement by both condylar fractures can be successfully treated by orthognathic surgery. Determination of occlusal plane and visualization from diagnostic wax up are mandatory for mandibular repositioning of model surgery. Stable occlusion and regular recall check up are needed for long-term outcome.

• 대한족부족관절학회지
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• 제2권1호
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• pp.19-29
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• 1998

The characteristics of the patients after the calcaneal fracture that were associated with an unsatisfactory outcome were subtalar incongruity, decreased Bohler angle ratio of the fractured to the normal side, an age of more than fifty years, work involving strenuous labor, and increased time missed from work due to the injury. The purpose of this study was to examine the reliability of measurements of the range of motion of the subtalar joint. To determine reliability, evaluates of the correlatioinship between the degree of the displacement of the subtalar joint and Circle draw test after the calcaneal fracture. Fifty patients who had had fifty five calcaneal fractures were managed with open reduction and internal fixation. The results were reviewed retrospectively, between 4months and three years after the operation, with use of an evaluation system for the subtalar joint and with plain radiographs. At follow up evaluation, the result was assessed on the basis of restoration of anatomy and function of the subtalar joint. We evaluated the subtalar joint with plain films that consist of anteroposterior projection, lateral projection, calcaneal axial view, and Broden's view, and the measurements of the displacement of the subtalar joint surface after the calcaneal fracture. And we evaluated the range of motion of the subtalar joint with Circle draw test for physical evaluation. Circle draw test was evaluated and demonstrated the motion of flexion-supination-adduction and extension-pronation-abduction of the subtalar joint. And there are correlationship between the degree of the displacement and range of motion of the subtalar joint after the calcaneal fracture. The report critically reviews methords used to measure Circle draw test for physical examination of the follow up after the calcaneal fracture.

• Journal of Advanced Marine Engineering and Technology
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• 제33권4호
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• pp.533-538
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• 2009

The magnitude of constraint effect $A_2$ values on the non-linear elastic plastic fracture toughness was experimentally estimated by using displacement at various measuring positions near crack tip. Constraint effect $A_2$ value was dependent on specimen configuration and on the measured displacement near crack front. The crack tip opening displacement in the vicinity of the crack tip front should be estimated within plastic region when appropriately constraint effect was calculated. It was found that the magnitude of constrain effect |$A_2$| is below 8.0 at the crack tip. But an appropriate location to measure the effective constraint effects $A_2$ at the critical value of J that crack initiation is characterizable by is r = 2mm and ${\theta}=90^{\circ}$ away from original crack tip, and the constraint effect |$A_2$| estimated is 5.3.