• Structural Engineering and Mechanics
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• 제86권5호
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• pp.635-645
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• 2023

This study aims to simulate the mechanical behavior of the total prosthesis model of Charnley (CMK3) by the 3D finite element method and to determine the state of the stresses in the femoral components (prosthesis, cement, and bone). The components are subjected to a dynamic load due to three activities (normal walking, climbing stairs, and standing up a chair). Static loading is by selecting the maximum load for the same activities mentioned. The results show that the maximum stresses in the proximal part of the cement are very important. Moreover, new results obtained for different parameters were discussed in detail. It is understood that current research provides important lessons for the surgeon to contribute to the clinical diagnosis of durable implantations and a better understanding of the process of bone remodeling and bone prosthesis.

• The Korean Journal of Nuclear Medicine Technology
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• 제18권1호
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• pp.49-61
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• 2014

Purpose: With the aging of the population, the attack rate of osteoporotic vertebral compression fracture is in the increasing trend, and percutaneous vertebroplasty (PVP) is the most commonly performed standardized treatment. Although there is a research report of the excellence of usefulness of the SPECT/CT examination in terns of the exact diagnosis before and after the procedure, the bone cement material used in the procedure influences the image quality by forming an artifact in the CT image. Therefore, the objective of the research lies on evaluating the effect the bone cement gives to a SPECT/CT image. Materials and Methods: The images were acquired by inserting a model cement to each cylinder, after setting the background (3.6 kBq/mL), hot cylinder (29.6 kBq/mL) and cold cylinder (water) to the NEMA-1994 phantom. It was reconstructed with Astonish (Iterative: 4 Subset: 16), and non attenuation correction (NAC), attenuation correction (AC+SC-) and attenuation and scatter correction (AC+SC+) were used for the CT correction method. The mean count by each correction method and the count change ratio by the existence of the cement material were compared and the contrast recovery coefficient (CRC) was obtained. Additionally, the bone/soft tissue ratio (B/S ratio) was obtained after measuring the mean count of the 4 places including the soft tissue(spine erector muscle) after dividing the vertebral body into fracture region, normal region and cement by selecting the 20 patients those have performed PVP from the 107 patients diagnosed of compression fracture. Results: The mean count by the existence of a cement material showed the rate of increase of 12.4%, 6.5%, 1.5% at the hot cylinder of the phantom by NAC, AC+SC- and AC+SC+ when cement existed, 75.2%, 85.4%, 102.9% at the cold cylinder, 13.6%, 18.2%, 9.1% at the background, 33.1%, 41.4%, 63.5% at the fracture region of the clinical image, 53.1%, 61.6%, 67.7% at the normal region and 10.0%, 4.7%, 3.6% at the soft tissue. Meanwhile, a relative count reduction could be verified at the cement adjacent part at the inside of the cylinder, and the phantom image on the lesion and the count increase ratio of the clinical image showed a contrary phase. CRC implying the contrast ratio and B/S ratio was improved in the order of NAC, AC+SC-, AC+SC+, and was constant without a big change in the cold cylinder of the phantom. AC+SC- for the quantitative count, and AC+SC+ for the contrast ratio was analyzed to be the highest. Conclusion: It is considered to be useful in a clinical diagnosis if the application of AC+SC+ that improves the contrast ratio is combined, as it increases the noise count of the soft tissue and the scatter region as well along with the effect of the bone cement in contrast to the fact that the use of AC+SC- in the spine SPECT/CT examination of a PVP performed patient drastically increases the image count and enables a high density of image of the lesion(fracture).

• Journal of Periodontal and Implant Science
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• 제30권4호
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• pp.793-803
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• 2000

Procedures for treatment of molar furcation invasion defects range from open flap debridement, apically repositioned flap surgery, hemisection, tunneling or extraction, to regenerative therapies using bone grafting or guided tissue regenerative therapy, or a combination of both. Several clinical evaluations using regenerative techniques have reported the potential for osseous repair of treated furcation invasions. Regenerative treatment of maxillary molars are more difficult due to the multiple root anatomy and multiple furcation entrances therefore, purpose of this study was to evaluated histologically self-curing glass-ionomer cement and light-curing glass-ionomer cement as a barrier in the treatment of a bi-furcated maxillary premolar. Five adult beagle dogs were used in this experiment. With intrasulcular and crestal incision, mucoperiosteal flap was elevated. Following decortication with 1/2 high speed round bur, degree II furcation defect was made on maxillary third(P3), forth(P4) and fifth(P5) premolar. 2 month later experimental group were self-curing glassionomer cement and light-curing glassionomer cement. After 4, 8 weeks, the animals were sacrificed by vascular perfusion. Tissue block was excised including the tooth and prepared for light microscope with Gomori's trichrome staining. Results were as follows. 1. In all experiment group, there were not epithelial down growth and glass ionomer cement were encapsulated connective tissue. 2. In 4 weeks experiment I group slighly infiltrated inflammatory cells but not disturb the new bone or new cementum formation. 3. In 8 weeks, experiment groups I, II were encapsulated fine connective tissue. 4. Therefore glass-ionomer cement filling to the grade III maxillary furcations with multiple root anatomy and multiple furcation entrances were possible clinical methods and this technique is useful method for Maxillary furcation involvement.

• The Journal of the Korean bone and joint tumor society
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• 제3권2호
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• pp.112-118
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• 1997

Multicentric chondrosarcoma other than the mesenchymal subtype is rare separate entity. We experienced a case with nonmonomelic synchronous multicentric chondrosarcoma without any preexisting lesions of Oilier's disease or Maffucci's syndrome. To our knowledge, there was no report of synchronous nonmonomelic multicentric chondrosarcoma. A thirty-three year old man had right distal thigh pain of one and half year. Bone scan showed hot lesions on medial condyle of right femur and shaft of left femur. Plain X-ray showed osteolytic lesion on right femur and slight cortical thickening and calcific lesion was observed on left femoral shaft. Curettage and bone cement filling was done on both lesions. The pathology reports were grade I chondrosarcoma on both side of femur. At one month from operation, pathologic fracture of left femur occurred on bone cement-host bone junction. Conservative treatment and radiotherapy of 60Gy was done. At 8 months from operation, nonunion was evident. Segmental resection of left femur with contralateral fibula graft and second look operation on right condyle lesion were done. At 6 months from revision, fracture occurred at host-graft bone junction. We removed previous hardware and applied long DCP and massive autogenous bone graft. Afterwards, the patient looks good and union was progressing. But at 4 years from last operation, hypertrophic nonunion occurred. Another revision was done with condylar plate and bone graft and now he is well without any sign of local recurrence or metastasis.

• The Journal of Advanced Prosthodontics
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• 제9권3호
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• pp.217-223
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• 2017

PURPOSE. This study investigated the effects of silver nanoparticle (SN) loading into hydraulic calcium silicate-based Portland cement on its mechanical, antibacterial behavior and biocompatibility as a novel dental bone substitute. MATERIALS AND METHODS. Chemically reduced colloidal SN were combined with Portland cement (PC) by the concentrations of 0 (control), 1.0, 3.0, and 5.0 wt%. The physico-mechanical properties of silver-Portland cement nanocomposites (SPNC) were investigated through X-ray diffraction (XRD), setting time, compressive strength, solubility, and silver ion elution. Antimicrobial properties of SPNC were tested by agar diffusion against Streptococcus mutans and Streptococcus sobrinus. Cytotoxic evaluation for human gingival fibroblast (HGF) was performed by MTS assay. RESULTS. XRD certified that SN was successfully impregnated in PC. SPNC at above 3.0 wt% significantly reduced both initial and final setting times compared to control PC. No statistical differences of the compressive strength values were detected after SN loadings, and solubility rates of SPNC were below 3.0%, which are acceptable by ADA guidelines. Ag ion elutions from SPNC were confirmed with dose-dependence on the concentrations of SN added. SPNC of 5.0 wt% inhibited the growth of Streptococci, whereas no antimicrobial activity was shown in control PC. SPNC revealed no cytotoxic effects to HGF following ISO 10993 (cell viability > 70%). CONCLUSION. Addition of SN promoted the antibacterial activity and favored the bio-mechanical properties of PC; thus, SPNC could be a candidate for the futuristic dental biomaterial. For clinical warrant, further studies including the inhibitory mechanism, in vivo and long-term researches are still required.

• Journal of the Korean Ceramic Society
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• 제55권6호
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• pp.590-596
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• 2018

To improve the injection behavior of brushite cement, dense ${\beta}-Ca_3(PO_4)_2$ (${\beta}-TCP$) granules were added to the starting material. The spherical ${\beta}-TCP$ granules prepared by spray-drying and subsequent sintering at $1000{\sim}1200^{\circ}C$ accounted for fractions of from 0.5 to 0.7 of the total ${\beta}-TCP$. The injection behavior was evaluated by measuring the injected mass divided by the loaded mass of paste in the syringe pump. The injected amount was increased with the increase in the fraction and sintering temperature of ${\beta}-TCP$ granules, except at $1200^{\circ}C$. The increase in the fraction of ${\beta}-TCP$ and its sintering temperature resulted in a decrease in the plastic limit, which is the volume of water required to liquefy the compact. The rest water could be utilized in the cement with the reduced plastic limit for improved injectability. The amounts of rest water assigned for powdery phase were estimated, and correlated with the injectability of paste.

• Proceedings of the Materials Research Society of Korea Conference
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.52.1-52.1
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• 2011

In this work, the effect of the addition of bioactive glass in the biocompatibility and mechanical behavior of conventional TTCP/DCPA based bone cement were investigated. The cement was initially modified with chitosan and HPMC which cross-linked with citric acid to improved mechanical properties.The injectable bone substitutes were further modified by adding varying amounts of bioactive glass (0%, 10%, 20% and 30%) and its effects on the biocompatibility of the material were studied. Afterbio-glass powders were mixed with the optimized composition for HPMC and citric acid content,the IBS was incubated at $37^{\circ}C$ at different time intervals and showed progressive formation of HAp with increasing time. Mechanical properties like Vickers hardness and compressive strength were found to increase with the increasing amount of bioactive glass addition and that setting time was shortened. The fabricated IBS morphologies were further characterized using SEM. MTT assay was performed to check the cell cytotoxicity and cell proliferation for 1, 3 and 5 days. Cell morphology, adhesion and proliferation behavior of cell in the IBS by culturing MG-63 cells on the IBS for 20, 60 and 90 mins and 1, 3 and 5 days was also investigated. All the results showed increasing biocompatibility as the bioglass content increased. MTT results found the materials to be cytocompatible and SEM images showed that cells attached and proliferated successfully.

• Journal of Biosystems Engineering
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• 제29권4호
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• pp.347-356
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• 2004

치아인회석, 키토산, 시아노아크릴레이트 등의 생분해성 생체재료를 이용해 새로운 생체흡수성 골시멘트를 개발하고자 하였다. 이들 골시멘트들에 대해서 중합온도, 응고시간 등의 조작특성과 압축강도, 전단강도 등의 물성을 분석하였다. 특히, 치아인회석과 키토산의 미립가루와 부틸 시아노아크릴레이트의 강력접착제를 이용한 시멘트(B)에 대해서는 직접 접촉방법과 XTT 방법을 통해 세포독성을 분석하였고, 또한 쥐를 이용한 동물실험에서 시멘트(B)의 처리그룹에 따라 생체적합성을 분석하였다. 시아노아크릴레이트를 이용한 골시멘트의 최대중합온도는 약 33$^{\circ}C$, 조작(응고)시간은 3-6분, 압축강도는 약 15-25㎫, 전단강도는 약 0.4-l.7 ㎫를 나타내었다. 첨가제로 사용된 Lipiodol은 골시멘트의 주사성과 강력접착제의 초기 중합지연도를 높였고, 특히 송진가루는 시아노아크릴레이트의 초기중합을 지연시켰다. 시아노아크릴레이트를 이용한 시멘트(B)의 세포독성을 분석한 결과, 대부분의 처리 그룹에서 낮게 나타났고, 특히 키토산과 치아인회석을 사용한 경우 각각 세포 독성이 더 낮게 나타났다. 그리고 골시멘트(B)의 동물 생체적합성 실험의 방사선상 및 조직학적 분석에서도 뼈 형성 및 결합이 우수하게 나타났다.

• The Korean Journal of Pain
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• 제34권4호
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• pp.375-393
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• 2021

Percutaneous osteoplasty (POP) is defined as the injection of bone cement into various painful bony lesions, refractory to conventional therapy, as an extended technique of percutaneous vertebroplasty (PVP). POP can be applied to benign osteochondral lesions and malignant metastatic lesions throughout the whole skeleton, whereas PVP is restricted to the vertebral body. Common spinal metastases occur in the thoracic (70%), lumbosacral (20%), and cervical (10%) vertebrae, in order of frequency. Extraspinal metastases into the ribs, scapulae, sternum, and humeral head commonly originate from lung and breast cancers; extraspinal metastases into the pelvis and femoral head come from prostate, urinary bladder, colon, and uterine cervical cancers. Pain is aggravated in the dependent (or weight bearing) position, or during movement (or respiration). The tenderness and imaging diagnosis should match. The supposed mechanism of pain relief in POP is the augmentation of damaged bones, thermal and chemical ablation of the nociceptive nerves, and local inhibition of tumor invasion. Adjacent (facet) joint injections may be needed prior to POP (PVP). The length and thickness of the applied needle should be chosen according to the targeted bone. Bone cement is also selected by its osteoconduction, osteoinduction, and osteogenesis. Needle route should be chosen as a shortcut to reach the target bony lesions, without damage to the nerves and vessels. POP is a promising minimally invasive procedure for immediate pain relief. This review provides a technical survey for POPs in painful bony lesions.

• The Journal of Korean Academy of Prosthodontics
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• 제39권2호
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• pp.125-145
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• 2001

To compare the stress distribution patterns between cement-retained and screw-retained implant supported fixed prostheses according to four different abutment types, a three dimensional finite element analysis was performed. The hypothetical three unit fixed partial denture case was modelled on the three implants(10mm length and 3.75 diameter) in mandibular bone. Four angles of implantation(vertical, 10, 15 and 20 degree inclined mesially) were created and three different directions of force (vertical, oblique, horizontal) were applied at the center of the second premolar and distal end of the first molar for each cases. Within the limits of this study, the results were as follows, 1. In vertically installed cases, the more stress was concentrated at upper components, but mesially inclined cases, the more stress was concentrated at cortical bone. 2, The more inclined mesially the more stress was observed, especially at cortical bone. 3. The cement-retained models showed lower principal stress and more even stress distribution than the screw-retained models. 4. The similar stress distribution pattern was showed in model 1 and model 2, model 3 and model 4. 5. The more stress was observed when the loads were applied at the distal end of 1st molar than the center of 2nd premolar. 6 The fixture and the model as a whole, lesser stress values were observed when vertical loads were applied as compared to horizontal and oblique loads.