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1.
Article in Chinese | WPRIM | ID: wpr-880469

ABSTRACT

OBJECTIVE@#The design and development of split memory alloy sternum bone plate are discussed, and the effect of split memory alloy sternum bone plate internal fixation in the treatment of sternal fractures are analysed.@*METHODS@#The structure of the product is designed according to the anatomy and physiological characteristics of human bones, and the cross section shape of the product is designed according to the cross section shape of human bones. Internal fixation is effective in the treatment of sternal fracture.@*RESULTS@#The split memory alloy sternal plate was successfully designed and developed, and all the patients with sternal fractures treated by internal fixation were clinically healed, the hospitalization and fracture healing time were significantly shortened, and no obvious complications occurred.@*CONCLUSIONS@#The application of split memory alloy sternal plate internal fixation in the treatment of sternal fracture has the advantages of small trauma, simple operation, safety, reliable fixation, good histocompatibility and less complications, and is conducive to promoting fracture healing and respiratory function improvement.


Subject(s)
Alloys , Bone Plates , Fracture Fixation, Internal , Fracture Healing , Humans , Sternum/surgery
2.
Article in Chinese | WPRIM | ID: wpr-880436

ABSTRACT

Effects of heat treatment conditions (including temperature and time) on the shape memory recovery and corrosion resistance of NiTi self-expanding vascular stents were studied based on working mechanism and clinical use. The


Subject(s)
Alloys , Corrosion , Hot Temperature , Materials Testing , Stents , Surface Properties , Temperature , Titanium
3.
J. appl. oral sci ; 29: e20210089, 2021. tab, graf
Article in English | LILACS | ID: biblio-1340116

ABSTRACT

Abstract Background Optimal orthodontic force results in maximum rate of tooth movement without tissue damage. Even though starting orthodontic treatment with a thicker archwire may shorten treatment duration, the evidence on the effect of using 0.018-inch NiTi as the first alignment archwire on pulpal blood flow (PBF) status is still scarce. Objectives to record PBF changes and pain scores associated with using 0.018-inch NiTi as the first alignment archwire during fixed orthodontic treatment. Methodology Patients were selected from subjects attending postgraduate orthodontic teaching clinics at Jordan University of Science and Technology. In total, forty healthy patients who exhibited mild lower arch crowding were included. A split-mouth trial design was used. Each patient received two archwire sizes at one time joined in the midline by crimpable hook and applied in the lower arch. Patients were assigned into one of two groups based on archwire sizes used. Group 1: 0.014-inch and 0.018-inch NiTi (Six males, 14 females aged 19.4±1.33 years) and Group 2: 0.016-inch and 0.018-inch NiTi (Seven males, 13 females aged 19.6±1.45 years). The archwire size group was randomly allocated with a 1:1 allocation ratio. A Laser Doppler Flowmeter was used to measure PBF at different time intervals (T0-T5). Pain scores were recorded using a visual analogue scale (VAS). A repeated measures ANOVA and a post-hoc Bonferroni comparison tests were conducted to examine differences at the different time points before and during orthodontic alignment. Results For all studied archwire sizes, PBF decreased 20 minutes after their placement. Most PBF changes occurred within 24hours and continued to decrease until 72 hours after archwire placement where the maximum reduction was reached. Eventually, normal values were reverted within 1 month. PBF changes were similar between all alignment - groups. Conclusions Initial orthodontic alignment with 0.018-inch NiTi does not cause irreversible changes to pulpal vasculature or produces higher pain scores.


Subject(s)
Humans , Orthodontic Wires , Pain , Prospective Studies , Alloys
4.
Article in Chinese | WPRIM | ID: wpr-879278

ABSTRACT

Lower extremity movement is a complex and large range of limb movement. Arterial stents implanted in lower extremity are prone to complex mechanical deformation, so the stent is required to have high comprehensive mechanical properties. In order to evaluate the mechanical property of different stents, in this paper, finite element method was used to simulate and compare the mechanical properties of six nitinol stents (Absolute Pro, Complete SE, Lifestent, Protégé EverFlex, Pulsar-35 and New) under different deformation modes, such as radial compression, axial compression/tension, bending and torsion, and the radial support performance of the stents was verified by experiments. The results showed that the comprehensive performance of New stent was better than other stents. Among which the radial support performance was higher than Absolute Pro and Pulsar-35 stent, the axial support performance was better than Complete SE, Lifestent and Protégé EverFlex stent, the flexibility was superior to Protégé Everflex stent, and the torsion performance was better than Complete SE, Lifestent and Protégé Everflex stent. The TTR2 type radial support force tester was used to test the radial support performance of 6 types, and the finite element analysis results were verified. The mechanical properties of the stent are closely related to the structural size. The result provides a reference for choosing a suitable stent according to the needs of the diseased location in clinical applications.


Subject(s)
Alloys , Femoral Artery , Finite Element Analysis , Lower Extremity , Mechanical Phenomena , Prosthesis Design , Stents , Stress, Mechanical
5.
Rev. cient. odontol ; 8(2): e018, mayo-ago. 2020. ilus, tab
Article in Spanish | LILACS, LIPECS | ID: biblio-1119296

ABSTRACT

Antecedentes: Las limas rotatorias de níquel-titanio con tratamiento termomecánico se desarrollaron para permitir una mayor flexibilidad al instrumentar los conductos radiculares. Los instrumentos permitieron a los operadores tratar las curvaturas de los conductos con mayor facilidad. Los fabricantes están tratando de producir limas que funcionen de manera más eficiente y segura. Conocer las propiedades de las limas comercializadas es especialmente importante porque ayuda a elegir un sistema de lima apropiado. El objetivo de este estudio fue evaluar la flexibilidad de tres limas diferentes de níquel-titanio (NiTi) con tratamiento termomecánico en dos puntos diferentes. Materiales y métodos: Se midió la flexibilidad de tres limas NiTi con tratamiento termomecánico (ProTaper Gold, 2Shape y V-Taper Fanta Gold). Cada lima fue sujetada a 3 mm y 7 mm (n = 10/longitud/lima) y se utilizó una máquina de ensayo universal para doblarla a una fuerza máxima. Todos los datos fueron analizados estadísticamente por análisis de varianza de una vía y prueba de Tukey post hoc (p = 0,05) para determinar cualquier diferencia significativa. Resultados: Se halló diferencias estadísticamente significativas (p < 0,05). En general, V-Taper Fanta Gold fue la más rígida, ProTaper Gold mostró los mayores valores de fuerza y su deformación fue significativamente más flexible. Conclusión: Las limas ProTaper Gold mostraron una mayor flexibilidad en comparación con las otras limas estudiadas. (AU)


Background: Nickel-titanium rotary files with thermomechanical treatment were developed to allow greater flexibility when instrumenting the root canals. The instruments allowed operators to deal with duct curvatures more easily. Manufacturers are trying to produce files that work better efficiently and safely. Knowing the properties of marketed files is especially important in helping you choose an appropriate file system. The objective of this study was to evaluate the flexibility of three different nickel-titanium (NiTi) files with thermomechanical treatment at two different points along the file. Materials and methods: The flexibility of three NiTi files with thermomechanical treatment (Protaper Gold, 2Shape and V-Taper Fanta Gold) was measured. Each file was clamped at 3 mm and 7 mm (n = 10 / length / file) and a universal testing machine was used to bend the files to a maximum strength. All data were statistically analyzed by one-way analysis of variance and post-hoc Tukey test (P = 0.05) to determine any significant differences. Results: There were statistically significant differences (P <0.05). In general, V-Taper Fanta Gold was the most rigid, Protaper Gold showed the highest values of force and deformation was significantly more flexible. Conclusión: Protaper Gold files showed greater flexibility compared to the other files studied. (AU)


Subject(s)
Titanium , Pliability , Dental Instruments , Alloys , Nickel
6.
J. oral res. (Impresa) ; 9(4): 336-349, ago. 31, 2020. ilus, tab
Article in English | LILACS | ID: biblio-1179158

ABSTRACT

Background: Osseointegration allowed for a breakthrough in biomaterials and techniques and it has contributed to increased application of dental implants. However, insufficient bone level is a frequent problem and it creates an anatomically less favourable base for implant placement. The first surgical procedure should comprise the reconstruction of the alveolar bone height. CoCrMo alloys are nowadays considered as highly corrosion resistant and biocompatible materials in dentistry, and therefore has been suggested as a suitable biomaterial for guided bone regeneration and tissue engineering. Aim: To determine the use of CoCrMo alloy for implantable devices in oral and maxillofacial surgery and to discuss the potential of this alloy for bone regeneration and repair through a scoping review. Material and methods: The search was done by using various databases including PubMed, Thomson Reuters and Scopus. We selected English literature related to studies reporting the CoCrMo properties and manufacturing processes and findings related to bone-forming techniques. Data was compared qualitatively. Results: 90 studies were selected according to the inclusion criteria. We reported different manufacturing techniques and their advantages related to mechanical, chemical and biocompatible properties. Conclusion: Improved tissue reactions of CoCrMo implant devices can be acquired by the application of novel techniques and surface modifications. Moreover, several processes have demonstrated to improve the in vitro and in vivo biocompatibility of the CoCrMo alloy to promote the attachment, proliferation and guided differentiation of seeding cells.


Antecedentes: La osteointegración ha permitido un gran avance en biomateriales y técnicas, y ha contribuido un mayor uso de implantes dentales. Sin embargo, la existencia de un nivel óseo insuficiente es un problema frecuente y crea una base anatómicamente menos favorable para la colocación de implantes. El primer procedimiento quirúrgico debe comprender la reconstrucción de la altura del hueso alveolar. Las aleaciones de CoCrMo se consideran hoy en día como materiales altamente resistentes a la corrosión y biocompatibles en odontología y, por lo tanto, se ha sugerido como un biomaterial adecuado para la regeneración ósea guiada y la ingeniería de tejidos. Objetivo: Determinar el uso de la aleación CoCrMo para dispositivos implantables en cirugía oral y maxilofacial y discutir sobre el potencial de esta aleación para la regeneración y reparación ósea a través de una revisión de alcance. Material y Métodos: La búsqueda se realizó utilizando varias bases de datos, incluidas PubMed, Thomson Reuters y Scopus. Se seleccionó literatura inglesa relacionada con estudios que informan sobre las propiedades de CoCrMo y los procesos de fabricación y los hallazgos relacionados con las técnicas de formación de huesos. Los datos se compararon cualitativamente. Resultados: Se seleccionaron 90 estudios según los criterios de inclusión. y se reportaron diferentes técnicas de fabricación y sus ventajas relacionadas con propiedades mecánicas, químicas y biocompatibles. Conclusión: Las reacciones tisulares mejoradas de los dispositivos de implante CoCrMo pueden adquirirse mediante la aplicación de nuevas técnicas y modificaciones de la superficie. Además, varios procesos han demostrado mejorar la biocompatibilidad in vitro e in vivo de la aleación CoCrMo para promover la unión, proliferación y diferenciación guiada de las células de siembra.


Subject(s)
Humans , Surgery, Oral/methods , Biocompatible Materials , Alloys , Bone Regeneration , Dental Implants , Alveolar Ridge Augmentation
7.
Int. j. morphol ; 38(4): 909-913, Aug. 2020. tab, graf
Article in English | LILACS | ID: biblio-1124875

ABSTRACT

Porous titanium alloy scaffold was widely used in treating bone defect caused by traumatic injury and osteomyelitis, which was incapable of self-healing. The implantation of scaffold produced stress shielding thereby forming osteolysis. The objective of this study was to analysis trabecular morphological features of osseointegrated bone. 14 New Zealand rabbits were divided into two groups, surgery group and healthy control group. 7 rabbits in surgery group were selected to perform 3D printed porous titanium alloy scaffold implantation surgery with preload at the defect of femoral condyle for osseointegration. The other 7 rabbits in control group were feed free. After 90 days healing, femoral condyles were extracted to perform micro-CT scanning with hydroxyapatite calibration phantom. Mean bone mineral density (BMD), bone volume fraction (BV/TV), BS/TV (bone surface area ratio), Tb.Th (thickness of trabeculae), Tb.N (number of trabeculae), Tb.Sp (trabecular separation) and DA (degree of anisotropy) were calculated from micro-CT images. The results revealed that osseointegration inside and at the surface of scaffolds worked well from grey values of micro-CT images. After 12 weeks healing, mean bone mineral densities (BMD) in surgery group and healthy control group were calculated as 800±20mg/cm3 and 980±90mg/cm3, respectively. This revealed that the strength of trabeculae in surgery group might lower than that in the healthy group. Trabecular morphological parameters test showed that trabecular morphological parameters at the surface of scaffolds in the surgery group deteriorated significantly. It was found from micro-CT images that ingrowth bone was filled with pores of scaffold. Overall, the effect of osseointegration was promoted through the change of mechanical micro-environment in the scaffold region. Overall, preload could improve osseointegration effect in the long-term after surgery. However, the trabecular morphology in the surgery group was deteriorated, which might bring secondary fracture risk again.


La malla de aleación de titanio poroso se usó ampliamente en el tratamiento de defectos óseos causados por lesiones traumáticas y osteomielitis. El implante de la malla generó una protección contra el estrés, formando así osteolisis. El objetivo de este estudio fue analizar las características morfológicas trabeculares del hueso osteointegrado. Se dividieron 14 conejos (Neozelandeses) en dos grupos, grupo cirugía y grupo control saludable. Se seleccionaron 7 conejos en el grupo de cirugía para realizar una implantación de mallas de aleación de titanio poroso, impresas en 3D con precarga en el defecto del cóndilo femoral para la osteointegración. Los 7 conejos restantes del grupo control se mantuvieron sin alimentación. Después de 90 días de curación, se extrajeron los cóndilos femorales para realizar una exploración por micro-CT con un espectro de calibración de hidroxiapatita. Se calcularon a partir de imágenes de micro-CTDensidad mineral ósea media (DMO), fracción de volumen óseo (BV / TV), BS / TV (relación de área de superficie ósea), Tb.Th (espesor de trabéculas), Tb.N (número de trabéculas), Tb.Sp (trabecular separación) y DA (grado de anisotropía). Los resultados revelaron que la osteointegración dentro y en la superficie de los andamios funcionó bien a partir de los valores grises de las imágenes de micro-CT. Después de 12 semanas de curación, las densidades medias de minerales óseos (DMO) en el grupo cirugía y en el grupo control sano se calcularon como 800 ± 20 mg/cm3 y 980 ± 90 mg/cm3, respectivamente. Esto reveló que la fuerza de las trabéculas en el grupo de cirugía podría ser menor que la del grupo sano. La prueba de parámetros morfológicos trabeculares mostró que en el grupo de cirugía, la superficie de las mallas, se deterioraron significativamente. Se descubrió a partir de imágenes de microCT que el hueso en crecimiento estaba lleno de poros de andamio. En general, el efecto de la osteointegración se promovió mediante el cambio del microambiente mecánico en la región de la malla. En general, la precarga podría mejorar el efecto de osteointegración a largo plazo después de la cirugía. Sin embargo, la morfología trabecular en el grupo de cirugía se deterioró, lo que podría traer un nuevo riesgo de fractura secundaria.


Subject(s)
Animals , Rabbits , Bone Diseases/surgery , Osseointegration/physiology , Tissue Scaffolds/chemistry , Printing, Three-Dimensional , Prostheses and Implants , Titanium/chemistry , Porosity , Alloys , X-Ray Microtomography , Femur/surgery
8.
Ortodoncia ; 84(168-169): 50-55, jul. 2020 -jun.2021. ilus
Article in Spanish | LILACS, BINACIS, UNISALUD | ID: biblio-1292475

ABSTRACT

La secuencia de arcos en ortodoncia, sobre todo, durante el alineado y nivelado es un tema de gran interés. Para esta etapa se han sugerido fuerzas de 50 gf que no superan la presión hidrostática capilar y no producen reabsorción radicular. El Nitinol es la aleación indicada en sus distintas variantes. Las revisiones sistemáticas no han hallado ventaja de ninguna secuencia de arcos, incluso, equiparando arcos de acero con figuras con el Nitinol termoelástico. La selección de la secuencia de arcos para un paciente depende de las características de la maloclusión(AU)


The sequence of arches in orthodontics especially during alignment and leveling is a subject of great interest. For this stage 50 g forces that do not exceed the capillary hydrostatic pressure and do not produce root resorption have been suggested. Nitinol is the indicated alloy in its different variants. Systematic Reviews have found no advantage of any arch sequence even by matching steel arches with figures with thermoelastic Nitinol. The selection of arch sequence for a patient depends on the characteristics of malocclusion(AU)


Subject(s)
Orthodontic Wires , Root Resorption , Titanium , Tooth Movement Techniques , Alloys , Nickel
9.
Article in Korean | WPRIM | ID: wpr-786597

ABSTRACT

PURPOSE: The aim of this study is to evaluate the effectiveness of MnO₂-diatom microbubbler (DM) on the surface of prosthetic materials as a mouthwash by comparing the biofilm removal effect with those previously used as a mouthwash in dental clinic.MATERIALS AND METHODS: DM was fabricated by doping manganese dioxide nanosheets to the diatom cylinder surface. Scanning electron microscopy (SEM) was used to observe the morphology of DM and to analyze the composition of doped MnO₂. Stereomicroscope was used to observe the reaction of DM in 3% hydrogen peroxide. Non-precious metal alloys, zirconia and resin specimens were prepared to evaluate the effect of biofilm removal on the surface of prosthetic materials. And then Streptococcus mutans and Porphyromonas gingivalis biofilms were formed on the specimens. When 3% hydrogen peroxide solution and DM were treated on the biofilms, the decontamination effect was compared with chlorhexidine gluconate and 3% hydrogen peroxide solution by crystal violet staining.RESULTS: Manganese dioxide was found on the surface of the diatom cylinder, and it was found to produce bubble of oxygen gas when added to 3% hydrogen peroxide. For all materials used in the experiments, biofilms of the DM-treated groups got effectively removed compared to the groups used with chlorhexidine gluconate or 3% hydrogen peroxide alone.CONCLUSION: MnO₂-diatom microbubbler can remove bacterial membranes on the surface of prosthetic materials more effectively than conventional mouthwashes.


Subject(s)
Alloys , Biofilms , Chlorhexidine , Decontamination , Dental Clinics , Dental Plaque , Diatoms , Gentian Violet , Hydrogen Peroxide , In Vitro Techniques , Manganese , Membranes , Microscopy, Electron, Scanning , Mouthwashes , Oral Hygiene , Oxygen , Porphyromonas gingivalis , Streptococcus mutans
10.
Article in Chinese | WPRIM | ID: wpr-828162

ABSTRACT

In order to evaluate the safety performance of self-expandable NiTi alloy stents systematically, the dynamic safety factor drawn up by International Organization for Standardization, was used to quantitatively reflect the safety performance of stents. Based on the constitutive model of super-elastic memory alloy material in Abaqus and uniaxial tensile test data of NiTi alloy tube, finite element method and experiments on accelerated fatigue life were carried out to simulate the self-expansion process and the shape change process under the action of high and low blood pressure for three -type stents of 8×30 mm, 10×30 mm, 12×30 mm. By analyzing the changes of stress and strain of self-expanding NiTi alloy stent, the maximum stress and strain, stress concentration position, fatigue strength and possible failure modes were studied, thus the dynamic safety factor of stent was calculated. The results showed that the maximum stress and plastic strain of the stent increased with the increase of grip pressure, but the maximum stress and strain distribution area of the stent had no significant change, which were all concentrated in the inner arc between the support and the connector. The dynamic safety factors of the three stents were 1.31, 1.23 and 1.14, respectively, which indicates that the three stents have better safety and reliability, and can meet the fatigue life requirements of more than 10 years, and safety performance of the three stents decreases with the increase of stent's original diameter.


Subject(s)
Alloys , Finite Element Analysis , Nickel , Reproducibility of Results , Self Expandable Metallic Stents , Stress, Mechanical , Titanium
11.
Article in Chinese | WPRIM | ID: wpr-879375

ABSTRACT

Titanium alloy has good biological properties and is commonly used in orthopedics, but its bone integrity and antibacterial properties are poor, so surface modification is needed to make up for its shortcomings. Chitosan has good biocompatibility and film forming ability, and can be used as a carrier to introduce the target drug to the surface of titanium alloy, which can effectively improve the biological properties of titanium alloy materials and increase its application range. In this paper, the related research of chitosan surface modified titanium alloy materials in recent years is summarized. The modification methods of chitosan coating, the improvement of osteogenesisand antibacterial properties of titanium alloy materials are discussed in order to provide guidance for the clinical application of coating modification of titanium alloy materials.


Subject(s)
Alloys , Anti-Bacterial Agents/pharmacology , Chitosan , Orthopedics , Surface Properties , Titanium
12.
Article in Chinese | WPRIM | ID: wpr-879228

ABSTRACT

External support stent is a potential means for restricting the deformation and reducing wall stress of the vein graft, thereby improving the long-term patency of the graft in coronary artery bypass surgery. However, there still lacks a theoretical reference for choosing the size of stent based on the diameter of graft. Taking the VEST (venous external support) stent currently used in the clinical practice as the object of study, we constructed three models of VEST stents with different diameters and coupled them respectively to a model of the great saphenous vein graft, and numerically simulated the expansion-contraction process of the vein graft under the constraint of the stents to quantitatively evaluate the influence of stent size on the radial deformation and wall stress of the vein graft. The results showed that while the stent with a small diameter had a high restrictive effect in comparison with larger stents, it led to more severe concentration of wall stress and sharper changes in radial deformation along the axis of the graft, which may have adverse influence on the graft. In order to solve the aforementioned problems, we ameliorated the design of the stent by means of changing the cross-sectional shape of the thick and thin alloy wires from circle into rectangle and square, respectively, while keeping the cross-sectional areas of alloy wires and stent topology unchanged. Further numerical simulations demonstrated that the ameliorated stent evidently reduced the degrees of wall stress concentration and abrupt changes in radial deformation, which may help improve the biomechanical environment of the graft while maintaining the restrictive role of the stent.


Subject(s)
Alloys , Coronary Artery Bypass , Saphenous Vein/surgery , Stents
13.
Braz. dent. j ; 30(6): 607-616, Nov.-Dec. 2019. tab, graf
Article in English | LILACS | ID: biblio-1055448

ABSTRACT

Abstract Diamond-like carbon (DLC) film is a biocompatible hard coating material that can prevent the leaching of metal ions. This study evaluates the structural characteristics of DLC, with and without silver nanoparticles, deposited by plasma (PECVD) on titanium alloy (Ti-6Al-4V) and bone formation in contact with DLC films. Sixty Ti-6Al-4V samples were used divided in: uncoated, coated with DLC and coated with DLC-Ag. After structural characterization, samples were fixed bilaterally at the rabbit's mandible. After 15 and 90 days, samples were characterized again and bone formation in the area was analyzed by histomorphometry. Statistical analysis was performed by two-way ANOVA. Both the DLC and DLC-Ag films were firmly adhered and showed a high electrical resistance without significant changes in the Raman spectrum after in vivo integration. After 15 days, there were immature bone trabeculae in the interface and partially covering the surface. After 90 days, mature bone filled the interface and coved the surface. There was no statistically significant difference among the three groups in both periods. In conclusion, osseointegration with DLC, DLC-Ag and uncoated Ti-6Al-4V is similar. However, DLC and DLC-Ag coverings have the advantage of electrical insulation and can presumably control bacterial activity and ion leaching.


Resumo O filme de carbono semelhante a diamante (DLC) é um material de revestimento duro e biocompatível que pode impedir a corrosão com liberação de íons metálicos. Este estudo avaliou as características estruturais do filme de DLC, com e sem nanopartículas de prata (Ag), depositadas por plasma (PECVD) em liga de titânio (Ti-6Al-4V) e formação óssea em contato com filmes de DLC. Foram utilizadas 60 amostras de Ti-6Al-4V divididas em: não recobertas, recobertas com DLC e recobertas com DLC-Ag. Após caracterização estrutural, amostras foram fixadas bilateralmente na mandíbula de coelhos. Após 15 e 90 dias, as amostras foram novamente caracterizadas e a formação óssea na área foi analisada por histomorfometria. A análise estatística foi realizada por ANOVA dois fatores. Ambos os filmes DLC e DLC-Ag foram firmemente aderidos e mostraram uma alta resistência elétrica sem alterações significativas no espectro Raman após a osseointegração in vivo. Após 15 dias, havia trabéculas ósseas imaturas na interface e cobrindo parcialmente a superfície. Após 90 dias, o osso maduro preencheu a interface e a superfície. Não houve diferença estatisticamente significante entre os três grupos nos dois períodos. Em conclusão, a osseointegração com DLC, DLC-Ag e Ti-6Al-4V não revestido é similar. No entanto, os revestimentos DLC e DLC-Ag têm a vantagem do isolamento elétrico e podem presumivelmente controlar a atividade bacteriana e a corrosão com liberação de íons.


Subject(s)
Animals , Rabbits , Alloys , Metal Nanoparticles , Silver , Surface Properties , Titanium , Materials Testing , Carbon , Diamond
14.
Biomedical Engineering Letters ; (4): 435-447, 2019.
Article in English | WPRIM | ID: wpr-785530

ABSTRACT

In the recent years, there has been a growing interest in research community towards the application of smart materials for bio-medical structural health monitoring. Amongst the smart materials, directly bonded piezo sensors (DBPS), based on the electro-mechanical impedance (EMI) technique, have been successfully employed for the above purpose. The principle behind the EMI technique is that high frequency excitations (typically > 30 kHz) generated by a surface bonded PZT patch are used to detect changes in structural drive point impedance caused by cracks or any other type of damage. Bone healing and damage have been shown to be successfully monitored using the DBPS. However, in most of the diagnostic cases of live human and animal subjects, directly bonding a PZT patch is always an irritant or hazard for a live subject. To circumvent direct bonding, the authors have developed and experimentally demonstrated a non-bonded piezo sensor (NBPS) configuration as a good alternative to DBPS while maintaining the effectiveness of measurement well within discernible limits. This paper presents further improvement in the NBPS configuration aiming at autonomous operation of the gripping mechanism using shape memory alloy (SMA) wires. The experiments are performed on replicas of femur bone in healthy and osteoporosis state. This paper shows the effective use of SMA clamping for bone identification and its damage assessment in comparison to earlier mechanical gripping using jubilee clamps. This paper also covers impedance based identification applied to SMA and clamp based NBPS configurations. In place of raw admittance signatures, effective drive point impedance is utilized for the purpose of bone diagnostics which provides a more realistic assessment of the condition of bone.


Subject(s)
Alloys , Animals , Constriction , Diagnosis , Electric Impedance , Femur , Hand Strength , Humans , Memory , Osteoporosis
15.
Article in Korean | WPRIM | ID: wpr-770047

ABSTRACT

PURPOSE: To compare the results of two different instruments made of stainless steel and titanium alloy for correction of single thoracic adolescent idiopathic scoliosis (AIS) using pedicle screw instrumentation. MATERIALS AND METHODS: A total of 141 patients with single thoracic AIS treated with pedicle screw instrumentation and selective thoracic fusion were retrospectively reviewed after a follow-up of 2 years. The patients had a main thoracic curve of 40° to 75° and were divided into two groups based on instrument materials; S group (stainless steel, n=90) and T group (titanium alloy, n=51). The diameter of the stainless steel rod used was 7.0 mm while that of the titanium alloy rod was 6.35 mm or 6.0 mm. Standing long-cassette radiographic measurements including various coronal and sagittal parameters for the preoperative, early postoperative and 2-year postoperative follow-up were analyzed. There were no significant differences in the preoperative curve characteristics between the two groups. RESULTS: In the S group, the preoperative main thoracic curve of 51.3°±8.4° was improved to 19.0°±7.6° (63.1% correction) and the lumbar curve of 32.3°±8.4° spontaneously decreased to 12.7°±8.2° (62.9% correction) at 2 years postoperatively. In the T group, the preoperative main thoracic curve of 49.5°±8.4° and the lumbar curve of 30.3°±8.9° was improved to 18.8°±7.4° (62.2% correction) and 11.3°±5.4° (63.3% correction), respectively. The corrections of coronal curves were not statistically different between the two groups (p>0.05). The thoracic kyphosis was changed from 16.8°±8.5° to 24.3°±6.1° in the S group and from 19.6°±11.2° to 26.6°±8.5° in the T group. There were no significant differences in the changes of sagittal curves, coronal and sagittal balances at the 2-year follow-up and the number of fused segments and used screws between the two groups (p>0.05). CONCLUSION: When conducting surgery for single thoracic AIS using pedicles screw instrumentation, two different instruments made of stainless steel and titanium alloy showed similar corrections for coronal and sagittal curves.


Subject(s)
Adolescent , Alloys , Follow-Up Studies , Humans , Kyphosis , Pedicle Screws , Retrospective Studies , Scoliosis , Stainless Steel , Steel , Titanium
16.
Article in English | WPRIM | ID: wpr-763577

ABSTRACT

BACKGROUND: Adequate bone formation around titanium alloy implants is integral to successful implantation surgery. Stem cell-coated implants may accelerate peri-implant bone formation. This study investigates the effect of platelet-rich plasma (PRP) pretreatment on a titanium-alloy surface in terms of proliferation and osteogenic differentiation of human adipose-derived stem cells (hADSCs). METHODS: Allogenic leukocyte-depleted PRP was obtained from blood supernatants. The hADSCs were isolated from thigh subcutaneous fat tissue. Grit-blasted titanium plugs were used in two different groups. In one group, 200 µL of PRP was added to the grit-blasted titanium plugs. The hADSCs were seeded in two groups: grit-blasted titanium plugs with or without PRP. The number of hADSCs was measured after 4 hours, 3 days, and 7 days of culture using Cell Counting Kit-8. Osteogenesis of hADSCs was measured by using an alkaline phosphatase activity assay on days 7 and 14, and a calcium assay on days 14 and 21. Osteogenic gene expression was measured by using reverse transcription polymerase chain reaction analysis of alkaline phosphatase, osteocalcin, and type I collagen mRNA. The microscopic morphology of grit-blasted titanium plugs with or without PRP was examined with a field-emission scanning electron microscope using a JSM-7401F apparatus on days 1 and 7. RESULTS: Proliferation and osteogenic differentiation of hADSCs were found to be significantly higher on the grit-blasted titanium alloy preprocessed with PRP than the same alloy without pretreatment. Furthermore, a structural fibrillar mesh developed compactly on the grit-blasted titanium alloy with the PRP pretreatment. CONCLUSIONS: Our results demonstrate that a hADSC-based approach can be used for tissue-engineered peri-implant bone formation and that PRP pretreatment on the grit-blasted titanium alloy can improve proliferation and osteogenic differentiation of hADSCs.


Subject(s)
Alkaline Phosphatase , Alloys , Calcium , Cell Count , Collagen Type I , Gene Expression , Humans , Osteocalcin , Osteogenesis , Platelet-Rich Plasma , Polymerase Chain Reaction , Reverse Transcription , RNA, Messenger , Stem Cells , Subcutaneous Fat , Thigh , Titanium
17.
Article in English | WPRIM | ID: wpr-763002

ABSTRACT

The paper outlines the achievements and challenges in the additive manufacturing (AM) application to veterinary practice. The state-of-the-art in AM application to the veterinary surgery is presented, with the focus of AM for patient-specifi c implants manufacturing. It also provides critical discussion on some of the potential issues design and technology should overcome for wider and more eff ective implementation of additively manufactured parts in veterinary practices. Most of the discussions in present paper are related to the metallic implants, manufactured in this case using so-called powder bed additive manufacturing (PB-AM) in titanium alloy Ti–6AL–4V, and to the corresponding process of their design, manufacturing and implementation in veterinary surgery. Procedures of the implant design and individualization for veterinary surgery are illustrated basing on the four performed surgery cases with dog patients. Results of the replacement surgery in dogs indicate that individualized additively manufactured metallic implants signifi cantly increase chances for successful recovery process, and AM techniques present a viable alternative to amputation in a large number of veterinary cases. The same time overcoming challenges of implant individualization in veterinary practice signifi cantly contributes to the knowledge directly relevant to the modern medical practice. An experience from veterinary cases where organ-preserving surgery with 3D-printed patient-specifi c implants is performed provides a unique opportunity for future development of better human implants.


Subject(s)
Alloys , Amputation , Animals , Dogs , Humans , Osteosarcoma , Surgery, Veterinary , Titanium
18.
Yonsei Medical Journal ; : 882-886, 2019.
Article in English | WPRIM | ID: wpr-762117

ABSTRACT

Ameloblastoma in the tibia is rare. Limb reconstruction after tumor resection is challenging in terms of selection of the operative method. Here, we report a case of radical resection of an ameloblastoma in the mid-distal tibia combined with limb salvage using a three-dimensional (3D)-printed prosthesis replacement, with 1-year follow-up results. After receiving local institutional review board approval, a titanium alloy prosthesis was designed using a computer and manufactured with 3D-printing technology. During the operation, the stem of the prosthesis was inserted closely into the proximal tibial medullary cavity. Then, the metal ankle mortise and the talus were compacted closely. Radiographic results at 1-year follow up showed that the prosthesis was well placed, and no loosening was observed. The Musculoskeletal Tumor Society (MSTS) 93 functional score was 26 points, and the functional recovery percentage was 86.7%. Computer-assisted 3D-printing technology allowed for more volume and structural compatibility of the prosthesis, thereby ensuring a smooth operation and initial prosthetic stabilization. During the follow up, the presence of bone ingrowths on the porous surface of some segments of the prosthesis suggested good outcomes for long-term biological integration between the prosthesis and host bone.


Subject(s)
Alloys , Ameloblastoma , Ankle , Ethics Committees, Research , Extremities , Follow-Up Studies , Limb Salvage , Methods , Prostheses and Implants , Talus , Tibia , Titanium
19.
Article in English | WPRIM | ID: wpr-761419

ABSTRACT

PURPOSE: The present study was designed to examine the clinical fit of fixed dental prosthesis fabricated by the milling-sintering method using a presintered cobalt-chromium alloy. MATERIALS AND METHODS: Two single metal-ceramic crowns were fabricated via milling-sintering method and casting method in each of the twelve consecutive patients who required an implant-supported fixed prosthesis. In the milling-sintering method, the prosthetic coping was designed in computer software, and the design was converted to a non-precious alloy coping using milling and post-sintering process. In the casting method, the conventional manual fabrication process was applied. The absolute marginal discrepancy of the prostheses was evaluated intraorally using the triple-scan technique. Statistical analysis was conducted using Mann-Whitney U test (α=.05). RESULTS: Eight patients (66.7%) showed a lower marginal discrepancy of the prostheses made using the milling-sintering method than that of the prosthesis made by the casting method. Statistically, the misfit of the prosthesis fabricated using the milling-sintering method was not significantly different from that fabricated using the casting method (P=.782). There was no tendency between the amount of marginal discrepancy and the measurement point. CONCLUSION: The overall marginal fit of prosthesis fabricated by milling-sintering using a presintered alloy was comparable to that of the prosthesis fabricated by the conventional casting method in clinical use.


Subject(s)
Alloys , Clinical Study , Crowns , Dental Prosthesis , Humans , Methods , Prostheses and Implants
20.
Article in English | WPRIM | ID: wpr-742110

ABSTRACT

PURPOSE: The aim of this study is to evaluate the effects of various primers on the microtensile bond strength (µTBS) of resin cements to cobalt-chromium (Co-Cr) dental casting alloy. MATERIALS AND METHODS: Four adhesive primers (Universal primer, Metal primer II, Alloy primer, and Metal/Zirconia primer) and two resin cements (Panavia F2.0, G-CEM LinkAce) were tested. One hundred fifty Co-Cr beams were prepared from Co-Cr ingots via casting (6 mm length × 1 mm width × 1 mm thick). The metal beams were randomly divided into ten groups according to the adhesive primers and resin cements used; the no-primer groups served as the control (n = 15). After sandblasting with aluminum oxide (125 µm grain), the metal and resin cements were bonded together using a silicone mold. Prior to testing, all metal-resin beams were examined under stereomicroscope, and subjected to the µTBS test. The mean value of each group was analyzed via one-way ANOVA with Tukey's test as post hoc (α = .05) using SPSS software. RESULTS: The mean µTBS of all groups was ranged from 20 to 28 MPa. There is no statistically significant difference between groups (P > .05). Mixed failure, which is the combination of adhesive and cohesive failures, is the most prevalent failure mode in both the Panavia F2.0 and G-Cem LinkAce groups. CONCLUSION: The µTBS of all tested groups are relatively high; however, the primers used in this study result in no favorable effect in the µTBS of Panavia F2.0 and G-Cem LinkAce resin cement to Co-Cr alloy.


Subject(s)
Adhesives , Alloys , Aluminum Oxide , Fungi , Resin Cements , Silicon , Silicones
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