INTRODUCTION: The aim was to study nickel-titanium closed-coil springs in a clinically relevant test setting with respect to the accuracy of the "preactivation" for nickel-titanium closed-coil springs application and whether it is possible to keep activation forces constant during the whole time of treatment. METHODS: We tested 10 types of springs from 5 manufacturers under clinically relevant conditions, allowing us to study the interactions between load and temperature over time. Hystereses were compared using t tests. RESULTS: Springs with a large mechanical hysteresis also showed a large thermal hysteresis. After heating shock, these springs showed intensive force spikes and persistent high loads. Some springs showed negligible thermal and mechanical hysteresis. Such springs never showed any clinically significant persistent high loads. CONCLUSIONS: Springs with a large hysteresis were unable to keep activation forces constant during the whole time of treatment even after any preactivation, and they might cause persistently high loads and possibly overloading. Only springs with minor hysteresis, low temperature dependence of force, and a clinically useful plateau have the following clinical advantages: reduced chair time, optimal rates of tooth movement, reproducible clinical results, and conservation of anchorage.

• MeSH
• analýza zatížení zubů přístrojové vybavení   MeSH
• lidé MeSH
• mechanické jevy MeSH
• mechanický stres MeSH
• nikl chemie   MeSH
• nízká teplota MeSH
• ortodontické dráty * MeSH
• pružnost MeSH
• termodynamika MeSH
• testování materiálů MeSH
• titan chemie   MeSH
• torze mechanická MeSH
• vysoká teplota MeSH
• zubní slitiny chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• nikl MeSH
• titan MeSH
• titanium nickelide MeSH Prohlížeč
• zubní slitiny MeSH

The therapeutic applications of titanium-nickel (TiNi) shape memory clamps with optimized structural characteristics for fixation of small bone fragments in 64 patients are presented. Our fixative makes compressive stabilization possible and enables a patient to start rehabilitation very soon after surgery. The supporting splint immobilization never exceeded 12 days. Three aspects were studied: bone union, wound healing problems and histology. Non-union occurred in 4 patients treated with only one fixative. Two clamps implanted in non-parallel planes seem to be advisable to exclude the need for longer immobilization. Neither toxic manifestation nor episodes of an allergic reaction occurred. No suppuration appeared when a heat stimulus was supplied by using a contact resistance heater. Histological evaluation of the tissue covering the implants in 22 patients did not reveal any adverse reaction. Our study suggests that by using TiNi clamps in an appropriate way, satisfactory outcomes could be achieved with respect to both biofunctionality and biocompatibility.

• MeSH
• chirurgické nástroje * MeSH
• hojení fraktur fyziologie   MeSH
• interní fixátory MeSH
• kosti nohy (od hlezna dolů) zranění   chirurgie   MeSH
• lidé MeSH
• metakarpofalangeální kloub zranění   chirurgie   MeSH
• následné studie MeSH
• nikl * MeSH
• poranění nohy (od hlezna dolů) diagnostické zobrazování   chirurgie   MeSH
• poranění ruky diagnostické zobrazování   chirurgie   MeSH
• radiografie MeSH
• remodelace kosti fyziologie   MeSH
• slitiny * MeSH
• titan * MeSH
• tříštivé fraktury diagnostické zobrazování   patologie   chirurgie   MeSH
• vnitřní fixace fraktury škodlivé účinky   přístrojové vybavení   metody   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• práce podpořená grantem MeSH
• Názvy látek
• nikl * MeSH
• slitiny * MeSH
• titan * MeSH
• titanium nickelide MeSH Prohlížeč

This paper deals with composite structures for biomedical applications. For this purpose, an architectured tubular structure composed of Nickel Titanium (NiTi) Shape Memory Alloy (SMA) and silicone rubber was fabricated. One of the main interests of such structures is to ensure a good adhesion between its two constitutive materials. A previous study of the authors (Rey et al., 2014) has shown that the adhesion between NiTi and silicone rubber can be improved by an adhesion promoter or plasma treatment. However, adhesion promoters are often not biocompatible. Hence, plasma treatment is favored to be used in the present study. Three different gases were tested; air, argon and oxygen. The effects of these treatments on the maximum force required to pull-out a NiTi wire from the silicone rubber matrix were investigated by means of pull-out tests carried out with a self-developed device. Among the three gases, a higher maximum force was obtained for argon gas in the plasma treatment. A tube shaped architectured NiTi/silicone rubber structure was then produced using this treatment. The composite was tested by means of a bulge test. Results open a new way of investigations for architectured NiTi-silicone structures for biomechanical applications.

• Klíčová slova
• Adhesion, Architectured composite, Biomedical applications, Filled silicone rubber, Interface, NiTi,
• MeSH
• argon chemie   MeSH
• kyslík chemie   MeSH
• nikl krev   chemie   MeSH
• pevnost v tahu MeSH
• silikonové elastomery chemie   MeSH
• slitiny chemie   MeSH
• testování materiálů MeSH
• titan krev   chemie   MeSH
• vzduch MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• argon MeSH
• kyslík MeSH
• nikl MeSH
• silikonové elastomery MeSH
• slitiny MeSH
• titan MeSH
• titanium nickelide MeSH Prohlížeč

Nickel-titanium alloy (nitinol, NiTi) is a biomaterial with unique thermal shape memory, superelasticity and high damping properties. Therefore NiTi has been used in medical applications. In this in vitro study, the effect of NiTi alloy (with two surface modifications - helium and hydrogen) on gene expression profile of selected interleukins (IL-1β, IL-6 and IL-8) and matrix metalloproteinases (MMP-1 and MMP-2) in human physiological osteoblasts and human osteoarthritic osteoblasts was examined to respond to a question of the different behavior of bone tissue in the implantation of metallic materials in the presence of cells affected by the osteoarthritic process. The cells were cultivated in contact with NiTi and with or without LPS (bacterial lipolysaccharide). Changes in expression of target genes were calculated by 2-ΔΔCt method. An increased gene expression of IL-1β in osteoarthritic osteoblasts, with even higher expression in cells collected directly from the metal surface was observed. In case of physiological osteoblasts, the change in expression was detected after LPS treatment in cells surrounding the disc. Higher expression levels of IL-8 were observed in osteoarthritic osteoblasts after NiTi treatment in contact with alloy, and in physiological osteoblasts without relation to location in combination of NiTi and LPS. IL-6 was slightly increased in physiological osteoblastes after application of LPS. MMP-1 expression level was obviously significantly higher in osteoarthritic osteoblasts with differences regarding the metal surface and location. MMP-2 expression was decreased in both cell lines after LPS treatment. In conclusion, results of present study show that the NiTi alloy and the treatment by LPS, especially repeated doses of LPS, change the gene expression of selected ILs and MMPs in human osteoblast cell cultures. Some of the changes were depicted solely to osteoarthritic osteoblasts.

• MeSH
• biokompatibilní materiály chemie   farmakologie   MeSH
• cytokiny MeSH
• kultivované buňky MeSH
• lidé MeSH
• lipopolysacharidy MeSH
• nikl farmakologie   MeSH
• osteoartróza * MeSH
• osteoblasty účinky léků   metabolismus   MeSH
• regulace genové exprese účinky léků   MeSH
• testování materiálů MeSH
• titan farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biokompatibilní materiály MeSH
• cytokiny MeSH
• lipopolysacharidy MeSH
• nikl MeSH
• titan MeSH
• titanium nickelide MeSH Prohlížeč

Metallic biomaterial alloys composed of nickel and titanium have unique thermal shape memory, superelastic, and high damping properties, which are widely used in the medicine. The major parameter evaluated in the studies regarding the behaviour of the material in the contact with organism or cells is biocompatibility. The aim of the studies is to clarify the differences in the proliferation, growth, and morphology especially in the cell cultures. The cytotoxicity is affected among other by release of the metal ions in the presence of the metal alloy, which is further dependent on the possible treatments of the material and the corrosive properties. To evaluate the cytotoxicity, wide range of tests including the Sulforhodamine B assay and MTT tests, expression profiles, cell survival tests such as apoptotic test are used. The review compares the cell behaviour in contact with the material alloys composed of nickel and titanium with respect to different materials composition and different surface treatment that affects the ion release. Even though the results published so far are controversial, almost all data suggest sufficient biocompatibility in medical use.

• Klíčová slova
• Alloy, Biocompatibility, Biomaterial, Cell, NiTi,
• MeSH
• apoptóza účinky léků   MeSH
• biokompatibilní materiály chemie   farmakologie   MeSH
• endoteliální buňky pupečníkové žíly (lidské) cytologie   účinky léků   fyziologie   MeSH
• kmenové buňky cytologie   účinky léků   fyziologie   MeSH
• krysa rodu Rattus MeSH
• kultivované buňky MeSH
• lidé MeSH
• myocyty hladké svaloviny cytologie   účinky léků   fyziologie   MeSH
• nádorové buněčné linie MeSH
• nikl chemie   farmakologie   MeSH
• proliferace buněk účinky léků   MeSH
• rhodaminy chemie   MeSH
• titan chemie   farmakologie   MeSH
• tuková tkáň cytologie   účinky léků   fyziologie   MeSH
• viabilita buněk účinky léků   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• biokompatibilní materiály MeSH
• lissamine rhodamine B MeSH Prohlížeč
• nikl MeSH
• rhodaminy MeSH
• titan MeSH
• titanium nickelide MeSH Prohlížeč