Effects of conditions for anodization and cyclic precalcification treatments on surface characteristics and bioactivity / 대한치과재료학회지

The purpose of this study was to investigate the effects of the anodization and cyclic calcification treatment on the surface characteristic and bioactivity of the titanium thin sheet in order to obtain basic data for the production of bioactive titanium membrane. A 30×20×0.08 mm titanium sheets were prepared, and then they were pickled for 10 seconds in the solution which was mixed with HNO₃: HF: H₂O in a ratio of 12: 7: 81. The TiO₂ nanotube layer was formed to increase the specific surface area of the titanium, and then the cyclic calcification treatment was performed to induce precipitation of hydroxiapatite by improvement of the bioactivity. The corrosion resistance test, wettability test and immersion test in simulated body solution were conducted to investigate the effect of these surface treatments. The nanotubes formed by the anodization treatment have a dense structure in which small diameter tubes are formed between relatively large diameter tubes, and their inside was hollow and the outer walls were coupled to each other. The hydroxyapatite precipitates were well combined on the nanotubes by the penetration into the nanotube layer by successive cyclic calcification treatment, and the precipitation of hydroxyapatite tended to increase proportionally after immersion in simulated body solution as the number of cycles increased. In conclusion, it was confirmed that induction of precipitation of hydroxyapatite by cyclic calcification treatment after forming the nanotube TiO₂ nanotube layer on the surface of the titanium membrane can contribute to improvement of bioactivity.

Titanium specimens with different surface character affect the proliferation and IL-6 and Cbfα1 expres-sion in osteoblasts / 实用口腔医学杂志

Objective:To investigate the effects of titanium spcimens with different surface character on the proliferation and mRNA expression of IL-6 and Cbfα1 in osteoblasts.Methods:Titanium surface was treated by smooth pretreatment(PT),sandblast and acid etch(SLA)and anodic oxidation(AD)respectively.The morphology and the elements analysis of the spcimens were inspected and detected by SEMand EDS.The surface contact angle was measured by contact angle meter.MC3T3-E1 cells were cultured on the titanium surface and cells cultured on tissue culture plate were served as the control group.The proliferation was measured by MTT assay.The mRNA expression of IL-6 and Cbfα1 was quantified by RT-qPCR.Results:The sample surface in PT group showed scrat-ches,in SLA group showed multiple three dimensional structure,in AD group exhibited porous structure.The elements of the sample surface of group PT,SLA and AD were Ti,Ti/Al and Ti/O respectively;the contact angles were 54.47°±3.33°,75.42°±8.32° and 38.91 °±4.00°respectively(P<0.05).The cells in AD group showed higher proliferation than those in PT and SLA groups(P<0.05).In AD group IL-6 mRNA expression decreased and Cbfα1 mRNA increased more than in PT and SLA groups(P<0.05). Conclusion:Titanium spcimens treated with AD may promote cell proliferation,decrease IL-6 mRNA expression and increase Cbfα1 mRNA expression in MC3T3 cells.Implats treated with AD might have some advantages in early osseointegration.

A histomorphometric study of dental implants with different surface characteristics

PURPOSE: One of the major keys to achieve successful osseointegration of the implant is its surface properties. The aim of this study was to investigate the bone response to dental implants with different surface characteristics using the rabbit tibia model. Tricalcium phosphate (TCP) coated, anodic oxidized and turned (control) surfaces were compared. MATERIALS AND METHODS: Seventy two implants were placed in the tibia of eighteen rabbits. Nine rabbits were sacrificed at 3 weeks of healing and the remaining nine were sacrificed at 6 weeks of healing. The bone-to-implant contact (BIC) and the bone volume density (BVD) were assessed by light microscope after 3 and 6 weeks of healing. RESULTS: Statistical analysis showed that no significant differences in the BIC and BVD were observed between the different implant surfaces and the control group at 3 weeks and 6 weeks of healing. Data also suggested that the BVD of all the surfaces showed significant difference at 3 and 6 weeks. CONCLUSION: The present study has showed that osseointegration occurred in all investigated types of surface-treated implants. In the current study all of the threads of the implants were observed to calculate BIC and BVD values (instead of choosing some of the threads from the bone cortex for example), which didn't make BIC or BVD percentage values better than in the control group, therefore the clinical relevance of these results remains to be shown.

The effect of Ca-P coatings of anodized implant surface on response of osteoblast-like cells in vitro / 대한치과보철학회지

PURPOSE: The purpose of this study was to evaluate the response of osteoblast-like cells to Ca-P coated surface obtained via Ion beam-assisted deposition (IBAD) method and Sol-Gel process on anodized surface by cellular proliferation and differentiation. MATERIAL AND METHODS: The surface of a commercially pure titanium (Grade IV) discs with dimension of 10mm diameter and 2 mm thickness was modified by anodic oxidation under a constant voltage of 300 V. The experimental groups were coated with Ca-P by the IBAD method and Sol-Gel process on anodized surface. The surface roughness (Ra) of specimens was measured by optical interferometer and each surface was examined by SEM. To evaluate cell response, MG63 cells were cultured and cell proliferation, ALP activity and the ability of cell differentiation were examined. Also, cell morphology was examined by SEM. The significant of each group was verified by Kruskal-Wallis Test (alpha= .05). RESULTS: The Ra value of Ca-P coated surface by IBAD method was significantly higher than Ca-P coated surface by Sol-gel process (P<.05). The level of cell proliferation and ALP activity was higher in Ca-P coated surface by IBAD method (P<.05). The expression of ALP showed higher level expression in Ca-P coated surface by IBAD method. Cells grown on Ca-P coated surface by IBAD method were uniformly distributed and developed a very close layer. CONCLUSION: These experiments showed better performances of Ca-P coated surface by IBAD method with respect to Ca-P coated surface by Sol-gel process. Ca-P coated surface by IBAD method appear to give rise more mature osteoblast characteristics and might result in increased bone growth and bone-implant contact.

The bone formation around anodic oxidized titanium implants in the tinbiae of ovarectomized rats

Anodic spark deposition method(ASD) surface treated titanium implant possesses a considerable osteoconductive potential that promoting a high level of implant osseointegration in normal bone. The purpose of this study was to observe the ASD implant's osseointegration in the osteoporosis-induced animal model. Twenty four rats, 10 weeks of age, were ovarectomized and 5 weeks later divided into two groups : ASD implant group and control implant group. Titanium screw implants (diameter; 2.0 mm, length, 3.5 mm; pitch-height, 0.4 mm) were designed for this study. Experimental implants were ASD treated and no treatment on control implants. ASD implants and control implants were placed in to left tibiae of rats. The rats were sacrificed at different time interval(1, 2, 4 and 8 weeks after implantation) for histopathologic observation and immunohisto -chemistrical observation, with collagen type I, fibronectin, integrin alpha2beta1 and integrin alpha5beta1 antibodies. The results obtained from this study were as follow: 1. Histopathologic findings, overall tissue response and the pattern of bone formation in both groups were similar. In ASD group, more newly formed bone was seen at 1 week and 2weeks than control group. 2. The levels of type I collagen and fibronectin expression were the most abundant at 2weeks and decreased gradually in both groups. Fibronectin and type I collagen expression in ASD group were stronger than control group but no significance. 3. The levels of integrin alpha2beta1 and Integrin alpha5beta1 expression were most abundant at 2 weeks and decreased gradually in both groups. No significant difference was observed in both groups. From this results, anodic oxidized titanium implants were more advantages in early stage of bone formation than control group, but have no significance in tissue responses and late bone formations. It could be stated that although anodic oxidized titanium implant possesses considerable osteoconductive potential but in osteoporotic bone condition dental implant procedure should performed after improving or treating the osteoporotic bone condition.

Micromorphometric Influence of Anodic oxidation surface implant conditioned with tetracycline-HCl / 대한치주과학회지

The present study was performed to evaluate the effect of Tetracycline-HCl on the change of implant surface microstructure according to application time. Anodic oxidation surface were utilized. Implant surface was rubbed with 50mg/ml Tetracycline-HCl solution for 1/2min., 1min., 1 1/2min., 2min., 2 1/2min. and 3min. respectively in the test group. Then, specimens were processed for Ra Value test and scanning electron microscopic observation. The results of this study were as follows. 1. The anodic oxidation surface roughness tests don't show significant difference on conditioning with saline and Tetracycline-HCl. 2. The anodic oxidized surfaces showed the craterous structures. The surface conditioning with Tetracycline-HCl didn't influence on its micro-morphology. In conclusion, Anodic oxidation implant surface is stable to detoxificate with 50mg/ml Tetracycline-HCl of implant surface.

Comparison between TiUniteTM and another oxidized implant using the rabbit tibia model / 대한치과보철학회지

STATEMENT OF PROBLEM: Various anodic oxidation techniques can be applied to dental implant surfaces. But the condition for optimal anodized surfaces has not been described yet. PURPOSE: The purpose of this investigation was to compare an implant that was oxidized by another method with TiUnite(TM) through resonance frequency analysis and histomorphometry. MATERIAL AND METHODS: Turned (control), TiUnite(TM) and another oxidized fixtures, which used Ca2+ solution for anodic oxidation, were placed in the tibiae of 5 New Zealand White rabbits. The bone responses were evaluated and compared by consecutive resonance frequency analysis once a week for 6 weeks and histomorphometry after a healing period of 6 weeks. RESULTS: At the first week, both oxidized implants showed significantly higher implant stability quotient (ISQ) values than the control. No significant differences in resonance frequency analysis were found between the two oxidized groups for 6 weeks. The means and standard deviations of bone-to-implant contact (BIC) ratios were 71.0 +/- 4.2 for TiUnite(TM), 67.5 +/- 10.3 for the Ca2+-based oxidation fixture, 22.8 +/- 6.5 for the control. Both oxidized implants were significantly superior in osseointegration to the turned one. There was, however, no statistically significant difference between the two oxidized implants. CONCLUSION: TiUnite(TM) and the Ca2+ -based oxidation fixture showed superior early bone response than the control with respect to resonance frequency analysis and histomorphometry. No significant differences between the oxidized groups, however, were found in this investigation using the rabbit tibia model.

Surface characteristics and bioactivity of anodically oxidized titanium surfaces / 대한치과보철학회지

STATEMENT OF PROBLEM: Recently, anodic oxidation of cp-titanium is a popular method for treatment of titanium implant surfaces. It is a relatively easy process, and the thickness, structure, composition, and the microstructure of the oxide layer can be variably modified. Moreover the biological properties of the oxide layer can be controlled. PURPOSE: In this study, the roughness, microstructure, crystal structure of the variously treated groups (current, voltage, frequency, electrolyte, thermal treatment) were evaluated. And the specimens were soaked in simulated body fluid (SBF) to evaluate the effects of the surface characteristics and the oxide layers on the bioactivity of the specimens which were directly related to bone formation and integration. MATERIALS AND METHODS: Surface treatments consisted of either anodization or anodization followed thermal treatment. Specimens were divided into seven groups, depending on their anodizing treatment conditions: constant current mode (350V for group 2), constant voltage mode (155V for group 3), 60 Hz pulse series (230V for group 4, 300V for group 5), and 1000 Hz pulse series (400V for group 6, 460V for group 7). Non-treated native surfaces were used as controls (group 1). In addition, for the purpose of evaluating the effects of thermal treatment, each group was heat treated by elevating the temperature by 5degrees C per minute until 600degrees C for 1 hour, and then bench cured. Using scanning electron microscope (SEM), porous oxide layers were observed on treated surfaces. The crystal structures and phases of titania were identified by thin-film x-ray diffractmeter (TF-XRD). Atomic force microscope (AFM) was used for roughness measurement (Sa, Sq). To evaluate bioactivity of modified titanium surfaces, each group was soaked in SBF for 168 hours (1 week), and then changed surface characteristics were analyzed by SEM and TF-XRD. RESULTS: On basis of our findings, we concluded the following results. 1. Most groups showed morphologically porous structures. Except group 2, all groups showed fine to coarse convex structures, and the groups with superior quantity of oxide products showed superior morphology. 2. As a result of combined anodization and thermal treatment, there were no effects on composition of crystalline structure. But, heat treatment influenced the quantity of formation of the oxide products (rutile / anatase). 3. Roughness decreased in the order of groups 7,5,2,3,6,4,1 and there was statistical difference between group 7 and the others (p<0.05), but group 7 did not show any bioactivity within a week. 4. In groups that implanted ions (Ca/P) on the oxide layer through current and voltage control, showed superior morphology, and oxide products, but did not express any bioactivity within a week. 5. In group 3, the oxide layer was uniformly organized with rutile, with almost no titanium peak. And there were abnormally more [101] orientations of rutile crystalline structure, and bonelike apatite formation could be seen around these crystalline structures. CONCLUSION: As a result of control of various factors in anodization (current, voltage, frequency, electrolytes, thermal treatment), the surface morphology, micro-porosity, the 2nd phase formation, crystalline structure, thickness of the oxide layer could be modified. And even more, the bioactivity of the specimens in vitro could be induced. Thus anodic oxidation can be considered as an excellent surface treatment method that will able to not only control the physical properties but enhance the biological characteristics of the oxide layer. Furthermore, it is recommended in near future animal research to prove these results.

Surface analyses of titanium substrate modified by anodization and nanoscale Ca-P deposition / 대한치과보철학회지

STATEMENT OF PROBLEM: Nano-scale calcium-phosphate coating on the anodizing titanium surface using ion beam-assisted deposition (IBAD) has been recently introduced to improve the early osseointegration. However, not much is known about their surface characteristics that have influence on tissue-implant interaction. PURPOSE. This study was aimed to investigate microtopography, surface roughness, surface composition, and wettability of the titanium surface modified by the anodic oxidation and calcium phosphate coating using IBAD. MATERIAL AND METHODS: Commercially pure titanium disks were used as substrates. The experiment was composed of four groups. Group MA surfaces represented machined surface. Group AN was anodized surface. Group CaP/AN was anodic oxidized and calcium phosphate coated surfaces. Group SLA surfaces were sandblasted and acid etched surfaces. The prepared titanium discs were examined as follows. The surface morphology of the discs was examined using SEM. The surface roughness was measured by a confocal laser scanning microscope. Phase components were analyzed using thin-film x-ray diffraction. Wettability analyses were performed by contact angle measurement with distilled water, formamide, bromonaphtalene and surface free energy calculation. RESULTS: (1) The four groups showed specific microtopography respectively. Anodized and calcium phosphate coated specimens showed multiple micropores and tiny homogeneously distributed crystalline particles (2) The order of surface roughness values were, from the lowest to the highest, machined group, anodized group, anodized and calcium phosphate deposited group, and sandblasted and acid etched group. (3) Anodized and calcium phosphate deposited group was found to have titanium and titanium anatase oxides and exhibited calcium phosphorous crystalline structures. (4) Surface wettability was increased in the order of calcium phosphate deposited group, machined group, anodized group, sandblasted and acid etched group. CONCLUSION: After ion beam-assisted deposition on anodized titanium, the microporous structure remained on the surface and many small calcium phosphorous crystals were formed on the porous surface. Nanoscale calcium phosphorous deposition induced roughness on the microporous surface but hydrophobicity was increased.

Surface characteristics of anodic oxidized titanium according to the pore size / 대한치과보철학회지

Statement of problem. The success of osseointegration can be enhanced with an implant that has improved surface characteristics. Anodic oxidation is one of the surface modifying method to achieve osseointegration. Voltage of anodic oxidation can change surface characteristics and cell activity. Purpose. This study was performed to evaluate MG63 cell responses such as affinity, proliferation and to compare surface characteristics of anodic oxidized titanium in various voltage. Material and method. The disks for cell culture were fabricated from grade 3 commercially pure titanium, 1 mm in thickness and 12 mm in diameter. Surfaces of 4 different roughness were prepared. Group 1 had a machined surface, used as control. Group 2 was anodized under 220 V, group 3 was anodized under 300 V and group 4 was anodized under 320 V. The microtopography of specimens was observed by scanning electron microscope (JSM-840A, JEOL, Japan) and atomic force microscope(Autoprobe CP, Park Scientific Instrument, USA). The surface roughness was measured by confocal laser scanning microscope(Pascal, LSM5, Zeiss, Germany). The crystal structure of the titanium surface was analyzed with x-ray diffractometer(D8 advanced, Bruker, Germany). MG63 osteoblast-like cells were cultured on these specimens. The cell morpholgy was observed by field emission electron microscope(Hitachi S-4700, Japan). The cell metabolic and proliferative activity was evaluated by MTT assay. Results and conclusion. With in limitations of this in vitro study, the following conclusions were drawn. 1. In anodizing titanium surface, we could see pores which did not show in contol group. In higher anodizing voltage, pore size was increased. 2. In anodizing titanium surface, we could see anatase. In higher anodizing voltage, thicker oxide layer increased crystallinity(anatase, anatase and rutile mixed). 3. MG63 cells showed more irregular, polarized and polygonal shape and developed more lamellipodi in anodizing group as voltage increased. 4. The activity of cells in MTT assay increased significantly in group 3 and 4 in comparison with group 1 and 2. However, there was no difference between group 3 and 4 at P<0.05. Proliferation of MG63 cells increased significantly in pore size(3-5.5 micrometer) of group 3 and 4 in comparison with in pore size(0.2-1 micrometer) of group 2.

Resonance frequency analysis of impl-ants with anodized surface oxides / 대한치과보철학회지

The present experimental study was designed to address two issues. The first was to investigate whether oxidation voltage of titanium implants influenced bone tissue responses after an in vivo implantation. The second aim was to investigate secondary stability change after 1 to 3months period. Screw-shaped implants with a wide range of oxide properties were prepared by electrochemical oxidation methods, where the oxide thickness varied in the range of 3-15micrometer. The micro structure revealed pore sizes of 1-3micrometer, the crystal structures of the titanium oxide were amorphous, anatase and a mixture of anatase and rutile type. Bone tissue responses were evaluated by resonance frequency measurements that were undertaken 1 to 3months after insertion in the rabbit tibia. It was concluded that no statistical difference of RFA values was found between the groups, RFA gains after 1month and 3months were calculated.

Bone response of three different surface implants: histomorphometric and resonance frequency analysis in dogs / 대한치과보철학회지

STATEMENT OF PROBLEM: Reducing treatment time in implant dentistry is a matter of main concern. There are so many factors affecting the success rate of immediate or early loaded implant for the initial bone response. The especially microscopic properties of implant surfaces play a major role in the osseous healing of dental implant. PURPOSE: The aims of this study were to perform a histologic and histomorphometric comparison of the healing characteristics anodically roughened surface, HA coated surface and RBM surface implant, and to compare of ISQ values measured by Osstell(TM) for resonance frequency analysis in dogs mandible during 2 weeks. MATERIAL AND METHOD: Bone blocks from 2 dogs were caught after covered healing for 0 day(2h); Group I, 1 week; Group II and 2 weeks; Group III. One longitudinal section was obtained for each implant and stained with hematoxylin and eosin. Histomorphometric analysis was done with Kappa Imagebase system to calculate bone-to-implant contact and bone volumes inside the threads. ISQ values were measured in every time of surgery schedule. CONCLUSION: The experiment revealed that : 1. The percentages of bone-to-implant contact on the fixture in each group were not significantly different(P > 0.05). 2. The percentages of bone area inside the threads on the fixture in each group were not significantly different(P > 0.05). 3. The ISQ level showed clinical stability of each fixture during 2 weeks(all ISQ level >_71).

The vitro bioactivity of new titanium alloy modified by anodic oxidation and its effects on osteoblast-like adhesion / 实用口腔医学杂志

Objective: To study the vitro bioactivity of the Ti-24Nb-4Zr-7.9Sn (TNZS) disks modified by anodic oxidation(AD) and its effects on adhesion of human osteoblast-like MG63 cells. Methods:The TNZS titanium alloy disks were treated with anodic oxidation and the bioactivity was assessed by investigating the formation of apatite on the film surface after soaking in simulated body fluids. The surface composition of the specimens after immersion was evaluated by EDX and X-ray diffraction. MG63 osteoblast-like cells were seeded on the Ti6Al4V,TNZS,AD-TNZS disks, and then the number of attached cells were counted and the cell morphology was examined at each given period. Results:The apatite can form on the treated TNZS disks after soaking in SBF for 6 days. The ratio of attached MG63 on AD-TNZS disks after 60 or 120 min seeding were significant higher than that on other samples and the cells on AD-TNZS disks spread better. Conclusion:The TNZS alloy modified by anodic oxidation can induce apatite formation in SBF and increase the early attachment of osteoblasts.

Effect of titanium alloy modified by anodic oxidation on the proliferation and differentiation of osteoblasts / 实用口腔医学杂志

0.05) among the three groups in cell proliferation in 1~10 d cultures and in total protein content in 4~7 d cultures. At 4 and 7 days, ALP activity of MG63 cells cultivated on AD-TNZS disks was significantly higher than that of cells on the other samples(P