Young-Taeg Sul

The current hard tissue implants research aims to accelerate bone healing by designing surfaces that are bioactive. However, the role of the inflammatory response to these surfaces is so far incompletely described. The aim of the study was to evaluate early inflammatory response in vitro to a potentially bioactive surface--an anodized surface with Mg ions incorporated (anodized/Mg)--and to compare it to a turned, a blasted, and an anodized surface. An interferometer was used for topographical characterizations. The disks were incubated with human mononuclear cells. Adherent cells were investigated with respect to number of cells, viability, differentiation, and cytokine production with and without lipopolysaccharide stimulation after 24 and 72 hours. The number of adhered mononuclear cells differed significantly between the different modified surfaces, with the highest number on the anodized surface. However, there were no significant differences in cytokine production and differentiation between the different modified surfaces. The amount of anti-inflammatory mediator interleukin-10 remained over time, while the number of cells and pro-inflammatory cytokine tumor necrosis factor-alpha decreased. The cells were viable on all surfaces, respectively. The anodized surfaces with and without Mg ions showed an increased cell adherence, however, otherwise an inflammatory response similar to the turned and blasted surfaces. Furthermore, the potentially bioactive anodized/Mg surface showed a similar response to the TiUnite-like anodized surface despite the former having a surface roughness of a smoother character.

This study compared the speed and strength of osseointegration and osteoconductivity between an oxidized experimental magnesium (Mg) implant, an oxidized commercially available TiUnite implant, and a dual acid-etched surface Osseotite implant. The aim was to investigate which surface properties enhance bone response to implants, and thereby to test a biochemical bonding theory. A total of 60 screw implants (20 of each design) were inserted through 1 cortex into the tibiae of 10 rabbits. Surface chemistry, oxide thickness, morphology, crystal structure, and surface roughness were evaluated. After healing times of 3 and 6 weeks, all bone implants were unscrewed with removal torque (RTQ) devices, and the bone specimens were subjected to histomorphometry. RTQ values for Mg, TiUnite, and Osseotite implants were 27.1, 21.3, and 15.4 Ncm, with new bone formation values of 29%, 18%, and 15%, respectively, at 3 weeks. At 6 weeks the RTQ values were 37.5, 36.4, and 21.5 Ncm, with new bone formation values of 39%, 31%, and 26%, respectively. Mg implants demonstrated significantly greater RTQ values (P = .008 and P = .0001) and more new bone formation (P = .031 and P = .030) than Osseotite at 3 and 6 weeks, respectively. Mg implants also showed higher RTQ values at 3 weeks and new bone formation at 6 weeks than TiUnite, but neither were significant (P > .05). TiUnite showed significantly higher RTQ values than Osseotite at 6 weeks (P = .001), but was not significant at 3 weeks (P > .05). Osseointegration rate (deltaRTQ/deltaweeks) was significantly faster for Mg (P = .011) and TiUnite (P = .001) implants between 3 and 6 weeks of healing time, but was not significant for Osseotite. The results indicate that surface chemistry facilitated more rapid and stronger osseointegration of the Mg implants despite their minimal roughness compared to the moderately roughened TiUnite. This suggests potential advantages of Mg implants for reducing high implant failure rates in the early postimplantation stage and in compromised bone, making it possible to shorten bone healing time from surgery to functional loading, and enhancing the possibility of immediate/early loading.

Objectives: The study presented was designed to investigate the speed and the strength of osseointegration of oxidized implants at early healing times in comparison which machined, turned implants.Material and methods: Screw‐shaped titanium implants were prepared and divided into two groups: magnesium ion incorporated, oxidized implants (Mg implants, n=10) and machined, turned implants (controls, n=10). Mg implants were prepared using micro‐arc oxidation methods. Surface oxide properties of implants such as surface chemistry, oxide thickness, morphology/pore characteristics, crystal structures and roughness were characterized with various surface analytic techniques. Implants were inserted into the tibiae of ten New Zealand white rabbits. After a follow‐up period of 3 and 6 weeks, removal torque (RTQ), osseointegration speed (ΔRTQ/Δhealing time) and integration strength of implants were measured. Bonding failure analysis of the bone‐to‐implant interface was performed.Results: The speed the and strength of osseointegration of Mg implants were significantly more rapid and stronger than for turned implants at follow‐up periods of 3 and 6 weeks. Bonding failure for Mg implants dominantly occurred within the bone tissue, whereas bonding failure for turned implants mainly occurred at the interface between implant and bone.Conclusions: Oxidized, bioactive implants are rapidly and strongly integrated in bone. The present results indicate that the rapid and strong integration of oxidized, bioactive Mg implants to bone may encompass immediate/early loading of clinical implants.

To investigate detailed surface characterization of oxidized implants in a newly invented electrolyte system and to determine optimal surface oxide properties to enhance the bone response in rabbits. A total of 100 screw-type titanium implants were prepared and divided into 1 control group (machine-turned implants) and 4 test groups (magnesium ion-incorporated oxidized implants). Forty implants were used for surface analyses. A total of 60 implants, 12 implants from each group, were placed in the tibiae of 10 New Zealand white rabbits and measured with a removal torque test after a healing period of 6 weeks. For the test groups, the oxide thicknesses ranged from about 1,000 to 5,800 nm; for the control group, mean oxide thickness was about 17 nm. The surface morphology showed porous structures for test groups and nonporous barrier film for the control group. Pore diameter ranged from < or = 0.5 microm to < or = 3.0 microm. In regard to surface roughness, arithmetic average height deviation (Sa) values varied from 0.68 to 0.98 microm for test implants and 0.55 microm for control implants; developed surface ratio (Sdr) values ranged from 10.6% to 46% for the test groups and were about 10.6% for the control group. A mixture of anatase and rutile-type crystals were observed in the test groups; amorphous-type crystals were observed in the control group. After a healing period of 6 weeks, removal torque measurements in all 4 test groups demonstrated significantly greater implant integration as compared to machine-turned control implants (P < or = .033). Determinant oxide properties of oxidized implants are discussed in association with bone responses. Of all surface properties, RTVs were linearly increased as relative atomic concentrations of magnesium ion increase. Surface properties of the oxidized implants in the present study, especially surface chemistry, influenced bone responses. The surface chemistry of the optimal oxidized implant should be composed of approximately 9% magnesium at relative atomic concentration in titanium oxide matrix and have an oxide thickness of approximately 1,000 to 5,000 nm, a porosity of about 24%, and a surface roughness of about 0.8 microm in Sa and 27% to 46% in Sdr; its oxide crystal structure should be a mixture of anatase- and rutile-phase crystals.

Background: In oral implantology there has been a general trend away from machine‐turned minimally rough and acid‐etched and blasted implants toward intermediary roughened surfaces. Mechanical interlocking at micron resolution is claimed to be the dominant reason for the fixation of such implants in bone. However, clinical demands for stronger and faster bone bonding to the implant (eg, in immediately loaded and compromised bone cases) have motivated the development of novel surfaces capable of chemical bonding.Purpose: The purpose of the present study is to investigate bone tissue reactions to a newly developed calcium‐incorporated oxidized implant. The specific aim is to assess the effect of calcium surface chemistry on the bone response.Materials and Methods: Calcium (Ca) ion‐incorporated implants were prepared by micro arc oxidation methods. Surface oxide properties were characterized by using various surface analytic techniques involving scanning electron microscopy, x‐ray diffractometry, x‐ray photoelectron spectroscopy, and optical interferometry. Twenty screw‐shaped commercially pure (CP) titanium implants (10 turned implants [controls] and 10 Ca‐incorporated implants [tests]) were inserted in the femoral condyles of 10 New Zealand White rabbits.Results: After a healing period of 6 weeks, resonance frequency analyses and removal torque measurements of the Ca‐incorporated oxidized implants demonstrated statistically significant improvements of implant integration with bone in comparison to machine‐turned control implants (p = 0.013 and p = 0.005, respectively).Conclusions: The Ca‐reinforced surface chemistry of the oxidized implants significantly improved bone responses in a rabbit model. The present study suggests that biochemical bonding at the bone‐implant interface, in combination with mechanical interlocking, may play a dominant role in the fixation of Ca‐incorporated oxidized implants in bone. The observed rapid and strong integration of test Ca implants may have clinical implications for immediate or early loading and improved performance in compromised bone.

The aim was to answer a fundamental question: Do the chemical properties of titanium implants influence osseointegration? Screw-type implants produced of turned commercially pure (grade 1) titanium (controls) and electrochemically calcium-deposited titanium implants (Ca test implants) were placed in the tibiae and femora of a total of 10 mature New Zealand white rabbits. The macro arc oxidation method was applied for Ca implants. Surface oxides were characterized with different analytic techniques, including x-ray photoelectron spectroscopy, auger electron spectroscopy, scanning electron microscopy, thin-film x-ray diffractometry, and TopScan 3D. The bone response was evaluated by biomechanical tests, histology, and histomorphometry. After a follow-up period of 6 weeks, test Ca implants showed a significant increase in mean peak removal torque (P = .0001) and in the histomorphometric measurement of bone-to-metal contact around the implants (P = .028) in comparison to controls. In addition, more mature mineralized bone was observed adjacent to test Ca implants compared to controls, as evaluated on 10-microm undecalcified, toluidine blue-stained, cut, and ground sections. The potential role of surface Ca chemistry to a superior bone response is discussed with specific reference to interaction with Ca(+)-binding proteins and function as binding sites of calcium phosphate mineral. The present results suggest that the surface chemical composition of titanium implants is of great importance for the bone response. Ca ion-deposited titanium implants showed fast and strong osseointegration in the rabbit bone model.

The present experimental study was designed to address two issues. The first was to investigate whether oxide properties of titanium implants influenced bone tissue responses after an in vivo implantation time of six weeks. If such a result was found, the second aim was to investigate which oxide properties are involved in such bone tissue responses. 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 200 nm to 1000 nm. The surface morphology was prepared in two substantially different ways, i.e. barrier and porous oxide film structures. The micropore structure revealed pore sizes of 8 μm in diameter, with a range in opening area from 1.27 μm² to 2.1 μm². Porosity ranged from 12.7% to 24.4%. The crystal structures of the titanium oxide were amorphous, anatase and a mixture of anatase and rutile type. The chemical compositions consisted mainly of TiO₂. Surface roughness ranged from 0.96 μm to 1.03 μm (Sa). Each group of test samples showed its own, defined status with respect to these various parameters. The oxide properties of turned commercially pure titanium implants were used in the control group, which was characterized by an oxide thickness of 17.4 ± 6.2 nm, amorphous type in crystallinity, TiO₂ in chemical composition, and a surface roughness of 0.83 μm (Sa). Bone tissue responses were evaluated by resonance frequency measurements and removal torque tests that were undertaken six weeks after implant insertion in rabbit tibia. Implants that had an oxide thickness of approximately 600, 800 and 1000 nm demonstrated significantly stronger bone responses in the evaluation of removal torque values than did implants that had an oxide thickness of approximately 17 and 200 nm (P < 0.05). However, there were no difference between implants with oxide thicknesses of 17 and 200 nm (P = 0.99). It was concluded that oxide properties of titanium implants, which include oxide thickness, micropore configurations and crystal structures, greatly influence the bone tissue response in the evaluation of removal torque values. However, it is not fully understood whether these oxide properties influence the bone tissue response separately or synergistically.