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Improved cytocompatibility of nanosecond-pulsed laser-treated commercially pure Ti surfaces
Abstract
In this study, we developed a surface modification technology for implants using commercially pure (cp) Ti. The technology used in this study leads to reduction in the time required for adhesion between bone and surfaces of implants. The existence ofmicroasperities and oxide layers is important to induce calcium phosphate precipitation and bone formation activity of osteoblasts. In addition, we focused on nanosecondpulsed laser treatment as a method to create both microasperities and oxide layers. First, we observed surface morphologies formed by laser treatment. An oxide layer with high oxygen concentration and microasperities on the order of 10 nm to 10 μmwere produced. Moreover, the OH groups were created on the laser-treated surface. Second, by culturing osteoblasts on the laser-treated cp Ti surface, its effects on cell shape, proliferation, and activity of bone formation were evaluated. Even though cell proliferation was at a comparable level in these two surfaces, the ALP activity per cell number was improved by about four times in the laser-treated surface compared with that in the polished surface. On the laser-treated cp Ti surface, it was considered that the bone formation activity of osteoblasts was promoted without inhibiting cell proliferation. From the results of this study, it is possible to conclude that by treating cp Ti surfaces with a laser, a surface with good cytocompatibility can be created.
... Surface chemistry is also an important factor in controlling bone response, in addition to the surface morphology. Nanosecond-pulse laser irradiation can alter not only the surface morphology and roughness but also the condition of the titanium oxide layer by heat input, resulting in better cytocompatibility 15,16) . Fukayo et al. 17) evaluated tissue response towards nanosecondpulsed laser-treated titanium after implantation into the tibiae of rabbits or the extracted sockets of rat maxillary molars. ...
... For laser treatment, each zirconia surface was treated with a Nd:YAG nanosecond-pulsed laser in a striped pattern as described in previous reports 15,16) . The processing parameters for laser treatment are listed in Table 1. ...
... It is supposed that heating by laser irradiation will also cause changes to the atomic population on the zirconia surface. With titanium, laser irradiation produces a thicker oxide layer and greater numbers of OH groups on the surface 15,16) . It was concluded that surface asperities and an OHgroup-inclusive oxide layer induced the enhancement of proliferation and cell activity of osteoblasts 16) . ...
Two type of partially stabilized zirconia, namely yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and ceria-stabilized tetragonal zirconia polycrystals including aluminum oxide nanocomposite (Ce-TZP), were irradiated by nanosecond-pulsed Nd:YAG laser and the regular structure with concave and convex of each 30 μm width and 30 μm depth were prepared on both surfaces. In the case of Ce-TZP, the surface was changed to be black after laser irradiation. EDX measurement revealed the reduction of more amounts of oxygen atoms on Ce-TZP compared to Y-TZP. Laser irradiated zirconia implants were inserted into the bone defects of rat femur during 4 weeks. As a control, large grid sandblasted and acid etching (blastedHF) implant was used. Laser treatment for Y-TZP provided greater degree of bone-implant contact ratio than blastedHF treated Y-TZP (p<0.05). In the case of Ce-TZP, however, laser treatment showed no clear effect on bone response.
... As described above, both the microtopography and chemical surface characteristics are crucial factors for improving the surface of titanium for use in dental implants. Focus on a nanosecond-pulsed laser (NPL) capable of melting on the surface and formation of some compounds [19], we have previously studied the use of the NPL surface modification method to generate microasperities and an oxide layer on titanium surfaces, and found that NPL treatment improved their bioactivity [20,21]. The presence of the oxide layer promoted the precipitation of hydroxyapatites on titanium surfaces in simulated body fluid (SBF) [20]. ...
... Moreover, the alkaline phosphatase (ALP) activity per cell was approximately four times greater for the laser-treated series than for the polished series. A cell proliferation test indicated that osteoblast functionality was increased when laser-treated surfaces were used, without damaging the proliferative capabilities of the cells [21]. Additionally, we evaluated bone and gingival connective tissue responses towards NPL-treated titanium implants. ...
... Although it has been demonstrated that the bone affinity of titanium implants can be affected by the hydroxyl groups generated by NPL treatment [19][20][21][22][23][24], the mechanism by which hydroxyl groups are generated on the titanium surface by NPL treatment remains unknown. To address this, we evaluated pure Ti surfaces treated by NPL using different defocus distances, and investigated the relationship between the generation of hydroxyapatites/cell viability and the characteristics of the NPL-treated Ti surfaces. ...
In this paper, we study a process for modifying the surface microtopography of the Ti oxide layer using a nanosecond-pulsed laser (NPL). Even now, the mechanism by which hydroxyl groups are generated on the titanium surface treated by NPL is not clear. Hence, we evaluated the surface properties of the NPL defocus distances on pure titanium surfaces, and investigated the relationship between the generation of hydroxyapatites/cell viability and the titanium surface characteristics. The NPL defocus distance was varied from 0 to 4 mm. Defocus distances of 0 and 2 mm generated microtopographical features on the titanium surface, and the resulting surfaces exhibited a greater density of OH groups than the surface treated with a defocus distance of 4 mm. The surfaces treated using defocus distances of 0 and 2 mm were found to be coated with microspherical hydroxyapatite composed of coexisting plate- and needle-like crystals after immersion in simulated body fluid, and alkaline phosphatase activity assays indicated improved cell compatibility. The improvements in biocompatibility and cell compatibility were due to the pocket-like microtopographical structures formed along the processing trace. These pockets contained a large amount of OH groups, and promoted the growth of hydroxyapatite.
... Mizutani et al. treated titanium by using a nanosecond-pulse laser with a defocus technique 17,18) . That is, when the laser was aimed at the titanium surface, the laser beam was not focused on the material surface. ...
... The crystal structure of titanium oxide is both rutile and anatase. Titanium treated by a nanosecond-pulse laser with a defocus technique exhibited better compatibility for osteoblast-like cells 18) . ...
... One was 3.5 mm in diameter and 7.0 mm in length for rabbit bone response experiments ( 3.5 Ti, Fig. 1a) and the other was 1.0 mm in diameter and 4.5 mm in length for rat gingival connective tissue response experiments ( 1.0 Ti, Fig. 1b). The surfaces of these implants were treated with a Nd: YVO 4 nanosecond-pulsed laser, as previously described [17][18] . The processing parameters of the laser for 3.5 Ti and 1.0 Ti cylindrical implants are listed in Tables 1 and 2, respectively. ...
The aim of this study was to evaluate bone and gingival connective tissue responses towards nanosecond-pulsed laser-treated titanium implants. A Nd:YVO4 nanosecond-pulse laser with a defocus technique was used to modify the surfaces of two types of cylindrical titanium implants. One had a 3.5 mm diameter and 7.0 mm length (∅3.5 Ti) to assess rabbit bone responses; the other a 1.0 mm diameter and 4.5 mm length (∅1.0 Ti) to assess rat gingival connective tissue responses. Laser-treated titanium implants, a ∅3.5 Laser-Ti and ∅1.0 Laser-Ti, were obtained by defocus irradiation. Collagen immobilized ∅1.0Laser-Ti (∅1.0 Coll/Laser-Ti) implants were obtained by a tresyl chloride-activated method. Laser-Ti surfaces had micro-scale roughened oxide layers and parallel arranged grooves. Sa (average roughness) and Sdr (interfacial area ratio) values of the Laser-Ti were significantly higher than those of Ti (titanium) implants (p<0.05). The ∅3.5 implants were implanted into the bone defects of rabbits to evaluate bone responses and ∅1.0 implants were implanted into the extracted sockets of rat maxilla to evaluate gingival connective tissue responses. After implantation periods, the specimens were excised and non-decalcified thin sections prepared to evaluate histological responses. After 12 weeks of implantation in the rabbit experiments, bone-to-implant contact for the Laser-Ti implants was significantly higher than for the Ti in both tibia and femoral condyle (p<0.05). Improved attachment of gingival connective tissue to the implant surface was observed for Laser-Ti and Coll/Laser-Ti in the rat maxilla. Polarized light microscopy showed perpendicular rod-like attachments of gingival collagen fibers on the Laser-Ti and Coll/Laser-Ti implant surfaces. Ti implants had no discernible attachments with gingival connective tissue along the implant surface. In conclusion, nanosecond-pulsed laser treatment with a defocus technique produced roughened titanium surfaces with parallel grooves and micro-roughened asperities. Laser treatment of implants resulted in improved bone responses and attachment of gingival connective tissue.
... Surface modification processes without the use of bone cement have been introduced to improve the osteoconductivity and bonding strength between human bones and bio-implants [3][4][5][6][7][8][9][10][11][12] because the surfaces of bioimplants are in contact with body tissues. For example, Kokubo et al. [3,4] investigated the effects of pretreatment with alkali hydroxide solutions on the formation of hydroxyapatite (HAp) on commercially pure (CP) titanium in simulated body fluid to produce a bioactive material surface. ...
Fine particle peening (FPP) using hydroxyapatite (HAp) shot particles can form a HAp layer on room-temperature substrates by the transfer and microstructural modification of the shot particles. In this study, FPP with HAp shot particles was applied to form a HAp surface layer and improve the fatigue properties of Ti–6Al–4V extra-low interstitial (ELI) for use in bio-implants. The surface microstructures of the FPP-treated specimens were characterized by micro-Vickers hardness testing, scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction, and X-ray photoelectron spectroscopy. FPP with HAp shot particles successfully formed a HAp layer on the surface of Ti–6Al–4V ELI in a relatively short period by shot particle transfer at room temperature; however, the thickness and elemental composition of the HAp layer were independent of the FPP treatment time. The original HAp crystal structure remained in the surface-modified layer formed on Ti–6Al–4V ELI after FPP. Furthermore, FPP increased the surface hardness and generated compressive residual stresses at the treated surface of Ti–6Al–4V ELI. Four-point bending fatigue tests were performed at stress ratios of 0.1 and 0.5 to examine the effect of FPP with HAp shot particles on the fatigue properties of Ti–6Al–4V ELI. The fatigue life of the FPP-treated specimen was longer than that of the un-peened specimen because of the formation of a work-hardened layer with compressive residual stress. However, no clear improvement in the fatigue limit of Ti–6Al–4V ELI occurred after FPP with HAp shot particles because of subsurface failures from characteristic facets.
Functional surface creation technologies have garnered increasing attention over the years. These technologies can provide various functions to a material by establishing a fine structure on the material surface and responding to the needs of industrial products with distinguished functions or high values. In addition, by creating a “composite fine structure,” which is composed of two kinds of structures with different scales, the enhancement of functions and emergence of new functionalities can be expected. Hence, our study combined a micrometer-scale V-shaped groove structure using an ultra-precision cutting and nanometer-scale ultra-fine periodic structure (LIPSS) using a short-pulsed laser. Then, we clarified the creation principle and studied the functionality of the structure, specifically, its wettability. As a result, it was found that optical behavior inside the V-shaped groove changed; therefore, the composite structure changed depending on the groove angle, laser polarization direction, and number of times of irradiation. In addition, it was found that the water wettability changed depending on the type of formed micro-nano composite structures. Moreover, the wettability could be controlled by depending on how the structure is used.
Titanium alloys are widely used for the hard tissue substitute implants. However, it is necessary to improve interfacial biocompatibility to reduce adhesion period. For improvement of biocompatibility of Ti-6Al-4V ELI alloys, texture and chemical composition on contact part with biological tissue play very important roles. In this research, micro texture was generated on the Ti-6Al-4V ELI alloy surfaces utilizing laser irradiation, in order to improve biocompatibility. The biocompatibility was evaluated by osteoblast cell culture assays. The results indicated the surface having micro texture improve biocompatibility as compared with untreated surface. This was considered in order the fact that the formed modified surface had hydrophilicity, thereby improving the cell compatibility, and the cell adhesion due to the complicated shape. In addition, mist of glycerophosphoric acid calcium aqueous solution was applied on the laser irradiated area. As result, micro texture including Ca and P elements was generated on the Ti-6Al-4V ELI alloy surfaces. When laser was irradiated, glycerophosphoric acid calcium aqueous solution was applied as mist flowed on the test pieces as droplet. The velocity of droplet fluid was relatively fast, so that laser irradiation was unhindered access to the surface of test pieces and the treatment was stable. In order to estimate biocompatibility, culture assays using osteoblast cells were conducted on the treated surface having micro texture including Ca and P elements. As results, it was clearly that biocompatibility of the specimen treated by laser with glycerophosphoric acid calcium aqueous solution mist more improved than either untreated specimen or treated specimen soaked in glycerophosphoric acid calcium aqueous solution.
The combined effects of low-temperature nitriding (LTN) and cold rolling on the microstructure of commercially pure titanium (CP titanium) were investigated. The grain size of the LTN-treated CP titanium decreased with increasing thickness reduction due to the cold rolling pre-treatment and with decreasing the nitriding temperature. The fatigue limit for the nitrided CP titanium depended on the grain size beneath the nitrided layer and increased with decreasing the nitriding temperature because of the suppression of grain-coarsening. Furthermore, the LTN at 873 K decreased the friction coefficient and reduced the wear loss of CP titanium during the ball-on-disk dry friction tests.
In recent years, one common cure for losses in joint function caused by osteoarthritis or rheumatoid arthritis is replacement with an artificial joint. For this reason, it is necessary to add osteoconductivity to artificial joint component surfaces that make contact with bone, thereby reducing the period of time necessary to fixate the bone tissue and the artificial joint component. With the intent of efficiently machining the joint shape by electrical discharge machining (EDM) and simultaneously formation of a surface with osteoconductivity, this study discusses the possibility of adding osteoconductivity to a titanium EDMed surface.
Apatite formation due to mineralization has important implications in the biological function of hard tissues. The mechanical properties of mineralized tissues such as teeth enamel, dentin, and bone depend strongly on the apatite structure in the tissue. The control of both volume fraction and apatite texture is important in determining the structural characteristics. It is also important to create an apatite layer on the surface of implanted materials to improve biocompatibility between the surface and the tissues. In this study, apatite deposition and formation on Ti plates and bone surfaces were studied by means of electric stimulation conducted in apatite-neutralizing solution. Apatite particles were deposited not only on the Ti plate surfaces but also on the bone, combined with Ti wires wrapped under DC loading. Apatite crystal growth was observed on the samples during electric stimulation.
A cell culture module capable of cooling stimulus to collect cells efficiently on a metal culture substrate was developed. We evaluated the cell collection ratio and morphology of the collected cells. Following a cooling stimulus (0°C) for 20 min, the number of collected cells was increased by 50% compared to that collected after trypsin treatment without pipetting from the metal culture substrate. Following the cooling stimulus, cells were observed by fluorescence microscopy and scanning electron microscopy; the cell filopodia were shrunken compared to non-cooling-stimulated cells. Furthermore, the combination of collagenase and cooling stimulation resulted in the collection of a comparable number of cells as that obtained using only trypsin. Thus, cell proliferation was improved compared to that following trypsin treatment. Therefore, this method can be applied for culturing cells that are susceptible to trypsin damage.
We investigated the influence of iron-based workpiece materials on the characteristics of the Si layers by electrical discharge coating. It was found that the chemical elements of the precipitations were uniformly dispersed in the layers on the workpieces containing precipitations a few micrometers in diameter. By contrast, voids occurred in the layer on the workpiece containing bigger precipitations because the precipitations that had not totally melted in the coating process were the starting points of the voids. In addition, the surface of the Si layer on FC250 was extremely rough, and the distribution of the chemical elements of the layer was inhomogeneous. However, the layer was amorphous, and the friction coefficient of the layer was lower than that of the workpiece.
To combine the advantages of different electrolytes in anodic oxidation, pure titanium samples were anodized in CH(3) COOH electrolyte according to a novel anodizing treatment regime and then in H(2) SO(4) electrolyte in potentialstatic mode. The in vitro bioactivity of the as-prepared titanium samples was evaluated by simulated body fluid (SBF) test. In addition, MG63 osteoblast-like cells were cultured on surfaces of the as-prepared titanium samples to evaluate osteoblast adhesion ability. The titanium samples after the two-step anodization treatment were covered by titania layers of anatase and/or rutile with several micrometres thickness and presented a multi-level porous surface morphology consisting of interlaced grooves about 20-μm wide overlaid with submicron scale pores. The SBF test results showed that the crystal titania layers prepared at appropriate conditions were able to induce apatite-forming in 7 days, indicating that the abundance of surface Ti-OH groups and (101)-oriented rutile structure both played important roles in in vitro bioactivity of titania layers. The cell experiment results showed that the macroscopic grooves could effectively promote osteoblast adhesion and growth and submicron scale pores might be beneficial to osteoblast adhesion. The two-step anodization treatment might be a promising candidate for surface modification of titanium implant.
Bone Tissue Engineering (BTE) and Dental Implantology (DI) require the integration of implanted structures, with well characterized surfaces, in bone. In this work we have challenged acid-etched titanium (AET) and Laser Sintered Titanium (LST) surfaces with either human osteoblasts or stem cells from human dental pulps (DPSCs), to understand their osteointegration and clinical use capability of derived implants. DPSCs and human osteoblasts were challenged with the two titanium surfaces, either in plane cultures or in a roller apparatus within a culture chamber, for hours up to a month. During the cultures cells on the titanium surfaces were examined for histology, protein secretion and gene expression. Results show that a complete osteointegration using human DPSCs has been obtained: these cells were capable to quickly differentiate into osteoblasts and endotheliocytes and, then, able to produce bone tissue along the implant surfaces. Osteoblast differentiation of DPSCs and bone morphogenetic protein production was obtained in a better and quicker way, when challenging stem cells with the LST surfaces. This successful BTE in a comparatively short time gives interesting data suggesting that LST is a promising alternative for clinical use in DI.
Mice osteoblast cells were cultured on samples of 316L stainless steel and titanium alloy (Ti-6Al-4V) with different surface treatments. The resulting cell differentiation was correlated with the solid surface tension and electron-acceptor surface tension parameter of the biomaterial samples. Both of these characteristics were determined through contact angle measurements, using the Lifshitz–van der Waals/Lewis acid–base interaction model. Before calculating the surface tension of the biomaterials, the experimental contact angles were corrected for the effect of roughness using the Wenzel equation. For this calculation, the roughness characteristics of the solid surfaces were determined using atomic force microscopy and interferometric profilometry at the nano-scale and micro-scale, respectively. It was found that osteoblast cell differentiation directly related to the implant surface tension and electron-acceptor properties. The alkaline phosphatase activity increased both with increasing surface tension and increasing electron-acceptor surface tension parameter of the implant materials. These results suggest that the formation of surface hydroxyl groups with acidic character gives rise to enhanced attachment of osteoblast cells.
We investigated the effect of Cistanche deserticola Ma. (CD) on bone formation by cultured osteoblasts.
The mineralized nodule formation assay was used to examine the in-vitro effects of CD on bone formation. Alkaline phosphatase (ALP), bone morphogenetic proteins (BMP)-2 and osteopontin (OPN) mRNA expression was analysed by quantitative real-time polymerase chain reaction. The mechanism of action of CD extract was investigated using Western blotting. The in-vivo anti-osteoporotic effect of CD extract was assessed in ovariectomized mice.
CD extract had no effect on the proliferation, migration or wound healing of cultured osteoblasts, but increased ALP, BMP-2 and OPN mRNA and bone mineralization. Mitogen-activated protein kinase (MAPK) or nuclear factor (NF)-κB inhibitors reduced CD extract-induced bone formation and ALP, BMP-2 and OPN expression. However, CD extract did not affect osteoclastogenesis. In addition, CD extract prevented the bone loss induced by ovariectomy in vivo.
CD may be a novel bone formation agent for the treatment of osteoporosis.
The β-titanium alloys have recently become important in bone implant applications. In this study, micro-arc oxidation (MAO) was used to modify the surface of β-titanium alloy (Ti–13Cr–3Al–1Fe) using NaH2PO4 solution as an electrolyte. The microstructure of the oxidized layer as a function of the applied voltage and treatment time were investigated. The cellular adhesion, proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 pre-osteoblast were measured to reveal the cell compatibility of the treated specimens.The experimental results show that microstructure of the oxidized layer can be greatly affected by the discharge voltage and treatment time during MAO treatment as α-titanium metal and α + β titanium are. The oxidized layer can gradually increase its thickness, pore size and surface roughness as a function of the discharge voltage and treatment time, which at the same time increases the rutile phase constituent. The osteoblast cell compatibility presented by the treated specimens is increased but less sensitive to the process parameters, even though the associated difference in morphology and crystalline form are found to be tremendous.
The factors responsible for modifications to the wettability characteristics of a titanium (Ti6Al4V) alloy bio-metal following Nd:YAG laser treatment and the effects thereof on the response of osteoblast cells were considered in this work. It was found that interaction of the Nd:YAG laser beam with the Ti6Al4V alloy resulted in the wettability characteristics of the bio-metal improving. Such improvements in the wettability characteristics of the Ti6Al4V alloy were found to be due to: an increase in the surface roughness; and increase in the surface oxygen content and an increase in the polar component of the surface energy. From the cell response tests it was determined that the osteoblast cell adhesion and proliferation on the Nd:YAG laser treated Ti6Al4V alloy samples was considerably greater than on the untreated samples. By isolating the effects of surface roughness it was possible to confirm or refute the existence of a correlation between wettability characteristics and osteoblast cell bioactivity for the Nd:YAG laser treated Ti6Al4V alloy. The findings indicated that the aspects of wettability characteristics: surface oxygen content and polar component of the surface energy play an important role in promoting cell proliferation, particularly when surface roughness was simultaneously increased. Thus it was possible to conclude that the wettability characteristics of the Nd:YAG laser treated Ti6Al4V alloy were correlated to osteoblast cell bioactivity.
Osteoblasts grown on microstructured Ti surfaces enhance osteointegration by producing local factors that regulate bone formation as well as bone remodeling, including the RANK ligand decoy receptor osteoprotegerin (OPG). The objective of this study was to explore the mechanism by which surface microstructure and surface energy mediate their stimulatory effects on OPG expression. Titanium disks were manufactured to present different surface morphologies: a smooth pretreatment surface (PT, Ra<0.2microm), microstructured sandblasted/acid etched surface (SLA, Ra=3-4microm), and a microstructured Ti plasma-sprayed surface (TPS, Ra=4microm). Human osteoblast-like MG63 cells were cultured on these substrates and the regulation of OPG production by TGF-beta1, PKC, and alpha2beta1 integrin signaling determined. Osteoblasts produced increased amounts of OPG as well as active and latent TGF-beta1 and had increased PKC activity when grown on SLA and TPS. Exogenous TGF-beta1 increased OPG production in a dose-dependent manner on all surfaces, and this was prevented by adding blocking antibody to the TGF-beta type II receptor or by reducing TGF-beta1 binding to the receptor by adding exogenous soluble type II receptor. The PKC inhibitor chelerythrine inhibited the production of OPG in a dose-dependent manner, but only in cultures on SLA and TPS. shRNA knockdown of alpha2 or a double knockdown of alpha2beta1 also reduced OPG, as well as production of TGF-beta1. These results indicate that substrate-dependent OPG production is regulated by TGF-beta1, PKC, and alpha2beta1 and suggest a mechanism by which alpha2beta1 signaling increases PKC, resulting in TGF-beta1 production and TGF-beta1 then acts on its receptor to increase transcription of OPG.
The osteoblastic cell-line hFOB 1.19 with the potential to proliferate and differentiate revealed that cellular differentiation is not affected by material and roughness on newly developed zirconia implant materials. Materials under investigation were surfaces machined titanium (Ti-m), modified titanium (TiUnite, machined zirconia (TZP-A-m), modified zirconia (ZiUnitemachined alumina-toughened zirconia (ATZ-m) and modified alumina-toughened zirconia (ATZ-mod). After surface description by scanning electron microscopy (SEM) and atomic force microscopy (AFM), cellular proliferation (EZ4U, Casy1) and differentiation were examined after days 1, 3, 7, 14, 21, and 28. Osteogenic differentiation was visualized by alkaline phosphatase staining, mineralization assay (alizarin red) and by expression analysis (RT-PCR) of bone- and extracellular matrix-related genes. Proliferation on rough surfaces was reduced on both titanium and zirconia. Cell-attachment and cytoskeleton organization documented by confocal laser scanning microscopy (CLSM) elucidated attenuated cell attachment within the first 4h to be the reason for impaired proliferation. A specific up-regulation of m-RNAs in an early event (RUNX2, NELL-1, RUNX3, and BMP7) and a late event (Integrin B3) could be observed on TiUnite and ZiUnite. For titanium an up-regulation of IBSP and Integrin B1 could be described at day 21. In total, differentiation was neither affected by material nor by roughness.
The influence of thin carbonate-containing apatite (CA) coating on the trabecular bone response to titanium implants was investigated.
Thin CA coatings were deposited by a new method known as the molecular precursor method. Using a precursor solution composed of an EDTA-calcium complex, a CA film was deposited on the titanium surfaces. Uncoated and CA-coated titanium were placed in the trabecular bone of the left and right femoral condyles of 16 rabbits. After implantation periods of 2, 4, 8, and 12 weeks, the bone-implant interface was evaluated histologically and histomorphometrically.
Histologic evaluation revealed new bone formation around the uncoated and CA-coated implant surfaces after only 4 weeks of implantation. After 12 weeks, mature trabecular bone surrounded all implants. At 4 and 8 weeks of implantation, no difference existed in bone contact between uncoated and CA-coated implants. After 12 weeks of implantation, the CA-coated implant group showed a significantly higher percentage of bone contact than the uncoated implant group.
The present study demonstrated that thin CA coatings applied using the molecular precursor method showed greater bone-to-implant contact during the healing phase than uncoated controls. The results were similar to those observed with implants with calcium phosphate coatings deposited with a physical vapor deposition technique.