Histological and mechanical evaluation of self-setting calcium phosphate cements in a sheep vertebral bone void model

We investigated the histological and compressive properties of three different calcium phosphate cements (CPCs) using a sheep vertebral bone void model. One of the CPCs contained barium sulfate to enhance its radiopacity. Bone voids were surgically created in the lumbar region of 23 ovine spines - L3, L4, and L5 (n = 69 total vertebral bodies) - and the voids were filled with one of the three CPCs. A fourth group consisted of whole intact vertebrae. Histologic evaluation was performed for 30 of the 69 vertebrae 2 or 4 months after surgery along with radiographic evaluation. Compressive testing was performed on 39 vertebrae 4 months after surgery along with micro-CT analysis. All three CPCs were biocompatible and extremely osteoconductive. Osteoclasts associated with adjacent bone formation suggest that each cement can undergo slow resorption and replacement by bone and bone marrow. Compressive testing did not reveal a significant difference in the ultimate strength, ultimate strain, and structural modulus, among the three CPCs and intact whole vertebrae. Micro-CT analysis revealed good osseointegration between all three CPCs and adjacent bone. The barium sulfate did not affect the CPCs biocompatibility or mechanical properties. These results suggest that CPC might be a good alternative to polymethylmethacrylate for selected indications.     

Comparison of two methods of fatigue testing bone cement

Two different methods have been used to fatigue test four bone cements. Each method has been used previously, but the results have not been compared. The ISO 527-based method tests a minimum of 10 samples over a single stress range in tension only and uses Weibull analysis to calculate the median number of cycles to failure and the Weibull modulus. The ASTM F2118 test regime uses fewer specimens at various stress levels tested in fully reversed tension–compression, and generates a stress vs. number of cycles to failure (S–N) or Wöhler curve. Data from specimens with pores greater than 1 mm across is rejected. The ISO 527-based test while quicker to perform, provides only tensile fatigue data, but the material tested includes pores, thus the cement is closer to cement in clinical application. The ASTM regime uses tension and compression loading and multiple stress levels, thus is closer to physiological loading, but excludes specimens with defects obviously greater than 1 mm, so is less representative of cement in vivo. The fatigue lives between the cements were up to a factor 15 different for the single stress level tension only tests, while they were only a factor of 2 different in the fully reversed tension–compression testing. The ISO 527-based results are more sensitive to surface flaws, thus the differences found using ASTM F2118 are more indicative of differences in the fatigue lives. However, ISO 527-based tests are quicker, so are useful for initial screening.     

Comparison of the mechanical properties of Simplex P, Zimmer Regular, and LVC bone cements

The mechanical properties of the three cement preparations most widely used in the United States were compared by conducting tensile and fatigue tests on Simplex P, LVC, and Zimmer Regular bone cements. Specimens of all three cement preparations were prepared for mechanical testing with and without centrifugation of the cement immediately after mixing. Although the results of the tensile testing revealed a few specific instances of significant differences in the tensile properties of the three cement preparations, there was no consistent evidence that one cement was superior in tension to the others. However, the fatigue properties of Simplex P were consistently and significantly superior to the fatigue properties of both LVC and Zimmer Regular bone cements. Centrifugation of the cement immediately after mixing significantly improved both the tensile and fatigue properties of all three bone cements. However, the fatigue strength of centrifuged Simplex P was substantially and significantly superior to the fatigue strength of the centrifuged LVC and Zimmer Regular bone cements. Since in total joint replacements bone cement is subjected to cyclic loading, these data suggest that centrifuged Simplex P is a preferable bone cement to LVC and to Zimmer Regular cement with or without centrifugation.     

A radiopaque polymeric matrix for acrylic bone cements

As part of the search for an alternative to inorganic radiopaque agents, this work studies the possibility of modifying bone cement formulations by incorporating a radiopaque monomer, that is, 4-iodophenol methacrylate (IPMA), in the liquid phase. The monomer was synthesized in the laboratory, and cements were prepared by the standard method. The influence on the different cement characteristics of various monomer concentrations was studied. It was seen that the setting time decreased as the percentage of monomer increased. The radiopacity attained in the 15 vol.% IPMA formulations was about the same as that for a cement containing 10 wt.% barium sulphate. Dynamic and static mechanical properties were measured. The materials did not show significant differences in the glass transition temperature. However, static mechanical properties showed enhanced compressive strength, tensile strength, and elastic modulus with respect to conventional cements formulated with barium sulphate. Histological studies showed a good response of muscular tissue to implanted specimens.     

Mechanical performance of acrylic bone cements containing different radiopacifying agents

The effect that three different radiopacifying agents, two of them inorganic (BaSO4, ZrO2) and one organic (an iodine containing monomer, IHQM) have on the static and dynamic mechanical properties of acrylic bone cements was studied. Compressive and tensile strength, fracture toughness and fatigue crack propagation were evaluated. The effect of the inorganic fillers depends on their size and morphology. In relation to the radiolucent cement, the addition of zirconium dioxide improved significantly the tensile strength, the fracture toughness and the fatigue crack propagation resistance. In contrast, the addition of barium sulphate produced a decrease of the tensile strength, but did not affect the fracture toughness and improved the crack propagation resistance. When the iodine containing monomer was used, although the tensile strength and the fracture toughness increased, the fatigue crack propagation resistance remained as low as it was for the radiolucent cement.     

Tensile characteristics of ten commercial acrylic bone cements

The mechanical properties of acrylic bone cement, used in orthopedic surgery, are very influential in determining successful long-term stability of a prosthesis. A large number of commercial formulations are available, differing in chemical composition and physical properties of both powder and monomer constituents. In this study, the static and dynamic tensile characteristics of a number of the most commonly used bone cements (Palacos R, Simplex P, CMW 1 & 3, Sulfix-60, Zimmer Dough), along with some newer formulations (Endurance, Duracem 3, Osteobondtrade mark and Boneloc), have been investigated under the same testing regimes. Testing was performed in air at room temperature. Significant differences in both static and fatigue properties were found between the various bone cements. Tensile tests revealed that Palacos R, Sulfix-60, and Simplex P had the highest values of ultimate tensile strength, closely followed by CMW 3, while Zimmer Dough cement had the lowest strength. Fatigue testing was performed under stress control, using sinusoidal loading in tension-tension, with an upper stress level of 22MPa. The two outstanding cements when tested in these cyclic conditions were Simplex P and Palacos R, with the highest values of Weibull median cycles to failure. Boneloc bone cement demonstrated the lowest cycles to failure. While the testing regimes were not designed to replicate exact conditions experienced by the bone cement mantle in vivo, there was a correlation between these results and clinical outcome.     

Mechanical behaviour of a new acrylic radiopaque iodine-containing bone cement

In total hip replacement, fixation of a prosthesis is in most cases obtained by the application of methacrylic bone cements. Most of the commercially available bone cements contain barium sulphate or zirconium dioxide as radiopacifier. As is shown in the literature, the presence of these inorganic particles can be unfavourable in terms of mechanical and biological properties. Here, we describe a new type of bone cement, where X-ray contrast is obtained via the introduction of an iodine-containing methacrylate copolymer; a copolymer of methylmethacrylate and 2-[4-iodobenzoyl]-oxo-ethylmethacrylate (4-IEMA) is added to the powder component of the cement. The properties of the new I-containing bone cement (I-cement) are compared to those of a commercially available bone cement, with barium sulphate as radiopacifier (B-cement). The composition of the I-cement is adjusted such that similar handling properties and radiopacity as for the commercial cement are obtained. In view of the mechanical properties, it can be stated that the intrinsic mechanical behaviour of the I-cement, as revealed from compression tests, is superior to that of B-cement. Concerning the fatigue behaviour it can be concluded that, though B-cement has a slightly higher fatigue crack propagation resistance than I-cement, the fatigue life of vacuum-mixed I-cement is significantly better than that of B-cement. This is explained by the presence of BaSO4 clumps in the commercial cement; these act as crack initiation sites. The mechanical properties (especially fatigue resistance) of the new I-cement warrant its further development toward clinical application.     

Combined Influence of Barium Sulfate Content and Co-monomer Concentration on Properties of PMMA Bone Cements for Vertebroplasty

In this work, the combined influence of barium sulfate content and co-monomer concentration on the properties of acrylic bone cement for percutaneous vertebroplasty (PVP) was investigated using a response surface methodology. Cements were prepared with methyl methacrylate (MMA) and either diethyl amino ethyl methacrylate (DEAEM) or dimethyl amino ethyl methacrylate (DMAEM) as co-monomer in the liquid phase, while variable amounts of barium sulfate were incorporated to the solid phase in order to improve the radiopacity of cements. It was found that various properties such as peak temperature, setting time, residual monomer content, mechanical properties and injectability, had an effect on the occurrence of interactions (combined effect) between the barium sulfate and DEAEM in bone cements formulations when independent variables were at their maximum.     

硫酸钙骨水泥增强椎弓根螺钉置入骨质疏松椎体的瞬时稳定性

背景：由于内固定在骨质疏松骨上锚着力较差影响了其稳定性,因此需要新的固定方法,使用骨水泥或骨替代物增强内固定技术可以较好地解决这个问题。 目的：评价硫酸钙骨水泥增强的椎弓根螺钉置入骨质疏松椎体后的瞬时稳定性。 方法：选取新鲜小牛脊柱椎体,测量骨密度后,随机分为4组：①正常椎体椎弓根螺钉内固定组。②正常椎体椎弓根螺钉+硫酸钙骨水泥增强内固定组。③骨质疏松椎体椎弓根螺钉内固定组。④骨质疏松椎体椎弓根螺钉+硫酸钙骨水泥增强内固定组。将相同规格的椎弓根螺钉拧入测试椎体的椎弓根,测试其即刻最大轴向拔出力和最大破坏功耗,以评价硫酸钙骨水泥增强椎弓根螺钉的瞬时稳定性。 结果与结论：骨质疏松椎体较正常椎体的螺钉最大拔出力、最大破坏功耗明显减少(P < 0.05),而二者分别以骨水泥增强后的螺钉最大拔出力、最大破坏功耗明显增加(P < 0.05);正常组和骨质疏松组以骨水泥增强后螺钉的最大拔出力、最大破坏功耗相当。提示硫酸钙骨水泥增强后可以增加内固定螺钉的瞬时稳定性,硫酸钙骨水泥可以应用于骨质疏松患者骨折内固定的增强,具有较好的临床应用前景。中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程全文链接：     

Characterization of bone cements prepared with functionalized methacrylates and hydroxyapatite

Bone cements prepared with methyl methacrylate and either methacrylic acid or diethyl amino ethyl methacrylate as comonomers were characterized by infrared spectroscopy, nuclear magnetic resonance, gel permeation chromatography, dynamic mechanical thermal analysis, and mechanical testing. Selected formulations containing these functionalized methacrylates were filled with hydroxyapatite and studied in terms of their properties in tension, compression and bending, and X-ray diffraction. It was found that residual monomer was not greatly affected by the presence of either acid or basic comonomers in the unfilled bone cements. In contrast, molecular weight, curing times, and glass transition temperature were composition dependent. For samples with acidic comonomer, a faster curing time, higher molecular weight, and higher glass transition temperatures were observed with respect to those with the basic comonomer. X-ray diffraction revealed that the crystalline structure was not affected by the nature of comonomer in the bone cement while scanning electron microscopy showed that hydroxyapatite remained as clusters in the bone cement.The mechanical properties of filled bone cements depended mainly on composition and type of testing. Hydroxyapatite-filled bone cements fullfilled the minimum compressive strength (70 MPa) required for bone cement use. However, the minimum tensile strength (30 MPa) was only fullfilled by cements prepared without comonomer and those containing methacrylic acid. The minimum bending strength requirement (50 MPa) was not satisfied by any of the formulations studied.     

Improved fatigue life of acrylic bone cements reinforced with zirconia fibers

Poly(methyl methacrylate) (PMMA) bone cements have a long and successful history of use for implant fixation, but suffer from a relatively low fracture and fatigue resistance which can result in failure of the cement and the implant. Fiber or particulate reinforcement has been used to improve mechanical properties, but typically at the expense of the pre-cured cement viscosity, which is critical for successful integration with peri-implant bone tissue. Therefore, the objective of this study was to investigate the effects of zirconia fiber reinforcement on the fatigue life of acrylic bone cements while maintaining a relatively low pre-cured cement viscosity. Sintered straight or variable diameter fibers (VDFs) were added to a PMMA cement and tested in fully reversed uniaxial fatigue until failure. The mean fatigue life of cements reinforced with 15 and 20 vol% straight zirconia fibers was significantly increased by ～40-fold, on average, compared to a commercial benchmark (Osteobond?) and cements reinforced with 0–10 vol% straight zirconia fibers. The mean fatigue life of a cement reinforced with 10 vol% VDFs was an order of magnitude greater than the same cement reinforced with 10 vol% straight fibers. The time-dependent viscosity of cements reinforced with 10 and 15 vol% straight fibers was comparable to the commercial benchmark during curing. Therefore, the addition of relatively small amounts of straight and variable diameter zirconia fibers was able to substantially improve the fatigue resistance of acrylic bone cement while exhibiting similar handling characteristics compared to current commercial products.     

Gentamicin release from two-solution and powder-liquid poly(methyl methacrylate)-based bone cements by using novel pH method

The release of gentamicin as a function of time was measured for Palacos and two-solution bone cements by using a novel pH technique. The pH of an aqueous solution of gentamicin is a function of the gentamicin concentration and it decreases linearly over concentrations of 0.0-0.1 wt %. Therefore, a new, direct, and inexpensive in vitro technique was developed based on continuous readings of the pH in phosphate-buffered saline (PBS) at 37 degrees C to determine the release kinetics of gentamicin from poly(methyl methacrylate) (PMMA)-based bone cement. In addition, this method was used to compare the release profiles of Palacos R-40 bone cement with a two-solution bone cement developed in our laboratory and loaded with two different concentrations of gentamicin sulfate. Finally, the pH-based method was used to track the elution of gentamicin in both mixed and static conditions to determine the effect of mixing on the diffusion of gentamicin out of the cement. It was found that Palacos R-40 released 4.95 +/- 0.22 wt % of its gentamicin after 24 h in PBS solution. This data compares favorably with previously reported values of gentamicin elution from Palacos R-40, which ranged from 3 to 8 wt % of the total amount of incorporated gentamicin, depending on the size and the surface area of the samples. The results show that Palacos samples released 4.84 +/- 0.27 mg after 24 h, a two-solution cement loaded with an equivalent concentration of gentamicin sulfate released 3.81 +/- 0.52 mg, and two-solution cement loaded with twice the concentration of Palacos released 5.53 +/- 0.26 mg of gentamicin. A higher percentage of release was recorded from Palacos than from the two-solution bone cement, and the effect of PBS mixing conditions on the release kinetics was only significant in the early stages of release and not at 24 h. It was concluded that monitoring the pH is an effective technique to measure gentamicin release from PMMA-based bone cements in PBS solution.     

Performance of vertebral cancellous bone augmented with compliant PMMA under dynamic loads

Increased fracture risk has been reported for the adjacent vertebral bodies after vertebroplasty. This increase has been partly attributed to the high Young's modulus of commonly used polymethylmethacrylate (PMMA). Therefore, a compliant bone cement of PMMA with a bulk modulus closer to the apparent modulus of cancellous bone has been produced. This compliant bone cement was achieved by introducing pores in the cement. Due to the reduced failure strength of that porous PMMA cement, cancellous bone augmented with such cement could deteriorate under dynamic loading. The aim of the present study was to assess the potential of acute failure, particle generation and mechanical properties of cancellous bone augmented with this compliant cement in comparison to regular cement. For this purpose, vertebral biopsies were augmented with porous- and regular PMMA bone cement, submitted to dynamic tests and compression to failure. Changes in Young's modulus and height due to dynamic loading were determined. Afterwards, yield strength and Young's modulus were determined by compressive tests to failure and compared to the individual composite materials. No failure occurred and no particle generation could be observed during dynamical testing for both groups. Height loss was significantly higher for the porous cement composite (0.53+/-0.21%) in comparison to the biopsies augmented with regular cement (0.16+/-0.1%). Young's modulus of biopsies augmented with porous PMMA was comparable to cancellous bone or porous cement alone (200-700 MPa). The yield strength of those biopsies (21.1+/-4.1 MPa) was around two times higher than for porous cement alone (11.6+/-3.3 MPa).     

Characterization of bone cements prepared with functionalized methacrylates and hydroxyapatite.

Bone cements prepared with methyl methacrylate and either methacrylic acid or diethyl amino ethyl methacrylate as comonomers were characterized by infrared spectroscopy, nuclear magnetic resonance, gel permeation chromatography, dynamic mechanical thermal analysis, and mechanical testing. Selected formulations containing these functionalized methacrylates were filled with hydroxyapatite and studied in terms of their properties in tension, compression and bending, and X-ray diffraction. It was found that residual monomer was not greatly affected by the presence of either acid or basic comonomers in the unfilled bone cements. In contrast, molecular weight, curing times, and glass transition temperature were composition dependent. For samples with acidic comonomer, a faster curing time, higher molecular weight, and higher glass transition temperatures were observed with respect to those with the basic comonomer. X-ray diffraction revealed that the crystalline structure was not affected by the nature of comonomer in the bone cement while scanning electron microscopy showed that hydroxyapatite remained as clusters in the bone cement.The mechanical properties of filled bone cements depended mainly on composition and type of testing. Hydroxyapatite-filled bone cements fullfilled the minimum compressive strength (70 MPa) required for bone cement use. However, the minimum tensile strength (30 MPa) was only fullfilled by cements prepared without comonomer and those containing methacrylic acid. The minimum bending strength requirement (50 MPa) was not satisfied by any of the formulations studied.     

Graft copolymers of methyl methacrylate and poly([R]-3-hydroxybutyrate) macromonomers as candidates for inclusion in acrylic bone cement formulations: Compression testing

Graft copolymers of methyl methacrylate and biodegradable, biocompatible bacterial poly([R]-3-hydroxybutyrate) (PHB) blocks were synthesized and evaluated as possible constituents in acrylic bone cements for use in orthopaedic applications. The copolymers were produced by conventional free radical copolymerization and incorporated in one commercially available acrylic bone cement brand, Antibiotic Simplex (AKZ). Cements with formulations containing 6.7 and 13.5 wt % of PMMA-graft-PHB were prepared. The morphology of the graft copolymer particles was suggested to influence the ability of the modified cement to be processed. Formulations containing more than about 20 wt % of the graft copolymer resulted in cement doughs that, both after first preparation and several hours later, were either sandy or soft spongy in texture and, thus, would be unacceptable for use in orthopaedic applications. The morphologies of the powders and the volumetric porosity (p) and ultimate compressive strength (UCS) of the cured cements were determined. Micro computed tomography showed that the cements presented average porosities of 13.5-16.9%. It was found that, while the powder particle shape and size for the experimental cements were markedly different from those of AKZ, there was no significant difference in either p or UCS for these cements. The latter was determined to be about 85 MPa for the modified cements and 84 MPa for Antibiotic Simplex. Furthermore, the UCS of all the cements exceeded the minimum level for acrylic bone cements, as stipulated by ASTM F-451.     

Biocompatibility of a new radiopaque iodine-containing acrylic bone cement

Radiopacity in the vast majority of the commercially available acrylic bone cements that are used clinically is provided by particles of either BaSO(4) or ZrO(2). Literature reports have shown these agents to have a detrimental effect on some mechanical properties of the cements as well as on its biological response. We, therefore, have developed a new type of bone cement, for which radiopacity results from the presence of an iodine-containing methacrylic copolymer. The focus of the present work was the comparison of the biocompatibility of this new cement and a commercially available cement that contains barium sulfate. In vitro experiments show that both cements are cytocompatible materials, for which no toxic leachables are found. Implantation of the cements in a rabbit for three months resulted in the occasional presence of a thin fibrous tissue at the cement-bone interface, which is common for acrylic bone cements. Consideration of all the results led to the conclusion that the new cement is as biocompatible as the BaSO(4)-containing one.     

Rapid and reliable biomechanical screening of injectable bone cements for autonomous augmentation of osteoporotic vertebral bodies: appropriate values of elastic constants for finite element models

We performed finite element analysis studies on 3 three-dimensional representations of a single vertebral body: a regular cube, made of low-density polyurethane foam (foam cube analog); a regular cube considered composed of cancellous bone only (bone cube analog)); and the body of the L2 vertebra (full anatomical body model). Each finite element model was subjected to a compressive load of 2300 N, uniformly distributed over its superior surface. The cancellous and cortical bones were assigned anisotropic elastic properties, while the foam and the endplate material were considered to have isotropic properties. In each representation, the elastic properties of the material(s) were adjusted (from the initial values that were used) to give a stiffness of the representation that was equal to that of the mean result for fresh cadaveric osteoporotic single vertebral bodies, as obtained from ex vivo experimental studies reported in the literature (1226 +/- 996 N mm(-1)). Thus, any one of these representations, when used with the final adjusted value(s) of the elastic constants and modified to include a cylindrical hole filled with a specific volume of bolus of an injected bone cement, may be utilized in the rapid and reliable experimental ex vivo and/or numerical screening of these cements for use in autonomous vertebral body augmentation. This approach has many advantages over those that are currently being used, which are either characterization of the cement in isolation from the vertebral body or use of cadaveric vertebral bodies.     

Evaluation of the particle release of porous PMMA cements during curing

Poly(methyl methacrylate) (PMMA) remains the most common bone substitute material used for vertebroplasty. A possible downside with this material is that the Young’s modulus of the cement is significantly higher than that of osteoporotic vertebral cancellous bone. In consequence, an increased fracture risk has been demonstrated for the adjacent vertebral bodies after reinforcement. A solution could be to prepare porous bone cements with a lower bulk modulus as suggested by De Wijn (De Wijn JR. Poly(methyl methacrylate)-aqueous phase blends: in situ curing porous materials. J Biomed Mater Res 1976;10:625–35). The potential of such porous PMMA cements for application in vertebroplasty has been shown in the literature. The present study was performed to study the release of particles, e.g. powder particles such as barium sulfate or hydroxyapatite, from PMMA cements containing an aqueous phase. The aqueous phase was introduced to act as a pore-forming phase to soften the cement and is thought to be released when applied in vivo. Cement particle release is not suitable for the application as they may cause adverse reactions such as embolism. The purpose of the present study was to investigate the amount of the particles released in relation to various aqueous solutions and different preparation methods. As a result of the work presented here, a method was found to reduce the particle release by delayed admixing of the aqueous phase to the partially polymerized PMMA/MMA mixture. This method leads to a reduction in particle release of more than 50%, e.g. reduced from 1.3 to 0.6 g particles per 4 ml of cement. Despite these improvements, particle release could not be reduced to a suitable level comparable to regular vertebroplasty cement. Therefore, the practicability of the initially promising invention of porous PMMA, in order to make regular PMMA cement more compliant with cancellous bone remains an unsolved issue.     

Effect of surface modification of polymer beads on the mechanical properties of acrylic bone cement

The effect of surface modification of polymer filler on the static mechanical properties of acrylic bone cement was studied. The surface of polymer beads was modified with carboxylic and amino groups by photochemical reaction with azide compounds. Monomer modifiers (maleic anhydride, methacrylic acid and p-aminostyrene) are attached to the functionalized surface of polymer beads. Functional allyl groups, which are capable of the graft polymerisation reaction, are attached to the surface via photochemical reaction with N-(2-nitro-4-azidophenyl)-N-(-propen) amine. This approach to bone cement provides the additional covalent bonds between the polymer beads and the inter-bead matrix. The static mechanical properties of bone cements containing modified polymer beads were investigated and compared with the static mechanical properties of unmodified cements. The absolute values of compressive strength for the modified and unmodified cements were found to be similar. An increase in flexural strength for the modified cements (dry and after water storage) was observed. The structure of the surface functional groups affects the methyl methacrylate grafting resulting in a higher value of flexural strength for the maleic anhydride- and p-aminostyrene-modified cements. The scanning electron microscopy examination of the fracture surface of the cement samples showed an improvement of the adhesion between the beads and the matrix after modification.     

Interfacial tensile strength between polymethylmethacrylate-based bioactive bone cements and bone

We have developed two types of polymethylmethacrylate (PMMA)-based bioactive bone cements containing bioactive glass beads (designated GBC) or apatite-wollastonite containing glass-ceramic powder (designated AWC) as the filler. A new method was used to evaluate the bone-cement interfacial strength of these bioactive bone cements. Two types of bioactive bone cements (GBC and AWC) and PMMA cement (CMW-1) were put in a frame attached to the smooth tibial metaphyseal cortex of the rabbit and polymerized in situ. The load required to detach the cement from the bone was measured at 4, 8, and 16 weeks after implantation. The interfacial tensile strength of GBC and AWC showed significantly higher values than PMMA cement from 4 weeks, and increased with time. For GBC, strength reached a maximum value of 12.39 +/- 1.79 kgf 16 weeks after implantation. Histological examination of rabbit tibiae up to 16 weeks demonstrated no intervening layer between the bioactive bone cements and the bone, whereas fibrous tissue was observed at the interface between the PMMA cement and the bone. From this study, we conclude that PMMA-based bioactive bone cements have a relatively higher adhesiveness at the interface than the conventionally used PMMA cement, showing potential as a promising alternative.