High modulus nanopowder reinforced dimethacrylate matrix composites for dental cement applications

Results from the study of a novel, high modulus nanopowder filled resin composite are presented. This composite is developed to serve (1) as a high stiffness support to all-ceramic crowns and (2) as a means of joining independently fabricated crown core and veneer layers. Nanosized Al(2)O(3) (average particle size 47 nm) reinforcement provides stiffness across joins. Two systems are examined: Al(2)O(3) with 50:50 bis-GMA:TEGDMA monomers (ALBT) and Al(2)O(3) with pure TEGDMA (ALT). To obtain higher filler levels, surfactant is used to aid mixing and increase maximum weight percent of nanopowder filler from 72 to 80. The loading level of Al(2)O(3) has significant effects on composite properties. The elastic modulus for cured ALBT systems increases from 4.6 GPa (0 wt % filler) to 29.2 GPa (80 wt % filler). The elastic modulus for cured ALT systems increases from 3.0 GPa (0 wt % filler) to 22.9 GPa (80 wt % filler). Similarly, ALBT hardness increases from 200 MPa (0% filler) to 949 MPa (80 wt % filler), and ALT hardness increases from 93 MPa (0% filler) to 760 MPa (80 wt % filler). Our results indicate that with a generally monodispersed nanosized high modulus filler relatively high elastic modulus resin based composite cements are possible.     

Fretting wear properties of hydroxyapatite, alumina containing high density polyethylene biocomposites against zirconia

Considering the importance of wear on the materials performance in biomedical applications, the major objective of the present work is to investigate the friction and fretting wear behavior of various HDPE-based composites against zirconia counterbody, both in air and simulated body fluid (SBF) environment. Both Al(2)O(3) and/or HAp fillers (upto 40 vol %) have been incorporated in HDPE to improve the hardness and elastic modulus of HDPE. The fretting wear study indicates that extremely low COF (approximately 0.055-0.075) as well as higher wear resistance (wear rate in the order of approximately 10(-6) mm(3)/N m) can be achieved with the newly developed composites in SBF. A low wear depth of 3-7 microm is recorded, irrespective of fretting environment. Besides reporting the phenomenological tribological data, major focus has been on to understand the underlying mechanism of material removal at fretting contacts. Such understanding has been established in discussing the wear mechanisms in terms of deformation of polymer matrix, tribolayer formation, and wear debris generation.     

Tribological investigation of novel HDPE-HAp-Al2O3 hybrid biocomposites against steel under dry and simulated body fluid condition

Among various biocompatible polymers, polyethylene based materials have received wider attention because of its excellent stability in body fluid, inertness, and easy formability. Attempts have been made to improve their physical properties (modulus/strength) to enable them to be used as load bearing hard tissue replacement applications. Among such attempts, high density polyethylene (HDPE)-hydroxyapatite (HAp) composite (HAPEX), has already been developed for total hip replacement (THR) acetabular cup and low load bearing bone tissue replacement. In the present work, alumina has been added as a partial replacement of HAp phase to improve the mechanical and tribological properties of the HAPEX composite. In an attempt to assess the suitability of the developed composite in THR application, the tribological properties against steel counterbody under both in air and simulated body fluid (SBF), have been investigated and efforts have been made to understand the wear mechanisms. The fretting wear study indicates the possibility of achieving extremely low COF (Coefficient of Friction approximately 0.09) as well as higher wear resistance (order of 10(-6) mm(3)/N m) with the newly developed composites in SBF. A low wear depth of approximately 4.6-5.3 microm is recorded, irrespective of fretting environment. The implication of the work is that optimal and combined addition of bioactive and bioinert ceramic filler to HDPE can provide a good opportunity to obtain hybrid biocomposites with better combination of physical properties (modulus, hardness) as well as low friction and high wear resistance.     

Biaxial flexure strength and low temperature degradation of Ce-TZP/Al2O3 nanocomposite and Y-TZP as dental restoratives

The purpose of the present study was to evaluate the mechanical durability of a zirconia/alumina nanocomposite stabilized with cerium oxide (Ce-TZP/Al(2)O(3) nanocomposite) in comparison to yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and discuss its application on ceramic dental restorations. The disk-shaped specimens of both materials were stored in physiological saline solution at 80 degrees C for 30 days, in 4% acetic acid at 80 degrees C for 30 days, and in an autoclave at 121 degrees C for 10 days. Before and after storage, specimens were subjected to the biaxial flexure test and to the determination of the monoclinic zirconia content. After autoclaving, Y-TZP showed remarkable increasing of the content of monoclinic zirconia: 0.3 vol % before and 49.9 vol % after, and slight decreasing of biaxial flexure strength: 1046 MPa before and 892 MPa after; whereas Ce-TZP/Al(2)O(3) nanocomposite showed no significant difference in the monoclinic content (4.8-5.5 vol %) and the biaxial flexure strength (1371-1422 MPa) after storage in any conditions. It is concluded that, compared to Y-TZP, the Ce-TZP/Al(2)O(3) nanocomposite has a high biaxial flexure strength along with a satisfactory durability in terms of low-temperature aging degradation in above conditions. This study indicates that the Ce-TZP/Al(2)O(3) nanocomposite demonstrates excellent mechanical durability for dental restorations such as all-ceramic bridges.     

Mechanical properties, phase stability, and biocompatibility of (Y, Nb)-TZP/Al(2)O(3) composite abutments for dental implant

ZrO(2)/Al(2)O(3) composites were prepared by mixing a tetragonal ZrO(2), stabilized by 5.31 mol% Y(2)O(3) and 4.45 mol% Nb(2)O(5), and various amounts of Al(2)O(3). Influence of the amount of Al(2)O(3) on strength and toughness and tetragonal phase stability in the composites under autoclave conditions was investigated. In addition, in vitro and in vivo biocompatibility of the composites was examined. The composite, prepared with addition of 20 vol% Al(2)O(3), exhibited the highest strength of 700 MPa and toughness of 8.1 MPa. m(1/2) and showed no hydrothermal degradation while aging in an autoclave. The biocompatibility of the composite exhibited no cytotoxicity and no significant adverse soft-tissue response for up to 3 months implant period in guinea pigs.     

F掺杂对纳米Al_2O_3/HA复合陶瓷的结构与性能影响

本研究采用化学沉淀法制备了纳米Al_2O_3/HA复合粉体,采用热压烧结法制备了Al_2O_3/HA复合生物陶瓷,并研究了F掺杂量对复合陶瓷物相组成和力学性能的影响。结果证明复合陶瓷的力学性能随着F掺杂量的提高而逐渐增大,当F掺杂量x=1时,复合陶瓷的力学性能最佳,其弯曲强度和断裂韧性分别为147.2 MPa和2.19 MPa·m~(1/2)。当F掺杂量高于0.5时,可以抑制复合陶瓷中HA的分解,并且在烧结过程中有AlF3相生成,可促进复合陶瓷的致密化。F掺杂可以提高复合陶瓷的生物活性,但是F掺杂量对复合陶瓷的生物活性影响不大。     

Friction and wear properties of novel HDPE--HAp--Al2O3 biocomposites against alumina counterface

In an effort to enhance physical properties of biopolymers (high-density polyethylene, HDPE) in terms of elastic modulus and hardness, various ceramic fillers, like alumina (Al2O3) and hydroxyapatite (HAp) are added, and therefore it is essential to assess the friction and wear resistance properties of HDPE biocomposites. In this perspective, HDPE composites with varying ceramic filler content (upto 40 vol%) were fabricated under the optimal compression molding conditions and their friction and wear properties were evaluated against Al2O3 at fretting contacts. All the experiments were conducted at a load of 10 N for duration of 100,000 cycles in both dry as well as simulated body fluid (SBF). Such planned set of experiments has been designed to address three important issues: (a) whether the improvement in physical properties (hardness, E-modulus) will lead to corresponding improvement in friction and wear properties; (b) whether the fretting in SBF will provide sufficient lubrication in order to considerably enhance the tribological properties, as compared to that in ambient conditions; and (c) whether the generation of wear debris particles be reduced for various compositionally modified polymer composites, in comparison to unreinforced HDPE. The experimental results indicate the possibility of achieving extremely low coefficient of friction (COF approximately 0.047) as well as higher wear resistance (wear rate in the order of approximately 10(-7) mm3 N(-1) m(-1)) with the newly developed composites in SBF. A low wear depth of 3.5-4 microm is recorded, irrespective of fretting environment. Much effort has been put forward to correlate the friction and wear mechanisms with abrasion, adhesion, and wear debris formation.     

In vitro biological evaluation of beta-TCP/HDPE--A novel orthopedic composite: a survey using human osteoblast and fibroblast bone cells

Beta-tricalcium phosphate reinforced high density polyethylene (beta-TCP/HDPE) was prepared to simulate bone composition and to study its capacity to act as bone tissue. This material was produced by replacing the mineral component and collagen soft tissue of the bone with beta-TCP and HDPE, respectively. The biocompatibility of the composite samples with different volume fractions of TCP (20, 30 and 40 vol %) was examined in vitro using two osteoblast cell lines G-292 and Saos-2, and also a type of fibroblast cell isolated from bone tissue, namely human bone fibroblast (HBF) by proliferation, and cell adhesion assays. Cell-material interaction with the surface of the composite samples was examined by scanning electron microscopy (SEM). The effect of beta-TCP/HDPE on the behavior of osteoblast and fibroblast cells was compared with those of composite and negative control samples; polyethylene (PE) and tissue culture polystyrene (TPS), respectively. In general, the results showed that the composite samples containing beta-TCP as reinforcement supported a higher rate of proliferation by various bone cells after 3, 7, and 14 days of incubation compared to the composite control sample. Furthermore, more osteoblast cells were attached to the surface of the composite samples when compared to the composite control samples after the above incubation periods (p < 0.05), while in the case of HBF an equal or even higher number of cells adhered to PE was observed. The number of adhered osteoblast cells was almost equal and in some days even higher than the number of adhered cells on negative control sample, while in the case of fibroblast this difference was significantly higher than TPS (p < 0.05). Adhered cells presented a normal morphology by SEM and many of the cells were observed to be undergoing cell division. These findings indicate that beta-TCP/HDPE composites are biocompatible, nontoxic, and act to stimulate proliferation and adhesion of the cells, whether osteoblast or fibroblast.     

In vitro evaluation of biocompatibility of beta-tricalcium phosphate-reinforced high-density polyethylene; an orthopedic composite

Beta-tricalcium phosphate-reinforced high-density polyethylene (beta-TCP/HDPE) is a new biomaterial which was made as a copy of bone composition with the aim of replacement of bony tissues. The composite samples were prepared using medical grade TCP powder and granular polyethylene. The raw materials were first compounded and the resulting composite preforms were compression molded into desired shape. The biocompatibility of composite samples with different volume fractions of TCP (20, 30, and 40 vol %) was assessed by proliferation, alkaline phosphatase (ALP), and cell adhesion assays using G-292 osteoblast cells. Cell-material interaction on the surface of the composites was observed by scanning electron microscopy (SEM). The effect of beta-TCP/HDPE on the behavior of G-292 cells was compared with those of a composite and a negative control samples. Results showed the composite samples had a higher proliferation rate of G-292 cells in the presence of composite samples as compared to the composite control sample after 3, 7, and 14 days of incubation period. ALP production after incubation in the presence of composite samples was seen to peak on the day 7. The number of adhered cells on the composite samples was higher than the numbers adhered on composite and negative control samples after the above incubation periods. Morphology investigation of adhered cells by SEM indicated a normal morphology and also many of the cells were in the process of cell division. The above results indicate that beta-TCP/HDPE samples are biocompatible, nontoxic, and in some cases show an increase in the proliferation rate of the cells, ALP production, and cell adhesion as compared to the control counterparts.     

Antibacterial silver-containing silica glass prepared by sol-gel method

Recently, various inorganic antibacterial materials containing silver have been developed and some of them are in commercial use. Colorless and more chemically durable materials which slowly release the silver ion for a long period are, however, desirable to be developed for medical applications such as composite resin for dental restoration. In the present study, Si(OC2H5)4, Al(NO3)3 x 9H2O, AgNO3, HNO3, C2H5OH and H2O solutions with various Al/Ag atomic ratios under a constant Si/Ag atomic ratio of 1/0.023 were kept at 40 degrees C for gelation and drying. Thus obtained gels were pulverized into fine powders with average particle size of approximately 10 microm and then heat-treated at 900-1000 degrees C for 2 h. For the composition Al/Ag = 0, a yellow-colored glass was formed, since the silver existed in the form of metallic colloids in the glass. However, for the compositions Al/Ag > or = 1, colorless glasses were successfully obtained, since the silver existed in the form of Ag+ ions in the glasses. For the composition Al/Ag = 0, the silver ions got released rapidly into the water, whereas, for the compositions Al/Ag > or = 1, they gradually got released into the water at a controlled rate. A composite of the obtained powders with Al/Ag atomic ratio of 1 with Bis-GMA/TEGDMA in 70:30 weight ratio showed excellent antibacterial property. The sol-gel derived silica glass powders containing silver with compositions Al/Ag > or = 1 are believed to be useful as an antibacterial material for medical applications such as filler of composite resin for dental restoration.     

Testing of silicon nitride ceramic bearings for total hip arthroplasty

Modern ceramic bearings used in total hip arthroplasty (THA) consist of a femoral head (ball) articulating inside a hemispherical acetabular cup (socket); the ball and socket are made of alumina (Al(2)O(3)) and Al(2)O(3)-based composite materials. In the present study, total hip bearings were made from a different ceramic material, silicon nitride (Si(3)N(4)), by sintering and hot isostatic pressing of powders. The resulting material had improved mechanical properties over modern Al(2)O(3) THA bearings, with a flexural strength of 920 +/- 70 MPa, a Weibull modulus of 19, and a fracture toughness of 10 +/- 1 MPa m(1/2). Unlike zirconia-based ceramics that have also been used in THA, accelerated aging of Si(3)N(4) did not adversely affect the flexural strength. In simulated wear tests, Si(3)N(4) acetabular cups produced low-volumetric wear whether articulating against Si(3)N(4) or cobalt-chromium (CoCr) femoral heads. The results of this investigation suggest that Si(3)N(4) may allow improved THA bearings that combine the reliability of metal femoral heads with the low wear advantages of ceramic materials.     

Direct anchorage of Al2O3-ceramic hip components: three years of clinical experience and results of further animal studies.

The biocompatibility of high-purity dense Al2O3-ceramics had been shown to open the possibility of direct cement-free anchorage of joint endoprostheses. Three years of clinical experience with ceramic-metal composite total hip prostheses confirm the biomechanical design criteria used for the acetabular components. They also allow for additional conclusions regarding the reaction of bone tissue towards a bioinert implant. Further research activities are directed towards a solution for biomechanically stable anchorage of the femoral component of hip prostheses.     

Effect of reinforcement particle size on in vitro behavior of beta-tricalcium phosphate-reinforced high-density polyethylene: a novel orthopedic composite

Beta-tricalcium phosphate-reinforced high-density polyethylene (beta-TCP/HDPE) is a new biomaterial, which was made to simulate bone composition and study its capacity to act like bony tissues. This material was produced by replacing mineral component and collagen soft tissue of bone with beta-TCP and HDPE, respectively. The biocompatibility of composite samples with different volume fractions of TCP (20, 30, and 40 vol %) and two different particle sizes (80-100 and 120-140 mesh size) was examined in vitro using the osteoblast cell line G-292 by proliferation, alkaline phosphatase (ALP) production, and cell adhesion assays. Cell-material interaction on the surface of the composites was observed by scanning electron microscopy (SEM). The effect of beta-TCP particle size on behavior of the osteoblast cell line was compared between two groups of the composite samples containing smaller and larger reinforcement particle sizes as well as with those of a negative control. In general, results showed that the composite samples containing larger particles supported a higher rate of proliferation and ALP production by osteoblast cells after 3, 7, and 14 days of incubation compared to the composite samples with smaller particle size and control. Furthermore, more cells were attached to the surface of composite samples containing larger particle size when compared to the smaller particle size composites (p<0.05). This number was nearly equal with numbers adhered on negative control [tissue culture polystyrene (TPS)] and significantly higher in comparison with composite control [polyethylene (PE)] (p<0.05). Adhered cells presented a normal morphology by SEM and many of the cells were seen to be undergoing cell division. These findings indicate that beta-TCP/HDPE composites are biocompatible, nontoxic, and in some cases, act to stimulate proliferation of the cells, ALP production, and cell adhesion when compared to the control counterparts. Furthermore, beta-TCP/HDPE samples with larger reinforcement particle size were shown to possess better biological properties.     

Hydroxyapatite whiskers provide improved mechanical properties in reinforced polymer composites

Synthetic hydroxyapatite (HA) whiskers have been utilized as a new, biocompatible reinforcement for orthopedic biomaterials. High-density polyethylene (HDPE) was reinforced with either the synthesized HA whiskers or a commercially available spherical HA powder using a novel powder processing technique that facilitated uniform dispersion of the reinforcements in the matrix prior to compression molding. Composites were processed for up to 60 vol % HA whiskers and up to 50 vol % spherical HA. The mechanical properties of the new composite biomaterials were examined by uniaxial tensile tests. As expected, increased volume fraction of either reinforcement type over 0-50 vol % resulted in increased elastic modulus, a maximum in ultimate tensile stress, and decreased work to failure. Composites reinforced with HA whiskers had higher elastic modulus, ultimate tensile strength, and work to failure relative to composites reinforced with spherical HA. Thus, HA whisker-reinforced HDPE composites possessed improved mechanical properties over those reinforced with spherical HA. HA whisker-reinforced composites were anisotropic due to alignment of the whiskers in the matrix during processing.     

Preparation and characterization of Al2O3 reinforced hydroxyapatite.

The microstructure of Al2O3 reinforced hydroxyapatite (HA-Ca5(PO4)3OH) was studied. It was demonstrated that in this composite the Al2O3 particles are uniformly distributed in a matrix of spherical HA agglomerates formed by primary needlelike HA particles present before making green compact. In the HA + 20 wt% Al2O3 system, hydroxyapatite is partially decomposed into alpha-Ca3(PO4)2 and CaO with H2O vapour during sintering. Subsequently, the CaO is combined with Al2O3 to produce calcium aluminates (CaAl2O4 and CaAl4O7).     

The effect of varying Al2O3 percentage in hydroxyapatite/Al2O3 composite materials: morphological, chemical and cytotoxic evaluation

Hydroxyapatite (HA) and HA-alumina (HA/Al2O3) composites, with Al2O3 contents of 5, 10, 20, and 30%, were synthesized using a wet precipitation method and sintered at 900 and 1300 degrees C. We investigated the effect of sintering temperature and relative concentration of HA and Al2O3 on the chemical composition, surface morphology, and cytotoxicity of the composite powders. The XRD results show that in the 1300 degrees C composites, HA partially decomposed into CaO which combined with Al2O3 to form different calcium aluminates. For the 900 degrees C composites the CaO phase was not detected, though a Ca/P ratio larger than 1.67 measured by XPS suggests that CaO was present in trace amounts. SEM-EDX analysis indicated that the HA microstructure was affected by the sintering temperature, and this HA is present on the surface of Al2O3 particles. The cytotoxicity of the composites was assessed indirectly using the MTT assay. The short-term effect of leachables was quantified by exposing a L929 mouse fibroblast cell line to the degradation products released by the composites after immersion in the cell culture medium. Degradation products were less toxic to L-929 at lower extract concentrations (10, 50%) than at 100% concentration. Cell viability was also influenced by leachable size.     

Textural characterization of finished and polished composites over time of intraoral exposure

This in situ study sought to evaluate the surface roughness evolution of resin composites finished and polished by different methods. A total of 108 rectangular-shaped specimens of a microfilled and a hybrid composite were cured against a Mylar matrix strip and left unpolished or instrumented with diamond burs, Al2O3-coated disks, Al2O3-impregnated UDMA disk, or with diamond burs followed by either one of the disks. After specimens had been profiled for the average surface roughness (Ra, microm), 18 volunteers wore a removable palatal appliance, which accommodated one specimen of each one of the 12 groups investigated. Surface roughness for up to 28 days of intraoral exposure was then measured at 1- or 7-day intervals. A split-plot ANOVA (alpha = 0.05) revealed a significant interaction between group and time. Tukey's test and regression analyses ascertained that initially finishing with burs only provided the roughest surface to both composites. Unpolished surfaces and those specimens polished with Al2O3-coated disks, regardless of previous use of diamond burs, attained smoother surface. The Al2O3-impregnated UDMA disk was capable of smoothening the surface of the hybrid material previously finished with diamond burs. The roughness achieved after finishing and polishing composites may be either smoothened or roughened after intraoral exposure. On the basis of the roughness range, it is advisable to use Al2O3-coated disks, regardless of whether diamond burs were previously used. Al2O3-impregnated UDMA disks (with or without previous application of diamond burs) may be also suitable for instrumenting hybrid restoratives.     

Preparation of epoxy-SiO2 hybrid sol-gel material for bone cement

An organic-inorganic hybrid material, epoxy-SiO(2), was prepared by incorporating epoxy structure units covalently into a SiO(2) glass network via the sol-gel approach. The precursor was obtained by the reaction of diglycidyl ether of bisphenol A (DGEBA) with 3-aminopropyl trimethoxysilane (APTS). The precursor was then hydrolyzed and co-condensated with tetraethyl orthosilicate (TEOS) in tetrahydrofuran (THF) at room temperature to yield epoxy-SiO(2) hybrid sol-gel material having a 50 wt % SiO(2) content. Thermal properties of the hybrid material were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The hybrid sol-gel material epoxy-SiO(2) was the solid, powder component of bone cement. The liquid component contains bis-phenol-A glycidyl methacrylate (Bis-GMA), triethyleneglycol dimethacrylate (TEGDMA), and methyl methacrylate (MMA) with 25, 55, and 20 vol %, respectively. We discuss the comparison between the new epoxy-SiO(2) bone cement and the commercial Simplex P bone cement. Mechanical properties such as Young's modulus, compressive strength, hardness, and impact strength of the new epoxy-SiO(2) bone cement exceeded those of Simplex P bone cement. The tensile and bending strengths of the new epoxy-SiO(2) bone cement were approximately the same as those of Simplex P bone cement. In order to evaluate the biocompatibility of the new bone cement, an MTT test and optical microscopy were conducted in cell culture. Results indicated that the new epoxy-SiO(2) bone cement exhibits very low cytotoxicity compared with Simplex P bone cement.     

Reinforcement of electrospun membranes using nanoscale Al2O3 whiskers for improved tissue scaffolds

Poly(ε-caprolactone) (PCL) is a promising material for tissue engineering applications; however, it can be difficult to create scaffolds with the morphology, hydrophilicity, and mechanical properties necessary to support tissue growth. Typically, pure PCL scaffolds have good cellular adhesion, but somewhat low mechanical properties (elastic modulus and tensile strength). This study addresses these issues by incorporating Al(2)O(3) whiskers as reinforcements within PCL membranes generated by electrospinning. Membranes were prepared with Al(2)O(3) content ranging from 1 to 20 wt % and characterized using XRD, TEM, and SEM to determine composition and morphology. The Al(2)O(3) whiskers were well dispersed within the PCL fibers, and the membranes had a highly porous morphology. The elastic modulus was significantly improved by the well aligned whisker reinforcements as verified by tensile testing. The cell morphology and proliferation studies demonstrate Al(2)O(3) whisker reinforced PCL scaffolds maintained the good biocompatibility. These improvements demonstrate that Al(2)O(3) whisker reinforced PCL scaffolds can be considered as a biocompatible material for tissue engineering and dental applications.     

Ce-TZP/Al2O3 nanocomposite as a bearing material in total joint replacement

The objectives of this study were to investigate the biocompatibility, phase stability, and wear properties of a newly developed Ce-TZP/Al(2)O(3) nanocomposite, as compared to conventional ceramics, and to determine whether the new composite could be used as a bearing material in total joint prostheses. In tests of mechanical properties, this composite showed significantly higher toughness than conventional Y-TZP. For biocompatibility tests, cylindrical specimens of both the Ce-TZP/Al(2)O(3) nanocomposite and monolithic alumina were implanted into the paraspinal muscles of male Wistar rats. The tissue reactions were almost the same, and at 24 weeks after implantation, thin fibrous capsules with almost no inflammation were observed around both of them. There were no significant differences in membrane thickness between the two ceramics. After hydrothermal treatment in 121 degrees C vapor for 18 h, the new composite showed complete resistance to aging degradation, whereas Y-TZP showed a phase transformation of 25.3 vol% (initial 0.4%) to the monoclinic form. According to the results of pin-on-disk tests, the wear rates of Ce-TZP/Al(2)O(3) nanocomposite and alumina were 0.55 +/- 0.04 x 10(-7) and 2.12 +/- 0.37 x 10(-7)mm(3)/Nm, respectively. The results of this study suggest that the Ce-TZP/Al(2)O(3) nanocomposite is a promising alternative ceramic component for total joint replacement.