Osteoporotic Goat Spine Implantation Study Using a Synthetic, Resorbable Ca/P/S-Based Bone Substitute.

One primary purpose of the present study is to clarify whether the highly porous, resorbable Ca/P/S-based bone substitute used in this study would still induce an osteoporotic bone when implanted into the osteoporotic vertebral defects of ovariectomized (OVX) goats, or the newly-grown bone would expectantly be rather healthy bone. The bone substitute material used for the study is a synthetic, 100% inorganic, highly porous and fast-resorbable Ca/P/S-based material (Ezechbone Granule CBS-400). The results show that the OVX procedure along with a low calcium diet and breeding away from light can successfully induce osteoporosis in the present female experimental goats.

Physical/Chemical Properties and Resorption Behavior of a Newly Developed Ca/P/S-Based Bone Substitute Material.

Properly regulating the resorption rate of a resorbable bone implant has long been a great challenge. This study investigates a series of physical/chemical properties, biocompatibility and the behavior of implant resorption and new bone formation of a newly developed Ca/P/S-based bone substitute material (Ezechbone Granule CBS-400). Experimental results show that CBS-400 is comprised majorly of HA and CSD, with a Ca/P/S atomic ratio of 54.

Microstructural investigation of stress-assisted α″-α' phase transformation in cold-rolled Ti-7.5Mo alloy.

The present study investigated the microstructure and stress-assisted α″-α' phase transformation of a solution-treated Ti-7.5Mo alloy being cold-rolled with a series of different thickness reductions using transmission electron microscopic (TEM) and electron backscatter diffraction (EBSD) techniques. The EBSD/IPF results indicated a substantially random texture in ST sample.

Structure, properties and animal study of a calcium phosphate/calcium sulfate composite cement.

In-vitro and in-vivo studies have been conducted on an in-house-developed tetracalcium phosphate (TTCP)/dicalcium phosphate anhydrous (DCPA)/calcium sulfate hemihydrate (CSH)-derived composite cement. Unlike most commercial calcium-based cement pastes, the investigated cement paste can be directly injected into water and harden without dispersion. The viability value of cells incubated with a conditioned medium of cement extraction is >90% that of Al2O3 control and >80% that of blank medium.

Setting solution concentration effect on properties of a TTCP/DCPA-derived calcium phosphate cement.

The present work was to investigate the effects of concentration of (NH(4))(2)HPO(4) (diammonium hydrogen phosphate) setting solution on properties of a tetracalcium phosphate (TTCP)/dicalcium phosphate anhydrous (DCPA)--derived calcium phosphate cement. Experimental results indicated that working/setting time of the cement paste decreased with increasing (NH(4))(2)HPO(4) concentration of the setting solution. After being immersed in Hanks' solution for 1 day or longer, the XRD intensities of initial TTCP and DCPA phases largely decreased, while apatite phase became dominant.

Mechanical testing and osteointegration of titanium implant with calcium phosphate bone cement and autograft alternatives.

The purpose of this study was to evaluate the osteointegration of a titanium (Ti) implant with the calcium phosphate cement (CPC) and autograft prostheses by pull-out test and histological examination. Stems of sixty Ti cylinders were bilaterally inserted into femoral medullary canals in 30 rabbits at the 1st, 4th, 12th, 26th and 70th postoperative weeks. The bone autograft and CPC were filled into the pre-trimmed bone marrow cavity with a polymethyl methacrylate retarder in the distal end, and then a Ti cylinder was inserted into femurs.

Effect of ball milling on structures and properties of dispersed-type dental amalgam.

Objectives: The purpose of the present study was to investigate the effect of ball milling on the initial mercury vapor release rate and mechanical properties such as compressive strength, diametral tensile strength and creep value, of the dispersed-type dental amalgam, and comparison was made with respect to two commercial amalgam alloys.

Methods: Ball milling was employed to modify the configuration of the originally spherical-shaped Ag-Cu-Pd dispersant alloy particles. Improvement in mechanical properties while maintaining a low early-stage mercury vapor release rate of the amalgam is attempted.

In-vitro and in-vivo evaluation of a new Ti-15Mo-1Bi alloy.

The newly developed Ti-15Mo-1Bi alloy not only possesses all the desirable mechanical properties inherent to beta-Ti Mo alloys, but may even enjoy better clinical applicability with the addition of bismuth element, which has long been administered as antibacterial and antitumor medicines. A significantly higher viability of 3T3 cells was demonstrated when they were grown on Ti-15Mo-1Bi alloy than on Ti-15Mo and Ti-6Al-4V. Cells incubated in the medium conditioned by Bi powder at 37 degrees C for 96 h exhibited viability similar to that in the blank group and higher than that in the Ni conditioned group.

In vivo testing of nanoparticle-treated TTCP/DCPA-based ceramic surfaces.

This study reports the development of a non-dispersive calcium phosphate cement (nd-CPC) paste containing tetracalcium phosphate and anhydrous dicalcium phosphate that can be used as a filling material in dental and orthopedic applications. The nd-CPC bone cement is compared with two commercial materials, OsteoSet and Collagraft bone grafts. Gross examination of retrieved implants/bone composite samples indicated that none of the implants in this study evoked an inflammatory response.

Brittle and ductile adjustable cement derived from calcium phosphate cement/polyacrylic acid composites.

Objectives: Bone filler has been used over the years in dental and biomedical applications. The present work is to characterize a non-dispersive, fast setting, modulus adjustable, high bioresorbable composite bone cement derived from calcium phosphate-based cement combined with polymer and binding agents. This cement, we hope, will not swell in simulated body fluid and keep the osteogenetic properties of the dry bone and avoid its disadvantages of being brittle.

Bioresorption behavior of tetracalcium phosphate-derived calcium phosphate cement implanted in femur of rabbits.

One primary focus of the present study was to clarify the crucial resorption-location relationship of a recently developed single-phase TTCP-derived calcium phosphate cement (CPC) implanted in rabbit femur in a systematic and quantitative way. Gross examination of retrieved CPC/bone composite samples indicated that the CPC implant did not evoke inflammatory response, necrosis or fibrous encapsulation in surrounding bony tissues. Histological examination revealed excellent CPC-host bone bonding.

Effect of heat treatment on structure and properties of dispersed-type dental amalgam.

Effect of heat treatment of Ag-Cu-Pd dispersant particles on the structure, mechanical properties and mercury vapor release rate of an Ag-Cu-Sn/Ag-Cu-Pd-based dental amalgam has been investigated. Experimental results indicate that crystallinity of dispersant Ag-Cu-Pd alloy increases with increasing HTT, with most notable increase occurring between 100 and 200 degrees C. Increasing HTT of Ag-Cu-Pd alloy does not change much of the mercury/alloy ratio for amalgamation, but largely reduces working/setting time of the amalgam.

Bone formation at the surface of low modulus Ti-7.5Mo implants in rabbit femur.

The biocompatibility of the Ti-7.5Mo alloy was examined, because the alloy has a high-strength/modulus ratio and thus is a potential candidate for orthopedic applications. Cell viability assay using 3T3 cells revealed that the Ti-7.

Gamma-radiation-induced changes in structure and properties of tetracalcium phosphate and its derived calcium phosphate cement.

The purpose of the present study was to investigate the gamma-radiation effect on the structure and properties of the single-phase tetracalcium phosphate (TTCP) powder and its derived calcium phosphate cement (CPC). Experimental results show that low-dosed (0-30 kGy) CPC has a setting time of 10-12 min, while high-dosed (40-120 kGy) CPC has a setting time of 8-10 min. The low dose gamma-radiation does not significantly change porosity volume fraction or compressive strength of the CPC.

A comparison of the fatigue behavior of cast Ti-7.5Mo with c.p. titanium, Ti-6Al-4V and Ti-13Nb-13Zr alloys.

The purpose of the present study is to compare the high-cycle fatigue behavior of newly developed Ti-7.5Mo alloy with that of c.p.

Transmission electron microscopic study on setting mechanism of tetracalcium phosphate/dicalcium phosphate anhydrous-based calcium phosphate cement.

This work studied transmission electron microscopy on the setting mechanism of tetracalcium phosphate/dicalcium phosphate anhydrous (TTCP/DCPA)-based calcium phosphate cement. The results suggest the process for early-stage apatite formation as the follows: when TTCP and DCPA powders are mixed in the phosphate-containing solution, the TTCP powder is quickly dissolved because of its higher solubility in the acidic solution. The dissolved calcium and phosphate ions, along with those ions readily in the solution, are then precipitated predominantly on the surface of DCPA particles.