| Purpose:This study aimed to evaluate the effects of Ti-Nb-Zr-Ta-Si alloy implants on mineral apposition rate(MAR) and new bone-to-implant contact(BIC) in rabbits, compared with commercial pure titanium(Cp Ti).It could provide theory base for novel titanium alloy implant to apply in the clinic.Materials and Methods:Twelve Ti-Nb-Zr-Ta-Si alloy implants were placed into right femur sites in six rabbits, and CpTi implants were used as controls in the left femur. At four weeks and eight weeks after implantation, animals were sacrificed, respectively.1. The surface characterization analysis was performed by scanning electron microscope(SEM) before implants were inserted into rabbits, in order to analyze the difference of surface characterization between Ti-Nb-Zr-Ta-Si alloy implants and CpTi implants.2. The embedded samples containing implants were cut into half along the long axis of the implant by using a diamond saw. After the embedded block was prepared by polishers, SEM accompanying with energy dispersive X-ray detector(EDX) observed the bone-to-implant surface, and evaluated the chemical element map of bone-to-implant interface.3. Tetracycline and alizarin red were administered three weeks andone week before euthanization, respectively. After samples were prepared into undecalcified sections, Confocal laser scanning microscope(CLSM)was used to observed positive mineral sites with fluorochrome markers and captured photographs. The MAR was calculated by measuring the linear distance between two labels with image processing software(Image-Pro Plus 6.0).4. Toluidine blue staining was performed on undecalcified sections and observed by high-resolution optical microscope for histology and histomorphology evaluation. The image processing software(Image-Pro Plus 6.0) was used to calculate the BIC.Results:1. SEM showed that Ti-Nb-Zr-Ta-Si alloy implants and CpTi implants had similar polished surface topography under the same processing condition of high-energy ball milling and subsequent reactive sintering technique.2. The SEM images revealed that there was a direct contact between the implants surface and the new bone in all groups. No presence of fibrous tissue existed between the implant surface and the existing bone.The EDX analysis was performed to determine elemental apposition of the interface between the new bone and the implant. The elemental maps of the compositions confirmed the interfacial bone formation along the implant and indicated the presence of calcium(Ca), phosphorus(P),oxygen(O), titanium(Ti) and silicon(Si).3. Tetracycline and alizarin red labels were observed by CLSM and located in the bone-implant interface and bone lacunae, which indicated these were positive mineral sites. After a healing period of four weeks,Ti-Nb-Zr-Ta-Si alloy implants showed significantly higher MAR compared to CpTi implants(p<0.05), whereas there was no significant difference between Ti-Nb-Zr-Ta-Si alloy implants and CpTi implants(p>0.05) at eight weeks.4. Toluidine blue staining photographs were captured under a light microscope. The new bone was in close direct contact with the implant surface. The newly formed bone was distinguishable from the existing bone by a reversal line(dark blue or purple). A number of bone lacunae were observed within the new bone tissue. No significant difference of the BIC was observed between Ti-Nb-Zr-Ta-Si alloy implants and CpTi implants after a healing period of four weeks and eight weeks.Conclusion:This study showed that Ti-Nb-Zr-Ta-Si alloy implants could establish a comparable close direct contact and osseointegration to CpTi implants, and promote more favorable mineral apposition rate in the early phase of bone formation, and someday it may be an alternative as a material for dental implants. |
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