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The host response to titanium alloy (Ti-6Al-4V) is not always favorable as a fibrous layer may form at the skeletal tissue-device interface, causing aseptic loosening. Recently, sphene (CaTiSiO(5)) ceramics were developed by incorporating Ti in the Ca-Si system, and found to exhibit improved chemical stability. The aim of this study is to evaluate the in vitro response of human osteoblast-like cells, human osteoclasts and human microvascular endothelial cells to sphene ceramics and determine whether coating Ti-6Al-4V implants with sphene enhances anchorage to surrounding bone. The study showed that sphene ceramics support human osteoblast-like cell attachment with organized cytoskeleton structure and express increased mRNA levels of osteoblast-related genes. Sphene ceramics were able to induce the differentiation of monocytes to form functional osteoclasts with the characteristic features of f-actin and alpha(v)beta(3) integrin, and express osteoclast-related genes. Human endothelial cells were also able to attach and express the endothelial cell markers ZO-1 and VE-Cadherin when cultured on sphene ceramics. Histological staining, enzyme histochemistry and immunolabelling were used for identification of mineralized bone and bone remodelling around the coated implants. Ti-6Al-4V implants coated with sphene showed new bone formation and filled the gap between the implants and existing bone in a manner comparable to that of the hydroxyapatite coatings used as control. The new bone was in direct contact with the implants, whereas fibrous tissue formed between the bone and implant with uncoated Ti-6Al-4V. The in vivo assessment of sphene-coated implants supports our in vitro observation and suggests that they have the ability to recruit osteogenic cells, and thus support bone formation around the implants and enhance osseointegration.

Calcium phosphate ceramics are widely used as coating materials to orthopedic implants and are found to enhance initial bony ingrowth by stimulating osseous apposition to the implant surface. In this study, two novel calcium orthophosphate materials were selected for coating onto the commonly used orthopedic implant material Ti-6Al- 4V. One was calcium alkali orthophosphate with the crystalline phase Ca10[K/Na](PO4)7 with a small addition of SiO2 (AW-Si) and the other was calcium orthophosphate composed of 70 mol % fluorapatite, Ca10(PO4)6F2 and 30 mol % CaZr4(PO4)6 (FA7Z). The coated implants were placed in cortical and cortico-cancellous bone of sheep femur for six weeks. Retrieved samples were tested for osseointegration and mechanical strength. It was found that both coatings produced enhanced bone/implant contact rate compared to the control when implanted in cortico-cancellous bone. This study demonstrates that the two coatings have the capability of encouraging bone growth, and hence the potential for being used as coating materials on Ti implants.

This study evaluated the effect of titanium endosseous dental implants coupled to dissimilar materials on the capacity of preosteoblasts in bone marrow culture to differentiate, to form alkaline phosphatase-positive colonies, and to mineralize. Ten UCLA abutments were cast in each of 4 alloys: Type III gold, ceramometal gold, commercially pure grade I titanium, and titanium-aluminum-vanadium (Ti-6Al-4V); 10 ceramic abutments and 30 sterile Brånemark System implants were also used. Five abutments of each material and 5 implants were incubated individually in rat bone marrow culture, as were 5 of each abutment attached to an implant; bone marrow cultures not containing test samples were used as controls. Following 17 days of culture, the solution potentials of individual abutments (except ceramic), the implant, and the implant-abutment couples were measured in the test medium. One dish of each group of 5 was then stained for bone nodule mineralization; the remainder were quantified by area for alkaline phosphatase staining. Statistical analysis of measured in vitro potentials showed that the uncoupled samples formed 2 groups, and coupled samples formed 3 groups. Analysis of variance for alkaline phosphatase-positive area values showed no significant differences between coupled or uncoupled groups and the control. Normal cell differentiation and morphology as well as a lack of zones of inhibition, were observed. Bone nodule mineralization was evident in all groups. It was concluded that the presence of these commonly used implant abutment biomaterials coupled to titanium endosseous dental implants had no adverse effects on the in vitro capacity of preosteoblasts in marrow to differentiate and to form mineralized bone nodules, despite measured differences in solution potentials.

Objectives: Comparison of the effect of stainless steel and titanium low-contact dynamic compression plate application on the vascularity and mechanical properties of cortical bone after fracture., Design: Randomized, prospective., Setting: Orthopaedic research laboratory., Animals: Ten large (greater than twenty-five kilogram) adult dogs., Intervention: A short, midshaft spiral tibial fracture was created, followed by lag screw fixation and neutralization with an eight-hole, 3.5-millimeter, low-contact dynamic compression plate (LCDCP) made of either 316L stainless steel (n = five) or commercially pure titanium (n = five). After surgery, animals were kept with unrestricted weight-bearing in individual stalls for ten weeks., Main Outcome Measurements: Cortical bone blood flow was assessed by laser Doppler flowmetry using a standard metalshafted probe (Periflux Pf303, Perimed, Jarfalla, Sweden) applied through holes in the custom-made LCDCPs at five sites. Bone blood flow was determined at four times: (a) prefracture, (b) postfracture, (c) postplating, and (d) ten weeks postplating. After the dogs were killed, the implant was removed and both the treated tibia and contralateral tibia were tested for bending stiffness and load to failure., Results: Fracture creation decreased cortical perfusion in both groups at the fracture site (p = 0.02). The application of neither stainless steel nor titanium LCDCPs further decreased cortical bone blood flow after fracture creation. However, at ten weeks postplating, cortical perfusion significantly increased compared with acute postplating levels in the stainless steel (p = 0.003) and titanium (p = 0.001) groups. Cortical bone blood flow ten weeks postplating was not significantly different between the titanium group and the stainless steel group. Biomechanical tests performed on the tibiae with the plates removed did not reveal any differences in bending stiffness nor load required to cause failure between the two groups., Conclusions: Both titanium and stainless steel LCDCPs were equally effective in allowing revascularization, and neither provided a significant advantage in biomechanical properties of fracture healing at ten weeks.