Methyl methacrylate used in bone cements has drawbacks of toxicity, high exotherm, and considerable shrinkage. A new resin, based on silorane/oxirane chemistry, has been shown to have little toxicity, low exotherm, and low shrinkage. We hypothesized that silorane-based resins may also be useful as components of bone cements as well as other bone applications and began testing on bone cell function in vitro and in vivo. MLO-A5, late osteoblast cells, were exposed to polymerized silorane (SilMix) resin (and a standard polymerized bisGMA/TEGDMA methacrylate (BT) resin and compared to culture wells without resins as control. A significant cytotoxic effect was observed with the BT resin resulting in no cell growth, whereas in contrast, SilMix resin had no toxic effects on MLO-A5 cell proliferation, differentiation, nor mineralization. The cells cultured with SilMix produced increasing amounts of alkaline phosphatase (1.8-fold) compared to control cultures. Compared to control cultures, an actual enhancement of mineralization was observed in the silorane resin-containing cultures at days 10 and 11 as determined by von Kossa (1.8–2.0 fold increase) and Alizarin red staining (1.8-fold increase). A normal bone calcium/phosphate atomic ratio was observed by elemental analysis along with normal collagen formation. When used in vivo to stabilize osteotomies, no inflammatory response was observed, and the bone continued to heal. In conclusion, the silorane resin, SilMix, was shown to not only be non cytototoxic, but actually supported bone cell function. Therefore, this resin has significant potential for the development of a nontoxic bone cement or bone stabilizer.

We have synthesized a filler-reinforced silorane composite that has potential applications in orthopaedic surgery, such as for a bone stabilizer. The purpose of the present work was to develop a method for estimating four properties of this material; namely, maximum exotherm temperature, flexural strength, flexural modulus, and fracture toughness. The method involved the use of mixture design-of-experiments and regression analysis of results obtained using 23 formulations of the composite. We validated the estimation method by showing that, for each of four composite formulations that were not included in the method development, the value of each of the aforementioned properties was not significantly different from that obtained experimentally. Our estimation method has the potential for use in the development of a wide range of orthopaedic materials.

Two series of silicate glasses were processed to micron-size, sub-micron size, and nanoparticles using three different milling systems: ball milling, attrition, and high-energy milling. The effect of milling time and media size on particle size and contamination were investigated in aqueous and isopropanol suspensions. The particle size was determined using a laser-diffraction particle size analyzer and scanning electron microscopy. The smallest glass particles with a median particle size of 0.3 μm were achieved by a two-step comminution process in a high energy mill.

Improvements in body armor and battlefield medical care have resulted in an increase in survival rates but also an increase in survivable battlefield extremity injuries (Covey 2002; Covey 2006; Owens, Kragh et al. 2007). It is well known that these traumatic extremity injuries require adequate stabilization to achieve an optimal healing outcome. Extremity fractures also affect a large proportion of the civilian population. In 2005, 5.7 million Americans suffered an injury resulting in bone fracture (CDC/NCHS). Transport of these domestically injured individuals to medical facilities also requires stabilization to avoid further injury.

There has been little change in the formulation of bone cements since Sir John Charnley first developed them in the 1970s. Bone cements are methacrylate based systems packaged in two components [1]. The powder component contains a mixture of polymethyl methacrylate (PMMA), methyl methacrylate-styrene-copolymer, and a radio opacifier (either barium sulfate or zirconium oxide) [2]. The second component is a liquid monomer typically containing methyl methacrylate, N, N-dimethyl-p-toluidine (activator), and hydroquinone. Flexural strength and flexural modulus of bone cements range between 60–75 MPa and 2.2–3.3 GPa, respectively [3, 4]. ISO 5833 requires bone cements to have a strength greater than 50 MPa and a modulus greater than 1.8 GPa [5].

While great strides have been made in the design of dental composites and orthopaedic implants, improvements are still needed. For instance the life span of dental polymer composites is known to be significantly shorter than traditional amalgam restorations [1]. Similarly, the early failure rate of orthopaedic implants often leads to an intentional delay in the treatment of painful, debilitating joints to ensure patients don’t outlive the functional life of their prosthetics [2]. Stress concentrations within biomaterials may be partially to blame for these premature failures.

The aesthetic appeal of composite-resin restoratives promotes their use, however their functional life is significantly shorter when compared to their metal counterparts.1 One possible reason is the effect of polymerization stress on marginal integrity. Shrinkage of the composite, and its associated stress, has been found to cause gap formation and stress interactions between the restorative and the adhesive. These gaps offer an ideal niche for bacteria, and, when compounded by the mechanical strain of chewing, can lead to premature failure of the restorative.2,3 Additionally, it is well known that incomplete conversion of the double bonds occurs during methacrylate polymerizations.4–7 A high degree of conversion is needed to prevent the presence of potentially hazardous monomers.8