Employing the Taguchi method in optimizing the scaffold production process for artificial bone grafts

The Taguchi method of experimental design is very well suited to improving the production process of synthetic bone grafts for several reasons. Firstly, the effect of many different process variables can be examined simultaneously, which ensures that beneficial factor combinations are not overlooked, Secondly, it is very efficient and easy to apply, so that it does not require large amounts of time or resources to conduct a given set of experiments. This makes it possible to conduct a series of experiments that result in continuous process improvement. Finally, using a Taguchi signal-to-noise ratio permits the concurrent optimization of the process and the reduction of process variability. The ease of use, efficiency, and focus on decreasing variability while optimizing the response more than outweigh the disadvantage of the Taguchi method of experimental design, as compared with the many other experimental approaches currently in use. The current application of the Taguchi method was successful in optimizing the mechanical properties of the Si-mHA synthetic bone grafts. The compression strength was doubled while maintaining the appropriate porosity level and microstructure for bioactivity. The mean value of the compression strength obtained was 5.8 MPa with a density of 0.515 gm/cm(3). Three levels of porosity were identified namely, macro-, meso-, and micro-porosity. The mean values of pore sizes were 400, 100 and 6 mu m, respectively. By using the Taguchi method in conjunction with a statistical experimental design, the various steps of the scaffold production process such as slurry preparation, coating process, drying, calcining and sintering processes were optimized. The final optimized process gave highly reproducible results. The manner in which the Taguchi method was used to produce synthetic bone scaffolds with desired properties is described. (C) 2008 Elsevier B.V. All rights reserved.