Experimental Design and Response Surface Analysis as Available Tools for Statistical Modeling and Optimization of Electrodeposition Processes

Corrosion evaluation of orthodontic wires in artificial saliva solutions by using response surface methodology

“…3 (from known on denominated Design 1) was used to evaluate the effects of the studied wire, SS or Ni-Ti (w), the solution pH (pH), and the exposition time to the corrosive medium (t), on the weight loss (∆m) and on the Ni 2+ concentration (C Ni ) released during the experimental time. It means that the three parameters w, pH, and t were simultaneously varied between two levels, -1 and +1, in which the -1 level represents the lowest value of the parameter, while the +1 level corresponds to the highest value of the parameter 18 . The experimental design matrix, as well as the codified and the real values of the studied parameters are presented in Table 4.…”

“…In this design, only solutions 1 and 2 of Table 3 were used. All experiments were carried out in duplicates to evaluate the experimental error 18 . At the end of the assays the wires were cleaned with water and alcohol, dried with warm air, and weighted again, using the same analytical balance.…”

“…X i X j is the term of interaction between two of the parameters, while X i X j X k represents the interaction among all the studied parameters; b i are the equation coefficients. Statistical tests (p = 0.05) were then used to verify whether the analyzed effects were statistically significant 18 . In the Equations presented in this work only the parameters that affected the system at a level of statistical significance (p < 0.05) are shown.…”

“…In most of the in vitro works, the conventional and classical univariate methods are used to evaluate this process. In these methods, most of the parameters are maintained at constant values while one of them is varied in a chosen direction 18 . The use of univariate methods means that, in practice, the best conditions to avoid corrosion (pH, F -concentration, exposition time, the wire material, the wire surface treatment, etc.)…”

“…One way to achieve a better approach, given the complexity of the corrosion processes in the oral cavity, is to use experimental design and response surface methodology, in which all the parameters are varied simultaneously, showing the responses of their synergic and antagonistic interactions. These methodologies both drastically reduce the number experiments needed to optimize the process and give statistical inference on the optimum conditions 18 .…”