Finite element analysis: Is it justifiable?

Abstract

In recent years, more specifically in the recent months, I have received a large number of articles to review that rely on the finite element method (FEM) or finite element analysis (FEA) to study different matters related to orthodontics. Some of these are excellent works, but the vast majority are of very low quality and present neither a proper justification for using FEA nor a correct method of execution. Thus, I write this editorial to give some insight to researchers and clinicians who might be planning or attempting a study in which FEM is used as an analysis tool. The first point I want to emphasize strongly is the objective of the study and logic for considering FEA. Clear justification is needed regarding how the results would affect every day clinical practice. Several papers I have reviewed justify their use of FEA by the logic that such a study has not yet been performed to specifically examine a particular appliance, bracket, or wire. This is not a strong justification because how the forces are applied in the mouth is a major factor to be considered; if the new appliances are using similar mechanics, then why the need for a new analysis? Another issue is that some authors acknowledge that there are already FEM studies or FEA published on their topic, but they justify the need for another one because they modify 1 small aspect (eg, a small change in assumed material properties) or they use different treatment modalities. By no surprise, the common trend is that the conclusions of the new study are similar to what other authors have already found in their respective studies. One of the most common rationales for a new study is the application of FEM or FEA to an appliance or treatment modality that has been proven successful in clinical practice, even presenting papers proving this. When a clinical outcome is already understood, the authors should seriously consider how a new FEA could truly add to our understanding of the problem or improve the clinical practice. Our understanding of an FEA is to apply it to solve complicated mechanics-based issues that are hard to answer clinically or in practice. The findings of the analysis would help the clinician determine the changes needed to fix the treatment that is causing problems or manufacturers improve their product to reduce side effects. If there is no tangible outcome that could influence treatment protocols, the appliance, or a combination of the 2, then authors should ask themselves what the FEA they want to conduct will really elucidate. If it is simply, “this hasn't been done yet,” then is it truly worthwhile? Beyond the issues surrounding the use of FEM or FEA and their clinical applications, authors should also consider whether they truly have the skillset to conduct a proper analysis. FEA is a complex mathematical tool that is primarily used to solve mechanics-based problems in which an analytical or exact mathematical solution is not possible. Although this is absolutely the case with many problems in orthodontics, thus likely requiring the use of FEM, authors should not automatically assume that using this tool is straightforward. A range of complex issues surrounding material properties, boundary conditions, mesh density, and the numerical solution can all change the output of the FEA significantly. Just because a user gets an answer from a simulation, it does not mean the solution is accurate. Recent advances in FEA software have made it much more user friendly, which has been a double-edged sword. Although it has facilitated solving more complex problems in orthodontics, it also allows those less skilled in such methods to obtain a solution while not necessarily understanding how the solution was reached. A recent article by Romanyk et al1Romanyk D.L. Vafaeian B. Addison O. Adeeb S. The use of finite element analysis in dentistry and orthodontics: critical points for model development and interpreting results.Semin Orthod. 2020; 26: 162-173Abstract Full Text Full Text PDF Scopus (6) Google Scholar provides greater detail on these more technical points and would be worthwhile for more clinically focused authors to read before considering using FEM or FEA methods in their work. To summarize, if a study using FEM or FEA is being planned or performed, I suggest the authors answer the following questions:1.Is the justification for this analysis strong and relevant?2.Does FEA have the potential to solve an existing clinical problem?3.Can this FEA change clinical practice or a treatment methodology?4.Has the problem been explored technically, and are the methods truly representative of the physical problem? If the answer to any of these questions is “No,” then more work should be done on the FEM or FEA before executing it and submitting for journal consideration.