Original ArticlesComparative Three-Dimensional Finite Element Analysis on Miniplate and Lag Screw Fixation to Symphysis FracturesErtem, Sinan Yasin DDS, PhDAuthor Information Department of Oral and Maxillofacial Surgery, School of Dentistry, Ankara Yildirim Beyazit University, Ankara, Turkey. Address correspondence and reprint requests to Sinan Yasin Ertem, DDS, PhD, Ankara Yildirim Beyazit Universitesi, Fatih cad Cagla sok. No. 2 Kecioren 06010 Ankara, Turkey; E-mail: email@example.com Received 30 June, 2019 Accepted 23 December, 2019 This research was funded by the Kirikkale University, Office of Scientific Research Projects (Grant number: 2014/024). The author reports no conflicts of interest. Supplemental digital contents are available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.jcraniofacialsurgery.com). Journal of Craniofacial Surgery: June 2020 - Volume 31 - Issue 4 - p 983-988 doi: 10.1097/SCS.0000000000006314 Buy SDC Metrics Abstract The purpose of this study was to compare the amount of stress on the fracture site via three-dimensional finite element analysis between lag screw and miniplate systems. Solid mathematical models were created from the CT of a patient and a fracture observed in the symphysis area. On the fracture site mini plates and lag screws applied to the bone to fixate segments. The physiologic mastication chewing forces were applied for simulation. These 2 fixation methods: were evaluated by their amount of stress values. The maximum Von Misses stress lag screw model was 2727 MPa on the apex of the lag screw and 934 MPa on the fracture site of the screw. At the miniplate model, the maximum Von Misses stress was 571 MPa on the head of the miniplate screw, and it was 202 MPa on the fracture site. Thus, lag screw model causes at least 4 times higher stress values than mini plate model. The stress level of lag screw model is higher than miniplate model. However, when the chewing forces are taken into account, the amount of stress in the lag screw system is also acceptable in clinical applications. © 2020 by Mutaz B. Habal, MD.