title: Evaluation of contributions of orthodontic mini-screw design factors based on FE analysis and the Taguchi method.
abstract: This study determines the relative effects of changes in bone/mini-screw osseointegration and mini-screw design factors (length, diameter, thread shape, thread depth, material, head diameter and head exposure length) on the biomechanical response of a single mini-screw insertion. Eighteen CAD and finite element (FE) models corresponding to a Taguchi L(18) array were constructed to perform numerical simulations to simulate mechanical responses of a mini-screw placed in a cylindrical bone. The Taguchi method was employed to determine the significance of each design factor in controlling strain. Simulation results indicated that mini-screw material, screw exposure length and screw diameter were the major factors affecting bone strain, with percentage contributions of 63%, 24% and 7%, respectively. Bone strain decreased obviously when screw material had the high elastic modulus of stainless/titanium alloys, a small exposure length and a large diameter. Other factors had no significant on bone strain. The FE analysis combined with the Taguchi method efficiently identified the relative contributions of several mini-screw design factors, indicating that using a strong stainless/titanium alloys as screw material is advantageous, and increase in mechanical stability can be achieved by reducing the screw exposure length. Simulation results also revealed that mini-screw and bone surface contact can provide sufficient mechanical retention to perform immediately load in clinical treatment.
authors.affiliation: Department of Biomedical Engineering, National Yang-Ming University, Taipei 112, Taiwan. cllin@mail.cgu.edu.tw
authors.forename: Chun-Li
authors.initials: CL
authors.lastname: Lin
authors.forename: Jian-Hong
authors.initials: JH
authors.lastname: Yu
authors.forename: Heng-Liang
authors.initials: HL
authors.lastname: Liu
authors.forename: Chih-Hao
authors.initials: CH
authors.lastname: Lin
authors.forename: Yang-Sung
authors.initials: YS
authors.lastname: Lin
mesh_terms: D000465:Algorithms; D001863:Bone Screws; D001842:Bone and Bones / Q000502:physiology* / Q000601:surgery*; D003198:Computer Simulation; D017076:Computer-Aided Design; D003799:Dental Stress Analysis; D019544:Equipment Failure Analysis; D020342:Finite Element Analysis; D017276:Friction; D006801:Humans; D008904:Miniaturization; D008954:Models, Biological; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation* / Q000379:methods; D016382:Orthodontic Appliance Design