新型聚醚醚酮(PEEK)應用於齒顎矯正舌側維持器之機械特性分析

A new high-performance polymeric material polyetheretherketone (PEEK) that meets the requirements of fixed lingual retainer (FLR) is gradually attracting the attention of dentists. PEEK can be processed via digital workflow to provide better adaptation; however, the appropriate dimensions and mechanical properties of PEEK-made FLR are still unclear. Herein, we aim to develop the optimal design of PEEK-made FLR via the finite element method (FEM) and three-point bending test (TPBT). Seventy-five three-dimensional models were created, based on three cross-section shapes (rectangular, oval and hemielliptical), five thicknesses (0.4, 0.6, 0.8, 1.0 and 1.2 mm) and five widths (0.7, 0.9, 1.1, 1.3 and 1.5 mm), and a 0.9 mm (0.036-inch) stainless steel wire (SSW) was used as a control. The shape optimization was determined using FEM with the elastic modulus (4.8GPa) and yield stress (110MPa) of PEEK. Six shape-optimized PEEK samples and one stainless steel wire (SSW) were then fabricated and further performed the TPBT to investigate the effect of lingual and biting forces. When applying the forces, the Von Mises stress on the PEEK models decreased as the width and thickness increased, and the effect of thickness was greater than that of width. Compared to SSW, the acceptable lingual stresses on the PEEK as FLR showed 161.72 to 318.75 MPa and that of biting stresses showed 6480.10 to 7899.08 MPa. Besides, PEEK exhibited lower deformations than SSW and can overcome the force of the lip, tongue and the load during mastication. Within the limitation of this in vitro study, the PEEK-made FLR with a hemi-elliptical cross-sectional shape and a thickness/width of 1.5/1.0 with good comfort and comparable performance to SSW.